Synthesis, characterization and antimicrobial studies of Schiff base complexes

NASA Astrophysics Data System (ADS)

Zafar, Hina; Ahmad, Anis; Khan, Asad U.; Khan, Tahir Ali

2015-10-01

The Schiff base complexes, MLCl2 [M = Fe(II), Co(II), Ni(II), Cu(II) and Zn(II)] have been synthesized by the template reaction of respective metal ions with 2-acetylpyrrole and 1,3-diaminopropane in 1:2:1 M ratio. The complexes have been characterized by elemental analyses, ESI - mass, NMR (1H and 13C), IR, XRD, electronic and EPR spectral studies, magnetic susceptibility and molar conductance measurements. These studies show that all the complexes have octahedral arrangement around the metal ions. The molar conductance measurements of all the complexes in DMSO indicate their non-electrolytic nature. The complexes were screened for their antibacterial activity in vitro against Gram-positive (Streptococcus pyogenes) and Gram-negative (Klebsiella pneumoniae) bacteria. Among the metal complexes studied the copper complex [CuLCl2], showed highest antibacterial activity nearly equal to standard drug ciprofloxacin. Other complexes also showed considerable antibacterial activity. The relative order of activity against S. Pyogenes is as Cu(II) > Zn(II) > Co(II) = Fe(II) > Ni(II) and with K. Pneumonia is as Cu(II) > Co(II) > Zn(II) > Fe(II) > Ni(II).

Synthesis, characterization and anti-microbial evaluation of Cu(II), Ni(II), Pt(II) and Pd(II) sulfonylhydrazone complexes; 2D-QSAR analysis of Ni(II) complexes of sulfonylhydrazone derivatives

NASA Astrophysics Data System (ADS)

Özbek, Neslihan; Alyar, Saliha; Alyar, Hamit; Şahin, Ertan; Karacan, Nurcan

2013-05-01

Copper(II), nickel(II), platinum(II) and palladium(II) complexes with 2-hydroxy-1-naphthaldehyde-N-methylpropanesulfonylhydrazone (nafpsmh) derived from propanesulfonic acid-1-methylhydrazide (psmh) were synthesized, their structure were identified, and antimicrobial activity of the compounds was screened against three Gram-positive and three Gram-negative bacteria. The results of antimicrobial studies indicate that Pt(II) and Pd(II) complexes showed the most activity against all bacteria. The crystal structure of 2-hydroxy-1-naphthaldehyde-N-methylpropanesulfonylhydrazone (nafpsmh) was also investigated by X-ray analysis. A series of Ni(II) sulfonyl hydrazone complexes (1-33) was synthesized and tested in vitro against Escherichia coli and Staphylococcus aureus. Their antimicrobial activities were used in the QSAR analysis. Four-parameter QSAR models revealed that nucleophilic reaction index for Ni and O atoms, and HOMO-LUMO energy gap play key roles in the antimicrobial activity.

Characterization and biological studies on Co(II), Ni(II) and Cu(II) complexes of carbohydrazones ending by pyridyl ring.

PubMed

Abu El-Reash, G M; El-Gammal, O A; Ghazy, S E; Radwan, A H

2013-03-01

The chelating behavior of ligands based on carbohydrazone core modified with pyridine end towards Co(II), Ni(II) and Cu(II) ions have been examined. The ligands derived from the condensation of carbohydrazide with 2-acetylpyridine (H(2)APC) and 4-acetylpyridine (H(2)APEC). The (1)H NMR, IR data and the binding energy calculations of H(2)APC revealed the presence of two stereoisomers syn and anti in the solid state and in the solution. The (1)H NMR, IR data and the binding energy calculations confirmed the presence of H(2)APEC in one keto form only in the solid state and in the solution. The spectroscopic data confirmed that H(2)APC behaves as a monobasic pentadentate in Co(II) and Cu(II) complexes and as mononegative tetradentate in Ni(II) complex. On the other hand, H(2)APEC acts as a mononegative tridentate in Co(II) complex, neutral tridentate in Ni(II) complex and neutral bidentate in Cu(II) complex. The electronic spectra and the magnetic measurements of complexes as well as the ESR of the copper complexes suggested the octahedral geometry. The bond length and bond angles were evaluated by DFT method using material studio program. The thermal behavior and the kinetic parameters of degradation were determined using Coats-Redfern and Horowitz-Metzger methods. The antioxidant (DDPH and ABTS methods), anti-hemolytic and in vitro Ehrlich ascites of the compounds have been screened. Copyright © 2012 Elsevier B.V. All rights reserved.

Asymmetric synthesis of α-amino acids via homologation of Ni(II) complexes of glycine Schiff bases. Part 2: aldol, Mannich addition reactions, deracemization and (S) to (R) interconversion of α-amino acids.

PubMed

Sorochinsky, Alexander E; Aceña, José Luis; Moriwaki, Hiroki; Sato, Tatsunori; Soloshonok, Vadim

2013-11-01

This review provides a comprehensive treatment of literature data dealing with asymmetric synthesis of α-amino-β-hydroxy and α,β-diamino acids via homologation of chiral Ni(II) complexes of glycine Schiff bases using aldol and Mannich-type reactions. These reactions proceed with synthetically useful chemical yields and thermodynamically controlled stereoselectivity and allow direct introduction of two stereogenic centers in a single operation with predictable stereochemical outcome. Furthermore, new application of Ni(II) complexes of α-amino acids Schiff bases for deracemization of racemic α-amino acids and (S) to (R) interconversion providing additional synthetic opportunities for preparation of enantiomerically pure α-amino acids, is also reviewed. Origin of observed diastereo-/enantioselectivity in the aldol, Mannich-type and deracemization reactions, generality and limitations of these methodologies are critically discussed.

Highly anisotropic exchange interactions in a trigonal bipyramidal cyanide-bridged Ni(II)3Os(III)2 cluster.

PubMed

Palii, Andrei V; Reu, Oleg S; Ostrovsky, Sergei M; Klokishner, Sophia I; Tsukerblat, Boris S; Hilfiger, Matthew; Shatruk, Michael; Prosvirin, Andrey; Dunbar, Kim R

2009-06-25

This article is a part of our efforts to control the magnetic anisotropy in cyanide-based exchange-coupled systems with the eventual goal to obtain single-molecule magnets with higher blocking temperatures. We give the theoretical interpretation of the magnetic properties of the new pentanuclear complex {[Ni(II)(tmphen)(2)](3)[Os(III)(CN)(6)](2)} x 6 CH(3)CN (Ni(II)(3)Os(III)(2) cluster). Because the system contains the heavy Os(III) ions, spin-orbit coupling considerably exceeds the contributions from the low-symmetry crystal field and exchange coupling. The magnetic properties of the Ni(II)(3)Os(III)(2) cluster are described in the framework of a highly anisotropic pseudo-spin Hamiltonian that corresponds to the limit of strong spin-orbital coupling and takes into account the complex molecular structure. The model provides a good fit to the experimental data and allows the conclusion that the trigonal axis of the bipyramidal Ni(II)(3)Os(III)(2) cluster is a hard axis of magnetization. This explains the fact that in contrast with the isostructural trigonal bipyramidal Mn(III)(2)Mn(II)(3) cluster, the Ni(II)(3)Os(III)(2) system does not exhibit the single-molecule magnetic behavior.

EPR, UV-vis, magnetic, spectral studies and electrochemical behaviour of mononuclear transition metal complexes derived from novel hexa-aza-macrotricyclic ligand

NASA Astrophysics Data System (ADS)

Chandra, Sulekh; Gupta, Nidhi; Gupta, Rachna; Bawa, Sukhwant Singh

2005-11-01

Aza-macrocyclic complexes have gained importance because of their pharmacological properties [N.K. Singh, Srivastava, Trans. Met. Chem. 25 (2000) 133]. Hexa-aza-macrocyles containing glutarimide efficiently coordinate as hexa-dentate ligand, to give complexes of Cu(II) possessing tetragonal structure and Mn(II), Co(II) and Ni(II) metal ions that are essentially octahedral. Spectroscopic, and chemical characterizations of these systems are presented in this article. For Ni(II) complexes results on electron transfer processes measured by cyclic voltammetry and colourimetry have been studied.

Synthesis, characterization and anti-microbial activity of a novel macrocyclic ligand derived from the reaction of 2,6-pyridinedicarboxylic acid with homopiperazine and its Co(II), Ni(II), Cu(II), and Zn(II) complexes

NASA Astrophysics Data System (ADS)

Soleimani, Esmaiel

2011-05-01

The preparation of a novel macrocyclic ligand ( 1), N,N'-diethylhomopiperazinyl,2,6-pyridinedicarboxylate and its Co(II), Ni(II), Cu(II), and Zn(II) complexes are described. The ligand was prepared in EtOH from the reaction of dipotassium salt of 2,6-pyridinedicarboxylic acid with 1,2-dibromoethane in the presence of homopiperazine. Reaction of macrocyclic ligand ( 1) in EtOH with CoCl 2.6H 2O, NiCl 2.6H 2O, CuCl 2.2H 2O, and ZnCl 2·2H 2O yielded the complexes with the general formula [M(L)Cl 2] {where M = Co(II) ( 2), Ni(II) ( 3), Cu(II) ( 4), Zn ( 5), respectively}. The analysis of IR, 1H and 13C NMR spectral data of macrocyclic ligand ( 1) and its Zn(II) complex ( 5) together with their molar conductivity values, and the magnetic moments of the complexes suggest that the macrocyclic ligand ( 1) is bonded to metal(II) ions through two oxygen atoms of ester moiety and the two nitrogen atoms of homopiperazine ring. The electronic spectral data of these complexes in DMSO are in good agreement with the octahedral coordination of M(II) ions. The ligand field parameters for these complexes, i.e. splitting energy and Racah parameter were calculated to be 14,945 and 673 cm -1 for the Co(II) ( 2), 16,260 and 774 cm -1 for the Ni(II) ( 3) complexes respectively. The spliting energy of 17,262 cm -1 was obtained for the Cu(II) complex ( 4).

Theoretical study of the magnetic behavior of hexanuclear Cu(II) and Ni(II) polysiloxanolato complexes.

PubMed

Ruiz, Eliseo; Cano, Joan; Alvarez, Santiago; Caneschi, Andrea; Gatteschi, Dante

2003-06-04

A theoretical density functional study of the exchange coupling in hexanuclear polysiloxanolato-bridged complexes of Cu(II) and Ni(II) is presented. By calculating the energies of three different spin configurations, we can obtain estimates of the first-, second-, and third-neighbor exchange coupling constants. The study has been carried out for the complete structures of the Cu pristine cluster and of the chloroenclathrated Ni complex as well as for the hypotethical pristine Ni compound and for magnetically dinuclear analogues M(2)Zn(4) (M = Cu, Ni).

Structural Investigations of the Nickel-Induced Inhibition of Truncated Constructs of the JMJD2 Family of Histone Demethylases Using X-ray Absorption Spectroscopy

PubMed Central

Giri, Nitai Charan; Passantino, Lisa; Sun, Hong; Zoroddu, Maria Antonietta; Costa, Max; Maroney, Michael J.

2013-01-01

Occupational and/or environmental exposure to nickel has been implicated in various types of cancer, and in vitro exposure to nickel compounds results in accumulation of Ni(II) ions in cells. One of the major targets of Ni(II) ions inside the cell is Fe(II)- and αKG-dependent dioxygenases. Using JMJD2A and JMJD2C as examples, we show that JMJD2 family of histone demethylases, which are products of putative oncogenes as well as Fe(II)- and αKG-dependent dioxygenases, are highly sensitive to inhibition by Ni(II) ions. In this work, X-ray absorption spectroscopy (XAS) has been used to investigate the Fe(II) active site of truncated JMJD2A and JMJD2C (1 – 350 aa) in the presence and absence of αKG and/or substrate to obtain mechanistic details of the early steps in catalysis that precede O2 binding in histone demethylation by the JMJD2 family of histone demethylases. Zinc K-edge XAS has been performed on the resting JMJD2A (with iron in the active site) to confirm the presence of the expected structural zinc site. XAS of the Ni(II)-substituted enzymes has also been performed to investigate the inhibition of these enzymes by Ni(II) ions. Our XAS results indicate that the five-coordinate Fe(II) center in the resting enzyme is retained in the binary and ternary complexes. In contrast, the Ni(II) center is six-coordinate in the resting enzyme, binary and ternary complexes. XAS results indicate that both Fe(II) and Ni(II) bind αKG in the binary and ternary complexes. The electron density build-up that is observed at the Fe(II) center in the presence of αKG and substrate is not observed at the Ni(II) center. Thus, both electronic and steric factors are responsible for Ni-induced inhibition of the JMJD2 family of histone demethylases. Ni-induced inhibition of these enzymes may explain the alteration of the epigenetic mechanism of gene expression that is responsible for Ni-induced carcinogenesis. PMID:23692052

DNA cleavage, antibacterial, antifungal and anthelmintic studies of Co(II), Ni(II) and Cu(II) complexes of coumarin Schiff bases: Synthesis and spectral approach

NASA Astrophysics Data System (ADS)

Patil, Sangamesh A.; Prabhakara, Chetan T.; Halasangi, Bhimashankar M.; Toragalmath, Shivakumar S.; Badami, Prema S.

2015-02-01

The metal complexes of Co(II), Ni(II) and Cu(II) have been synthesized from 6-formyl-7,8-dihydroxy-4-methylcoumarin with o-toluidine/3-aminobenzotrifluoride. The synthesized Schiff bases and their metal complexes were structurally characterized based on IR, 1H NMR, 13C NMR, UV-visible, ESR, magnetic, thermal, fluorescence, mass and ESI-MS studies. The molar conductance values indicate that complexes are non-electrolytic in nature. Elemental analysis reveals ML2·2H2O [M = Co(II), Ni(II) and Cu(II)] stoichiometry, where 'L' stands for a singly deprotonated ligand. The presence of co-ordinated water molecules were confirmed by thermal studies. The spectroscopic studies suggest the octahedral geometry. Redox behavior of the complexes were confirmed by cyclic voltammetry. All the synthesized compounds were screened for their antibacterial (Escherichia coli, Pseudomonas auregenosa, klebsiella, Proteus, Staphylococcus aureus and salmonella) antifungal (Candida, Aspergillus niger and Rhizopus), anthelmintic (Pheretima posthuma) and DNA cleavage (Calf Thymus DNA) activity.

DNA cleavage, antibacterial, antifungal and anthelmintic studies of Co(II), Ni(II) and Cu(II) complexes of coumarin Schiff bases: synthesis and spectral approach.

PubMed

Patil, Sangamesh A; Prabhakara, Chetan T; Halasangi, Bhimashankar M; Toragalmath, Shivakumar S; Badami, Prema S

2015-02-25

The metal complexes of Co(II), Ni(II) and Cu(II) have been synthesized from 6-formyl-7,8-dihydroxy-4-methylcoumarin with o-toluidine/3-aminobenzotrifluoride. The synthesized Schiff bases and their metal complexes were structurally characterized based on IR, (1)H NMR, (13)C NMR, UV-visible, ESR, magnetic, thermal, fluorescence, mass and ESI-MS studies. The molar conductance values indicate that complexes are non-electrolytic in nature. Elemental analysis reveals ML2·2H2O [M = Co(II), Ni(II) and Cu(II)] stoichiometry, where 'L' stands for a singly deprotonated ligand. The presence of co-ordinated water molecules were confirmed by thermal studies. The spectroscopic studies suggest the octahedral geometry. Redox behavior of the complexes were confirmed by cyclic voltammetry. All the synthesized compounds were screened for their antibacterial (Escherichia coli, Pseudomonas auregenosa, klebsiella, Proteus, Staphylococcus aureus and salmonella) antifungal (Candida, Aspergillus niger and Rhizopus), anthelmintic (Pheretima posthuma) and DNA cleavage (Calf Thymus DNA) activity. Copyright © 2014 Elsevier B.V. All rights reserved.

Synthesis, structural studies and antimicrobial activity of N'-((2Z, 3E)-3-(hydroxyimino)butan-2-ylidene)-2-phenylacetohydrazide and its Co(II), Ni(II) complexes

NASA Astrophysics Data System (ADS)

Karadeniz, Şeyma; Ataol, Cigdem Yuksektepe; Şahin, Onur; İdil, Önder; Bati, Hümeyra

2018-06-01

A new aroylhydrazoneoxime, N'-((2Z, 3E)-3-(hydroxyimino)butan-2-ylidene)-2-phenylacetohydrazide ligand (LH2) and its Ni(II) and Co(II) complexes, have been synthesized and characterized by elemental and thermal analyses, IR and UV-vis spectroscopy, magnetic moment and X-ray diffraction. The antimicrobial activities of these compounds were tested by using minimal inhibitory concentration method (MIC). The ligand-containing aroylhydrazone and oxime groups and its Ni complex crystallize in the triclinic system and P 1 - space group, while its Co complex crystallizes in the monoclinic system and the C 2/c space group. X-ray results show that the ligand in the keto form is transformed into enolic form when it forms coordination. From elemental analysis data, the stoichiometry of Co(II) complex was found to be 1:2 (metal/ligand), but 1:1 for Ni(II). IR spectra indicate that the ligand acts as monoanionic NNO- tridentate and coordination takes place form through the oxime nitrogen, imine nitrogen, and enolate oxygen atoms.

Macroscopic and microscopic investigation of Ni(II) sequestration on diatomite by batch, XPS, and EXAFS techniques.

PubMed

Sheng, Guodong; Yang, Shitong; Sheng, Jiang; Hu, Jun; Tan, Xiaoli; Wang, Xiangke

2011-09-15

Sequestration of Ni(II) on diatomite as a function of time, pH, and temperature was investigated by batch, XPS, and EXAFS techniques. The ionic strength-dependent sorption at pH < 7.0 was consistent with outer-sphere surface complexation, while the ionic strength-independent sorption at pH = 7.0-8.6 was indicative of inner-sphere surface complexation. EXAFS results indicated that the adsorbed Ni(II) consisted of ∼6 O at R(Ni-O) ≈ 2.05 Å. EXAFS analysis from the second shell suggested that three phenomena occurred at the diatomite/water interface: (1) outer-sphere and/or inner-sphere complexation; (2) dissolution of Si which is the rate limiting step during Ni uptake; and (3) extensive growth of surface (co)precipitates. Under acidic conditions, outer-sphere complexation is the main mechanism controlling Ni uptake, which is in good agreement with the macroscopic results. At contact time of 1 h or 1 day or pH = 7.0-8.0, surface coprecipitates occur concurrently with inner-sphere complexes on diatomite surface, whereas at contact time of 1 month or pH = 10.0, surface (co)precipitates dominate Ni uptake. Furthermore, surface loading increases with temperature increasing, and surface coprecipitates become the dominant mechanism at elevated temperature. The results are important to understand Ni interaction with minerals at the solid-water interface, which is helpful to evaluate the mobility of Ni(II) in the natural environment.

Synthesis, spectroscopic characterization, DFT calculations and biological evaluation of benzothiazole derivative bearing Mn(II) and Ni(II) metal ions

NASA Astrophysics Data System (ADS)

El-Gamel, Nadia E. A.; Ali, Korany A.

2017-11-01

N-(benzo[d]thiazol-2-yl)-3-oxo-3-phenylpropanamide ligand and its Nickel and Manganese complexes have been synthesized and characterized by elemental and thermal analyses, IR, diffuse reflectance, mass and UV-Vis spectra, molar conductance and magnetic moment measurements. The decomposition mechanism and thermal stability of the investigated complexes are interpreted in terms of their structures. The thermal behaviour of the complexes has been studied and different thermodynamic parameters are calculated using Coats-Redfern method. N-(benzo[d]thiazol-2-yl)-3-oxo-3-phenylpropanamide is a neutral bidentate ligand coordinating metal ions via thiazole ring nitrogen and amide carbonyl O forming high spin octahedral complexes with Mn(II) (2) and distorted square planar in case of Ni(II) (1). Natural bond orbital analysis and geometry optimization were carried out at DFT/B3LYP/6-31G(d) level of theory for the ligand and the mentioned complexes. Ab inito computations at the HF/6-31G(d) level of the theory is conducted in order to detect any probability of a hydrogen bond formation in the ligand. The dipole moment of the Ni(II) and Mn(II) complexes is recorded to be 9.69 and 7.39 Debye, respectively, indicating that the complexes are more polarized than the ligand 2.39 Debye. The in vitro biological activity of the metal chelates is screened against the Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli), fungus (Aspergillus flavus, Candida albicans). Ni(II) complexes displayed the highest activity against Candida albicans and Staphylococcus aureus with MIC values of 13, 30 μg/cm3, respectively.

Synthesis, characterization, and ligand exchange reactivity of a series of first row divalent metal 3-hydroxyflavonolate complexes.

PubMed

Grubel, Katarzyna; Rudzka, Katarzyna; Arif, Atta M; Klotz, Katie L; Halfen, Jason A; Berreau, Lisa M

2010-01-04

A series of divalent metal flavonolate complexes of the general formula [(6-Ph(2)TPA)M(3-Hfl)]X (1-5-X; X = OTf(-) or ClO(4)(-); 6-Ph(2)TPA = N,N-bis((6-phenyl-2-pyridyl)methyl)-N-((2-pyridyl)methyl)amine; M = Mn(II), Co(II), Ni(II), Cu(II), Zn(II); 3-Hfl = 3-hydroxyflavonolate) were prepared and characterized by X-ray crystallography, elemental analysis, FTIR, UV-vis, (1)H NMR or EPR, and cyclic voltammetry. All of the complexes have a bidentate coordinated flavonolate ligand. The difference in M-O distances (Delta(M-O)) involving this ligand varies through the series, with the asymmetry of flavonolate coordination increasing in the order Mn(II) approximately Ni(II) < Cu(II) < Zn(II) < Co(II). The hypsochromic shift of the absorption band I (pi-->pi*) of the coordinated flavonolate ligand in 1-5-OTf (relative to that in free anion) increases in the order Ni(II) < Mn(II) < Cu(II) < Zn(II), Co(II). Previously reported 3-Hfl complexes of divalent metals fit well with this ordering. (1)H NMR studies indicate that the 3-Hfl complexes of Co(II), Ni(II), and Zn(II) exhibit a pseudo-octahedral geometry in solution. EPR studies suggest that the Mn(II) complex 1-OTf may form binuclear structures in solution. The mononuclear Cu(II) complex 4-OTf has a distorted square pyramidal geometry. The oxidation potential of the flavonolate ligand depends on the metal ion present and/or the solution structure of the complex, with the Mn(II) complex 1-OTf exhibiting the lowest potential, followed by the pseudo-octahedral Ni(II) and Zn(II) 3-Hfl complexes, and the distorted square pyramidal Cu(II) complex 4-OTf. The Mn(II) complex [(6-Ph(2)TPA)Mn(3-Hfl)]OTf (1-OTf) is unique in the series in undergoing ligand exchange reactions in the presence of M(ClO(4))(2).6H(2)O (M = Co, Ni, Zn) in CD(3)CN to produce [(6-Ph(2)TPA)M(CD(3)CN)(n)](X)(2), [Mn(3-Hfl)(2).0.5H(2)O], and MnX(2) (X = OTf(-) or ClO(4)(-)). Under similar conditions, the 3-Hfl complexes of Co(II), Ni(II), and Cu(II) undergo flavonolate ligand exchange to produce [(6-Ph(2)TPA)M(CD(3)CN)(n)](X)(2) (M = Co, Ni, Cu; n = 1 or 2) and [Zn(3-Hfl)(2).2H(2)O]. An Fe(II) complex of 3-Hfl, [(6-Ph(2)TPA)Fe(3-Hfl)]ClO(4) (8), was isolated and characterized by elemental analysis, FTIR, UV-vis, (1)H NMR, cyclic voltammetry, and a magnetic moment measurement. This complex reacts with O(2) to produce the diiron(III) mu-oxo compound [(6-Ph(2)TPAFe(3Hfl))(2)(mu-O)](ClO(4))(2) (6).

Spectroscopic evaluation of Co(II), Ni(II) and Cu(II) complexes derived from thiosemicarbazone and semicarbazone

NASA Astrophysics Data System (ADS)

Chandra, Sulekh; Kumar, Anil

2007-12-01

Co(II), Ni(II) and Cu(II) complexes were synthesized with thiosemicarbazone (L 1) and semicarbazone (L 2) derived from 2-acetyl furan. These complexes were characterized by elemental analysis, molar conductance, magnetic moment, mass, IR, electronic and EPR spectral studies. The molar conductance measurement of the complexes in DMSO corresponds to non-electrolytic nature. All the complexes are of high-spin type. On the basis of different spectral studies six coordinated geometry may be assigned for all the complexes except Co(L) 2(SO 4) and Cu(L) 2(SO 4) [where L = L 1 and L 2] which are of five coordinated square pyramidal geometry.

Synthesis, magnetic, spectral, and antimicrobial studies of Cu(II), Ni(II) Co(II), Fe(III), and UO 2(II) complexes of a new Schiff base hydrazone derived from 7-chloro-4-hydrazinoquinoline

NASA Astrophysics Data System (ADS)

El-Behery, Mostafa; El-Twigry, Haifaa

2007-01-01

A new hydrazone ligand, HL, was prepared by the reaction of 7-chloro-4-hydrazinoquinoline with o-hydroxybenzaldehyde. The ligand behaves as monoprotic bidentate. This was accounted for as the ligand contains a phenolic group and its hydrogen atom is reluctant to be replaced by a metal ion. The ligand reacted with Cu(II), Ni(II), Co(II), Fe(III), and UO 2(II) ions to yield mononuclear complexes. In the case of Fe(III) ion two complexes, mono- and binuclear complexes, were obtained in the absence and presence of LiOH, respectively. Also, mixed ligand complexes were obtained from the reaction of the metal cations Cu(II), Ni(II) and Fe(III) with the ligand (HL) and 8-hydroxyquinoline (8-OHqu) in the presence of LiOH, in the molar ratio 1:1:1:1. It is clear that 8-OHqu behaves as monoprotic bidentate ligand in such mixed ligand complexes. The ligand, HL, and its metal complexes were characterized by elemental analyses, IR, UV-vis, mass, and 1H NMR spectra, as well as magnetic moment, conductance measurements, and thermal analyses. All complexes have octahedral configurations except Cu(II) complex which has an extra square-planar geometry, while Ni(II) mixed complex has also formed a tetrahedral configuration and UO 2(II) complex which formed a favorable pentagonal biprymidial geometry. Magnetic moment of the binuclear Fe(III) complex is quite low compared to calculated value for two iron ions complex and thus shows antiferromagnetic interactions between the two adjacent ferric ions. The HL and metal complexes were tested against one stain Gram positive bacteria ( Staphylococcus aureus), Gram negative bacteria ( Escherichia coli), and fungi ( Candida albicans). The tested compounds exhibited higher antibacterial acivities.

Novelmetal-organic photocatalysts: Synthesis, characterization and decomposition of organic dyes

NASA Astrophysics Data System (ADS)

Gopal Reddy, N. B.; Murali Krishna, P.; Kottam, Nagaraju

2015-02-01

An efficient method for the photocatalytic degradation of methylene blue in an aqueous medium was developed using metal-organic complexes. Two novel complexes were synthesized using, Schiff base ligand, N‧-[(E)-(4-ethylphenyl)methylidene]-4-hydroxybenzohydrazide (HL) and Ni(II) (Complex 1)/Co(II) (Complex 2) chloride respectively. These complexes were characterized using microanalysis, various spectral techniques. Spectral studies reveal that the complexes exhibit square planar geometry with ligand coordination through azomethine nitrogen and enolic oxygen. The effects of catalyst dosage, irradiation time and aqueous pH on the photocatalytic activity were studied systematically. The photocatalytic activity was found to be more efficient in the presence of Ni(II) complexes than the Co(II) complex. Possible mechanistic aspects were discussed.

Synthesis, spectroscopic, anticancer, antibacterial and antifungal studies of Ni(II) and Cu(II) complexes with hydrazine carboxamide, 2-[3-methyl-2-thienyl methylene

NASA Astrophysics Data System (ADS)

Chandra, Sulekh; Vandana; Kumar, Suresh

2015-01-01

Schiff's base ligand(L) hydrazine carboxamide, 2-[3-methyl-2-thienyl methylene] and its metal complexes have been synthesized and characterized by elemental analysis, molar conductance, various spectroscopic techniques such as electronic, IR, 1H NMR, mass, EPR. Molar conductance of complexes in DMF solution corresponds to non-electrolyte. Complexes have general composition [M(L)2X2], where M = Ni(II) and Cu(II), X = Cl-, NO3-, CH3COO- and ½SO42-. On the basis of above spectral studies, an octahedral geometry has been assigned for Ni(II) complexes and tetragonal geometry for Cu(II) complexes except [Cu(L)2SO4] which possesses five coordinated trigonal bipyramidal geometry. These metal complexes were also tested for their anticancer, antibacterial and antifungal activities to assess their inhibition potential. Anticancer activity of ligand and its metal complexes were evaluated using SRB fluorometric assay and Adriamycin (ADR) was applied as positive control. Schiff's base ligand and its metal complexes were screened for their antibacterial and antifungal activity against Escherichia coli, Bacillus cereus and Aspergillus niger, Aspergillus flavus, respectively. Kirby-Bauer single disk susceptibility test was used for antibacterial activity and well diffusion method for antifungal activity of the compounds on the used fungi.

Structural, spectroscopic and thermal characterization of 2-tert-butylaminomethylpyridine-6-carboxylic acid methylester and its Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and UO(2)(II) complexes.

PubMed

Mohamed, Gehad G; El-Gamel, Nadia E A

2005-04-01

Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and UO(2)(II) complexes with the ligand 2-tert-butylaminomethylpyridine-6-carboxylic acid methylester (HL(2)) have been prepared and characterized by elemental analyses, molar conductance, magnetic moment, thermal analysis and spectral data. 1:1 M:HL(2) complexes, with the general formula [M(HL(2))X(2)].nH(2)O (where M = Co(II) (X = Cl, n = 0), Ni(II) (X = Cl, n = 3), Cu(II) (grey colour, X = AcO, n = 1), Cu(II) (yellow colour, X = Cl, n = 0) and Zn(II) (X = Br, n = 0). In addition, the Fe(III) and UO(2)(II) complexes of the type 1:2 M:HL(2) and with the formulae [Fe(L(2))(2)]Cl and [UO(2)(HL(2))(2)](NO(3))(2) are prepared. From the IR data, it is seen that HL(2) ligand behaves as a terdentate ligand coordinated to the metal ions via the pyridyl N, carboxylate O and protonated NH group; except the Fe(III) complex, it coordinates via the deprotonated NH group. This is supported by the molar conductance data, which show that all the complexes are non-electrolytes, while the Fe(III) and UO(2)(II) complexes are 1:1 electrolytes. IR and H1-NMR spectral studies suggest a similar behaviour of the Zn(II) complex in solid and solution states. From the solid reflectance spectral data and magnetic moment measurements, the complexes have a trigonal bipyramidal (Co(II), Ni(II), Cu(II) and Zn(II) complexes) and octahedral (Fe(III), UO(2)(II) complexes) geometrical structures. The thermal behaviour of the complexes is studied and the different dynamic parameters are calculated applying Coats-Redfern equation.

Thermodynamic Characteristics of Reactions of the Formation of Complexes between Triglycine and Ni2+ Ions in Aqueous Solution

NASA Astrophysics Data System (ADS)

Gorboletova, G. G.; Metlin, A. A.; Bychkova, S. A.

2018-05-01

Thermal effects of reactions of the formation of complexes between Ni(II) and triglycine are determined via direct calorimetry in aqueous solutions at 298.15 K and ionic strengths of 0.2, 0.5, and 1.0 (KNO3). Standard thermodynamic characteristics (Δr H°, Δr G°, Δr S°) of complexing processes in the investigated systems are calculated. The structures of triglycinate complexes NiL+, NiH-1L, NiL2, NiH-2L2- 2, NiL- 3, and NiH-3L4- 3 are introduced to compare the obtained values and data on the thermodynamics of triglycinate complexes of Ni(II).

Synthesis, Spectroscopic, and Antimicrobial Studies on Bivalent Nickel and Copper Complexes of Bis(thiosemicrbazone)

PubMed Central

Chandra, Sulekh; Raizada, Smriti; Tyagi, Monika; Gautam, Archana

2007-01-01

A series of metal complexes of Cu(II) and Ni(II) having the general composition [M(L)X2] with benzil bis(thiosemicarbazone) has been prepared and characterized by element chemical analysis, molar conductance, magnetic susceptibility measurements, and spectral (electronic, IR, EPR, mass) studies. The IR spectral data suggest the involvement of sulphur and azomethane nitrogen in coordination to the central metal ion. On the basis of spectral studies, an octahedral geometry has been assigned for Ni(II) complexes but a tetragonal geometry for Cu(II) complexes. The free ligand and its metal complexes have been tested in vitro against a number of microorganisms in order to assess their antimicrobial properties. PMID:18273385

Synthesis of first row transition metal selenomaltol complexes.

PubMed

Spiegel, Michael T; Hoogerbrugge, Amanda; Truksa, Shamus; Smith, Andrew G; Shuford, Kevin L; Klausmeyer, Kevin K; Farmer, Patrick J

2018-06-21

We report an efficient, one-step synthesis of the chelator 3-hydroxy-2-methyl-4-selenopyrone (selenomaltol). Complexes of selenomaltol with Fe(iii), Ni(ii), Cu(ii) and Zn(ii) have been prepared and studied by NMR, X-ray crystallography, cyclic voltammetry, EPR and electronic absorption. The Ni(ii) and Cu(ii) complexes show chemically reversible oxidations which are suggested to be ligand-based. Nuclear independent chemical shifts (NICS) analysis is used to compare aromaticity of the heterocyclic rings of selenomaltol and its chelates. The compounds described here should significantly expand the scope and utility of unusual O,Se-donor chelates.

Synthesis, characterization and physicochemical studies of new chelating resin 1, 8-(3, 6-dithiaoctyl)-4-polyvinylbenzenesulphonate (dpvbs) and its metallopolymer Cu(II), Ni(II), Co(II) and Fe(III) complexes

NASA Astrophysics Data System (ADS)

Khalil, Tarek E.; Elbadawy, Hemmat A.; El-Dissouky, Ali

2018-02-01

A new chelating resin, 1,8-(3,6-dithiaoctyl)-4-polyvinylbenzenesulphonate (dpvbs) has been synthesized by coupling Amberlite XAD-16 with (2,2‧-ethylenedithio) diethanol using pyridine/CH2Cl2 mixture as a solvent. The chelating resin and its metallopolymer Cu(II), Ni(II), Co(II) and Fe(III) complexes have been synthesized and characterized by EDS, SEM, XPS, elemental analysis, spectral (IR, UV/Vis, EPR). The thermal analysis of the resin and its metallopolymer complexes indicated an endothermic spontaneous sorption mechanism with the liberation of water of hydration of the metal ions and that adsorbed by the free resin. At the solid liquid interface, the degrees of freedom increased during the sorption of the metal ions onto the resin. The surface area of polymer support and its metallopolymer complexes are estimated by (BJH) method. The batch equilibrium method was used for studying the metal sorption and selectivity at different pH values and different contact times at room temperature. ICP-AES was used to estimate the metal capacity of the resin for sorption of Cu(II), Ni(II), Co(II) and Fe(III) from aqueous solutions utilizing the batch equilibrium method. The sorption tendency of the metal ions by the resin was found to be: Cu(II) > Fe(III) > Co(II) > Ni(II). Adsorption kinetics was found to be fit the pseudo-second order model.

Structural and Biological Behaviour of Co(II), Cu(II) and Ni(II) Metal Complexes of Some Amino Acid Derived Schiff-Bases

PubMed Central

Chohan, Zahid H.; Praveen, M.; Ghaffar, A.

1997-01-01

Biologically active tridentate amino acid (Alanine, Glycine & Tyrosine) derived Schiff-bases and their Co(II), Cu(II) & Ni(II) complexes have been synthesised and characterised on the basis of their conductance and magnetic measurements, elemental analysis and 13C-NMR, 1H-NMR, IR and electronic spectral data. These Schiff-bases and their complexes have been evaluated for their antibacterial activity against bacterial species such as Staphylococcus aureus, Escherichia coli, Klebsiella pneumonae, Proteus vulgarus and Pseudomonas aeruginosa and this activity data show the metal complexes to be more antibacterial than the Schiff-bases against one or more bacterial species. PMID:18475798

Synthesis, characterization and in vitro antimicrobial studies of Co(II), Ni(II) and Cu(II) complexes derived from macrocyclic compartmental ligand

NASA Astrophysics Data System (ADS)

El-Gammal, O. A.; Bekheit, M. M.; El-Brashy, S. A.

2015-02-01

New Co(II), Ni(II) and Cu(II) complexes derived from tetradentate macrocyclic nitrogen ligand, (1E,4E,8E,12E)-5,8,13,16-tetramethyl-1,4,9,12-tetrazacyclohexadeca-4,8,12,16-tetraene (EDHDH) have been synthesized. The complexes have been characterized by elemental analysis, spectral (IR, UV-Vis, 1H NMR and ESR (for Cu(II) complex)) mass, and magnetic as well as thermal analysis measurements. The complexes afforded the formulae: [Cu(EDHDH)Cl2]·2EtOH and [M(EDHDH)X2]·nH2O where M = Co(II) and Ni(II), X = Cl- or OH-, n = 1,0, respectively. The data revealed an octahedral arrangement with N4 tetradentate donor sites in addition to two Cl atoms occupying the other two sites. ESR spectrum of Cu2+ complex confirmed the suggested geometry with values of a α2and β2 indicating that the in-plane σ-bonding and in-plane π-bonding are appreciably covalent, and are consistent with very strong σ-in-plane bonding in the complexes. The molecular modeling is drawn and showed the bond length, bond angle, chemical reactivity, energy components (kcal/mol) and binding energy (kcal/mol) for all the title compounds using DFT method. Also, the thermal behavior and the kinetic parameters of degradation were determined using Coats-Redfern and Horowitz-Metzger methods. Moreover, the in vitro antibacterial studies of all compounds screened against pathogenic bacteria (two Gram +ve and two Gram -ve) to assess their inhibiting potential. The assay indicated that the inhibition potential is metal ion dependent. The ligand, EDHDH, Co(II) and Cu(II) complexes exhibited a remarkable antibacterial activity against Streptococcus Pyogenes as Gram +ve and Proteus vulgaris as Gram -ve bacterial strains. On the other hand, Ni(II) complex revealed a moderate antibacterial activity against both Gram +ve organisms and no activity against Gram -ve bacterial strain.

2,6-Diiminopiperidin-1-ol: an overlooked motif relevant to uranyl and transition metal binding on poly(amidoxime) adsorbents

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kennedy, Zachary C.; Cardenas, Allan Jay P.; Corbey, Jordan F.

2016-01-01

Glutardiamidoxime, a structural motif on sorbents used in uranium extraction from seawater, was discovered to cyclize in situ at room temperature to 2,6-diimino-piperidin-1-ol in the presence of uranyl nitrate. The new diimino motif was also generated when exposed to competing transition metals Cu(II) and Ni(II). Multinuclear μ-O bridged U(VI), Cu(II), and Ni(II) complexes featuring bound diimino ligands were isolated. A Cu(II) complex with the historically relevant cyclic imide dioxime motif is also reported for structural comparison to the reported diimino complexes.

Synthesis, spectral characterization, structural investigation and antimicrobial studies of mononuclear Cu(II), Ni(II), Co(II), Zn(II) and Cd(II) complexes of a new potentially hexadentate N2O4 Schiff base ligand derived from salicylaldehyde

NASA Astrophysics Data System (ADS)

Keypour, Hassan; Shayesteh, Maryam; Rezaeivala, Majid; Chalabian, Firoozeh; Elerman, Yalcin; Buyukgungor, Orhan

2013-01-01

A new potentially hexadentate N2O4 Schiff base ligand, H2L derived from condensation reaction of an aromatic diamine and salicylaldehyde, and its metal complexes were characterized by elemental analyses, IR, UV-Vis, EI-MS, 1H and 13C NMR spectra, as well as conductance measurements. It has been originated that the Schiff base ligand with Cu(II), Ni(II), Co(II), Cd(II) and Zn(II) ions form mononuclear complexes on 1:1 (metal:ligand) stoichiometry. The conductivity data confirm the non-electrolytic nature of the complexes. Also the crystal structures of the complexes [ZnL] and [CoL] have also been determined by using X-ray crystallographic technique. The Zn(II) and Co(II) complexes show a tetrahedral configuration. Electronic absorption spectra of the Cu(II) and Ni(II) complexes suggest a square-planar geometry around the central metal ion. The synthesized compounds have antibacterial activity against the three Gram-positive bacteria: Bacillus cereus, Enterococcus faecalis and Listeria monocytogenes and also against the three Gram-negative bacteria: Salmonella paraB, Citrobacter freundii and Enterobacter aerogenes. The results showed that in some cases the antibacterial activity of complexes were more than nalidixic acid and amoxicillin as standards.

Synthesis, structural elucidation, biological, antioxidant and nuclease activities of some 5-Fluorouracil-amino acid mixed ligand complexes

NASA Astrophysics Data System (ADS)

Shobana, Sutha; Subramaniam, Perumal; Mitu, Liviu; Dharmaraja, Jeyaprakash; Arvind Narayan, Sundaram

2015-01-01

Some biologically active mixed ligand complexes (1-9) have been synthesized from 5-Fluorouracil (5-FU; A) and amino acids (B) such as glycine (gly), L-alanine (ala) and L-valine (val) with Ni(II), Cu(II) and Zn(II) ions. The synthesized mixed ligand complexes (1-9) were characterized by various physico-chemical, spectral, thermal and morphological studies. 5-Fluorouracil and its mixed ligand complexes have been tested for their in vitro biological activities against some pathogenic bacterial and fungal species by the agar well diffusion method. The in vitro antioxidant activities of 5-Fluorouracil and its complexes have also been investigated by using the DPPH assay method. The results demonstrate that Cu(II) mixed ligand complexes (4-6) exhibit potent biological as well as antioxidant activities compared to 5-Fluorouracil and Ni(II) (1-3) and Zn(II) (7-9) mixed ligand complexes. Further, the cleaving activities of CT DNA under aerobic conditions show moderate activity with the synthesized Cu(II) and Ni(II) mixed ligand complexes (1-6) while no activity is seen with Zn(II) complexes (7-9). Binding studies of CT DNA with these complexes show a decrease in intensity of the charge transfer band to the extent of 5-15% along with a minor red shift. The free energy change values (Δ‡G) calculated from intrinsic binding constants indicate that the interaction between mixed ligand complex and DNA is spontaneous.

A Trinuclear Ni(II) Enediolate Complex: Synthesis, Characterization, and O2 Reactivity

PubMed Central

Arif, Atta M.; Berreau, Lisa M.

2009-01-01

Using a new N4-donor chelate ligand having a mixture of hydrophobic phenyl and hydrogen bond donor appendages, a trinuclear Ni(II) complex of the doubly deprotonated form of 2-hydroxy-1,3-diphenylpropane-1,3-dione was isolated, characterized (X-ray crystallography, elemental analysis, UV-vis, 1H NMR, FTIR, magnetic moment measurement), and evaluated for O2 reactivity. This complex, [(6-NA-6-Ph2TPANi)2(μ-PhC(O)C(O)C(O)Ph)2Ni](ClO4)2 (4), has two terminal pseudo octahedral Ni(II) centers supported by the tetradentate chelate ligand, and a central square planar Ni(II) ion ligated by oxygen atoms of two bridging enediolate ligands. In CH3CN, 4 exhibits a deep orange/brown color and λmax = 463 nm (ε = 16,000 M-1cm-1). The room temperature magnetic moment of 4, determined by Evans method, is μeff = 5.3(2) μB. This is consistent with the presence of two non-interacting high-spin Ni(II) centers, a diamagnetic central Ni(II) ion, and an overall quintet ground state. Exposure of a CH3CN solution of 4 to O2 results in the rapid loss of the orange/brown color to give a green solution. The products identified from this reaction are [(κ3-6-NA-6-Ph2TPA)Ni(O2Ph)(H2O)]ClO4 (5), benzil (PhC(O)C(O)Ph), and CO. Identification of 5 was achieved via its independent synthesis and comparison of its 1H NMR and mass spectral features with those of the 6-NA-6-Ph2TPA-containing product generated upon reaction of 4 with O2. The independently prepared sample of 5 was characterized by X-ray crystallography, elemental analysis, UV-vis, mass spectrometry, and FTIR. The O2 reactivity of 4 has relevance to the active site chemistry of Ni(II)-containing acireductone dioxygenase (Ni(II)-ARD). PMID:18959363

Synthesis, characterization and antimicrobial activity of some nickel, cadmium and mercury complexes of 5-methyl pyrazole-3yl-N-(2‧-methylthiophenyl) methyleneimine, (MPzOATA) ligand

NASA Astrophysics Data System (ADS)

Mandal, Susmita; Mondal, Monojit; Biswas, Jayanta Kumar; Cordes, David B.; Slawin, Alexandra M. Z.; Butcher, Ray J.; Saha, Manan; Chandra Saha, Nitis

2018-01-01

Herein, we report the syntheses and structures of Ni(II) complexes, [Ni(MPzOATA)2] (Cl) (PF6) (I), [Ni(MPzOATA)2](ClO4)2.CH3CN (II) & [Ni(MPzOATA)2](BF4)2.H2O (III); Cd(II) complex, [Cd(MPzOATA)Cl2]2 (IV) and a Hg(II) complex, [Hg(MPzOATA)Cl2] (V), of a pyrazole based 'NNS' donor ligand, 5-methylpyrazole-3yl-N-(2‧-methylthiophenyl)methyleneimine, (MPzOATA). The complexes are characterized by elemental analyses, electronic, IR, 1H- NMR (only for IV &V) spectral parameters, conductivity and fluorescence measurements. X-ray crystallographic data of the complexes reveal that the Ni(II) complexes have NiN4S2 octahedral coordination, one of them is a mixed-anion complex having Cl- and PF6- as counter anions; the Cd(II) complex is a chloro bridged binuclear complex with octahedral coordination environment around each metal centre, while the Hg(II) complex is a square pyramidal one. Among the reported complex species, the Ni(II) complexes are non-fluorescent, while the Cd(II) and Hg(II) complexes can be used as potential photoactive materials as indicated from their characteristic emission properties. The reported complexes are screened for their antimicrobial activities against some Gram positive and Gram negative microbial strains, and they are found to be potential antimicrobial agents in broad spectrum against both Gram positive and Gram negative bacteria.

Bio-important antipyrine derived Schiff bases and their transition metal complexes: Synthesis, spectroscopic characterization, antimicrobial, anthelmintic and DNA cleavage investigation

NASA Astrophysics Data System (ADS)

Manjunath, M.; Kulkarni, Ajaykumar D.; Bagihalli, Gangadhar B.; Malladi, Shridhar; Patil, Sangamesh A.

2017-01-01

Spectroscopic (IR, NMR, UV-vis, ESR, ESI-mass), magnetic and TGA studies suggests octahedral geometry for all the CoII, NiII and CuII complexes of the Schiff bases, derived from 4-aminoantipyrine and 8-formyl-7-Hydroxy-4-methylcoumarin/5-formyl-6-hydroxycoumarin, coordinated through ONO donor sites. Antibacterial (Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella typhi), antifungal (Aspergillus niger, Aspergillus flavus and Cladosporium) and DNA cleavage properties of the metal complexes are investigated. The results suggested that some of the synthesized compounds are potential antimicrobials. The synthesized compounds tested for their anthelmintic activities and it was found that CoII and NiII complexes exhibited good anthelmintic properties.

Synthesis, spectral and theoretical studies of Ni(II), Pd(II) and Pt(II) complexes of 5-mercapto-1,2,4-triazole-3-imine-2‧-hydroxynaphyhaline

NASA Astrophysics Data System (ADS)

Gaber, Mohamed; El-Ghamry, Hoda; Atlam, Faten; Fathalla, Shaimaa

2015-02-01

Ni(II), Pd(II) and Pt(II) complexes of 5-mercapto-1,2,4-triazole-3-imine-2‧-hydroxynaphthaline have been isolated and characterized by elemental analysis, IR, 1H NMR, EI-mass, UV-vis, molar conductance, magnetic moment measurements and thermogravimetric analysis. The molar conductance values indicated that the complexes are non-electrolytes. The magnetic moment values of the complexes displayed diamagnetic behavior for Pd(II) and Pt(II) complexes and tetrahedral geometrical structure for Ni(II) complex. From the bioinorganic applications point of view, the interaction of the ligand and its metal complexes with CT-DNA was investigated using absorption and viscosity titration techniques. The Schiff-base ligand and its metal complexes have also been screened for their antimicrobial and antitumor activities. Also, theoretical investigation of molecular and electronic structures of the studied ligand and its metal complexes has been carried out. Molecular orbital calculations were performed using DFT (density functional theory) at B3LYP level with standard 6-31G(d,p) and LANL2DZ basis sets to access reliable results to the experimental values. The calculations were performed to obtain the optimized molecular geometry, charge density distribution, extent of distortion from regular geometry, the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO), Mulliken atomic charges, reactivity index (ΔE), dipole moment (D), global hardness (η), softness (σ), electrophilicity index (ω), chemical potential and Mulliken electronegativity (χ).

Synthesis, X-ray structure and cytotoxic effect of nickel(II) complexes with pyrazole ligands.

PubMed

Sobiesiak, Marta; Lorenz, Ingo-Peter; Mayer, Peter; Woźniczka, Magdalena; Kufelnicki, Aleksander; Krajewska, Urszula; Rozalski, Marek; Budzisz, Elzbieta

2011-12-01

Here we present the synthesis of the new Ni(II) complexes with chelating ligands 1-benzothiazol-2-yl-3,5-dimethyl-1H-pyrazole (a), 5-(2-hydroxyphenyl)-3-methyl-1-(2-pyridylo)-1H-pyrazole-4-carboxylic acid methyl ester (b) and 1-benzothiazol-2-yl-5-(2-hydroxyphenyl)-3-methyl-1H-pyrazole-4-carboxylic acid methyl ester (c). These ligands a-c create solid complexes with Ni(II). The crystal and molecular structures of two complexes were determined by X-ray diffraction method. Thermal stability of two complexes with ligand c by TG/DTG and DSC methods were also shown. Cytotoxic activity of all the complexes against three tumour cell lines and to normal endothelial cells (HUVEC) was also estimated. Complexes with ligand c exhibited relatively high cytotoxic activity towards HL-60 and NALM-6 leukaemia cells and WM-115 melanoma cells. Cytotoxic effectiveness of one of these complexes against melanoma WM-115 cells was two times higher than that of cisplatin. The protonation constant log K=9.63 of ligand b corresponding to the phenol 2-hydroxy group has been determined in 10% (v/v) DMSO/water solution (25°C). The coordination modes (formation of two monomeric species: NiL and NiL(2)) in the complexes with Ni(II) are discussed for b on the basis of the potentiometric and UV/Vis data. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

Exhaustive oxidation of a nickel dithiolate complex: some mechanistic insights en route to sulfate formation.

PubMed

Hosler, Erik R; Herbst, Robert W; Maroney, Michael J; Chohan, Balwant S

2012-01-21

A study of the step-wise oxidation of a Ni(II) diaminodithiolate complex through the formation of sulfate, the ultimate sulfur oxygenate, is reported. Controlled oxygenations or peroxidations of a neutral, planar, tetracoordinate, low-spin Ni(II) complex of a N(2)S(2)-donor ligand, (N,N'-dimethyl-N-N'-bis(2-mecaptoethyl)-1,3-propanediaminato) nickel(ii) (1), led to a series of sulfur oxygenates that have been isolated and characterized by ESI-MS and single-crystal X-ray diffraction. A monosulfenate complex (2) was detected by ESI-MS as a product of oxidation with one equivalent of H(2)O(2). However, this complex proved too unstable to isolate. Reaction of the dithiolate (1) with two equivalents of H(2)O(2) or one O(2) molecule leads to the formation of a monosulfinate complex (3), which was isolated and fully characterized by crystallography. The oxidation product of the monosulfinate (3) produced with either O(2) or H(2)O(2) is an interesting dimeric complex containing both sulfonate and thiolate ligands (4), this complex was fully characterized by crystallography, details of which were reported earlier by us. A disulfonate complex (7) is produced by reaction of 1 in the presence of O(2) or by reaction with exactly six equivalents of H(2)O(2). This complex was isolated and also fully characterized by crystallography. Possible intermediates in the conversion of the monosulfinate complex (3) to the disulfonate complex (7) include complexes with mixed sulfonate/sulfenate (5) or sulfonate/sulfinate (6) ligands. Complex 5, a four-oxygen adduct of 1, was not detected, but the sulfonate/sulfinate complex (6) was isolated and characterized. The oxidation chemistry of 1 is very different from that reported for other planar cis-N(2)S(2) Ni(ii) complexes including N,N'-dimethyl-N-N'-bis(2-mecaptoethyl)-1,3-ethylenediaminato) nickel(II), (8), and N,N'-bis(mercaptoethyl)-1,5-diazacyclooctane nickel(II). To address the structural aspects of the reactivity differences, the crystal structure of 8 was also determined. A comparison of the structures of planar Ni(II) complexes containing cis-dithiolate ligands, strongly suggests that the differences in reactivity are determined in part by the degree of flexibility that is allowed by the NN' chelate ring.

Syntheses, structures, and properties of trinuclear complexes [M(bpca)(2)(M'(hfac)(2))(2)], constructed with the complexed bridging ligand [M(bpca)(2)] [M, M' = Ni(II), Mn(II); Cu(II), Mn(II); Fe(II), Mn(II); Ni(II), Fe(II); and Fe(II), Fe(II); Hbpca = Bis(2-pyridylcarbonyl)amine, Hhfac = Hexafluoroacetylacetone].

PubMed

Kamiyama, Asako; Noguchi, Tomoko; Kajiwara, Takashi; Ito, Tasuku

2002-02-11

Five trinuclear complexes [M(bpca)(2)(M'(hfac)(2))(2)] (where MM'(2) = NiMn(2), CuMn(2), FeMn(2), NiFe(2), and FeFe(2); Hbpca = bis(2-pyridylcarbonyl)amine; and Hhfac = hexafluoroacetylacetone) were synthesized almost quantitatively by the reaction of [M(bpca)(2)] and [M'(hfac)(2)] in 1:2 molar ratio, and their structures and magnetic properties were investigated. Three complexes, with M' = Mn, crystallize in the same space group, Pna2(1), whereas two complexes, with M' = Fe, crystallize in P4(1), and complexes within each set are isostructural to one another. In all complexes, [M(bpca)(2)] acts as a bis-bidentate bridging ligand to form a linear trinuclear complex in which three metal ions are arranged in the manner M'-M-M'. The central metal ion is in a strong ligand field created by the N(6) donor set, and hence the Fe(II) in the [Fe(bpca)(2)] moiety is in a low-spin state. The terminal metal ions (M') are surrounded by O(6) donor sets with a moderate ligand field, which leads to the high-spin configuration of Fe(II). Three metal ions in all complexes are almost collinear, and metal-metal distances are ca. 5.5 A. The magnetic behavior of NiMn(2) and NiFe(2) shows a weak ferromagnetic interaction between the central Ni(II) ion and the terminal Mn(II) or Fe(II) ions. In these complexes, sigma-spin orbitals of the central Ni(II) ion and those of terminal metal ions have different symmetry about a 2-fold rotation axis through the Ni-N(amide)-M'(terminal) atoms, and this results in orthogonality between the neighboring sigma-spin orbitals and thus ferromagnetic interactions.

Spectroscopic and biological studies of new mononuclear metal complexes of a bidentate NN and NO hydrazone-oxime ligand derived from egonol

NASA Astrophysics Data System (ADS)

Babahan, Ilknur; Emirdağ-Öztürk, Safiye; Poyrazoğlu-Çoban, Esin

2015-04-01

A novel ligand, vicinal dioxime ligand (egonol-hydrazone glyoxime) (LH2) was synthesized and characterized using 1H NMR, 13C NMR, MS, AAS, infrared spectroscopy, and magnetic susceptibility measurements. Mononuclear nickel (II), copper (II) and cobalt (II) complexes with a metal:ligand ratio of 1:2 for LH2 were also synthesized. Zn(II) forms complex [Zn(LH)Cl2] with a metal to ligand ratio of 1:1. IR spectrum shows that the ligand act in a bidentate manner and coordinates N4 donor groups of the ligands to NiII, CuII, CoII and ZnII ions. The detection of H-bonding (Osbnd H⋯O) in the [M(LH)2] metal complexes by IR spectra supported the square-planar MN4 coordination of Ni(II), Cu(II) and Co(II) complexes. The antimicrobial activities of compounds LH2 and their Ni(II), Cu(II), Co(II) and Zn(II) complexes were evaluated using the disc diffusion method against 16 bacteria and 5 yeasts. The minimal inhibitory concentrations (MICs) against all the bacteria and yeasts were also determined. Among the attempted test compounds, it is showed that all the compounds (L, LH2, [Ni(LH)2], [Cu(LH)2], [Co(LH)2(H2O)2], [Zn(LH)Cl2]) were effective against used test microorganisms.

Selective and sensitized spectrophotometric determination of trace amounts of Ni(II) ion using α-benzyl dioxime in surfactant media

NASA Astrophysics Data System (ADS)

Ghaedi, Mehrorang

2007-02-01

Highly sensitive and interference-free sensitized spectrophotometric method for the determination of Ni(II) ions is described. The method is based on the reaction between Ni(II) ion and benzyl dioxime in micellar media in the presence of sodium dodecyl sulfate (SDS). The absorbance is linear from 0.1 up to 25.0 μg mL -1 in aqueous solution with repeatability (RSD) of 1.0% at a concentration of 1 μg mL -1 and a detection limit of 0.12 ng mL -1 and molar absorption coefficient of 68,600 L mol -1 cm -1. The influence of reaction variables including type and amount of surfactant, pH, and amount of ligand and complexation time and the effect of interfering ions are investigated. The proposed procedure was applied to the determination of trace amounts of Ni(II) ion in tap water, river water, chocolate and vegetable without separation or organic solvent extraction.

Synthesis, characterization and biological activity of Cu(II), Ni(II) and Zn(II) complexes of biopolymeric Schiff bases of salicylaldehydes and chitosan.

PubMed

de Araújo, Eliene Leandro; Barbosa, Hellen Franciane Gonçalves; Dockal, Edward Ralph; Cavalheiro, Éder Tadeu Gomes

2017-02-01

Schiff bases have been prepared from biopolymer chitosan and salicylaldehyde, 5-methoxysalicylaldehyde, and 5-nitrosalicylaldehyde. Ligands were synthesized in a 1:1.5mol ratio, and their Cu(II), Ni(II) and Zn(II) complexes in a 1:1mol ratio (ligand:metal). Ligands were characterized by 1 H NMR and FTIR, resulting in degrees of substitution from 43.7 to 78.7%. Complexes were characterized using FTIR, electronic spectra, XPRD. The compounds were confirmed by the presence of an imine bond stretching in the 1630-1640cm -1 and νMetal-N and νMetal-O at <600cm -1 . Electronic spectra revealed that both Cu(II) and Ni(II) complexes present a square plane geometry. The crystallinity values were investigated by X-ray powder diffraction. Thermal behavior of all compounds was evaluated by TGA/DTG and DTA curves with mass losses related to dehydration and decomposition, with characteristic events for ligand and complexes. Schiff base complexes presented lower thermal stability and crystallinity than the starting chitosan. Residues were the metallic oxides as confirmed by XPRD, whose amounts were used in the calculation of the percentage of complexed metal ions. Surface morphologies were analyzed with SEM-EDAX. Preliminary cytotoxicity tests were performed using MTT assay with HeLa cells. Despite the differences in solubility, the free bases presented relatively low toxicity. Copyright © 2016 Elsevier B.V. All rights reserved.

Design, spectral characterization, thermal, DFT studies and anticancer cell line activities of Co(II), Ni(II) and Cu(II) complexes of Schiff bases derived from 4-amino-5-(pyridin-4-yl)-4H-1,2,4-triazole-3-thiol.

PubMed

Tyagi, Prateek; Chandra, Sulekh; Saraswat, B S; Yadav, Deepak

2015-06-15

A series of two biologically active Schiff base ligands L(1), L(2) have been synthesized in equimolar reaction of 4-amino-5-(pyridin-4-yl)-4H-1,2,4-triazole-3-thiol with thiophene-2-carbaldehyde and furan-2-carbaldehyde. The synthesized Schiff bases were used for complexation with different metal ions like Co(II), Ni(II) and Cu(II) by using a molar ratio of ligand: metal as 1:1 and 2:1. The characterization of Schiff bases and metal complexes was done by (1)H NMR, UV-Vis, TGA, IR, mass spectrometry and molar conductivity studies. The in DFT studies the geometries of Schiff bases and metal complexes were fully optimized with respect to the energy using the 6-31+g(d,p) basis set. On the basis of the spectral studies an octahedral geometry has been assigned for Co(II), Ni(II) and Cu(II) complexes. The effect of these complexes on proliferation of human breast cancer cell line (MCF-7) and human hepatocellular liver carcinoma cell line (Hep-G2) were studied and compared with those of free ligand. The anticancer cell line results reveal that all metal complexes show moderate to significant % cytotoxicity on cell line HepG2 and MCF-7. Copyright © 2015 Elsevier B.V. All rights reserved.

Two novel macroacyclic schiff bases containing bis-N 2O 2 donor set and their binuclear complexes: synthesis, spectroscopic and magnetic properties

NASA Astrophysics Data System (ADS)

Karaoglu, Kaan; Baran, Talat; Serbest, Kerim; Er, Mustafa; Degirmencioglu, Ismail

2009-03-01

Herein, we report two novel macroacyclic Schiff bases derived from tetranaphthaldehyde derivative compound and their binuclear Mn(II), Ni(II), Cu(II) and Zn(II) complexes. The structures of the compounds have been proposed by elemental analyses, spectroscopic data i.e. IR, 1H and 13C NMR, UV-Vis, electrospray ionisation mass spectra, molar conductivities and magnetic susceptibility measurements. The stoichiometries of the complexes derived from mass and elemental analysis correspond to the general formula [M 2L(ClO 4) n](ClO 4) 4-n, (where M is Mn(II), Ni(II), Cu(II), Zn(II) and L represents the Schiff base ligands).

Synthesis, spectral and theoretical studies of Ni(II), Pd(II) and Pt(II) complexes of 5-mercapto-1,2,4-triazole-3-imine-2'-hydroxynaphthaline.

PubMed

Gaber, Mohamed; El-Ghamry, Hoda; Atlam, Faten; Fathalla, Shaimaa

2015-02-25

Ni(II), Pd(II) and Pt(II) complexes of 5-mercapto-1,2,4-triazole-3-imine-2'-hydroxynaphthaline have been isolated and characterized by elemental analysis, IR, (1)H NMR, EI-mass, UV-vis, molar conductance, magnetic moment measurements and thermogravimetric analysis. The molar conductance values indicated that the complexes are non-electrolytes. The magnetic moment values of the complexes displayed diamagnetic behavior for Pd(II) and Pt(II) complexes and tetrahedral geometrical structure for Ni(II) complex. From the bioinorganic applications point of view, the interaction of the ligand and its metal complexes with CT-DNA was investigated using absorption and viscosity titration techniques. The Schiff-base ligand and its metal complexes have also been screened for their antimicrobial and antitumor activities. Also, theoretical investigation of molecular and electronic structures of the studied ligand and its metal complexes has been carried out. Molecular orbital calculations were performed using DFT (density functional theory) at B3LYP level with standard 6-31G(d,p) and LANL2DZ basis sets to access reliable results to the experimental values. The calculations were performed to obtain the optimized molecular geometry, charge density distribution, extent of distortion from regular geometry, the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO), Mulliken atomic charges, reactivity index (ΔE), dipole moment (D), global hardness (η), softness (σ), electrophilicity index (ω), chemical potential and Mulliken electronegativity (χ). Copyright © 2014 Elsevier B.V. All rights reserved.

Rates of nickel(II) capture from complexes with NTA, EDDA, and related tetradentate chelating agents by the hexadentate chelating agents EDTA and CDTA: Evidence of a "semijunctive" ligand exchange pathway

NASA Astrophysics Data System (ADS)

Boland, Nathan E.; Stone, Alan T.

2017-09-01

Many siderophores and metallophores produced by soil organisms, as well as anthropogenic chelating agent soil amendments, rely upon amine and carboxylate Lewis base groups for metal ion binding. UV-visible spectra of metal ion-chelating agent complexes are often similar and, as a consequence, whole-sample absorbance measurements are an unreliable means of monitoring the progress of exchange reactions. In the present work, we employ capillary electrophoresis to physically separate Ni(II)-tetradentate chelating agent complexes (NiL) from Ni(II)-hexadentate chelating agent complexes (NiY) prior to UV detection, such that progress of the reaction NiL + Y → NiY + L can be conveniently monitored. Rates of ligand exchange for Ni(II) are lower than for other +II transition metal ions. Ni(II) speciation in environmental media is often under kinetic rather than equilibrium control. Nitrilotriacetic acid (NTA), with three carboxylate groups all tethered to a central amine Lewis base group, ethylenediamine-N,N‧-diacetic acid (EDDA), with carboxylate-amine-amine-carboxylate groups arranged linearly, plus four structurally related compounds, are used as tetradentate chelating agents. Ethylenediaminetetraacetic acid (EDTA) and the structurally more rigid analog trans-cyclohexaneethylenediaminetetraacetic acid (CDTA) are used as hexadentate chelating agents. Effects of pH and reactant concentration are explored. Ni(II) capture by EDTA was consistently more than an order of magnitude faster than capture by CDTA, and too fast to quantify using our capillary electrophoresis-based technique. Using NiNTA as a reactant, Ni(II) capture by CDTA is independent of CDTA concentration and greatly enhanced by a proton-catalyzed pathway at low pH. Using NiEDDA as reactant, Ni(II) capture by CDTA is first order with respect to CDTA concentration, and the contribution from the proton-catalyzed pathway diminished by CDTA protonation. While the convention is to assign either a disjunctive pathway or adjunctive pathway to multidentate ligand exchange reactions, our results indicate that a third "semijunctive" pathway is necessary to account for slow reactions progressing through Lsbnd Nisbnd Y ternary complexes. Ligand exchange pathways with NTA-type chelating agents are assigned a disjunctive pathway, while pathways with EDDA-type chelating agents are assigned a semijunctive pathway. Based upon operative mechanism(s), magnitudes of exchange rates and effects of ambient geochemical conditions can be predicted.

Syntheses, spectroscopic and thermal analyses of cyanide bridged heteronuclear polymeric complexes: [M(L)2Ni(CN)4]n (Ldbnd N-methylethylenediamine or N-ethylethylenediamine; Mdbnd Ni(II), Cu(II), Zn(II) or Cd(II))

NASA Astrophysics Data System (ADS)

Karaağaç, Dursun; Kürkçüoğlu, Güneş Süheyla

2016-02-01

Polymeric tetracyanonickelate(II) complexes of the type [M(L)2Ni(CN)4]n (Ldbnd N-methylethylenediamine (men) or N-ethylethylenediamine (neen); Mdbnd Ni(II), Cu(II), Zn(II) or Cd(II)) have been prepared and characterized by FT-IR, Raman spectroscopy, thermal and elemental analysis techniques. Additionally, FT-IR and Raman spectral analyses of men and neen have experimentally and theoretically investigated in the range of 4000-250 cm-1. The corresponding vibration assignments of men and neen are performed by using B3LYP density functional theory (DFT) method together with 6-31 G(d) basis set. The spectral features of the complexes suggest that the coordination environment of the M(II) ions are surrounded by the two symmetry related men and neen ligands and the two symmetry related N atom of cyanide groups, whereas the Ni(II) atoms are coordinated with a square-planar to four C atoms of the cyanide groups. Polymeric structures of the complexes consist of one dimensional alternative chains of [M(L)2]2+ and [Ni(CN)4]2- moieties. The thermal decompositions in the temperature range 30-700 °C of the complexes were investigated in the static air atmosphere.

Asymmetric synthesis of α-amino acids via homologation of Ni(II) complexes of glycine Schiff bases. Part 3: Michael addition reactions and miscellaneous transformations.

PubMed

Aceña, José Luis; Sorochinsky, Alexander E; Soloshonok, Vadim

2014-09-01

The major goal of this review is a critical discussion of the literature data on asymmetric synthesis of α-amino acids via Michael addition reactions involving Ni(II)-complexes of amino acids. The material covered is divided into two conceptually different groups dealing with applications of: (a) Ni(II)-complexes of glycine as C-nucleophiles and (b) Ni(II)-complexes of dehydroalanine as Michael acceptors. The first group is significantly larger and consequently subdivided into four chapters based on the source of stereocontrolling element. Thus, a chiral auxiliary can be used as a part of nucleophilic glycine Ni(II) complex, Michael acceptor or both, leading to the conditions of matching vs. mismatching stereochemical preferences. The particular focus of the review is made on the practical aspects of the methodology under discussion and mechanistic considerations.

Synthesis, characterization and antibacterial activity of new sulfonyl hydrazone derivatives and their nickel(II) complexes

NASA Astrophysics Data System (ADS)

Özmen, Ümmühan Özdemir; Olgun, Gülçin

2008-08-01

Prophane sulfonic acid hydrazide (psh: CH 3CH 2CH 2SO 2NHNH 2) derivatives as salicylaldehydeprophanesulfonylhydrazone (salpsh), 5-methylsalicylaldehydeprophanesulfonylhydrazone (5-msalpsh), 2-hydroxyacetophenoneprophanesulfonylhydrazone (afpsh), 5-methyl-2-hydroxyacetophenoneprophanesulfonylhydrazone (5-mafpsh) and their Ni(II) complexes have been synthesized. The structure of these compounds has been investigated by using elemental analysis, FTIR, 1H NMR, LC/MS, UV-vis spectrophotometric method, magnetic susceptibility and conductivity measurements. The complexes were found to have general compositions [NiL2]. Square-planer structures are proposed for the Ni(II) complexes on the basis of magnetic evidence, electronic spectra and TGA data. Bacterial activities of sulfonyl hydrazone compounds were studied against gram-positive bacteria: Staphylococcus aureus, Bacillus subtilis, Bacillus magaterium and gram-negative bacteria: Salmonella enteritidis, Escherichia coli by using minimum inhibitory concentrations (MICs) method.

Design, synthesis and characterization of macrocyclic ligand based transition metal complexes of Ni(II), Cu(II) and Co(II) with their antimicrobial and antioxidant evaluation

NASA Astrophysics Data System (ADS)

Gull, Parveez; Malik, Manzoor Ahmad; Dar, Ovas Ahmad; Hashmi, Athar Adil

2017-04-01

Three new complexes Ni(II), Cu(II) and Co(II) were synthesized of macrocyclic ligand derived from 1, 4-dicarbonyl-phenyl-dihydrazide and O-phthalaldehyde in the ratio of 2:2. The synthesized compounds were characterized by elemental analyses, molar conductance, magnetic susceptibility measurements, FTIR, UV-Vis., Mass and 1H NMR spectral studies. The electronic spectra of the metal complexes indicate a six coordinate octahedral geometry of the central metal ion. These metal complexes and the ligand were evaluated for antimicrobial activity against bacteria (E. coli, B. subtilis, S. aureus) and fungi (A. niger, A. flavus, C. albicans) and compared against standard drugs chloramphenicol and nystatin respectively. In addition, the antioxidant activity of the compounds was also investigated through scavenging effect on DPPH radicals.

Comparative studies of mononuclear Ni(II) and UO2(II) complexes having bifunctional coordinated groups: Synthesis, thermal analysis, X-ray diffraction, surface morphology studies and biological evaluation

NASA Astrophysics Data System (ADS)

Fahem, Abeer A.

2012-03-01

Two Schiff base ligands derived from condensation of phthalaldehyde and o-phenylenediamine in 1:2 (L1) and 2:1 (L2) having bifunctional coordinated groups (NH2 and CHO groups, respectively) and their metal complexes with Ni(II) and UO2(II) have been synthesized and characterized by elemental analysis, molar conductance, magnetic susceptibilities and spectral data (IR, 1H NMR, mass and solid reflectance) as well as thermal, XRPD and SEM analysis. The formula [Ni(L1)Cl2]·2.5H2O, [UO2(L1)(NO3)2]·2H2O, [Ni(L2)Cl2]·1.5H2O and [UO2(L2)(NO3)2] have been suggested for the complexes. The vibrational spectral data show that the ligands behave as neutral ligands and coordinated to the metal ions in a tetradentate manner. The Ni(II) complexes are six coordinate with octahedral geometry and the ligand field parameters: Dq, B, β and LFSE were calculated while, UO2(II) complexes are eight coordinate with dodecahedral geometry and the force constant, FUsbnd O and bond length, RUsbnd O were calculated. The thermal decomposition of complexes ended with metal chloride/nitrate as a final product and the highest thermal stability is displayed by [UO2(L2)(NO3)2] complex. The X-ray powder diffraction data revealed the formation of nano sized crystalline complexes. The SEM analysis provides the morphology of the synthesized compounds and SEM image of [UO2(L2)(NO3)2] complex exhibits nano rod structure. The growth-inhibiting potential of the ligands and their complexes has been assessed against a variety of bacterial and fungal strains.

Study of structural, surface and hydrogen storage properties of boric acid mediated metal (sodium)-organic frameworks

NASA Astrophysics Data System (ADS)

Ozer, Demet; Köse, Dursun A.; Sahin, Onur; Oztas, Nursen A.

2018-04-01

Three boric acid mediated metal organic frameworks were synthesized by solution method with using succinic acid, fumaric acid and acetylene dicarboxylic acid as a ligand source and sodium as a metal source. The complexes were characterized by FT-IR, powder XRD, elemental analyses and single crystal measurements. The complexes with the formula, C4H18B2Na2O14, C4H16B2Na2O14 and C4H14B2Na2O14 were successfully obtained. BET surface area of complexes were calculated and found as 13.474 m2/g for catena-(tetrakis(μ2-hydroxo)-(μ2-trihydrogen borate)-(μ2-succinato)-di-sodium boric acid solvate), 1.692 m2/g for catena-(tetrakis(μ2-hydroxo)-(μ2-trihydrogen borate)-(μ2-fumarato)-di-sodium boric acid solvate) and 5.600 m2/g for catena-(tetrakis(μ2-hydroxo)-(μ2-trihydrogen borate)-(μ2-acetylenedicarboxylato)-di-sodium boric acid solvate). Hydrogen storage capacities of the complexes were also studied at 77 K 1 bar pressure and found as 0.108%, 0.033%, 0.021% by mass. When different ligands were used, the pore volume, pore width and surface area of the obtained complexes were changed. As a consequence, hydrogen storage capacities also changed.

Synthesis, spectroscopic characterization and biological activities of N4O2 Schiff base ligand and its metal complexes of Co(II), Ni(II), Cu(II) and Zn(II)

NASA Astrophysics Data System (ADS)

Al-Resayes, Saud I.; Shakir, Mohammad; Abbasi, Ambreen; Amin, Kr. Mohammad Yusuf; Lateef, Abdul

The Schiff base ligand, bis(indoline-2-one)triethylenetetramine (L) obtained from condensation of triethylenetetramine and isatin was used to synthesize the complexes of type, [ML]Cl2 [M = Co(II), Ni(II), Cu(II) and Zn(II)]. L was characterized on the basis of the results of elemental analysis, FT-IR, 1H and 13C NMR, mass spectroscopic studies. The stoichiometry, bonding and stereochemistries of complexes were ascertained on the basis of results of elemental analysis, magnetic susceptibility values, molar conductance and various spectroscopic studies. EPR, UV-vis and magnetic moments revealed an octahedral geometry for complexes. L and its Cu(II) and Zn(II) complexes were screened for their antibacterial activity. Analgesic activity of Cu(II) and Zn(II) complexes was also tested in rats by tail flick method. Both complexes were found to possess good antibacterial and moderate analgesic activity.

Coordination-driven self-assembly of a novel carbonato-bridged heteromolecular neutral nickel(II) triangle by atmospheric CO2 fixation.

PubMed

Mukherjee, Pampa; Drew, Michael G B; Estrader, Marta; Ghosh, Ashutosh

2008-09-01

Formation of a quasi-symmetrical mu 3-carbonato-bridged self-assembled heteromolecular triangle of Ni(II), [(mu 3-CO 3){Ni 2(salmeNH) 2(NCS) 2}{Ni(salmeNH 2) 2].Et 2O.H 2O (HsalmeNH = 2-[(3-methylamino-propylimino)-methyl]-phenol) involves atmospheric CO 2 uptake in a neutral medium, by spontaneous self-reorganization of the starting mononuclear Ni(II)-Schiff-base complex, [Ni(salmeNH) 2]. The environment around Ni(II) in two of the subunits is different from the third one. The starting complex, [Ni(salmeNH) 2], and one of the possible intermediate species, [Ni(salmeNH 2) 2(NCS) 2], which has a very similar coordination environment to that in the third Ni(II) center, have been characterized structurally. A plausible mechanism for the formation of such a triangle has also been proposed. The compound shows a very strong antiferromagnetic coupling. Fit as a regular triangular arrangement gave J = -53.1, g = 2.24, and R = 1.5 x 10 (-4).

Synthesis and spectroscopic studies on the new Schiff base derived from the 1:2 condensation of 2,6-diformyl-4-methylphenol with 5-aminouracil (BDF5AU) and its transition metal complexes. Influence on biologically active peptides-regulating aminopeptidases.

PubMed

Hueso-Ureña, Francisco; Illán-Cabeza, Nuria A; Moreno-Carretero, Miguel N; Martínez-Martos, José M; Ramírez-Expósito, María J

2003-04-01

The synthesis, spectroscopic (IR, 1H and 13C NMR, UV-Vis-NIR, EPR), magnetic measurements and biological studies of a number of complexes of Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Au(III) and Hg(II) of the Schiff base derived from the 1:2 condensation of 2,6-diformyl-4-methylphenol and 5-aminouracil, ((5-[[(3-[[(2,4-dioxopyrimidin-5(1H,3H)-yl)imino]methyl]-2-hydroxy-5-methylphenyl)methylene]amino]pyrimidine-2,4(1H,3H)-dione, hereafter denoted as BDF5AU) are reported. In all cases, the complexes appear to be monomeric. The deprotonated ligand in the phenolic oxygen atom shows a tridentate coordination mode through the two azomethine nitrogen atoms and the phenolic oxygen atom. The coordination of the neutral ligand takes place through the phenolic oxygen atom and one azomethine nitrogen atom and the carbonylic oxygen atom in fourth position of one uracil ring. The biological properties of some perchlorate complexes on the activity of some neutral, acid, basic and omega aminopeptidases (AP) are assayed, demonstrating a general inhibitory effect. Neutral and basic AP are mainly inhibited by Cu(II), Ni(II) and Cd(II) complexes, although tyrosyl-AP is activated by Zn(II) complex. Glutamyl-AP but not aspartyl-AP is inhibited by all the complexes assayed excepting Zn(II) complex. Finally, omega AP is inhibited by Ni(II) and Cd(II) complexes. Copyright 2003 Elsevier Science Inc.

Cu(II), Co(II) and Ni(II) complexes of new Schiff base ligand: Synthesis, thermal and spectroscopic characterizations

NASA Astrophysics Data System (ADS)

Refat, Moamen S.; El-Sayed, Mohamed Y.; Adam, Abdel Majid A.

2013-04-01

Cu(II), Co(II), and Ni(II) complexes were synthesized from 2-[(5-o-chlorophenylazo-2-hydroxybenzylidin)amino]-phenol Schiff base (H2L). Metal ions coordinate in a tetradentate or hexadentate features with these O2N donor ligand, which are characterized by elemental analyses, magnetic moments, infrared, Raman laser, electronic, and 1H NMR spectral studies. The elemental analysis suggests the stoichiometry to be 1:1 (metal:ligand). Reactions with Cu(II), Co(II) and Ni(II), resulted [Cu(H2L)(H2O)2(Cl)]Cl, [Co(H2L)(H2O)3]Cl2ṡ3H2O and [Ni(H2L)(H2O)2]Cl2ṡ6H2O. The thermal decomposition behavior of H2L complexes has been investigated by thermogravimetric analysis (TG/DTG) at a heating rate of 10 °C min-1 under nitrogen atmosphere. The brightness side in this study is to take advantage for the preparation and characterizations of single phases of CuO, CoO and NiO nanoparticles using H2L complexes as precursors via a solid-state decomposition procedure. The crystalline structures of products using X-ray diffractometer (XRD), morphology of particles by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) were investigated.

Electrochemical hydrogenation of a homogeneous nickel complex to form a surface adsorbed hydrogen-evolving species

DOE PAGES

Martin, Daniel J.; McCarthy, Brian D.; Donley, Carrie L.; ...

2014-12-04

Here, a Ni(ii) complex with nitrogen and sulfur donor ligands degrades electrochemically in the presence of acid in acetonitrile to form an electrode adsorbed film that catalytically evolves hydrogen.

Coordination Polymer: Synthesis, Spectral Characterization and Thermal Behaviour of Starch-Urea Based Biodegradable Polymer and Its Polymer Metal Complexes

PubMed Central

Malik, Ashraf; Parveen, Shadma; Ahamad, Tansir; Alshehri, Saad M.; Singh, Prabal Kumar; Nishat, Nahid

2010-01-01

A starch-urea-based biodegradable coordination polymer modified by transition metal Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) was prepared by polycondensation of starch and urea. All the synthesized polymeric compounds were characterized by Fourier transform-infrared spectroscopy (FT-IR), 1H-NMR spectroscopy, 13C-NMR spectroscopy, UV-visible spectra, magnetic moment measurements, differential scanning calorimeter (DSC), and thermogravimetric analysis (TGA). The results of electronic spectra and magnetic moment measurements indicate that Mn(II), Co(II), and Ni(II) complexes show octahedral geometry, while Cu(II) and Zn(II) complexes show square planar and tetrahedral geometry, respectively. The thermogravimetric analysis revealed that all the polymeric metal complexes are more thermally stable than the parental ligand. In addition, biodegradable studies of all the polymeric compounds were also carried out through ASTM standards of biodegradable polymers by CO2 evolution method. PMID:20414461

Direct Observation of Very Large Zero-Field Splitting in a Tetrahedral Ni(II)Se4 Coordination Complex.

PubMed

Jiang, Shang-Da; Maganas, Dimitrios; Levesanos, Nikolaos; Ferentinos, Eleftherios; Haas, Sabrina; Thirunavukkuarasu, Komalavalli; Krzystek, J; Dressel, Martin; Bogani, Lapo; Neese, Frank; Kyritsis, Panayotis

2015-10-14

The high-spin (S = 1) tetrahedral Ni(II) complex [Ni{(i)Pr2P(Se)NP(Se)(i)Pr2}2] was investigated by magnetometry, spectroscopic, and quantum chemical methods. Angle-resolved magnetometry studies revealed the orientation of the magnetization principal axes. The very large zero-field splitting (zfs), D = 45.40(2) cm(-1), E = 1.91(2) cm(-1), of the complex was accurately determined by far-infrared magnetic spectroscopy, directly observing transitions between the spin sublevels of the triplet ground state. These are the largest zfs values ever determined--directly--for a high-spin Ni(II) complex. Ab initio calculations further probed the electronic structure of the system, elucidating the factors controlling the sign and magnitude of D. The latter is dominated by spin-orbit coupling contributions of the Ni ions, whereas the corresponding effects of the Se atoms are remarkably smaller.

Complexes of ditopic carbo- and thio-carbohydrazone ligands--mononuclear, 1D chain, dinuclear and tetranuclear examples.

PubMed

Tandon, Santokh S; Dul, Marie-Claire; Lee, John L; Dawe, Louise N; Anwar, Muhammad U; Thompson, Laurence K

2011-04-14

Ligands based on carbo- and thio-carbohydrazone cores, modified with pyridine, carboxylate and oxime ends, have been examined. They display a tautomeric versatility based on the flexible nature of the hydrazone linkages, leading to varied coordination motifs. Examples of mononuclear (Co(II), Ni(II)), dinuclear (Co(III)), 1D chain (Cu(II)) and square [2 × 2] grid (Ni(II)) complexes are obtained. Ferromagnetic (Cu(II)) and antiferromagnetic (Ni(II)) exchange is observed, with spin coupling in the Ni(II)(4) square grids propagated through the μ-O and μ-S bridges. Weak antiferromagnetic exchange (J = -6.0 cm(-1)) is observed for the μ-O bridged grid, despite the large Ni-O-Ni angles (137-141°), while for the μ-S bridged grids much stronger exchange is observed (J = -148 cm(-1), -198 cm(-1)). This is much larger than expected based on the Ni-S-Ni bridge angles (151-169°), and is associated with the soft (less polarizing than oxygen) nature of the sulfur bridge, which would allow for much more efficient transmission of spin exchange than observed in the μ-O bridged case. Structures and variable temperature magnetic data are included, and spin exchange is analyzed using normal Heisenberg exchange models. No examples involving oxime (NO) bridging are reported, which reflects the positioning of the N,O and N,S donor combinations in each ligand, and the preferred coordination through these donor atoms. © The Royal Society of Chemistry 2011

Thermodynamic Modeling of Poorly Complexing Metals in Concentrated Electrolyte Solutions: An X-Ray Absorption and UV-Vis Spectroscopic Study of Ni(II) in the NiCl2-MgCl2-H2O System

PubMed Central

Zhang, Ning; Brugger, Joël; Etschmann, Barbara; Ngothai, Yung; Zeng, Dewen

2015-01-01

Knowledge of the structure and speciation of aqueous Ni(II)-chloride complexes is important for understanding Ni behavior in hydrometallurgical extraction. The effect of concentration on the first-shell structure of Ni(II) in aqueous NiCl2 and NiCl2-MgCl2 solutions was investigated by Ni K edge X-ray absorption (XAS) and UV-Vis spectroscopy at ambient conditions. Both techniques show that no large structural change (e.g., transition from octahedral to tetrahedral-like configuration) occurs. Both methods confirm that the Ni(II) aqua ion (with six coordinated water molecules at R Ni-O = 2.07(2) Å) is the dominant species over the whole NiCl2 concentration range. However, XANES, EXAFS and UV-Vis data show subtle changes at high salinity (> 2 mol∙kg-1 NiCl2), which are consistent with the formation of small amounts of the NiCl+ complex (up to 0.44(23) Cl at a Ni-Cl distance of 2.35(2) Å in 5.05 mol∙kg-1 NiCl2) in the pure NiCl2 solutions. At high Cl:Ni ratio in the NiCl2-MgCl2-H2O solutions, small amounts of [NiCl2]0 are also present. We developed a speciation-based mixed-solvent electrolyte (MSE) model to describe activity-composition relationships in NiCl2-MgCl2-H2O solutions, and at the same time predict Ni(II) speciation that is consistent with our XAS and UV-Vis data and with existing literature data up to the solubility limit, resolving a long-standing uncertainty about the role of chloride complexing in this system. PMID:25885410

Synthesis, characterization and molecular modeling of some transition metal complexes of Schiff base derived from 5-aminouracil and 2-benzoyl pyridine

NASA Astrophysics Data System (ADS)

Abdel-Monem, Yasser K.; Abouel-Enein, Saeyda A.; El-Seady, Safa M.

2018-01-01

Multidentate Schiff base (H2L) ligand results from condensation of 5-aminouracil and 2-benzoyl pyridine and its metal chloride (Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Pd(II), Fe(III), Cr(III), Ru(III), Zr(IV) and Hf(IV)) complexes were prepared. The structural features of the ligand and its metal complexes were confirmed by elemental analyses, spectroscopic methods (IR, UV-Vis, 1H NMR, mass), magnetic moment measurements and thermal studies. The data refer to the ligand coordinates with metal ions in a neutral form and shows different modes of chelation toward the metal atom. All complexes have octahedral skeleton structure, tetrahedrally Mn(II), Ni(II), trigonalbipyramidal Co(II) and square planner Pd(II). Thermal decomposition of complexes as well as the interaction of different types of solvent of crystallization are assigned by thermogravimetric analysis. Molecular modeling of prepared complexes were investigated to study the expected anticancer activities of the prepared complexes. All metal complexes have no interaction except the complexes of Pd(II), Fe(III) and Mn(II).

Antimicrobial, spectral, magnetic and thermal studies of Cu(II), Ni(II), Co(II), UO(2)(VI) and Fe(III) complexes of the Schiff base derived from oxalylhydrazide.

PubMed

Melha, Khlood Abou

2008-04-01

The Schiff base ligand, oxalyl [( 2 - hydroxybenzylidene) hydrazone] [corrected].H(2)L, and its Cu(II), Ni(II), Co(II), UO(2)(VI) and Fe(III) complexes were prepared and tested as antibacterial agents. The Schiff base acts as a dibasic tetra- or hexadentate ligand with metal cations in molar ratio 1:1 or 2:1 (M:L) to yield either mono- or binuclear complexes, respectively. The ligand and its metal complexes were characterized by elemental analyses, IR, (1)H NMR, Mass, and UV-Visible spectra and the magnetic moments and electrical conductance of the complexes were also determined. For binuclear complexes, the magnetic moments are quite low compared to the calculated value for two metal ions complexes and this shows antiferromagnetic interactions between the two adjacent metal ions. The ligand and its metal complexes were tested against a Gram + ve bacteria (Staphylococcus aureus), a Gram -ve bacteria (Escherichia coli), and a fungi (Candida albicans). The tested compounds exhibited high antibacterial activities.

Structural characterization and antimicrobial activities of transition metal complexes of a hydrazone ligand

NASA Astrophysics Data System (ADS)

Bakale, Raghavendra P.; Naik, Ganesh N.; Machakanur, Shrinath S.; Mangannavar, Chandrashekhar V.; Muchchandi, Iranna S.; Gudasi, Kalagouda B.

2018-02-01

A hydrazone ligand has been synthesized by the condensation of 2-nitrobenzaldehyde and hydralazine, and its Co(II), Ni(II), Cu(II) and Zn(II) complexes have been reported. Structural characterization of the ligand and its metal complexes has been performed by various spectroscopic [IR, NMR, UV-Vis, Mass], thermal and other physicochemical methods. The structure of the ligand and its Ni(II) complex has been characterized by single crystal X-ray diffraction studies. All the synthesized compounds have been screened for in vitro antimicrobial activity. The antibacterial activity is tested against Gram-positive strains Enterococcus faecalis, Streptococcus mutans and Staphylococcus aureus and Gram-negative strains Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumoniae using ciprofloxacin as the reference standard. Antifungal activity is tested against Candida albicans, Aspergillus fumigatus and Aspergillus niger using ketoconazole as the reference standard. The minimum inhibitory concentration (MIC) was determined for test compounds as well as for reference standard. Ligand, Cu(II) and Zn(II) complexes have shown excellent activity against Candida albicans.

Effects of ball milling on the physicochemical and sorptive properties of biochar: Experimental observations and governing mechanisms.

PubMed

Lyu, Honghong; Gao, Bin; He, Feng; Zimmerman, Andrew R; Ding, Cheng; Huang, Hua; Tang, Jingchun

2018-02-01

With the goal of combining the advantages of ball-milling and biochar technologies, a variety of ball-milled biochars (BM-biochars) were synthesized, characterized, and tested for nickel (Ni(II)) removal from aqueous solution. Ball milling increased only the external surface area of low temperature biochars, but still dramatically enhanced their ability to sorb aqueous Ni(II). For higher temperature biochars with relatively low surface area, ball milling increased both external and internal surface area. Measurements of pH, zeta potential, stability, and Boehm titration demonstrated that ball milling also added oxygen-containing functional groups (e.g., carboxyl, lactonic, and hydroxyl) to biochar's surface. With these changed, all the BM-biochars showed much better Ni(II) removal efficiency than unmilled biochars. Ball-milled 600 °C bagasse biochar (BMBG600) showed the greatest Ni(II) adsorption capacity (230-650 compared to 26-110 mmol/kg for unmilled biochar) and the adsorption was dosage and pH dependent. Compared with the unmilled biochar, BMBG600 also displayed faster adsorption kinetics, likely due to an increase in rates of intra-particle diffusion in the latter. Experimental and modeling results suggest that the increase in BM-biochar's external and internal surface areas exposed its graphitic structure, thus enhancing Ni(II) adsorption via strong cation-π interaction. In addition, the increase in acidic surface functional groups enhanced Ni(II) adsorption by BM-biochar via electrostatic interaction and surface complexation. Ball milling thus has great potential to increase the efficiency of environmentally friendly biochar for various environmental applications. Copyright © 2017 Elsevier Ltd. All rights reserved.

Solution structure of Mycobacterium tuberculosis NmtR in the apo-state: Insights into Ni(II)-mediated allostery

PubMed Central

Lee, Chul Won; Chakravorty, Dhruva K.; Chang, Feng-Ming James; Reyes-Caballero, Hermes; Ye, Yuzhen; Merz, Kenneth M.; Giedroc, David P.

2012-01-01

Mycobacterium tuberculosis is an obligate human respiratory pathogen that encodes approximately ten arsenic repressor (ArsR) family regulatory proteins that allow the organism to respond to a wide range of changes in its immediate microenvironment. How individual ArsR repressors have evolved to respond to selective stimuli is of intrinsic interest. The Ni(II)/Co(II)-specific repressor NmtR and related actinomycete nickel sensors harbor a conserved N-terminal αNH2-Gly2-His3-Gly4 sequence. Here, we present the solution structure of homodimeric apo-NmtR and show that the core of the molecule adopts a typical winged-helix ArsR repressor (α1-α2-α3-αR-β1-β2-α5) “open conformation” that is similar to the related zinc sensor Staphylococcus aureus CzrA, but harboring long, flexible N-terminal (residues 2-16) and C-terminal (residues 109-120) extensions. Ni(II) binding to the regulatory sites induces strong paramagnetic broadening of the α5 helical region and the extreme N-terminal tail to residue 10. Ratiometric pulse chase amidination mass spectrometry reveals that the rate of amidination of the Gly2 α-amino group is strongly attenuated in the Ni(II) complex relative to the apo-state and non-cognate Zn(II) complex. Ni(II) binding also induces dynamic disorder in the μs-ms timescale of key DNA interacting regions that likely contributes to the negative regulation of DNA binding by Ni(II). Molecular dynamics simulations and quantum chemical calculations reveal that NmtR readily accommodates a distal Ni(II) hexacoordination model involving the α-amine and His3 of the N-terminal region and α5 residues Asp91′, His93′, His104 and His107, which collectively define a new metal sensing site configuration in ArsR family regulators. PMID:22394357

Synthesis, characterization, antimicrobial activity and DFT studies of 2-(pyrimidin-2-ylamino)naphthalene-1,4-dione and its Mn(II), Co(II), Ni(II) and Zn(II) complexes

NASA Astrophysics Data System (ADS)

Chioma, Festus; Ekennia, Anthony C.; Ibeji, Collins U.; Okafor, Sunday N.; Onwudiwe, Damian C.; Osowole, Aderoju A.; Ujam, Oguejiofo T.

2018-07-01

A pyrimidine-based ligand, 2-(pyrimidin-2-ylamino)naphthalene-1,4-dione (L), has been synthesized by the reaction of 2-aminopyrimidine with 2-hydroxy-1,4-napthoquinone. Reaction of the ligand with Ni(II), Co(II), Mn(II) and Zn(II) acetate gave the corresponding metal complexes which were characterized by spectroscopic techniques, (infrared, electronic), elemental analysis, room-temperature magnetometry, conductance measurements and thermogravimetry-differential scanning calorimetry (TG-DSC) analyses. The room-temperature magnetic data and electronic spectral measurements of the complexes gave evidence of 4-coordinate square planar/tetrahedral geometry. The thermal analyses values obtained indicated the monohydrate complexes. The antimicrobial screening of the compounds showed mild to very good results. The Mn(II) complex showed the best result within in the range of 11.5-29 mm. The electronic, structural and spectroscopic properties of the complexes were further discussed using density functional theory. Molecular docking studies showed significant binding affinity with the drug targets and the metal complexes have potentials to be used as drugs.

Synthesis, crystal structures and properties of new homoleptic Ni(II)/Pd(II) β-oxodithioester chelates

NASA Astrophysics Data System (ADS)

Yadav, Chote L.; Manar, Krishna K.; Yadav, Manoj K.; Tiwari, Neeraj; Singh, Rakesh K.; Drew, Michael G. B.; Singh, Nanhai

2018-05-01

Six new cis-chelate complexes, [M(L)2] (L = methyl-3-hydroxy-3-(furyl)-2-propenedithioate L1, M = Ni(II) 1, Pd(II) 4; methyl-3-hydroxy-3-(thiophenyl)-2-propenedithioate L2, M = Ni(II) 2, Pd(II) 5 and methyl-3-hydroxy-3-(phenyl)-2-propenedithioate L3, M = Ni(II) 3, Pd(II) 6 have been prepared and characterized by elemental analyses, spectroscopy (IR, UV-Vis., 1H and 13C{1H} NMR). The structures of 2-6 have been revealed by X-ray crystallography. In all the crystal structures, the metal has four-coordinate slightly distorted square planar geometry with a cis-configuration of the ligands. Anti-leishmanial properties of the complexes have been studied; 2, 3 and 6 showed potential anti-promastigote and anti-amastigote activities with IC50 values of 1.70 ± 0.50, 1.62 ± 0.19, 9.20 ± 2.16 μg/mL and IC50 2.50 ± 0.10, 2.05 ± 0.40, 12.84 ± 3.46 μg/mL respectively. Cytotoxicity assays on these complexes showed toxicity on the promastigotes but less toxicity against RAW 264.7 cell lines at different concentrations. Palladium complexes 4, 5 and 6 show luminescent characteristics in CH2Cl2 solution at room temperature. Complexes 1-6 are weakly conducting (σrt = 10-4-10-6 S cm-1, Ea = 0.19-1.13 eV) but show semiconducting behavior in the solid phase.

Synthesis, structural and fungicidal studies of hydrazone based coordination compounds

NASA Astrophysics Data System (ADS)

Sharma, Amit Kumar; Chandra, Sulekh

2013-02-01

The coordination compounds of the Co(II), Ni(II) and Cu(II) metal ions derived from imine based ligand, benzil bis(carbohydarzone) were structurally and pharmaceutically studied. The compounds have the general stoichiometry [M(L)]X2 and [Co(L)X2], where M = Ni(II) and Cu(II), and X=NO3- and Cl- ions. The analytical techniques like elemental analyses, molar conductance measurements, magnetic susceptibility measurements, IR, UV/Visible, NMR, ESI mass and EPR were used to study the compounds. The key IR bands, i.e., amide I, amide II and amide III stretching vibrations accounts for the tetradentate metal binding nature of the ligand. The electronic and EPR spectral results suggest the square planar Ni(II) and Cu(II) complexes (giso = 2.11-2.22) and tetragonal geometry Co(II) complexes (giso = 2.10-2.17). To explore the compounds in the biological field, they were examined against the opportunistic pathogens, i.e., Alternaria brassicae, Aspergillus niger and Fusarium oxysporum. The partial covalent character of metal-ligand bond is supported by the orbital reduction factor k (0.62-0.92) and nephalauxetic parameter β (0.55-0.57).

Structure and spectroscopic investigations of a bi-dentate N‧-[(4-ethylphenyl)methylidene]-4-hydroxybenzohydrazide and its Co(II), Ni(II), Cu(II) and Cd(II) complexes: Insights relevant to biological properties

NASA Astrophysics Data System (ADS)

Gopal Reddy, N. B.; Krishna, P. Murali; Shantha Kumar, S. S.; Patil, Yogesh P.; Nethaji, Munirathinam

2017-06-01

The present paper describes the synthesis of novel ligand, N‧-[(4-ethylphenyl)methylidene]-4-hydroxy benzohydrazide (HL) and its Co(II), Ni(II), Cu(II) and Cd(II) complexes. The ligand (HL) crystallizes in orthorhombic lattice in P212121 space group with a = 7.9941 (7) Å, b = 11.6154 (10) Å, c = 15.2278 (13) Å, α = β = γ = 90°. Spectroscopic data gives the strong evidence that ligand is coordinated through azomethine nitrogen and enolic oxygen with metal ion. The DNA binding studies revealed that the complexes bind to CT-DNA via intercalation/electrostatic interaction. All the targeted compounds showed more pronounced DNA cleavage activity in the presence of H2O2 and also inhibit the growth of in vitro antibacterial activity against Gram-positive and Gram-negative bacteria.

Thermodynamic Analysis of Nickel(II) and Zinc(II) Adsorption to Biochar.

PubMed

Alam, Md Samrat; Gorman-Lewis, Drew; Chen, Ning; Flynn, Shannon L; Ok, Yong Sik; Konhauser, Kurt O; Alessi, Daniel S

2018-05-21

While numerous studies have investigated metal uptake from solution by biochar, few of these have developed a mechanistic understanding of the adsorption reactions that occur at the biochar surface. In this study, we explore a combined modeling and spectroscopic approach for the first time to describe the molecular level adsorption of Ni(II) and Zn(II) to five types of biochar. Following thorough characterization, potentiometric titrations were carried out to measure the proton (H + ) reactivity of each biochar, and the data was used to develop protonation models. Surface complexation modeling (SCM) supported by synchrotron-based extended X-ray absorption fine structure (EXAFS) was then used to gain insights into the molecular scale metal-biochar surface reactions. The SCM approach was combined with isothermal titration calorimetry (ITC) data to determine the thermodynamic driving forces of metal adsorption. Our results show that the reactivity of biochar toward Ni(II) and Zn(II) directly relates to the site densities of biochar. EXAFS along with FT-IR analyses, suggest that Ni(II) and Zn(II) adsorption occurred primarily through proton-active carboxyl (-COOH) and hydroxyl (-OH) functional groups on the biochar surface. SCM-ITC analyses revealed that the enthalpies of protonation are exothermic and Ni(II) and Zn(II) complexes with biochar surface are slightly exothermic to slightly endothermic. The results obtained from these combined approaches contribute to the better understanding of molecular scale metal adsorption onto the biochar surface, and will facilitate the further development of thermodynamics-based, predictive approaches to biochar removal of metals from contaminated water.

Synthesis, characterization and biological activity of complexes of 2-hydroxy-3,5-dimethylacetophenoneoxime (HDMAOX) with copper(II), cobalt(II), nickel(II) and palladium(II)

NASA Astrophysics Data System (ADS)

Singh, Bibhesh K.; Jetley, Umesh K.; Sharma, Rakesh K.; Garg, Bhagwan S.

2007-09-01

A new series of complexes of 2-hydroxy-3,5-dimethyl acetophenone oxime (HDMAOX) with Cu(II), Co(II), Ni(II) and Pd(II) have been prepared and characterized by different physical techniques. Infrared spectra of the complexes indicate deprotonation and coordination of the phenolic OH. It also confirms that nitrogen atom of the oximino group contributes to the complexation. Electronic spectra and magnetic susceptibility measurements reveal square planar geometry for Cu(II), Ni(II) and Pd(II) complexes and tetrahedral geometry for Co(II) complex. The elemental analyses and mass spectral data have justified the ML 2 composition of complexes. Kinetic and thermodynamic parameters were computed from the thermal decomposition data using Coats and Redfern method. The geometry of the metal complexes has been optimized with the help of molecular modeling. The free ligand (HDMAOX) and its metal complexes have been tested in vitro against Alternarie alternate, Aspergillus flavus, Aspergillus nidulans and Aspergillus niger fungi and Streptococcus, Staph, Staphylococcus and Escherchia coli bacteria in order to assess their antimicrobial potential. The results indicate that the ligand and its metal complexes possess antimicrobial properties.

Synthesis, characterization and biological activity of complexes of 2-hydroxy-3,5-dimethylacetophenoneoxime (HDMAOX) with copper(II), cobalt(II), nickel(II) and palladium(II).

PubMed

Singh, Bibhesh K; Jetley, Umesh K; Sharma, Rakesh K; Garg, Bhagwan S

2007-09-01

A new series of complexes of 2-hydroxy-3,5-dimethyl acetophenone oxime (HDMAOX) with Cu(II), Co(II), Ni(II) and Pd(II) have been prepared and characterized by different physical techniques. Infrared spectra of the complexes indicate deprotonation and coordination of the phenolic OH. It also confirms that nitrogen atom of the oximino group contributes to the complexation. Electronic spectra and magnetic susceptibility measurements reveal square planar geometry for Cu(II), Ni(II) and Pd(II) complexes and tetrahedral geometry for Co(II) complex. The elemental analyses and mass spectral data have justified the ML(2) composition of complexes. Kinetic and thermodynamic parameters were computed from the thermal decomposition data using Coats and Redfern method. The geometry of the metal complexes has been optimized with the help of molecular modeling. The free ligand (HDMAOX) and its metal complexes have been tested in vitro against Alternarie alternate, Aspergillus flavus, Aspergillus nidulans and Aspergillus niger fungi and Streptococcus, Staph, Staphylococcus and Escherchia coli bacteria in order to assess their antimicrobial potential. The results indicate that the ligand and its metal complexes possess antimicrobial properties.

Synthesis, characterization, and biological activity of some novel Schiff bases and their Co(II) and Ni(II) complexes: A new route for Co3O4 and NiO nanoparticles for photocatalytic degradation of methylene blue dye

NASA Astrophysics Data System (ADS)

Nassar, Mostafa Y.; Aly, Hisham M.; Abdelrahman, Ehab A.; Moustafa, Moustafa E.

2017-09-01

Six novel Co(II) and Ni(II)-triazole Schiff base complexes have been successfully synthesized by refluxing the prepared triazole Schiff bases with CoCl2·6H2O or NiCl2·6H2O. The Schiff base ligands were prepared through condensation of 3-R-4-amino-5-hydrazino-1,2,4-triazole with dibenzoylmethane [Rdbnd H, CH3, and CH2CH3; namely, L1, L2, and L3, respectively]. The prepared Co(II) and Ni(II) complexes have been identified using elemental analysis, FT-IR, UV-Vis, magnetic moment, conductivity, and thermal analysis. On the basis of the conductance results, it was concluded that all the prepared complexes are nonelectrolytes. Interestingly, the prepared Co(II) and Ni(II) complexes were employed as precursors for producing of Co3O4 and NiO nanoparticles, respectively. The produced nanostructures have been identified by XRD, HR-TEM, FT-IR and UV-Vis spectra. The produced nanoparticles revealed good photocatalytic activity for the degradation of methylene blue dye under UV illumination in presence of hydrogen peroxide. The percent of degradation was estimated to be 55.71% in 420.0 min and 90.43% in 360.0 min for Co3O4 and NiO, respectively. Moreover, the synthesized complexes, nano-sized Co3O4, and NiO products have been examined, employing modified Bauer- Kirby method, for antifungal (Candida albicans and Aspergillus flavus) and antibacterial (Staphylococcus aureus and Escherichia coli) activities.

Supramolecular complexes of Co(II), Ni(II) and Zn(II) p-hydroxybenzoates with caffeine: Synthesis, spectral characterization and crystal structure

NASA Astrophysics Data System (ADS)

Taşdemir, Erdal; Özbek, Füreya Elif; Sertçelik, Mustafa; Hökelek, Tuncer; Çelik, Raziye Çatak; Necefoğlu, Hacali

2016-09-01

Three novel complexes Co(II), Ni(II) and Zn(II) containing p-hydroxybenzoates and caffeine ligands were synthesized and characterized by elemental analysis, FT-IR and UV-vis Spectroscopy, molar conductivity and single crystal X-ray diffraction methods. The thermal properties of the synthesized complexes were investigated by TGA/DTA. The general formula of the complexes is [M(HOC6H4COO)2(H2O)4]·2(C8H10N4O2)·8H2O (where: M: Co, Ni and Zn). The IR studies showed that carboxylate groups of p-hydroxybenzoate ligands have monodentate coordination mode. The M2+ ions are octahedrally coordinated by two p-hydroxybenzoate ligands, four water molecules leading to an overall MO6 coordination environment. The medium-strength hydrogen bondings involving the uncoordinated caffeine ligands and water molecules, coordinated and uncoordinated water molecules and p-hydroxybenzoate ligands lead to three-dimensional supramolecular networks in the crystal structures.

Free metal ion depletion by "Good's" buffers. III. N-(2-acetamido)iminodiacetic acid, 2:1 complexes with zinc(II), cobalt(II), nickel(II), and copper(II); amide deprotonation by Zn(II), Co(II), and Cu(II).

PubMed

Lance, E A; Rhodes, C W; Nakon, R

1983-09-01

Potentiometric, visible, infrared, electron spin, and nuclear magnetic resonance studies of the complexation of N-(2-acetamido)iminodiacetic acid (H2ADA) by Ca(II), Mg(II), Mn(II), Zn(II), Co(II), Ni(II), and Cu(II) are reported. Ca(II) and Mg(II) were found not to form 2:1 ADA2- to M(II) complexes, while Mn(II), Cu(II), Ni(II), Zn(II), and Co(II) did form 2:1 metal chelates at or below physiological pH values. Co(II) and Zn(II), but not Cu(II), were found to induce stepwise deprotonation of the amide groups to form [M(H-1ADA)4-(2)]. Formation (affinity) constants for the various metal complexes are reported, and the probable structures of the various metal chelates in solution are discussed on the basis of various spectral data.

Synthesis, characterization, antibacterial activities and carbonic anhydrase enzyme inhibitor effects of new arylsulfonylhydrazone and their Ni(II), Co(II) complexes

NASA Astrophysics Data System (ADS)

Özdemir, Ümmühan Özmen; Arslan, Fatma; Hamurcu, Fatma

2010-01-01

Ethane sulfonic acide hydrazide ( esh: CH 3CH 2SO 2NHNH 2) derivatives as 5-methylsalicyl-aldehydeethanesulfonylhydrazone ( 5msalesh), 5-methyl-2-hydroxyacetophenoneethane sulfonylhydrazone ( 5mafesh) and their Ni(II), Co(II) complexes have been synthesized for the first time. The structure of these compounds has been investigated by elemental analysis, FT-IR, 1H NMR, 13C NMR, LC/MS, UV-vis spectrophotometric method, magnetic susceptibility, thermal studies and conductivity measurements. The antibacterial activities of synthesized compounds were studied against Gram positive bacteria; Staphylococcus aureus, Bacillus subtilis, Bacillus magaterium and Gram negative bacteria; Salmonella enteritidis, Escherichia coli by using the microdilution broth method. The biological activity screening showed that ligands have more activity than complexes against the tested bacteria. The inhibition activities of these compounds on carbonic anhydrase II (CA II) have been investigated by comparing IC 50 and Ki values and it has been found that 5msalesh and its complexes have more enzyme inhibition efficiency than other compounds.

DNA Binding, Cleavage and Antibacterial Activity of Mononuclear Cu(II), Ni(II) and Co(II) Complexes Derived from Novel Benzothiazole Schiff Bases.

PubMed

Vamsikrishna, Narendrula; Kumar, Marri Pradeep; Tejaswi, Somapangu; Rambabu, Aveli; Shivaraj

2016-07-01

A series of novel bivalent metal complexes M(L1)2 and M(L2)2 where M = Cu(II), Ni(II), Co(II) and L1 = 2-((benzo [d] thiazol-6-ylimino)methyl)-4-bromophenol [BTEMBP], L2 = 1-((benzo [d] thiazol-6-ylimino)methyl) naphthalen-2-ol [BTEMNAPP] were synthesized. All the compounds have been characterized by elemental analysis, SEM, Mass, (1)H NMR, (13)C NMR, UV-Vis, IR, ESR, spectral data and magnetic susceptibility measurements. Based on the analytical and spectral data four-coordinated square planar geometry is assigned to all the complexes. DNA binding properties of these complexes have been investigated by electronic absorption spectroscopy, fluorescence and viscosity measurements. It is observed that these binary complexes strongly bind to calf thymus DNA by an intercalation mode. DNA cleavage efficacy of these complexes was tested in presence of H2O2 and UV light by gel electrophoresis and found that all the complexes showed better nuclease activity. Finally the compounds were screened for antibacterial activity against few pathogens and found that the complexes have potent biocidal activity than their free ligands.

Synthesis, characterization, DFT calculations and molecular docking studies of metal (II) complexes

NASA Astrophysics Data System (ADS)

Ekennia, Anthony C.; Osowole, Aderoju A.; Olasunkanmi, Lukman O.; Onwudiwe, Damian C.; Olubiyi, Olujide O.; Ebenso, Eno E.

2017-12-01

Two novel ligands, 2-methyl-6-[(5-methyl benzothiazol-2-ylimino)-methyl]-2-methoxycyclohexa-1,5-dienol (HL1) and 2-methyl-6-[(5-floro-benzothiazol-2-ylimino)-methyl]-2-methoxycyclohexa-1,5-dienol (HL2) were synthesized from the condensation reaction of 2-hydroxy-3-methoxybenzaldehyde with 2-amino-6-methylbenzothiazole and 2-amino-6-florobenzothiazole respectively. Mononuclear Cu(II), Ni(II) and Co(II) complexes of the ligands were synthesized and characterized using elemental analysis, magnetic susceptibility, thermogravimetric, conductance, infrared and UV-visible spectroscopic measurements. The 1H NMR, 13C NMR, Dept-90 NMR spectroscopy of the ligands was also recorded to establish the formation of the Schiff bases. The analytical data of the complexes showed that the metal to ligand ratio was 1:1 for Cu(II), Ni(II) and Co(II) complexes of HL1 and Cu(II) complexes of HL2, while Ni(II) and Co(II) complexes of HL2 was 1:2. The infrared spectral data showed that the chelation behaviour of the ligands towards transition metal ions was through phenolic oxygen and azomethine nitrogen atoms. Molar conductivity revealed the non-electrolytic nature of all chelates in DMSO solution. The geometry of the complexes was deduced from thermal, magnetic susceptibility and UV-visible spectroscopic results and was further confirmed with DFT calculations. The compounds were subjected to in-vitro antibacterial screening using agar well diffusion method on some clinically isolated Gram positive and Gram negative bacteria strains. The compounds showed varied antibacterial activities. Molecular docking studies were carried out to study the molecular interaction between the compounds and different enzymes of the bacterial strains. The antioxidant potentials of the compounds were studied using ferrous ion chelating assay and 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. However, the complexes had better antioxidant potentials compared to the ligands.

Electrocatalytic Hydrogen Production by a Nickel(II) Complex with a Phosphinopyridyl Ligand.

PubMed

Tatematsu, Ryo; Inomata, Tomohiko; Ozawa, Tomohiro; Masuda, Hideki

2016-04-18

A novel nickel(II) complex [Ni(L)2 Cl]Cl with a bidentate phosphinopyridyl ligand 6-((diphenylphosphino)methyl)pyridin-2-amine (L) was synthesized as a metal-complex catalyst for hydrogen production from protons. The ligand can stabilize a low Ni oxidation state and has an amine base as a proton transfer site. The X-ray structure analysis revealed a distorted square-pyramidal Ni(II)  complex with two bidentate L ligands in a trans arrangement in the equatorial plane and a chloride anion at the apex. Electrochemical measurements with the Ni(II) complex in MeCN indicate a higher rate of hydrogen production under weak acid conditions using acetic acid as the proton source. The catalytic current increases with the stepwise addition of protons, and the turnover frequency is 8400 s(-1) in 0.1 m [NBu4 ][ClO4 ]/MeCN in the presence of acetic acid (290 equiv) at an overpotential of circa 590 mV. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mononuclear nickel (II) and copper (II) coordination complexes supported by bispicen ligand derivatives: Experimental and computational studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singh, Nirupama; Niklas, Jens; Poluektov, Oleg

2017-01-01

The synthesis, characterization and density functional theory calculations of mononuclear Ni and Cu complexes supported by the N,N’-Dimethyl-N,N’-bis-(pyridine-2-ylmethyl)-1,2-diaminoethane ligand and its derivatives are reported. The complexes were characterized by X-ray crystallography as well as by UV-visible absorption spectroscopy and EPR spectroscopy. The solid state structure of these coordination complexes revealed that the geometry of the complex depended on the identity of the metal center. Solution phase characterization data are in accord with the solid phase structure, indicating minimal structural changes in solution. Optical spectroscopy revealed that all of the complexes exhibit color owing to d-d transition bands in the visiblemore » region. Magnetic parameters obtained from EPR spectroscopy with other structural data suggest that the Ni(II) complexes are in pseudo-octahedral geometry and Cu(II) complexes are in a distorted square pyramidal geometry. In order to understand in detail how ligand sterics and electronics affect complex topology detailed computational studies were performed. The series of complexes reported in this article will add significant value in the field of coordination chemistry as Ni(II) and Cu(II) complexes supported by tetradentate pyridyl based ligands are rather scarce.« less

Nickel(II) biosorption from aqueous solutions by shrimp head biomass.

PubMed

Hernández-Estévez, Alejandro; Cristiani-Urbina, Eliseo

2014-11-01

The present study evaluates the capacity of shrimp (Farfantepenaeus aztecus) head to remove toxic Ni(II) ions from aqueous solutions. Relevant parameters that could affect the biosorption process, such as shrimp head pretreatment, solution pH level, contact time and initial Ni(II) concentration, were studied in batch systems. An increase in Ni(II) biosorption capacity and a reduction in the time required to reach Ni(II) biosorption equilibrium was manifested by shrimp head biomass pretreated by boiling in 0.5 N NaOH for 15 min; this biomass was thereafter denominated APSH. The optimum biosorption level of Ni(II) ions onto APSH was observed at pH 7.0. Biosorption increased significantly with rising initial Ni(II) concentration. In terms of biosorption dynamics, the pseudo-second-order kinetic model described Ni(II) biosorption onto APSH best. The equilibrium data adequately fitted the Langmuir isotherm model within the studied Ni(II) ion concentration range. According to this isotherm model, the maximum Ni(II) biosorption capacity of APSH was 104.22 mg/g. Results indicate that APSH could be used as a low-cost, environmentally friendly, and promising biosorbent with high biosorption capacity to remove Ni(II) from aqueous solutions.

Protein Tunnels: The Case of Urease Accessory Proteins.

PubMed

Musiani, Francesco; Gioia, Dario; Masetti, Matteo; Falchi, Federico; Cavalli, Andrea; Recanatini, Maurizio; Ciurli, Stefano

2017-05-09

Transition metals are both essential micronutrients and limited in environmental availability. The Ni(II)-dependent urease protein, the most efficient enzyme known to date, is a paradigm for studying the strategies that cells use to handle an essential, yet toxic, metal ion. Urease is a virulence factor of several human pathogens, in addition to decreasing the efficiency of soil organic nitrogen fertilization. Ni(II) insertion in the urease active site is performed through the action of three essential accessory proteins: UreD, UreF, and UreG. The crystal structure of the UreD-UreF-UreG complex from the human pathogen Helicobacter pylori (HpUreDFG) revealed the presence of tunnels that cross the entire length of both UreF and UreD, potentially able to deliver Ni(II) ions from UreG to apo-urease. Atomistic molecular dynamics simulations performed on the HpUreDFG complex in explicit solvent and at physiological ionic conditions demonstrate the stability of these protein tunnels in solution and provide insights on the trafficking of water molecules inside the tunnels. The presence of different alternative routes across the identified tunnels for Ni(II) ions, water molecules, and carbonate ions, all involved in urease activation, is highlighted here, and their potential role in the urease activation mechanism is discussed.

Kinetic and structural studies reveal a unique binding mode of sulfite to the nickel center in urease.

PubMed

Mazzei, Luca; Cianci, Michele; Benini, Stefano; Bertini, Leonardo; Musiani, Francesco; Ciurli, Stefano

2016-01-01

Urease is the most efficient enzyme known to date, and catalyzes the hydrolysis of urea using two Ni(II) ions in the active site. Urease is a virulence factor in several human pathogens, while causing severe environmental and agronomic problems. Sporosarcina pasteurii urease has been used extensively in the structural characterization of the enzyme. Sodium sulfite has been widely used as a preservative in urease solutions to prevent oxygen-induced oxidation, but its role as an inhibitor has also been suggested. In the present study, isothermal titration microcalorimetry was used to establish sulfite as a competitive inhibitor for S. pasteurii urease, with an inhibition constant of 0.19mM at pH7. The structure of the urease-sulfite complex, determined at 1.65Å resolution, shows the inhibitor bound to the dinuclear Ni(II) center of urease in a tridentate mode involving bonds between the two Ni(II) ions in the active site and all three oxygen atoms of the inhibitor, supporting the observed competitive inhibition kinetics. This coordination mode of sulfite has never been observed, either in proteins or in small molecule complexes, and could inspire synthetic coordination chemists as well as biochemists to develop urease inhibitors based on this chemical moiety. Copyright © 2015 Elsevier Inc. All rights reserved.

Complexation of nitrogen and sulphur donor Schiff's base ligand to Cr(III) and Ni(II) metal ions: Synthesis, spectroscopic and antipathogenic studies

NASA Astrophysics Data System (ADS)

Sharma, Amit Kumar; Chandra, Sulekh

2011-01-01

2,6-Diacetyl pyridine based ligand was synthesized by the reaction of 2,6-diacetyl pyridine with thiocarbohydrazide in presence of acetic acid. The coordination compounds with Cr(III) and Ni(II) metal ions having [Cr(L)X]X 2 and [Ni(L)X]X compositions (where L = ligand and X = NO 3-, Cl - and CH 3COO -) were synthesized and characterized by physicochemical and spectral studies. The studies like elemental analyses, molar conductance measurements, magnetic susceptibility measurements, IR, UV-Vis, NMR, mass and EPR reveal that the complexes are octahedral. The compounds were examined against the pathogenic fungal and bacterial strains like Alternaria brassicae, Aspergillus niger, Fusarium oxysporum, Xanthomonas compestris and Pseudomonas aeruginosa. A. niger causes the diseases Apergillosis and Otomycosis in humans.

Synthesis, structural characterization and DFT calculation on a square-planar Ni(II) complex of a compartmental Schiff base ligand

NASA Astrophysics Data System (ADS)

Biswas, Surajit; Dolai, Malay; Dutta, Arpan; Ali, Mahammad

2016-12-01

Reaction of a symmetric compartmental Schiff-base ligand, (H2L) with nickel(II) perchlorate hexahydrate in 1:1 M ratio in methanol gives rise to a mononuclear nickel(II) compound, NiL (1). The compound has been characterized by C, H, N microanalyses and UV-Vis spectra. The single crystal X-ray diffraction studies reveal a square planar geometry around the Ni(II) center. The compound crystallizes in monoclinic system with space group C2/c with a = 21.6425(6), b = 9.9481(3), c = 13.1958(4) Å, β = 107.728(2)°, V = 2706.16(14) Å3 and Z = 4. Ground state DFT optimization and TDDFT calculations on the ligand and complex were performed to get their UV-Vis spectral pattern.

Syntheses, spectroscopic characterization, thermal study, molecular modeling, and biological evaluation of novel Schiff's base benzil bis(5-amino-1,3,4-thiadiazole-2-thiol) with Ni(II), and Cu(II) metal complexes

NASA Astrophysics Data System (ADS)

Chandra, Sulekh; Gautam, Seema; Rajor, Hament Kumar; Bhatia, Rohit

2015-02-01

Novel Schiff's base ligand, benzil bis(5-amino-1,3,4-thiadiazole-2-thiol) was synthesized by the condensation of benzil and 5-amino-1,3,4-thiadiazole-2-thiol in 1:2 ratio. The structure of ligand was determined on the basis of elemental analyses, IR, 1H NMR, mass, and molecular modeling studies. Synthesized ligand behaved as tetradentate and coordinated to metal ion through sulfur atoms of thiol ring and nitrogen atoms of imine group. Ni(II), and Cu(II) complexes were synthesized with this nitrogen-sulfur donor (N2S2) ligand. Metal complexes were characterized by elemental analyses, molar conductance, magnetic susceptibility measurements, IR, electronic spectra, EPR, thermal, and molecular modeling studies. All the complexes showed molar conductance corresponding to non-electrolytic nature, expect [Ni(L)](NO3)2 complex, which was 1:2 electrolyte in nature. [Cu(L)(SO4)] complex may possessed square pyramidal geometry, [Ni(L)](NO3)2 complex tetrahedral and rest of the complexes six coordinated octahedral/tetragonal geometry. Newly synthesized ligand and its metal complexes were examined against the opportunistic pathogens. Results suggested that metal complexes were more biological sensitive than free ligand.

Synthesis, characterization and solid state electrical properties of 1-D coordination polymer of the type [Cu{sub x}Ni{sub 1-x}(dadb){center_dot}yH{sub 2}O]{sub n}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prasad, R.L., E-mail: rlpjc@yahoo.co.in; Kushwaha, A.; Shrivastava, O.N.

2012-12-15

New heterobimetallic complexes [Cu{sub x}Ni{sub 1-x}(dadb){center_dot}yH{sub 2}O]{sub n} {l_brace}where dadb=2,5-Diamino-3,6-dichloro-1,4-benzoquinone (1); x=1 (2), 0.5 (4), 0.25 (5), 0.125 (6), 0.0625 (7) and 0 (3); y=2; n=degree of polymerization{r_brace} were synthesized and characterized. Heterobimetallic complexes show normal magnetic moments, whereas, monometallic complexes exhibit magnetic moments less than the value due to spin only. Thermo-gravimetric analysis shows that degradation of the ligand dadb moiety is being controlled by the electronic environment of the Cu(II) ions in preference over Ni(II) in heterobimetallic complexes. Existence of the mixed valency/non-integral oxidation states of copper and nickel metal ions in the complex 4 has been attributedmore » from magnetic moment and ESR spectral results. Solid state dc electrical conductivity of all the complexes was investigated. Monometallic complexes were found to be semiconductors, whereas heterobimetallic coordination polymer 4 was found to exhibit metallic behaviour. Existence of mixed valency/ non-integral oxidation state of metal ions seems to be responsible for the metallic behaviour. - Graphical abstract: Contrast to the semiconductor monometallic complexes 2 and 3, the heterobimetallic complex 4 exhibits metallic behaviour attributed to the mixed valency/non-integral oxidation state of the metal ions concluded from magnetic and ESR spectral studies. Highlights: Black-Right-Pointing-Pointer 1-D coordination compounds of the type Cu{sub x}Ni{sub 1-x}(dadb){center_dot}yH{sub 2}O were synthesized and characterized. Black-Right-Pointing-Pointer Thermal degradation of the complexes provides an indication of long range electronic communication between metal to ligand. Black-Right-Pointing-Pointer On inclusion of Ni(II) into 1-D coordination polymer of Cu(II). (a) Cu(II) and Ni(II) ions exhibit non-integral oxidation state. (b) resulting heterobimetallic complex 4 exhibits metallic behaviour at all temperature range of the present study whereas monometallic complexes are semiconductor.« less

Mononuclear Ni(II) complexes of Schiff base ligands formed from unsymmetrical tripodal amines of differing arm lengths: Spectral, X-ray crystal structural, antimicrobial and DNA cleavage activity

NASA Astrophysics Data System (ADS)

Keypour, Hassan; Shayesteh, Maryam; Rezaeivala, Majid; Dhers, Sébastien; Küp, Fatma Öztürk; Güllü, Mithat; Ng, Seikweng

2017-11-01

The synthesis of two unsymmetrical N-capped tripodal amines, 2-((4-aminobutyl)(pyridin-2-ylmethyl)amino)ethanol (3) and 3-((2-aminoethyl)(pyridin-2-ylmethyl)amino)propan-1-ol (4) is reported. They feature a longer, 3-hydroxypropyl or butylamino arm than that in the analogues previously employed. All four tripodal amines, 1-4, are equipped with a 2-methylpyridyl-arm, and either an ethylamino-arm (1 and 4), propylamino-arm (2) or butylamino-arm (3). The amines, 3 and 4, have been employed in one pot condensation reactions with salicylaldehyde and its derivatives in the presence of Ni(II) metal ion. A series of new mononuclear complexes, [NiIILaldi](ClO4) or [NiIILaldi(solvent)](ClO4) with different geometry, of Schiff base ligands were generated. X-ray crystal structure determinations of [NiIILOMe3(H2O)](ClO4)·2H2O and [NiIILOMe4](ClO4) revealed them to be mononuclear. The Ni(II) ion in [NiIILOMe4](ClO4) complex is in a distorted square-planar environment whilst this ion is in distorted octahedral environment in [NiIILOMe3(H2O)](ClO4)·2H2O complex despite the longer arm length of L3. While, in related systems in our previous work, they had led to dimeric complexes. These results clearly showed that the variation of the arm lengths of the ligands and metal ions has a remarkable impact on the formation and structure of the complexes. The cleavage of DNA by all synthesised complexes was examined using gel electrophoresis experiments. Also, the antibacterial effects of components were determined against the three Gram-positive bacteria, and against the three Gram-negative bacteria and against the three yeast Candida albicans ATCC 10231, Candida krusei ATCC 1424 and Candida tropicalis ATCC 13803.

Tridentate N2S ligand from 2,2′-dithiodibenzaldehyde and N,N-dimethylethylenediamine: Synthesis, structure, and characterization of a Ni(II) complex with relevance to Ni Superoxide Dismutase

PubMed Central

Zimmerman, Joshua R.; Smucker, Bradley W.; Dain, Ryan P.; VanStipdonk, Michael J.

2011-01-01

Nickel Superoxide Dismutase (NiSOD) and the A-cluster of Carbon Monoxide Dehydrogenase/Acetyl Coenzyme A Synthase (CODH/ACS) both feature active sites with Ni coordinated by thiolate and amide donors. It is likely that the particular set of donors is important in tuning the redox potential of the Ni center(s). We report herein an expansion of our efforts involving the use of 2,2′-dithiodibenzaldehyde (DTDB) as a synthon for metal-thiolate complexes to reactions with Ni complexes of N,N-dimethylethylenediamine (dmen). In the presence of coordinating counterions, these reactions result in monomeric square-planar complexes of the tridentate N2S donor ligand derived from the Schiff-base condensation of dmen and DTDB. In the absence of a coordinating counterion, we have isolated a Ni(II) complex with an asymmetric N2S2 donor set involving one amine and one imine N donor in addition to two thiolate donors. This latter complex is discussed with respect to its relevance to the active site of NiSOD. PMID:21666847

Synthesis, spectroscopic characterization, electrochemical behaviour, reactivity and antibacterial activity of some transition metal complexes with 2-(N-salicylideneamino)-3-carboxyethyl-4,5-dimethylthiophene.

PubMed

Daniel, Varughese P; Murukan, B; Kumari, B Sindhu; Mohanan, K

2008-07-01

Mn(II), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes with a potentially tridentate Schiff base, formed by condensation of 2-amino-3-carboxyethyl-4,5-dimethylthiophene with salicylaldehyde were synthesized and characterized on the basis of elemental analyses, molar conductance values, magnetic susceptibility measurements, UV-vis, IR, EPR and NMR spectral data, wherever possible and applicable. Spectral studies reveal that the free ligand exists in a bifunctionally hydrogen bonded manner and coordinates to the metal ion in a tridentate fashion through the deprotonated phenolate oxygen, azomethine nitrogen and ester carbonyl group. On the basis of electronic spectral data and magnetic susceptibility measurements, suitable geometry has been proposed for each complex. The EPR spectral data of the Cu(II) complex showed that the metal-ligand bonds have considerable covalent character. The Ni(II) complex has undergone facile transesterification reaction when refluxed in methanol for a lengthy period. X-ray diffraction studies of Cu(II) complex showed that the complex has an orthorhombic crystal lattice. In view of the biological activity of thiophene derivatives, the ligand and the complexes were subjected to antibacterial screening. It has been observed that the antibacterial activity of the ligand increased on chelation with metal ion.

Synthesis and studies on Cu(II), Co(II), Ni(II) complexes of Knoevenagel β-diketone ligands.

PubMed

Sumathi, S; Tharmaraj, P; Sheela, C D; Anitha, C

2012-11-01

Transition metal complexes of various acetylacetone based ligands of the type ML [where M=Cu(II), Ni(II), Co(II); L=3-(aryl)-pentane-2,4-dione] have been synthesized. The structural features have been derived from their elemental analysis, magnetic susceptibility, molar conductance, IR, UV-Vis, (1)H NMR, Mass and ESR spectral studies. Conductivity measurements reveal that all the complexes are non-electrolytic in nature. Spectroscopic and other analytical data of the complexes suggest octahedral geometry for other metal(II) complexes. The redox behavior of the copper(II) complexes have been studied by cyclic voltammetry. The free ligands and their metal complexes have been screened for their in vitro biological activities against the bacteria Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus as well as the fungus Candida albicans by well diffusion method. The zone of inhibition value indicates that the most of the metal(II) complexes are found to possess increased activities compared to those of the free ligands. All synthesized compounds may serve as potential photoactive materials as indicated from their characteristic fluorescence properties. The second harmonic generation (SHG) efficiency of the ligands (L1-L3) was found to be considerable effect than that of urea and KDP (potassium dihydrogen phosphate). Copyright © 2012 Elsevier B.V. All rights reserved.

Synthesis and studies on Cu(II), Co(II), Ni(II) complexes of Knoevenagel β-diketone ligands

NASA Astrophysics Data System (ADS)

Sumathi, S.; Tharmaraj, P.; Sheela, C. D.; Anitha, C.

2012-11-01

Transition metal complexes of various acetylacetone based ligands of the type ML [where M = Cu(II), Ni(II), Co(II); L = 3-(aryl)-pentane-2,4-dione] have been synthesized. The structural features have been derived from their elemental analysis, magnetic susceptibility, molar conductance, IR, UV-Vis, 1H NMR, Mass and ESR spectral studies. Conductivity measurements reveal that all the complexes are non-electrolytic in nature. Spectroscopic and other analytical data of the complexes suggest octahedral geometry for other metal(II) complexes. The redox behavior of the copper(II) complexes have been studied by cyclic voltammetry. The free ligands and their metal complexes have been screened for their in vitro biological activities against the bacteria Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus as well as the fungus Candida albicans by well diffusion method. The zone of inhibition value indicates that the most of the metal(II) complexes are found to possess increased activities compared to those of the free ligands. All synthesized compounds may serve as potential photoactive materials as indicated from their characteristic fluorescence properties. The second harmonic generation (SHG) efficiency of the ligands (L1-L3) was found to be considerable effect than that of urea and KDP (potassium dihydrogen phosphate).

N-((5-chloropyridin-2-yl)carbamothioyl)furan-2-carboxamide and its Co(II), Ni(II) and Cu(II) complexes: Synthesis, characterization, DFT computations, thermal decomposition, antioxidant and antitumor activity

NASA Astrophysics Data System (ADS)

Yeşilkaynak, Tuncay; Özpınar, Celal; Emen, Fatih Mehmet; Ateş, Burhan; Kaya, Kerem

2017-02-01

N-((5-chloropyridin-2-yl)carbamothioyl)furan-2-carboxamide (HL: C11H8ClN3O2S) and its Co(II), Ni(II) and Cu(II) complexes have been synthesized and characterized by elemental analysis, FT-IR,1H NMR and HR-MS methods. The HL was characterized by single crystal X-ray diffraction technique. It crystallizes in the monoclinic system. The HL has the space group P 1 21/c 1, Z = 4, and its unit cell parameters are a = 4.5437(5) Å, b = 22.4550(3) Å, c = 11.8947(14) Å. The ligand coordinates the metal ions as bidentate and thus essentially yields neutral complexes of the [ML2] type. ML2 complex structures were optimized using B97D/TZVP level. Molecular orbitals of both HL ligand were calculated at the same level. Thermal decomposition of the complexes has been investigated by thermogravimetry. The complexes were screened for their anticancer and antioxidant activities. Antioxidant activity of the complexes was determined by using the DPPH and ABTS assays. The anticancer activity of the complexes was studied by using MTT assay in MCF-7 breast cancer cells.

Mononuclear thiocyanate containing nickel(II) and binuclear azido bridged nickel(II) complexes of N4-coordinate pyrazole based ligand: Syntheses, structures and magnetic properties

NASA Astrophysics Data System (ADS)

Solanki, Ankita; Monfort, Montserrat; Kumar, Sujit Baran

2013-10-01

Two mononuclear nickel(II) complexes [NiL1(NCS)2] (1) and [NiL2(NCS)2] (2) and two azido bridged binuclear nickel(II) complexes [Ni(()2()2] (3) and [Ni(()2()2] (4), where L1, L2, L1‧ and L2‧ are N,N-diethyl-N‧,N‧-bis((3,5-dimethyl-1H-pyrazol-1-yl)methyl)ethane-1,2-diamine (L1), N,N-bis((1H-pyrazol-1-yl)methyl)-N‧,N‧-diethylethane-1,2-diamine (L2), N,N-diethyl-N‧-((3,5-dimethyl-1H-pyrazol-1-yl)methyl)ethane-1,2-diamine (L1‧) and N-((1H-pyrazol-1-yl)methyl)-N‧,N‧-diethylethane-1,2-diamine (L2‧) have been synthesized and characterized by microanalyses and physico-chemical methods. Single crystal X-ray diffraction analyses revealed that complexes 1 and 2 are mononuclear NCS- containing Ni(II) complex with octahedral geometry and complexes 3 and 4 are end-on (μ-1,1) azido bridged binuclear Ni(II) complexes with distorted octahedral geometry. Variable temperature magnetic studies of the complexes 3 and 4 display ferromagnetic interaction with J values 19 and 32 cm-1, respectively.

Michael Addition Reactions between Chiral Equivalents of a Nucleophilic Glycine and (S)- or (R)-3-[(E)-Enoyl]-4-phenyl-1,3-oxazolidin-2-ones as a General Method for Efficient Preparation of β-Substituted Pyroglutamic Acids. Case of Topographically Controlled Stereoselectivity

PubMed Central

Soloshonok*, Vadim A.; Cai, Chaozhong; Yamada, Takeshi; Ueki, Hisanori; Ohfune, Yasufumi; Hruby, Victor J.

2006-01-01

This paper describes a systematic study of addition reactions between the chiral Ni(II) complex of the Schiff base of glycine with (S)-o-[N-(N-benzylprolyl)amino]benzophenone and (S)- or (R)-3-[(E)-enoyl]-4-phenyl-1,3-oxazolidin-2-ones as a general and synthetically efficient approach to β-substituted pyroglutamic acids and relevant compounds. These reactions were shown to occur at room temperature in the presence of nonchelating organic bases and, most notably, with very high (>98% diastereomeric excess (de)) stereoselectivity at both newly formed stereogenic centers. The stereochemical outcome of the reactions was found to be overwhelmingly controlled by the stereochemical preferences of the Michael acceptors, and the chirality of the glycine complex influenced only the reaction rate. Thus, in the reactions of both the (S)-configured Ni(II) complex and the Michael acceptors, the reaction rates were exceptionally high, allowing preparation of the corresponding products with virtually quantitative (>98%) chemical and stereochemical yields. In contrast, reactions of the (S)-configured Ni(II) complex and (R)-configured Michael acceptors proceeded at noticeably lower rates, but the addition products were obtained in high diastereo-and enantiomeric purity. To rationalize the remarkably high and robust stereoselectivity observed in these reactions, we consider an enzyme–substrate-like mode of interaction involing a topographical match or mismatch of two geometric figures. Excellent chemical and stereochemical yields, combined with the simplicity and operational convenience of the experimental procedures, render the present method of immediate use for preparing various β-substituted pyroglutamic acids and related compounds. PMID:16248672

Michael addition reactions between chiral equivalents of a nucleophilic glycine and (S)- or (R)-3-[(E)-enoyl]-4-phenyl-1,3-oxazolidin-2-ones as a general method for efficient preparation of beta-substituted pyroglutamic acids. Case of topographically controlled stereoselectivity.

PubMed

Soloshonok, Vadim A; Cai, Chaozhong; Yamada, Takeshi; Ueki, Hisanori; Ohfune, Yasufumi; Hruby, Victor J

2005-11-02

This paper describes a systematic study of addition reactions between the chiral Ni(II) complex of the Schiff base of glycine with (S)-o-[N-(N-benzylprolyl)amino]benzophenone and (S)- or (R)-3-[(E)-enoyl]-4-phenyl-1,3-oxazolidin-2-ones as a general and synthetically efficient approach to beta-substituted pyroglutamic acids and relevant compounds. These reactions were shown to occur at room temperature in the presence of nonchelating organic bases and, most notably, with very high (>98% diastereomeric excess (de)) stereoselectivity at both newly formed stereogenic centers. The stereochemical outcome of the reactions was found to be overwhelmingly controlled by the stereochemical preferences of the Michael acceptors, and the chirality of the glycine complex influenced only the reaction rate. Thus, in the reactions of both the (S)-configured Ni(II) complex and the Michael acceptors, the reaction rates were exceptionally high, allowing preparation of the corresponding products with virtually quantitative (>98%) chemical and stereochemical yields. In contrast, reactions of the (S)-configured Ni(II) complex and (R)-configured Michael acceptors proceeded at noticeably lower rates, but the addition products were obtained in high diastereo- and enantiomeric purity. To rationalize the remarkably high and robust stereoselectivity observed in these reactions, we consider an enzyme-substrate-like mode of interaction involving a topographical match or mismatch of two geometric figures. Excellent chemical and stereochemical yields, combined with the simplicity and operational convenience of the experimental procedures, render the present method of immediate use for preparing various beta-substituted pyroglutamic acids and related compounds.

Mycobacterium tuberculosis NmtR harbors a nickel sensing site with parallels to Escherichia coli RcnR†

PubMed Central

Reyes-Caballero, Hermes; Lee, Chul Won; Giedroc, David P.

2011-01-01

Mycobacterium tuberculosis NmtR is a Ni(II)/Co(II)-sensing metalloregulatory protein from the extensively studied ArsR/SmtB family. Two Ni(II) ions bind to the NmtR dimer to form octahedral coordination complexes with stepwise binding affinities of KNi1=1.2 (±0.1) × 1010 and KNi2=0.7 (±0.4) × 1010 M-1 (pH 7.0). A glutamine scanning mutagenesis approach reveals that Asp91, His93, His104 and His107, all contained within the C-terminal α5 helix, and His3 as part of the conserved α-NH2-Gly2-His3-Gly4 motif at the N-terminus make significant contributions to the magnitude of KNi. In contrast, substitution of residues from the C-terminal region, His109, Asp114 and His116, previously implicated in Ni(II) binding and metalloregulation in cells, gives rise to wild-type KNi and Ni(II)-dependent allosteric coupling free energies. Interestingly, deletion of residues 112-120 in the C-terminal region (Δ111 NmtR) reduces the Ni(II) binding stoichiometry to one per dimer and greatly reduces Ni(II) responsiveness. H3Q and Δ111 NmtRs also show clear perturbations in the rank order of metal responsiveness to Ni(II), Co(II) and Zn(II) that is distinct from wild-type NmtR. 15N relaxation experiments with apo-NmtR reveal that both N-terminal (residues 2-14) and C-terminal (residues 110-120) regions are unstructured in solution, and this property likely dictates the metal specificity profile characteristic of the Ni(II)-sensor NmtR relative to other ArsR family regulators. PMID:21819125

O2-dependent Aliphatic Carbon-carbon Bond Cleavage Reactivity in a Ni(II) Enolate Complex Having a Hydrogen Bond Donor Microenvironment; Comparison with a Hydrophobic Analog

PubMed Central

Grubel, Katarzyna; Fuller, Amy L.; Chambers, Bonnie M.; Arif, Atta M.; Berreau, Lisa M.

2010-01-01

A mononuclear Ni(II) complex having an acireductone type ligand, and supported by the bnpapa (N,N-bis((6-neopentylamino-2-pyridyl)methyl-N-((2-pyridyl)methyl)amine ligand, [(bnpapa)Ni(PhC(O)C(OH)C(O)Ph)]ClO4 (14), has been prepared and characterized by elemental analysis, 1H NMR, FTIR, and UV-vis. To gain insight into the 1H NMR features of 14, the air stable analog complexes [(bnpapa)Ni(CH3C(O)CHC(O)CH3)]ClO4 (16) and [(bnpapa)Ni(ONHC(O)CH3)]ClO4 (17) were prepared and characterized by X-ray crystallography, 1H NMR, FTIR, UV-vis, mass spectrometry, and solution conductivity measurements. Compounds 16 and 17 are 1:1 electrolyte species in CH3CN. 1H and 2H NMR studies of 14, 16, and 17 and deuterated analogs revealed that the complexes having six-membered chelate rings for the exogenous ligand (14 and 16) do not have a plane of symmetry within the solvated cation and thus exhibit more complicated 1H NMR spectra. Compound 17, as well as other simple Ni(II) complexes of the bnpapa ligand (e.g. [(bnpapa)Ni(ClO4)(CH3CN)]ClO4 (18) and [(bnpapaNi)2(μ-Cl)2](ClO4)2 (19)), exhibit 1H NMR spectra consistent with the presence of a plane of symmetry within the cation. Treatment of [(bnpapa)Ni(PhC(O)C(OH)C(O)Ph)]ClO4 (14) with O2 results in aliphatic carbon-carbon bond cleavage within the acireductone-type ligand and the formation of [(bnpapa)Ni(O2CPh)]ClO4 (9), benzoic acid, benzil, and CO. Use of 18O2 in the reaction gives high levels of incorporation (>80%) of one labeled oxygen atom into 9 and benzoic acid. The product mixture and level of 18O incorporation in this reaction is different than that exhibited by the analog supported the hydrophobic 6-Ph2TPA ligand, [(6-Ph2TPA)Ni(PhC(O)C(OH)C(O)Ph)]ClO4 (2). We propose that this difference is due to variations in the reactivity of bnpapa- and 6-Ph2TPA-ligated Ni(II) complexes with triketone and/or peroxide species produced in the reaction pathway. PMID:20039645

Complexation of nitrogen and sulphur donor Schiff's base ligand to Cr(III) and Ni(II) metal ions: synthesis, spectroscopic and antipathogenic studies.

PubMed

Sharma, Amit Kumar; Chandra, Sulekh

2011-01-01

2,6-diacetyl pyridine based ligand was synthesized by the reaction of 2,6-diacetyl pyridine with thiocarbohydrazide in presence of acetic acid. The coordination compounds with Cr(III) and Ni(II) metal ions having [Cr(L)X]X2 and [Ni(L)X]X compositions (where L=ligand and X=NO3-, Cl- and CH3COO-) were synthesized and characterized by physicochemical and spectral studies. The studies like elemental analyses, molar conductance measurements, magnetic susceptibility measurements, IR, UV-Vis, NMR, mass and EPR reveal that the complexes are octahedral. The compounds were examined against the pathogenic fungal and bacterial strains like Alternaria brassicae, Aspergillus niger, Fusarium oxysporum, Xanthomonas compestris and Pseudomonas aeruginosa. A. niger causes the diseases Apergillosis and Otomycosis in humans. Copyright © 2010. Published by Elsevier B.V.

Synthesis, spectroscopic, thermal and DFT calculations of 2-(3-amino-2-hydrazono-4-oxothiazolidin-5-yl) acetic acid binuclear metal complexes

NASA Astrophysics Data System (ADS)

Hassan, Walid M. I.; Badawy, M. A.; Mohamed, Gehad G.; Moustafa, H.; Elramly, Salwa

2013-07-01

The binuclear complexes of 2-(3-amino-2-hydrazono-4-oxothiazolidin-5-yl) acetic acid ligand (HL) with Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) ions were prepared and their stoichiometry was determined by elemental analysis. The stereochemistry of the studied series of metal complexes was established by analyzing their infrared, 1H NMR spectra and the magnetic moment measurements. According to the elemental analysis data, the complexes were found to have the formulae [Fe2L(H2O)8]Cl5 and [M2L(H2O)8]Cl3 (M = Co(II), Ni(II), Cu(II) and Zn(II)). The present analyses demonstrate that all metal ions coordinated to the ligand via O(9), O(11), N(16) and N(18) atoms. Thermal decomposition studies of the ligand-metal complexes have been performed to verify the status of water molecules present in these metal complexes and their general decomposition pattern. Density Functional Theory (DFT) calculations at the B3LYP/6-31G* level of theory have been carried out to investigate the equilibrium geometry of the ligand and complexes. Moreover, charge density distribution, extent of distortion from regular geometry, dipole moment and orientation have been performed and discussed.

Synthesis, spectroscopic characterization, DNA interaction and biological activities of Mn(II), Co(II), Ni(II) and Cu(II) complexes with [(1H-1,2,4-triazole-3-ylimino)methyl]naphthalene-2-ol

NASA Astrophysics Data System (ADS)

Gaber, Mohamed; El-Wakiel, Nadia A.; El-Ghamry, Hoda; Fathalla, Shaimaa K.

2014-11-01

Manganese(II), cobalt(II), nickel(II) and copper(II) complexes of [(1H-1,2,4-triazole-3-ylimino)methyl]naphthalene-2-ol have been synthesized. The structure of complexes have been characterized by elemental analysis, molar conductance, magnetic moment measurements and spectral (IR, 1H NMR, EI-mass, UV-Vis and ESR), and thermal studies. The results showed that the chloro and nitrato Cu(II) complexes have octahedral geometry while Ni(II), Co(II) and Mn(II) complexes in addition to acetato Cu(II) complex have tetrahedral geometry. The possible structures of the metal complexes have been computed using the molecular mechanic calculations using the hyper chem. 8.03 molecular modeling program to confirm the proposed structures. The kinetic and thermodynamic parameters of the thermal decomposition steps were calculated from the TG curves. The binding modes of the complexes with DNA have been investigated by UV-Vis absorption titration. The results showed that the mode of binding of the complexes to DNA is intercalative or non-intercalative binding modes. Schiff base and its metal complexes have been screened for their in vitro antimicrobial activities against Gram positive bacteria (Staphylococcus aureus), Gram negative bacteria (Escherichia coli and Pesudomonas aeruginosa), fungi (Asperigllus flavus and Mucer) and yeast (Candida albicans and Malassezia furfur).

Design, synthesis, spectral characterization, DNA interaction and biological activity studies of copper(II), cobalt(II) and nickel(II) complexes of 6-amino benzothiazole derivatives

NASA Astrophysics Data System (ADS)

Daravath, Sreenu; Kumar, Marri Pradeep; Rambabu, Aveli; Vamsikrishna, Narendrula; Ganji, Nirmala; Shivaraj

2017-09-01

Two novel Schiff bases, L1 = (2-benzo[d]thiazol-6-ylimino)methyl)-4,6-dichlorophenol), L2 = (1-benzo[d]thiazol-6-ylimino)methyl)-6-bromo-4-chlorophenol) and their bivalent transition metal complexes [M(L1)2] and [M(L2)2], where M = Cu(II), Co(II) and Ni(II) were synthesized and characterized by elemental analysis, NMR, IR, UV-visible, mass, magnetic moments, ESR, TGA, SEM, EDX and powder XRD. Based on the experimental data a square planar geometry around the metal ion is assigned to all the complexes (1a-2c). The interaction of synthesized metal complexes with calf thymus DNA was explored using UV-visible absorption spectra, fluorescence and viscosity measurements. The experimental evidence indicated that all the metal complexes strongly bound to CT-DNA through an intercalation mode. DNA cleavage experiments of metal(II) complexes with supercoiled pBR322 DNA have also been explored by gel electrophoresis in the presence of H2O2 as well as UV light, and it is found that the Cu(II) complexes cleaved DNA more effectively compared to Co(II), Ni(II) complexes. In addition, the ligands and their metal complexes were screened for antimicrobial activity and it is found that all the metal complexes were more potent than free ligands.

Syntheses, spectroscopic characterization, thermal study, molecular modeling, and biological evaluation of novel Schiff's base benzil bis(5-amino-1,3,4-thiadiazole-2-thiol) with Ni(II), and Cu(II) metal complexes.

PubMed

Chandra, Sulekh; Gautam, Seema; Rajor, Hament Kumar; Bhatia, Rohit

2015-02-25

Novel Schiff's base ligand, benzil bis(5-amino-1,3,4-thiadiazole-2-thiol) was synthesized by the condensation of benzil and 5-amino-1,3,4-thiadiazole-2-thiol in 1:2 ratio. The structure of ligand was determined on the basis of elemental analyses, IR, (1)H NMR, mass, and molecular modeling studies. Synthesized ligand behaved as tetradentate and coordinated to metal ion through sulfur atoms of thiol ring and nitrogen atoms of imine group. Ni(II), and Cu(II) complexes were synthesized with this nitrogen-sulfur donor (N2S2) ligand. Metal complexes were characterized by elemental analyses, molar conductance, magnetic susceptibility measurements, IR, electronic spectra, EPR, thermal, and molecular modeling studies. All the complexes showed molar conductance corresponding to non-electrolytic nature, expect [Ni(L)](NO3)2 complex, which was 1:2 electrolyte in nature. [Cu(L)(SO4)] complex may possessed square pyramidal geometry, [Ni(L)](NO3)2 complex tetrahedral and rest of the complexes six coordinated octahedral/tetragonal geometry. Newly synthesized ligand and its metal complexes were examined against the opportunistic pathogens. Results suggested that metal complexes were more biological sensitive than free ligand. Copyright © 2014 Elsevier B.V. All rights reserved.

Rational design of azide-bridged bimetallic complexes. Crystal structure and magnetic properties of Fe(III)MFe(III) (M = Ni(II) and Cu(II)) trinuclear species.

PubMed

Colacio, Enrique; Costes, Jean-Pierre; Domínguez-Vera, José M; Maimoun, Ikram Ben; Suárez-Varela, José

2005-01-28

The first examples of azide-bridged bimetallic trinuclear complexes ([M(cyclam)][FeL(N3)(mu1,5-N3)]2) (H2L = 4,5-dichloro-1,2-bis(pyridine-2-carboxamido) benzene) have been structurally and magnetically characterized.

Crystal structure, DNA binding, cleavage, antioxidant and antibacterial studies of Cu(II), Ni(II) and Co(III) complexes with 2-((furan-2-yl)methylimino)methyl)-6-ethoxyphenol Schiff base

NASA Astrophysics Data System (ADS)

Venkateswarlu, Kadtala; Kumar, Marri Pradeep; Rambabu, Aveli; Vamsikrishna, Narendrula; Daravath, Sreenu; Rangan, Krishnan; Shivaraj

2018-05-01

Three novel binary metal complexes; 1 [Cu(L)2], 2 [Ni(L)2] and 3 [Co(L)3] where, L (2-(((furan-2-yl) methylimino)methyl)-6-ethoxyphenol, C14H15NO3), were synthesized and characterized by various spectral techniques. Based on spectral studies square planar geometry is assigned for Cu(II) and Ni(II) complexes, whereas Co(III) owned octahedral geometry. Ligand, [Cu(L)2] and [Ni(L)2] are crystallized and found to be monoclinic crystal systems. CT-DNA absorption binding studies revealed that the complexes show good binding propensity (Kb = 5.02 × 103 M-1, 2.77 × 103 M-1, 1.63 × 104 M-1 for 1, 2 and 3 respectively). The role of these complexes in the oxidative and photolytic cleavage of supercoiled pBR322 DNA was studied and found that the complexes cleave the pBR322 DNA effectively. The catalytic ability of 1, 2 and 3 follows the order: 3 > 1 >2. Antioxidant studies of the new complexes revealed that they exhibit significant antioxidant activity against DPPH radical. The Schiff base and its metal complexes have been screened for antibacterial studies by Minimum Inhibitory Concentration method. It is observed that all metal complexes showed more activity than free ligand.

Synthesis, characterization, and reactivity of pentamethylcyclopentadienyl complexes of divalent cobalt and nickel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Michael Edward

1993-10-01

The thesis is divided into the following 4 chapters: synthesis, characterization, and reactivity of trinuclear pentamethylcyclopentadienyl cobalt and nickel clusters with triply-bridging methylidyne groups; chemical and physical properties of pentamethylcyclopentadienyl acetylacetonate complexes of Co(II) and Ni(II); synthesis, characterization, and reactivity of pentamethylcyclopentadienyl halide complexes of Co and Ni; and crystallographic studies of distortions in metallocenes with C 5-symmetrical cyclopentadienyl rings.

Structural, theoretical and corrosion inhibition studies on some transition metal complexes derived from heterocyclic system

NASA Astrophysics Data System (ADS)

Gupta, Shraddha Rani; Mourya, Punita; Singh, M. M.; Singh, Vinod P.

2017-06-01

A Schiff base, (E)-N‧-((1H-indol-3-yl)methylene)-2-aminobenzohydrazide (Iabh) and its Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes have been synthesized. These compounds have been characterized by different physico-chemical and spectroscopic tools (UV-Vis, IR, NMR and ESI-Mass). The molecular structure of Iabh is determined by single crystal X-ray diffraction technique. The ligand Iabh displays E-configuration about the >Cdbnd N- bond. The structure of ligand is stabilized by intra-molecular H-bonding. In all the metal complexes the ligand coordinates through azomethine-N and carbonyl-O resulting a distorted octahedral geometry for Mn(II), Co(II) and Cu(II) complexes in which chloride ions occupy axial positions. Ni(II) and Zn(II) complexes, however, form 4-coordinate distorted square planer and tetrahedral geometry around metal ion, respectively. The structures of the complexes have been satisfactorily modeled by calculations based on density functional theory (DFT) and time dependent-DFT (TD-DFT). The corrosion inhibition study of the compounds have been performed against mild steel in 0.5 M H2SO4 solution at 298 K by using weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). They show appreciable corrosion inhibition property.

Changes in spectrochemical and catalytic properties of biopolymer anchored Cu(II) and Ni(II) catalysts by electron beam irradiation.

PubMed

Antony, R; Suja Pon Mini, P S; Theodore David Manickam, S; Sanjeev, Ganesh; Mitu, Liviu; Balakumar, S

2015-01-01

Chitosan (a biopolymer) anchored Cu(II) and Ni(II) Schiff base complexes, [M(OIAC)Cl2] (M: Cu/Ni and OIAC: ([2-oxo-1H-indol-3-ylidene]amino)chitosan) were electron beam irradiated by different doses (100 Gy, 1 kGy and 10 kGy). The electron beam has shown potential impact on biopolymer's support, in detail chain linking and chain scissoring, as evidenced by viscosity studies, FT-IR and X-ray diffraction spectroscopic techniques. Due to these structural changes, thermal properties of the complexes were found to be changed. The surface of these heterogeneous complexes was also effectually altered by electron beam. As a consequence, pores and holes were created as probed by SEM technique. The catalytic activity of both non-irradiated and irradiated complexes was investigated in the aerobic oxidation of cyclohexane using hydrogen peroxide oxidant. The catalytic ability of the complexes was enhanced significantly after irradiation as the result of surface changes. The reusability of the complexes was also greatly affected because of the structural variations in polymeric support. In terms of both better catalytic activity along with the reusability, 1 kGy is suggested as the best dose to attain adequate increase in catalytic activity and good reusability. Copyright © 2015 Elsevier B.V. All rights reserved.

Ni(II) biosorption by Cassia fistula (Golden Shower) biomass.

PubMed

Hanif, Muhammad Asif; Nadeem, Raziya; Bhatti, Haq Nawaz; Ahmad, Najum Rashid; Ansari, Tariq Mehmood

2007-01-10

Cassia fistula is a fast-growing, medium-sized, deciduous tree which is now widely cultivated worldwide as an ornamental tree for its beautiful showy yellow flowers. Methods are required to reuse fallen leaves, branches, stem bark and pods when they start getting all over lawn. This investigation studies the use of these non-useful parts of C. fistula as naturally occurring biosorbent for the batch removal of Ni(II) in a well stirred system under different experimental conditions. The data showed that the maximum pH (pHmax) for efficient sorption of Ni(II) was 6 at which evaluated biosorbent dosage, biosorbent particle size, initial concentrations of Ni(II) and sorption time were 0.1 g/100 mL, <0.255 mm, up to 200 mg/L and 720 min, respectively. The experimental results were analyzed in terms of Langmuir and Freundlich isotherms. The Langmuir isotherm model fitted well to data of Ni(II) biosorption by C. fistula biomass as compared to the model of Freundlich. The kinetic studies showed that the sorption rates could be described better by a second order expression than by a more commonly applied Lagergren equation. The magnitude of the Gibbs free energy values indicates spontaneous nature of the sorption process. The sorption ability of C. fistula biomass for Ni(II) removal tends to be in the order: leaves

Nickel adsorption onto polyurethane ethylene and vinyl acetate sorbents.

PubMed

Iqbal, Munawar; Ali, Zahid; Qamar, M Afzal; Ali, Abid; Hussain, Fida; Abbas, Mazhar; Nisar, Jan

2017-07-01

The present study was conducted to appraise the efficiencies of polyurethane ethylene sorbent (PES) and vinyl acetate sorbent (VAS) for nickel (Ni) adsorption. Process variables, i.e. Ni(II) ions initial concentration, pH, contact time and adsorbent dosage were optimized by response surface methodology (RSM) approach. The Ni(II) adsorption was fitted to the kinetic models (pseudo-first-order and pseudo-second-order) and adsorption isotherms (Freundlich and Langmuir). At optimum conditions of process variables, 171.99 mg/g (64.7%) and 388.08 mg/g (92.7%) Ni(II) was adsorbed onto PES and VAS, respectively. The RSM analysis revealed that maximum Ni(II) adsorption can be achieved at 299 mg/L Ni(II) ions initial concentration, 4.5 pH, 934 min contact time and 1.3 g adsorbent dosage levels for PES, whereas the optimum values for VAS were found to be 402 mg/L Ni(II) ions initial concentration, 4.6 pH, 881 min contact time and 1.2 g adsorbent dosage, respectively. The -OH and -C = O- were involved in the Ni(II) adsorption onto PES and VAS adsorbents. At optimum levels, up to 53.67% and 80.0% Ni(II) was removed from chemical industry wastewater using PES and VAS, respectively, which suggest that PES and VAS could possibly be used for Ni(II) adsorption from industrial wastewater.

Chelation, spectroscopic characterization, biological activity and crystal structure of 2,3-butanedione isonicotinylhydrazone: Determination of Zr4+ after flotation separation

NASA Astrophysics Data System (ADS)

Al-Fulaij, O. A.; Jeragh, B.; El-Sayed, A. E. M.; El-Defrawy, M. M.; El-Asmy, A. A.

2015-02-01

New metal complexes of Co(II), Ni(II) Cu(II), Zn(II), Cd(II), Pd(II) and Hg(II) with 2,3-butanedione isonicotinylhydrazone [BINH] have been prepared and investigated. Single crystal for BINH is grown and solved as orthorhombic with P 21 21 2 space group. The formula of the ligand was assigned based on the elemental analysis, mass spectra and conductivity measurements. The complexes assigned the formulae [M(BINH-H)Cl]ṡnH2O (Mdbnd Co(II), Ni(II), Cu(II), Zn(II); n = 0 or 1); [Hg(BINH-H)(H2O)2Cl]; [Cd(BINH)Cl2]ṡ2H2O and [Pd(BINH)Cl2]ṡH2O. All complexes are nonelectrolytes. BINH acts as a tridentate ligand in [M(BINH-H)Cl]ṡnH2O and [Hg(BINH-H)(H2O)2Cl] coordinating through Cdbnd Oketonic, Csbnd Oamedic and Cdbnd Nhy and as a neutral bidentate through Cdbnd Oketonic and Cdbnd Nhy in [Cd(BINH)Cl2]ṡ2H2O and [Pd(BINH)Cl2]ṡH2O; the pyridine nitrogen has no rule in coordination. The data are supported by NMR (1H and 13C) spectra. The magnetic moments and electronic spectra provide a tetrahedral structure for the Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) complexes; square-planar for the Pd(II) complex and octahedral for the Hg(II) complex. The TGA of the complexes depicted the outer and inner water molecules as well as the final residue. The cobalt and cadmium complexes ended with the metal while the Cu(II), Zn(II) and Pd(II) complexes ended with complex species. [Hg(BINH-H)(H2O)2Cl] has no residue. The ligand is inactive against all tested organisms except for Bacillus thuringiensis. The Hg(II) complex is found more active than the other complexes. The flotation technique is found applicable for the separation of micro amount (10 ppm) of Zr4+ using 10 ppm of BINH and 1 × 10-5 mol L-1 of oleic acid at pH 6 with efficiency of 98% with no interferences.

Spectroscopic studies on 2-[2-(4-methylquinolin-2-yl)hydrazono]-1,2-diphenylethanone molecule and its metal complexes

NASA Astrophysics Data System (ADS)

Seleem, H. S.; El-Inany, G. A.; Mousa, M.; Hanafy, F. I.

2009-11-01

The electronic absorption spectra of a hydrazone: 2-[2-(4-methylquinolin-2-yl)hydrazono]-1,2-diphenylethanone (BHQ) derived from 2-hydrazino-4-methylquinoline and 1,2-diphenylethan-1,2-dione (benzil) have been studied in various solvents of different polarities. The dependence of the band shift Δ ύ on the solvent parameters viz.D, Z, ET, DN, AN, α, β and π* was discussed. Also, the effect of pH on the free hydrazone and its Co(II), Ni(II) and Cu(II) complexes was studied spectrophotometrically in 75% (v/v) dioxane-water in order to determine the dissociation and stability constants. The stoichiometry of the formed complexes was determined by three different methods: Job's, mole ratio and slope ratio which indicate the formation of 1:2, M:L complexes for Co(II) and Cu(II) and 1:1, Ni(II):L. Beer's law is valid in the range 0.32-7.04 μg/mL depending on the type of the metal ion. The use of BHQ as an indicator via a spectrophotometric titration of Cu(II) and Ni(II) with EDTA was efficient.

Removal of copper and iron by polyurethane foam column in FIA system for the determination of nickel in pierced ring.

PubMed

Vongboot, Monnapat; Suesoonthon, Monrudee

2015-01-01

Polyurethane foam (PUF) mini-column was used to eliminate copper and iron for the determination of nickel in pierced rings. The PUF mini-column was connected to FIA system for on-line sorption of copper and iron in complexes form of CuSCN(+) and FeSCN(2+). For this season, the acid solution containing a mixture of Ni(II), Fe(III), Cu(II) and SCN(-) ions was firstly flew into the PUF column. Then, the percolated solution which Fe(III) and Cu(II) ions is separated from analysis was injected into FIA system to react with 4-(2-pyridylazo) resorcinol (PAR) reagent in basic condition which this method is called pH gradient technique. The Ni-PAR complexes obtained were measured theirs absorbance at 500 nm by UV visible spectrophotometer. In this study, it was found that Cu(II) and Fe(III) were completely to form complexes with 400 mmol/L KSCN and entirely to eliminate in acidic condition at pH 3.0. In the optimum condition of these experiments, the method provided the linear relationship between absorbance and the concentration of Ni(II) in the range from 5.00 to 30.00 mg/L. Linear equation is y=0.0134x+0.0033 (R(2)=0.9948). Precision, assessed in the term of the relative standard deviation, RSD, and accuracy for multiple determinations obtained in values of 0.77-1.73% and 97.4%, respectively. The level of an average amount of Ni(II) in six piercing rings was evaluated to be 14.78 mg/g. Copyright © 2014 Elsevier B.V. All rights reserved.

Dinuclear complexes containing linear M-F-M [M = Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II)] bridges: trends in structures, antiferromagnetic superexchange interactions, and spectroscopic properties.

PubMed

Reger, Daniel L; Pascui, Andrea E; Smith, Mark D; Jezierska, Julia; Ozarowski, Andrew

2012-11-05

The reaction of M(BF(4))(2)·xH(2)O, where M is Fe(II), Co(II), Ni(II), Cu(II), Zn(II), and Cd(II), with the new ditopic ligand m-bis[bis(3,5-dimethyl-1-pyrazolyl)methyl]benzene (L(m)*) leads to the formation of monofluoride-bridged dinuclear metallacycles of the formula [M(2)(μ-F)(μ-L(m)*)(2)](BF(4))(3). The analogous manganese(II) species, [Mn(2)(μ-F)(μ-L(m)*)(2)](ClO(4))(3), was isolated starting with Mn(ClO(4))(2)·6H(2)O using NaBF(4) as the source of the bridging fluoride. In all of these complexes, the geometry around the metal centers is trigonal bipyramidal, and the fluoride bridges are linear. The (1)H, (13)C, and (19)F NMR spectra of the zinc(II) and cadmium(II) compounds and the (113)Cd NMR of the cadmium(II) compound indicate that the metallacycles retain their structure in acetonitrile and acetone solution. The compounds with M = Mn(II), Fe(II), Co(II), Ni(II), and Cu(II) are antiferromagnetically coupled, although the magnitude of the coupling increases dramatically with the metal as one moves to the right across the periodic table: Mn(II) (-6.7 cm(-1)) < Fe(II) (-16.3 cm(-1)) < Co(II) (-24.1 cm(-1)) < Ni(II) (-39.0 cm(-1)) ≪ Cu(II) (-322 cm(-1)). High-field EPR spectra of the copper(II) complexes were interpreted using the coupled-spin Hamiltonian with g(x) = 2.150, g(y) = 2.329, g(z) = 2.010, D = 0.173 cm(-1), and E = 0.089 cm(-1). Interpretation of the EPR spectra of the iron(II) and manganese(II) complexes required the spin Hamiltonian using the noncoupled spin operators of two metal ions. The values g(x) = 2.26, g(y) = 2.29, g(z) = 1.99, J = -16.0 cm(-1), D(1) = -9.89 cm(-1), and D(12) = -0.065 cm(-1) were obtained for the iron(II) complex and g(x) = g(y) = g(z) = 2.00, D(1) = -0.3254 cm(-1), E(1) = -0.0153, J = -6.7 cm(-1), and D(12) = 0.0302 cm(-1) were found for the manganese(II) complex. Density functional theory (DFT) calculations of the exchange integrals and the zero-field splitting on manganese(II) and iron(II) ions were performed using the hybrid B3LYP functional in association with the TZVPP basis set, resulting in reasonable agreement with experiment.

Synthesis, spectroscopic characterization, antimicrobial and antitumor studies of mono-, bi- and tri-nuclear metal complexes of a new Schiff base ligand derived from o-acetoacetylphenol

NASA Astrophysics Data System (ADS)

Adly, Omima M. I.; Shebl, Magdy; El-Shafiy, Hoda F.; Khalil, Saied M. E.; Taha, A.; Mahdi, Mohammed A. N.

2017-12-01

New mono-, bi- and trinuclear metal complexes of Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and UO2(VI) with a new Schiff base ligand H3L; ((E)-2-hydroxy-N‧-(4-(2-hydroxyphenyl)-4-oxobutan-2-ylidene)) benzohydrazide (H3L) have been synthesized. The ligand and its metal complexes were characterized by elemental analyses, IR, 1H NMR, electronic, ESR and mass spectra, conductivity and magnetic susceptibility measurements as well as thermal analyses. The metal complexes exhibited octahedral and tetrahedral geometrical arrangements. Kinetic parameters (Ea, A, ΔH, ΔS and ΔG) of the thermal decomposition stages have been evaluated using Coats-Redfern equations. Structural parameters of the synthesized compounds were calculated on the basis of DFT level implemented in the Gaussian 09 program and Hyperchem 7.52 and correlated with the experimental data. The antimicrobial activity of the present compounds was screened against Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis), Gram-negative bacteria (Salmonella typhimurium and Escherichia coli), yeast (Candida albicans) and fungus (Aspergillus fumigatus). The antitumor activity of the ligand and its Ni(II) and Cu(II) complexes was investigated against HepG2 cell line.

Nickel-quinolones interaction. Part 4. Structure and biological evaluation of nickel(II)-enrofloxacin complexes compared to zinc(II) analogues.

PubMed

Skyrianou, Kalliopi C; Psycharis, Vassilis; Raptopoulou, Catherine P; Kessissoglou, Dimitris P; Psomas, George

2011-01-01

The nickel(II) complexes with the second-generation quinolone antibacterial agent enrofloxacin in the presence or absence of the nitrogen-donor heterocyclic ligands 1,10-phenanthroline, 2,2'-bipyridine or pyridine have been synthesized and characterized. Enrofloxacin acts as bidentate ligand coordinated to Ni(II) ion through the ketone oxygen and a carboxylato oxygen. The crystal structure of (1,10-phenanthroline)bis(enrofloxacinato)nickel(II) has been determined by X-ray crystallography. UV study of the interaction of the complexes with calf-thymus DNA (CT DNA) has shown that they bind to CT DNA and bis(pyridine)bis(enrofloxacinato)nickel(II) exhibits the highest binding constant to CT DNA. The cyclic voltammograms of the complexes have shown that in the presence of CT DNA the complexes can bind to CT DNA by the intercalative binding mode which has also been verified by DNA solution viscosity measurements. Competitive study with ethidium bromide (EB) has shown that the complexes can displace the DNA-bound EB indicating that they bind to DNA in strong competition with EB. The complexes exhibit good binding propensity to human or bovine serum albumin protein having relatively high binding constant values. The biological properties of the complexes have been evaluated in comparison to the corresponding Zn(II) enrofloxacinato complexes as well as Ni(II) complexes with the first-generation quinolone oxolinic acid. Copyright © 2010 Elsevier Inc. All rights reserved.

trans-Bis(thio­cyanato-κN)tetra­kis­(3,4,5-trimethyl-1H-pyrazole-κN 2)nickel(II)–3,4,5-trimethyl-1H-pyrazole (1/1)

PubMed Central

Hossaini Sadr, Moayad; Engle, James T.; Ziegler, Christopher J.; Soltani, Behzad; Mousavi, Zahra

2011-01-01

In the title compound, [Ni(NCS)2(C6H10N2)4]·C6H10N2, the asymmetric unit comprises a NiII complex and a co-crystallised mol­ecule of 3,4,5-trimethyl-1H-pyrazole (PzMe3). The NiII atom is coordinated by four PzMe3 mol­ecules and two thio­cyanate anions to define a trans N4S2 distorted octa­hedral geometry. A number of intra­molecular N—H⋯N, N—H⋯S and C—H⋯N inter­actions contribute to the stability of the complex. The crystal structure is stabilized by inter­molecular N—H⋯S inter­actions, which link neighbouring mol­ecules into chains along the a axis. PMID:22219831

Nickel(II) biosorption by Rhodotorula glutinis.

PubMed

Suazo-Madrid, Alicia; Morales-Barrera, Liliana; Aranda-García, Erick; Cristiani-Urbina, Eliseo

2011-01-01

The present study reports the feasibility of using Rhodotorula glutinis biomass as an alternative low-cost biosorbent to remove Ni(II) ions from aqueous solutions. Acetone-pretreated R. glutinis cells showed higher Ni(II) biosorption capacity than untreated cells at pH values ranging from 3 to 7.5, with an optimum pH of 7.5. The effects of other relevant environmental parameters, such as initial Ni(II) concentration, shaking contact time and temperature, on Ni(II) biosorption onto acetone-pretreated R. glutinis were evaluated. Significant enhancement of Ni(II) biosorption capacity was observed by increasing initial metal concentration and temperature. Kinetic studies showed that the kinetic data were best described by a pseudo-second-order kinetic model. Among the two-, three-, and four-parameter isotherm models tested, the Fritz-Schluender model exhibited the best fit to experimental data. Thermodynamic parameters (activation energy, and changes in activation enthalpy, activation entropy, and free energy of activation) revealed that the biosorption of Ni(II) ions onto acetone-pretreated R. glutinis biomass is an endothermic and non-spontaneous process, involving chemical sorption with weak interactions between the biosorbent and Ni(II) ions. The high sorption capacity (44.45 mg g(-1) at 25°C, and 63.53 mg g(-1) at 70°C) exhibited by acetone-pretreated R. glutinis biomass places this biosorbent among the best adsorbents currently available for removal of Ni(II) ions from aqueous effluents.

Synthesis, characterization of 1,2,4-triazole Schiff base derived 3d-metal complexes: Induces cytotoxicity in HepG2, MCF-7 cell line, BSA binding fluorescence and DFT study

NASA Astrophysics Data System (ADS)

Tyagi, Prateek; Tyagi, Monika; Agrawal, Swati; Chandra, Sulekh; Ojha, Himanshu; Pathak, Mallika

2017-01-01

Two novel Schiff base ligands H2L1 and H2L2 have been synthesized by condensation reaction of amine derivative of 1,2,4-triazole moiety with 2-hydroxy-4-methoxybenzaldehyde. Co(II), Ni(II), Cu(II) and Zn(II) of the synthesized Schiff bases were prepared by using a molar ratio of ligand:metal as 1:1. The structure of the Schiff bases and synthesized metal complexes were established by 1H NMR, UV-Vis, IR, Mass spectrometry and molar conductivity. The thermal stability of the complexes was study by TGA. Fluorescence quenching mechanism of metal complexes 1-4 show that Zn(II) and Cu(II) complex binds more strongly to BSA. In DFT studies the geometries of Schiff bases and metal complexes were fully optimized with respect to the energy using the 6-31 + g(d,p) basis set. The spectral data shows that the ligands behaves as binegative tridentate. On the basis of the spectral studies, TGA and DFT data an octahedral geometry has been assigned for Co(II), Ni(II), square planar for Cu(II) and tetrahedral for Zn(II) complexes. The anticancer activity were screened against human breast cancer cell line (MCF-7) and human hepatocellular liver carcinoma cell line (Hep-G2). Result indicates that metal complexes shows increase cytotoxicity in proliferation to cell lines as compared to free ligand.

Electrochemical studies of DNA interaction and antimicrobial activities of MnII, FeIII, CoII and NiII Schiff base tetraazamacrocyclic complexes

NASA Astrophysics Data System (ADS)

Kumar, Anuj; Vashistha, Vinod Kumar; Tevatia, Prashant; Singh, Randhir

2017-04-01

Tetraazamacrocyclic complexes of MnII, FeIII, CoII and NiII have been synthesized by template method. These tetraazamacrocycles have been analyzed with various techniques like molar conductance, IR, UV-vis, mass spectral and cyclic voltammetric studies. On the basis of all these studies, octahedral geometry has been assigned to these tetraazamacrocyclic complexes. The DNA binding properties of these macrocyclic complexes have been investigated by electronic absorption spectra, fluorescence spectra, cyclic voltammetric and differential pulse voltammetric studies. The cyclic voltammetric data showed that ipc and ipa were effectively decreased in the presence of calf thymus DNA, which is a strong evidence for the interaction of these macrocyclic complexes with the calf thymus DNA (ct-DNA). The heterogeneous electron transfer rate constant found in the order: KCoII > KNiII > KMnII which indicates that CoII macrocyclic complex has formed a strong intercalated intermediate. The Stern-Volmer quenching constant (KSV) and voltammetric binding constant were found in the order KSV(CoII) > KSV(NiII) > KSV(MnII) and K+(CoII) > K+(NiII) > K+(MnII) which shows that CoII macrocyclic complex exhibits the high interaction affinity towards ct-DNA by the intercalation binding. Biological studies of the macrocyclic complexes compared with the standard drug like Gentamycin, have shown antibacterial activities against E. coli, P. aeruginosa, B. cereus, S. aureus and antifungal activity against C. albicans.

Biosorption of nickel by Lysinibacillus sp. BA2 native to bauxite mine.

PubMed

Prithviraj, Desale; Deboleena, Kashyap; Neelu, Nawani; Noor, Nahar; Aminur, Rahman; Balasaheb, Kapadnis; Abul, Mandal

2014-09-01

The current scenario of environmental pollution urges the need for an effective solution for toxic heavy metal removal from industrial wastewater. Bioremediation is the most cost effective process employed by the use of microbes especially bacteria resistant to toxic metals. In this study, Lysinibacillus sp. BA2, a nickel tolerant strain isolated from bauxite mine was used for the biosorption of Ni(II). Lysinibacillus sp. BA2 biomass had isoelectric point (pI) of 3.3. The maximum negative zeta potential value (-39.45) was obtained at pH 6.0 which was highly favourable for Ni(II) biosorption. 238.04mg of Ni(II) adsorbed on one gram of dead biomass and 196.32mg adsorbed on one gram of live biomass. The adsorption of Ni(II) on biomass increased with time and attained saturation after 180min with rapid biosorption in initial 30min. The Langmuir and Freundlich isotherms could fit well for biosorption of Ni(II) by dead biomass while Langmuir isotherm provided a better fit for live biomass based on correlation coefficient values. The kinetic studies of Ni(II) removal, using dead and live biomass was well explained by second-order kinetic model. Ni(II) adsorption on live biomass was confirmed by SEM-EDX where cell aggregation and increasing irregularity of cell morphology was observed even though cells were in non-growing state. The FTIR analysis of biomass revealed the presence of carboxyl, hydroxyl and amino groups, which seem responsible for biosorption of Ni(II). The beads made using dead biomass of Lysinibacillus sp. BA2 could efficiently remove Ni(II) from effluent solutions. These microbial cells can substitute expensive methods for treating nickel contaminated industrial wastewaters. Copyright © 2014 Elsevier Inc. All rights reserved.

Co(II), Ni(II), Cu(II) and Zn(II) complexes of tridentate ONO donor Schiff base ligand: Synthesis, characterization, thermal, non-isothermal kinetics and DFT calculations

NASA Astrophysics Data System (ADS)

Kusmariya, Brajendra S.; Mishra, A. P.

2017-02-01

We report here four mononuclear Co(II), Ni(II), Cu(II) and Zn(II) coordination compounds of general formula [M(L)2] {L = dcp; M = CoII, CuII & ZnII} and [M(L)(H2O)]·H2O {L = dcp; M = NiII} derived from tridentate 2,4-dichloro-6-{[(3-chloro-2-hydroxy-5-nitrophenyl)imino]methyl}phenol (dcp) ligand. These compounds were synthesized and characterized by elemental analysis, FT-IR, uv-vis, 1H NMR, molar conductance, magnetic moment, thermal, PXRD and SEM-EDX. The Powder X-ray Diffraction patterns and SEM analyses showed the crystalline nature of synthesized compounds. The peak broadening was explained in terms of crystallite size and the lattice strain using Scherrer and Williamson-Hall method. Thermogravimetric analysis was performed to determine the thermal stability of synthesized compounds under nitrogen atmosphere up to 820 K at 10 Kmin-1 heating rate. The kinetic and thermodynamic parameters of thermal decomposition were calculated using Coats-Redfern (C-R), Piloyan-Novikova (P-N) and Horowitz-Metzger (H-M) methods assuming first order degradation. The calculated optical band gap values of complexes were found to be in semiconducting range. To support the experimental findings, and derive some fruitful information viz. frequency calculations, HOMO-LUMO, energy gap (ΔE), molecular electrostatic potential (MEP), spin density, absorption spectra etc.; theoretical calculations by means of DFT and TD-DFT at B3LYP level were incorporated.

Synthesis, investigation and spectroscopic characterization of piroxicam ternary complexes of Fe(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) with glycine and DL-phenylalanine.

PubMed

Mohamed, Gehad G; El-Gamel, Nadia E A

2004-11-01

The ternary piroxicam (Pir; 4-hydroxy-2-methyl-N-(2-pyridyl)-2H-1,2-benzothiazine-3-carboxamide 1,1-dioxide) complexes of Fe(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) with various amino acids (AA) such as glycine (Gly) or DL-phenylalanine (PhA) were prepared and characterized by elemental analyses, molar conductance, IR, UV-Vis, magnetic moment, diffuse reflectance and X-ray powder diffraction. The UV-Vis spectra of Pir and the effect of metal chelation on the different interligand transitions are discussed in detailed manner. IR and UV-Vis spectra confirm that Pir behaves as a neutral bidentate ligand coordinated to the metal ions via the pyridine-N and carbonyl group of the amide moiety. Gly molecule acted as a uninegatively monodentate ligand and coordinate to the metal ions through its carboxylic group, in addition PhA acted as a uninegatively bidentate ligand and coordinate to the metal ions through its carboxylic and amino groups. All the chelates have octahedral geometrical structures while Cu(II)- and Zn(II)-ternary chelates with PhA have square planar geometrical structures. The molar conductance data reveal that most of these chelates are non electrolytes, while Fe(III)-Pir-Gly, Co(II)-, Ni(II)-, Cu(II)- and Zn(II)-Pir-PhA chelates were 1:1 electrolytes. X-ray powder diffraction is used as a new tool to estimate the crystallinity of chelates as well as to elucidate their geometrical structures.

Synthesis, investigation and spectroscopic characterization of piroxicam ternary complexes of Fe(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) with glycine and DL-phenylalanine

NASA Astrophysics Data System (ADS)

Mohamed, Gehad G.; El-Gamel, Nadia E. A.

2004-11-01

The ternary piroxicam (Pir; 4-hydroxy-2-methyl- N-(2-pyridyl)-2H-1,2-benzothiazine-3-carboxamide 1,1-dioxide) complexes of Fe(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) with various amino acids (AA) such as glycine (Gly) or DL-phenylalanine (PhA) were prepared and characterized by elemental analyses, molar conductance, IR, UV-Vis, magnetic moment, diffuse reflectance and X-ray powder diffraction. The UV-Vis spectra of Pir and the effect of metal chelation on the different interligand transitions are discussed in detailed manner. IR and UV-Vis spectra confirm that Pir behaves as a neutral bidentate ligand coordinated to the metal ions via the pyridine- N and carbonyl group of the amide moiety. Gly molecule acted as a uninegatively monodentate ligand and coordinate to the metal ions through its carboxylic group, in addition PhA acted as a uninegatively bidentate ligand and coordinate to the metal ions through its carboxylic and amino groups. All the chelates have octahedral geometrical structures while Cu(II)- and Zn(II)-ternary chelates with PhA have square planar geometrical structures. The molar conductance data reveal that most of these chelates are non electrolytes, while Fe(III)-Pir-Gly, Co(II)-, Ni(II)-, Cu(II)- and Zn(II)-Pir-PhA cheletes were 1:1 electrolytes. X-ray powder diffraction is used as a new tool to estimate the crystallinity of chelates as well as to elucidate their geometrical structures.

Porous silicon powder as an adsorbent of heavy metal (nickel)

NASA Astrophysics Data System (ADS)

Nabil, Marwa; Motaweh, Hussien A.

2018-04-01

New and inexpensive nanoporous silicon (NPS) powder was prepared by alkali chemical etching using sonication technique and was subsequently investigated as an adsorbent in batch systems for the adsorption Ni(II) ions in an aqueous solution. The optimum conditions for the Ni(II) ion adsorption capacity of the NPS powder were studied in detail by varying parameters such as the initial Ni(II) concentration, the solution pH value, the adsorption temperature and contact time. The results indicated that the maximum adsorption capacity and the maximum removal percent of Ni(II) reached 2665.33 mg/g and 82.6%, respectively, at an initial Ni(II) concentration of 100 mg/L, adsorption time of 30 min and no effect of the solution pH and adsorption temperature.

p53 activation by Ni(II) is a HIF-1α independent response causing caspases 9/3-mediated apoptosis in human lung cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wong, Victor C.; Morse, Jessica L.; Zhitkovich, Anatoly, E-mail: anatoly_zhitkovich@brown.edu

2013-06-15

Hypoxia mimic nickel(II) is a human respiratory carcinogen with a suspected epigenetic mode of action. We examined whether Ni(II) elicits a toxicologically significant activation of the tumor suppressor p53, which is typically associated with genotoxic responses. We found that treatments of H460 human lung epithelial cells with NiCl{sub 2} caused activating phosphorylation at p53-Ser15, accumulation of p53 protein and depletion of its inhibitor MDM4 (HDMX). Confirming the activation of p53, its knockdown suppressed the ability of Ni(II) to upregulate MDM2 and p21 (CDKN1A). Unlike DNA damage, induction of GADD45A by Ni(II) was p53-independent. Ni(II) also increased p53-Ser15 phosphorylation and p21more » expression in normal human lung fibroblasts. Although Ni(II)-induced stabilization of HIF-1α occurred earlier, it had no effect on p53 accumulation and Ser15 phosphorylation. Ni(II)-treated H460 cells showed no evidence of necrosis and their apoptosis and clonogenic death were suppressed by p53 knockdown. The apoptotic role of p53 involved a transcription-dependent program triggering the initiator caspase 9 and its downstream executioner caspase 3. Two most prominently upregulated proapoptotic genes by Ni(II) were PUMA and NOXA but only PUMA induction required p53. Knockdown of p53 also led to derepression of antiapoptotic MCL1 in Ni(II)-treated cells. Overall, our results indicate that p53 plays a major role in apoptotic death of human lung cells by Ni(II). Chronic exposure to Ni(II) may promote selection of resistant cells with inactivated p53, providing an explanation for the origin of p53 mutations by this epigenetic carcinogen. - Highlights: • Ni(II) is a strong activator of the transcription factor p53. • Apoptosis is a principal form of death by Ni(II) in human lung epithelial cells. • Ni(II)-activated p53 triggers caspases 9/3-mediated apoptotic program. • NOXA and PUMA are two main proapoptotic genes induced by Ni(II). • HIF-1α and p53 are independent stress responses to hypoxia-mimicking Ni(II)« less

Synthesis, spectroscopic, molecular structure, antioxidant, antimicrobial and antitumor behavior of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes of O2N type tridentate chromone-2-carboxaldehyde Schiff's base ligand

NASA Astrophysics Data System (ADS)

Ammar, Reda A.; Alaghaz, Abdel-Nasser M. A.; Zayed, Mohamed E.; Al-Bedair, Lamia A.

2017-08-01

Tridentate Schiff's base (HL) ligand was synthesized via condensation of salicylaldehyde and 3-hydroxypyridin-2-yliminomethyl-4H-chromen-4-one and their corresponding Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes have been synthesized. The isolated solid complexes were characterized by elemental analyses, molar conductance, spectral (IR, UV-Vis, 1H NMR), magnetic moment, EPR, and thermal measurements. The IR spectra showed that HL was coordinated to the metal ions in tridentate manner with O2N donor sites of the azomethine N, deprotonated phenolic-OH and carbonyl-O. The activation of thermodynamic parameters are calculated using Coast-Redfern and Horowitz-Metzger (HM). The octahedral geometry of the complexes is confirmed using DFT method from DMOL3 calculations, UV-Vis and magnetic moment measurements, ESR and ligand field parameters. Antioxidant activities have also been performed for all the compounds. The investigated ligand and metal complexes were screened for their in-vitro antimicrobial activities against different types of fungal and bacterial strains. The resulting data assert on the inspected compounds as a highly promising bactericides and fungicides. The antitumor activities of all inspected compounds were evaluated towards human liver Carcinoma (HepG2) cell line.

Synthesis, spectroscopic characterization, electrochemistry and biological evaluation of some binuclear transition metal complexes of bicompartmental ONO donor ligands containing benzo[b]thiophene moiety

NASA Astrophysics Data System (ADS)

Mahendra Raj, K.; Vivekanand, B.; Nagesh, G. Y.; Mruthyunjayaswamy, B. H. M.

2014-02-01

A series of new binucleating Cu(II), Co(II), Ni(II) and Zn(II) complexes of bicompartmental ligands with ONO donor were synthesized. The ligands were obtained by the condensation of 3-chloro-6-substituted benzo[b]thiophene-2-carbohydrazides and 4,6-diacetylresorcinol. The synthesized ligands and their complexes were characterized by elemental analysis and various spectroscopic techniques. Elemental analysis, IR, 1H NMR, ESI-mass, UV-Visible, TG-DTA, magnetic measurements, molar conductance and powder-XRD data has been used to elucidate their structures. The bonding sites are the oxygen atom of amide carbonyl, azomethine nitrogen and phenolic oxygen for ligands 1 and 2. The binuclear nature of the complexes was confirmed by ESR spectral data. TG-DTA studies for some complexes showed the presence of coordinated water molecules and the final product is the metal oxide. All the complexes were investigated for their electrochemical activity, only the Cu(II) complexes showed the redox property. Cu(II) complexes were square planar, whereas Co(II), Ni(II) and Zn(II) complexes were octahedral. Powder-XRD pattern have been studied in order to test the degree of crystallinity of the complexes and unit cell calculations were made. In order to evaluate the effect of antimicrobial activity of metal ions upon chelation, both the ligands and their metal complexes were screened for their antibacterial and antifungal activities by minimum inhibitory concentration (MIC) method. The results showed that the metal complexes were found to be more active than free ligands. The DNA cleaving capacities of all the complexes were analyzed by agarose gel electrophoresis method against supercoiled plasmid DNA. Among the compounds tested for antioxidant capacity, ligand 1 displayed excellent activity than its metal complexes.

Kinetic studies for Ni(II) biosorption from industrial wastewater by Cassia fistula (Golden Shower) biomass.

PubMed

Hanif, Muhammad Asif; Nadeem, Raziya; Zafar, Muhammad Nadeem; Akhtar, Kalsoom; Bhatti, Haq Nawaz

2007-07-16

The present study explores the ability of Cassia fistula waste biomass to remove Ni(II) from industrial effluents. C. fistula biomass was found very effective for Ni(II) removal from wastewater of Ghee Industry (GI), Nickel Chrome Plating Industry (Ni-Cr PI), Battery Manufacturing Industry (BMI), Tanner Industry: Lower Heat Unit (TILHU), Tannery Industry: Higher Heat Unit (TIHHU), Textile Industry: Dying Unit (TIDU) and Textile Industry: Finishing Unit (TIFU). The initial Ni(II) concentration in industrial effluents was found to be 34.89+/-0.01, 183.56+/-0.08, 21.19+/-0.01, 43.29+/-0.03, 47.26+/-0.02, 31.38+/-0.01 and 31.09+/-0.01mg/L in GI, Ni-Cr PI, BMI, TILHU, TIHHU, TIDU and TIFU, respectively. After biosorption the final Ni(II) concentration in industrial effluents was found to be 0.05+/-0.01, 17.26+/-0.08, 0.03+/-0.01, 0.05+/-0.01, 0.1+/-0.01, 0.07+/-0.01 and 0.06+/-0.01mg/L in GI, Ni-Cr PI, BMI, TILHU, TIHHU, TIDU and TIFU, respectively. The % sorption Ni(II) ability of C. fistula from seven industries included in present study tend to be in following order: TILHU (99.88)>GI (99.85) approximately BMI (99.85)>TIFU (99.80)>TIHHU (99.78)>TIDU (99.77)>Ni-Cr PI (90.59). Sorption kinetic experiments were performed in order to investigate proper sorption time for Ni(II) removal from wastewater. Batch metal ion uptake capacity experiments indicated that sorption equilibrium reached much faster in case of industrial wastewater samples (480min) in comparison to synthetic wastewater (1440min) using same biosorbent. The kinetic data were analyzed in term of pseudo-first-order and pseudo-second-order expressions. Pseudo-second-order model described well the sorption kinetics of Ni(II) onto C. fistula biomass from industrial effluents in comparison to pseudo-first-order kinetic model. Due to unique high Ni(II) sorption capacity of C. fistula waste biomass it can be concluded that it is an excellent biosorbent for Ni(II) uptake from industrial effluents.

DNA incision evaluation, binding investigation and biocidal screening of Cu(II), Ni(II) and Co(II) complexes with isoxazole Schiff bases.

PubMed

Ganji, Nirmala; Chityala, Vijay Kumar; Marri, Pradeep Kumar; Aveli, Rambabu; Narendrula, Vamsikrishna; Daravath, Sreenu; Shivaraj

2017-10-01

Two new series of binary metal complexes [M(L 1 ) 2 ] and [M(L 2 ) 2 ] where, M=Cu(II), Ni(II) & Co(II) and L 1 =4-((3,4-dimethylisoxazol-5-ylimino)methyl)benzene-1,3-diol; L 2 =2-((3,4-dimethylisoxazol-5-ylimino)methyl)-5-methoxyphenol were synthesized and characterized by elemental analysis, 1 H NMR, 13 C NMR, FT-IR, ESI mass, UV-Visible, magnetic moment, ESR, SEM and powder XRD studies. Based on these results, a square planar geometry is assigned for all the metal complexes where the Schiff base acts as uninegatively charged bidentate chelating agent via the hydroxyl oxygen and azomethine nitrogen atoms. DNA binding studies of all the complexes with calf thymus DNA have been comprehensively investigated using electronic absorption spectroscopy, fluorescence quenching and viscosity studies. The oxidative and photo cleavage affinity of metal complexes towards supercoiled pBR322 DNA has been ascertained by agarose gel electrophoresis assay. From the results, it is observed that all the metal complexes bind effectively to CT-DNA via an intercalative mode of binding and also cleave pBR322 DNA in a promising manner. Further the Cu(II) complexes have shown better binding and cleavage properties towards DNA. The antimicrobial activities of the Schiff bases and their metal complexes were studied on bacterial and fungal strains and the results denoted that the complexes are more potent than their Schiff base ligands. Copyright © 2017 Elsevier B.V. All rights reserved.

A novel tridentate coordination mode for the carbonatonickel system exhibited in an unusual hexanuclear nickel(II) mu3-carbonato-bridged complex.

PubMed

Anderson, James C; Blake, Alexander J; Moreno, Rafael Bou; Raynel, Guillaume; van Slageren, Joris

2009-11-14

The fixation of CO(2) at ambient temperature has been achieved by the reaction of Ni(cod)(2) and TMEDA in CO(2) saturated THF that yields a novel hexanuclear nickel(II) mu(3)-carbonato bridged complex [Ni(6)(mu(3)-CO(3))(4)(TMEDA)(6)(H(2)O)(12)](OH)(4) in 59% yield. The complex was characterised by MS analysis and the structure corroborated by single-crystal X-ray crystallography. The complex exhibits a rare carbonato binding mode for Ni(II) complexes and moderately strong antiferromagnetic interactions.

Symmetrical and unsymmetrical pincer complexes with group 10 metals: synthesis via aryl C-H activation and some catalytic applications.

PubMed

Niu, Jun-Long; Hao, Xin-Qi; Gong, Jun-Fang; Song, Mao-Ping

2011-05-21

Aryl-based pincer metal complexes with anionic terdentate ligands have been widely applied in organic synthesis, organometallic catalysis and other related areas. Synthetically, the most simple and convenient method for the construction of these complexes is the direct metal-induced C(aryl)-H bond activation, which can be fulfilled by choosing the appropriate functional donor groups in the two side arms of the aryl-based pincer preligands. In this perspective, we wish to summarize some results achieved by our group in this context. Successful examples include symmetrical chiral bis(imidazoline) NCN pincer complexes with Ni(II), Pd(II) and Pt(II), bis(phosphinite) and bis(phosphoramidite) PCP pincer Pd(II) complexes, unsymmetrical (pyrazolyl)phosphinite, (amino)phosphinite and (imino)phosphinite PCN pincer Pd(II) complexes, chiral (imidazolinyl)phosphinite and (imidazolinyl)phosphoramidite PCN pincer complexes with Ni(II) and Pd(II) as well as unsymmetrical (oxazolinyl)amine and (oxazolinyl)pyrazole NCN' pincer Pd(II) complexes. Among them, the P-donor containing complexes are efficiently synthesized by the "one-pot phosphorylation/metalation" method. The obtained symmetrical and unsymmetrical pincer complexes have been used as catalysts in Suzuki-Miyaura reaction (Pd), asymmetric Friedel-Crafts alkylation of indole with trans-β-nitrostyrene (Pt) as well as in asymmetric allylation of aldehyde and sulfonimine (Pd). In the Suzuki couplings conducted at 40-50 °C, some unsymmetrical Pd complexes exhibit much higher activity than the related symmetrical ones which can be attributed to their faster release of active Pd(0) species resulting from the hemilabile coordination of the ligands. Literature results on the synthesis of some related pincer complexes as well as their activities in the above catalytic reactions are also presented.

Involvement of organic acids and amino acids in ameliorating Ni(II) toxicity induced cell cycle dysregulation in Caulobacter crescentus: a metabolomics analysis.

PubMed

Jain, Abhishek; Chen, Wei Ning

2018-05-01

Nickel (Ni(II)) toxicity is addressed by many different bacteria, but bacterial responses to nickel stress are still unclear. Therefore, we studied the effect of Ni(II) toxicity on cell proliferation of α-proteobacterium Caulobacter crescentus. Next, we showed the mechanism that allows C. crescentus to survive in Ni(II) stress condition. Our results revealed that the growth of C. crescentus is severely affected when the bacterium was exposed to different Ni(II) concentrations, 0.003 mM slightly affected the growth, 0.008 mM reduced the growth by 50%, and growth was completely inhibited at 0.015 mM. It was further shown that Ni(II) toxicity induced mislocalization of major regulatory proteins such as MipZ, FtsZ, ParB, and MreB, resulting in dysregulation of the cell cycle. GC-MS metabolomics analysis of Ni(II) stressed C. crescentus showed an increased level of nine important metabolites including TCA cycle intermediates and amino acids. This indicates that changes in central carbon metabolism and nitrogen metabolism are linked with the disruption of cell division process. Addition of malic acid, citric acid, alanine, proline, and glutamine to 0.015 mM Ni(II)-treated C. crescentus restored its growth. Thus, the present work shows a protective effect of these organic acids and amino acids on Ni(II) toxicity. Metabolic stimulation through the PutA/GlnA pathway, accelerated degradation of CtrA, and Ni-chelation by organic acids or amino acids are some of the possible mechanisms suggested to be involved in enhancing C. crescentus's tolerance. Our results shed light on the mechanism of increased Ni(II) tolerance in C. crescentus which may be useful in bioremediation strategies and synthetic biology applications such as the development of whole cell biosensor.

Spectral Characterization and 3D Molecular Modeling Studies of Metal Complexes Involving the O, N-Donor Environment of Quinazoline-4(3H)-one Schiff Base and Their Biological Studies

PubMed Central

Siddappa, Kuruba; Mane, Sunilkumar B.

2014-01-01

A simple condensation of 3-amino-2-methylquinazoline-4-one with 2-hydroxy-1-naphthaldehyde produced new tridentate ONO donor Schiff base ligand with efficient yield. The structural characterization of ligand and its Cu(II), Ni(II), Co(II), Mn(II), Zn(II), and Cd(II) complexes were achieved by the aid of elemental analysis, spectral characterization such as (UV-visible, IR, NMR, mass, and ESR), and magnetic data. The analytical and spectroscopic studies suggest the octahedral geometries of Cu(II), Co(II), Ni(II) and Mn(II) complexes and tetrahedral geometry of Zn(II) and Cd(II) complexes with the tridentate ONO Schiff base ligand. Furthermore, the conclusions drawn from these studies afford further support to the mode of bonding discussed on the basis of their 3D molecular modeling studies by considering different bond lengths, bond angles, and bond distance. The ligand and its metal complexes evaluated for their antimicrobial activity against Staphylococcus aureus (MTCC number 7443), Bacillus subtilis (MTCC number 9878), Escherichia coli (MTCC number 1698), Aspergillus niger (MTCC number 281), and Aspergillus flavus (MTCC number 277). The MIC of these compounds was found to be most active at 10 μg/mL concentration in inhibiting the growth of the tested organisms. The DNA cleavage activity of all the complexes was studied by gel electrophoresis method. PMID:24678278

Nickel(II) and copper(II) complexes of N,N-dialkyl-N‧-3-chlorobenzoylthiourea: Synthesis, characterization, crystal structures, Hirshfeld surfaces and antimicrobial activity

NASA Astrophysics Data System (ADS)

Binzet, Gun; Gumus, Ilkay; Dogen, Aylin; Flörke, Ulrich; Kulcu, Nevzat; Arslan, Hakan

2018-06-01

We synthesized four new N,N-dialkyl-N‧-3-chlorobenzoylthiourea ligands (Alkyl: Dimethyl, diethyl, di-n-propyl and di-n-butyl) and their metal complexes with copper and nickel atoms. The structure of all synthesized compounds was fully characterized by physicochemical, spectroscopic and single crystal X-ray diffraction analysis techniques. The physical, spectral and analytical data of the newly synthesized metal complexes have shown the formation of 1:2 (metal:ligand) ratio. The benzoylthiourea ligands coordinate with metal atoms through oxygen and sulphur atoms. The metal atoms are in slightly distorted square-planar coordination geometry in Ni(II) or Cu(II) complex. Two oxygen and two sulphur atoms are mutually cis to each other in Ni(II) or Cu(II) complex. The intermolecular contacts in the compounds, which are HL1 and HL3, were examined by Hirshfeld surfaces and fingerprint plots using the data obtained from X-ray single crystal diffraction measurement. Besides these, their antimicrobial activities against Gram-positive bacteria (Bacillus subtilis, Staphylococcus aureus, Streptococcus pyogenes and Enterococcus faecalis) and Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) and anti-yeast activity (Candida glabrata, Candida parapsilosis and Candida albicans) were investigated. This exhibited some promising results towards testing organism. Among all the compounds, Ni(L1)2 complex showed high activity against Bacillus subtilis with MIC values at 7.81 μg/mL.

Relationship between Ni(II) and Zn(II) Coordination and Nucleotide Binding by the Helicobacter pylori [NiFe]-Hydrogenase and Urease Maturation Factor HypB*

PubMed Central

Sydor, Andrew M.; Lebrette, Hugo; Ariyakumaran, Rishikesh; Cavazza, Christine; Zamble, Deborah B.

2014-01-01

The pathogen Helicobacter pylori requires two nickel-containing enzymes, urease and [NiFe]-hydrogenase, for efficient colonization of the human gastric mucosa. These enzymes possess complex metallocenters that are assembled by teams of proteins in multistep pathways. One essential accessory protein is the GTPase HypB, which is required for Ni(II) delivery to [NiFe]-hydrogenase and participates in urease maturation. Ni(II) or Zn(II) binding to a site embedded in the GTPase domain of HypB modulates the enzymatic activity, suggesting a mechanism of regulation. In this study, biochemical and structural analyses of H. pylori HypB (HpHypB) revealed an intricate link between nucleotide and metal binding. HpHypB nickel coordination, stoichiometry, and affinity were modulated by GTP and GDP, an effect not observed for zinc, and biochemical evidence suggests that His-107 coordination to nickel toggles on and off in a nucleotide-dependent manner. These results are consistent with the crystal structure of HpHypB loaded with Ni(II), GDP, and Pi, which reveals a nickel site distinct from that of zinc-loaded Methanocaldococcus jannaschii HypB as well as subtle changes to the protein structure. Furthermore, Cys-142, a metal ligand from the Switch II GTPase motif, was identified as a key component of the signal transduction between metal binding and the enzymatic activity. Finally, potassium accelerated the enzymatic activity of HpHypB but had no effect on the other biochemical properties of the protein. Altogether, this molecular level information about HpHypB provides insight into its cellular function and illuminates a possible mechanism of metal ion discrimination. PMID:24338018

Relationship between Ni(II) and Zn(II) coordination and nucleotide binding by the Helicobacter pylori [NiFe]-hydrogenase and urease maturation factor HypB.

PubMed

Sydor, Andrew M; Lebrette, Hugo; Ariyakumaran, Rishikesh; Cavazza, Christine; Zamble, Deborah B

2014-02-14

The pathogen Helicobacter pylori requires two nickel-containing enzymes, urease and [NiFe]-hydrogenase, for efficient colonization of the human gastric mucosa. These enzymes possess complex metallocenters that are assembled by teams of proteins in multistep pathways. One essential accessory protein is the GTPase HypB, which is required for Ni(II) delivery to [NiFe]-hydrogenase and participates in urease maturation. Ni(II) or Zn(II) binding to a site embedded in the GTPase domain of HypB modulates the enzymatic activity, suggesting a mechanism of regulation. In this study, biochemical and structural analyses of H. pylori HypB (HpHypB) revealed an intricate link between nucleotide and metal binding. HpHypB nickel coordination, stoichiometry, and affinity were modulated by GTP and GDP, an effect not observed for zinc, and biochemical evidence suggests that His-107 coordination to nickel toggles on and off in a nucleotide-dependent manner. These results are consistent with the crystal structure of HpHypB loaded with Ni(II), GDP, and Pi, which reveals a nickel site distinct from that of zinc-loaded Methanocaldococcus jannaschii HypB as well as subtle changes to the protein structure. Furthermore, Cys-142, a metal ligand from the Switch II GTPase motif, was identified as a key component of the signal transduction between metal binding and the enzymatic activity. Finally, potassium accelerated the enzymatic activity of HpHypB but had no effect on the other biochemical properties of the protein. Altogether, this molecular level information about HpHypB provides insight into its cellular function and illuminates a possible mechanism of metal ion discrimination.

Cytogenetic toxicity effects of inorganic nickel and organic Ni(II) complexes on Brassica oleracea L. root meristem.

PubMed

Molas, J

2001-01-01

Experiments were carried out on the effect of nickel as an inorganic compound (NiSO4.7H2O) and organic Ni(II) complexes (i.e. Ni(II)-Glu and Ni(II)-EDTA) in concentrations of 20, 40 and 85 ?M dm-3 on meristematic cells of root tips of Brassica oleracea L. cv. Sława from Enkhouizen. All three tested chemical forms of nickel had a mitodepressive effect and inhibited root elongation. With respect to the degree of root elongation inhibition and mitodepressive effect, the tested forms of nickel can be put in the following order: Ni(II)-Glu NiSO4.7H2O Ni(II)-EDTA. In all three tested forms, nickel caused disturbances in mitotic divisions, resulting in anaphase bridges and binuclear cells, whose nuclei were joined by a bridge of condensed chromatin or separated. Inorganic nickel and Ni(II)-Glu in higher concentrations damaged nuclei (the amount of condensed chromatin increased), nucleoli (their structure became more condensed and vacuolisation was observed), endoplasmic reticulum (fragmentation, swelling of cisternae) and mitochondria (structure condensation).

Application of novel Ni(II) complex and ZrO2 nanoparticle as mediators for electrocatalytic determination of N-acetylcysteine in drug samples.

PubMed

Karimi-Maleh, Hassan; Salehi, Mehdi; Faghani, Fatemeh

2017-10-01

The electrooxidation of N-acetylcysteine (N-AC) was studied by a novel Ni(II) complex modified ZrO 2 nanoparticle carbon paste electrode [Ni(II)/ZrO 2 /NPs/CPE] using voltammetric methods. The results showed that Ni(II)/ZrO 2 /NPs/CPE had high electrocatalytic activity for the electrooxidation of N-AC in aqueous buffer solution (pH = 7.0). The electrocatalytic oxidation peak currents increase linearly with N-AC concentrations over the concentration ranges of 0.05-600μM using square wave voltammetric methods. The detection limit for N-AC was equal to 0.009μM. The catalytic reaction rate constant, k h , was calculated (7.01 × 10 2  M -1  s -1 ) using the chronoamperometry method. Finally, Ni(II)/ZrO 2 /NPs/CPE was also examined as an ultrasensitive electrochemical sensor for the determination of N-AC in real samples such as tablet and urine. Copyright © 2017. Published by Elsevier B.V.

Synthesis, characterization, crystal structure and DNA-binding studies of transition metal hydrazone complexes

NASA Astrophysics Data System (ADS)

Kanchanadevi, S.; Parveen, S.; Mahalingam, V.

2018-04-01

Three new complexes containing salicylaldazine (HL) ligand were synthesised by reacting suitable precursor complex [MCl2(PPh3)2] with the ligand (where M = Cu(II) or Ni(II) or Co(II)). The new complexes were characterised by various spectral studies such as IR, UV-Vis,1H NMR,EPR,fluorescence and elemental analyses. The binding modes of the complexes with HS-DNA have been studied by UV-Vis absorption titration. Binding of the complexes with bovine serum albumin (BSA) protein has been investigated using UV-visible, fluorescence and synchronous fluorescence spectroscopic methods. Redox behaviour of the complexes has been investigated by cyclic voltammetry.

Efficient flow injection and sequential injection methods for spectrophotometric determination of oxybenzone in sunscreens based on reaction with Ni(II).

PubMed

Chisvert, A; Salvador, A; Pascual-Martí, M C; March, J G

2001-04-01

Spectrophotometric determination of a widely used UV-filter, such as oxybenzone, is proposed. The method is based on the complexation reaction between oxybenzone and Ni(II) in ammoniacal medium. The stoichiometry of the reaction, established by the Job method, was 1:1. Reaction conditions were studied and the experimental parameters were optimized, for both flow injection (FI) and sequential injection (SI) determinations, with comparative purposes. Sunscreen formulations containing oxybenzone were analyzed by the proposed methods and results compared with those obtained by HPLC. Data show that both FI and SI procedures provide accurate and precise results. The ruggedness, sensitivity and LOD are adequate to the analysis requirements. The sample frequency obtained by FI is three-fold higher than that of SI analysis. SI is less reagent-consuming than FI.

Synthesis, characterization and in vitro anticancer activity of 18-membered octaazamacrocyclic complexes of Co(II), Ni(II), Cd(II) and Sn(II)

NASA Astrophysics Data System (ADS)

Kareem, Abdul; Zafar, Hina; Sherwani, Asif; Mohammad, Owais; Khan, Tahir Ali

2014-10-01

An effective series of 18 membered octaazamacrocyclic complexes of the type [MLX2], where X = Cl or NO3 have been synthesized by template condensation reaction of oxalyl dihydrazide with dibenzoylmethane and metal salt in 2:2:1 molar ratio. The formation of macrocyclic framework, stereochemistry and their overall geometry have been characterized by various physico-chemical studies viz., elemental analysis, electron spray ionization-mass spectrometry (ESI-MS), I.R, UV-Vis, 1H NMR, 13C NMR spectroscopy, X-ray diffraction (XRD) and TGA/DTA studies. These studies suggest formation of octahedral macrocyclic complexes of Co(II), Ni(II), Cd(II) and Sn(II). The molar conductance values suggest nonelectrolytic nature for all the complexes. Thermogravimatric analysis shows that all the complexes are stable up to 600 °C. All these complexes have been tested against different human cancer cell lines i.e. human hepatocellular carcinoma (Hep3B), human cervical carcinoma (HeLa), human breast adenocarcinoma (MCF7) and normal cells (PBMC). The newly synthesized 18-membered octaazamacrocyclic complexes during in vitro anticancer evaluation, displayed moderate to good cytotoxicity on liver (Hep3B), cervical (HeLa) and breast (MCF7) cancer cell lines, respectively. The most effective anticancer cadmium complex (C34H28N10CdO10) was found to be active with IC50 values, 2.44 ± 1.500, 3.55 ± 1.600 and 4.82 ± 1.400 in micro-molar on liver, cervical and breast cancer cell lines, respectively.

Synthesis, spectroscopic and DNA binding ability of CoII, NiII, CuII and ZnII complexes of Schiff base ligand (E)-1-(((1H-benzo[d]imidazol-2-yl)methylimino)methyl)naphthalen-2-ol. X-ray crystal structure determination of cobalt (II) complex.

PubMed

Yarkandi, Naeema H; El-Ghamry, Hoda A; Gaber, Mohamed

2017-06-01

A novel Schiff base ligand, (E)-1-(((1H-benzo[d]imidazol-2-yl)methylimino)methyl)naphthalen-2-ol (HL), has been designed and synthesized in addition to its metal chelates [Co(L) 2 ]·l2H 2 O, [Ni(L)Cl·(H 2 O) 2 ].5H 2 O, [Cu(L)Cl] and [Zn(L)(CH 3 COO)]. The structures of the isolated compounds have been confirmed and identified by means of different spectral and physicochemical techniques including CHN analysis, 1 H & 13 C NMR, mass spectral analysis, molar conductivity measurement, UV-Vis, infrared, magnetic moment in addition to TGA technique. The infrared spectral results ascertained that the ligand acts as monobasic tridentate binding to the metal centers via deprotonated hydroxyl oxygen, azomethine and imidazole nitrogen atoms. The UV-Vis, magnetic susceptibility and molar conductivity data implied octahedral geometry for Co(II) & Ni(II) complexes, tetrahedral for Zn(II) complex and square planar for Cu(II) complex. X-ray structural analysis of Co(II) complex 1 has been reported and discussed. Moreover, the type of interaction between the ligand & its complexes towards salmon sperm DNA (SS-DNA) has been examined by the measurement of absorption spectra and viscosity which confirmed that the ligand and its complexes interact with DNA via intercalation interaction as concluded from the values of binding constants (K b ). Copyright © 2017 Elsevier B.V. All rights reserved.

Spectral, thermal, kinetic, molecular modeling and eukaryotic DNA degradation studies for a new series of albendazole (HABZ) complexes

NASA Astrophysics Data System (ADS)

El-Metwaly, Nashwa M.; Refat, Moamen S.

2011-01-01

This work represents the elaborated investigation for the ligational behavior of the albendazole ligand through its coordination with, Cu(II), Mn(II), Ni(II), Co(II) and Cr(III) ions. Elemental analysis, molar conductance, magnetic moment, spectral studies (IR, UV-Vis and ESR) and thermogravimetric analysis (TG and DTG) have been used to characterize the isolated complexes. A deliberate comparison for the IR spectra reveals that the ligand coordinated with all mentioned metal ions by the same manner as a neutral bidentate through carbonyl of ester moiety and NH groups. The proposed chelation form for such complexes is expected through out the preparation conditions in a relatively acidic medium. The powder XRD study reflects the amorphous nature for the investigated complexes except Mn(II). The conductivity measurements reflect the non-electrolytic feature for all complexes. In comparing with the constants for the magnetic measurements as well as the electronic spectral data, the octahedral structure was proposed strongly for Cr(III) and Ni(II), the tetrahedral for Co(II) and Mn(II) complexes but the square-pyramidal for the Cu(II) one. The thermogravimetric analysis confirms the presence or absence of water molecules by any type of attachments. Also, the kinetic parameters are estimated from DTG and TG curves. ESR spectrum data for Cu(II) solid complex confirms the square-pyramidal state is the most fitted one for the coordinated structure. The albendazole ligand and its complexes are biologically investigated against two bacteria as well as their effective effect on degradation of calf thymus DNA.

Synthesis, spectroscopic characterization, electrochemistry and biological evaluation of some metal (II) complexes with ONO donor ligand containing benzo[b]thiophene and coumarin moieties

NASA Astrophysics Data System (ADS)

Mahendra Raj, K.; Mruthyunjayaswamy, B. H. M.

2014-09-01

Schiff base ligand 3-chloro-N‧-((7-hydroxy-4-methyl-2-oxo-2H-chromen-8-yl)methylene)benzo[b]thiophene-2-carbohydrazide and its Cu(II), Co(II), Ni(II) and Zn(II) complexes were synthesized, characterized by elemental analysis and various physico-chemical techniques like, IR, 1H NMR, ESI-mass, UV-Visible, thermogravimetry - differential thermal analysis, magnetic measurements and molar conductance. Spectral analysis indicates octahedral geometry for all the complexes. Cu(II) complex have 1:1 stoichiometry of the type [M(L)(Cl)(H2O)2], whereas Co(II), Ni(II) and Zn(II) complexes have 1:2 stoichiometric ratio of the type [M(L)2]. The bonding sites are the oxygen atom of amide carbonyl, nitrogen of azomethine function and phenolic oxygen of the Schiff base ligand via deprotonation. The thermogravimetry - differential thermal analysis studies gave evidence for the presence of coordinated water molecules in the composition of Cu(II) complex which was further supported by IR measurements. All the complexes were investigated for their electrochemical activity, but only the Cu(II) complex showed the redox property. In order to evaluate the effect of antimicrobial potency of metal ions upon chelation, ligand and its metal complexes along with their respective metal chlorides were screened for their antibacterial and antifungal activities by minimum inhibitory concentration (MIC) method. The results showed that the metal complexes were found to be more active than free ligand. Ligand and its complexes were screened for free radical scavenging activity by DPPH method and DNA cleavage activity using Calf-thymus DNA (Cat. No-105850).

Interaction with biomacromolecules and antiproliferative activities of Mn(II), Ni(II), Zn(II) complexes of demethylcantharate and 2,2'-bipyridine

NASA Astrophysics Data System (ADS)

Zhang, Fan; Lin, Qiu-Yue; Hu, Wan-Li; Song, Wen-Ji; Shen, Shu-Ting; Gui, Pan

2013-06-01

Three new transition metal complexes [Mn2(DCA)2(bipy)2]·5H2O (1), [M2(DCA)2(bipy)2(H2O)]·10H2O(M = Ni(II)(2);Zn(II)(3)), (DCA = demethylcantharate, 7-oxabicyclo[2,2,1]heptane-2,3-dicarboxylate, C8H8O5) were synthesized and characterized by elemental analysis, molar conductance, infrared spectra and X-ray diffraction techniques. Each metal ion was six-coordinated in complexes. Complex 1 has a Mn2O2 center. Complexes 2 and 3 have asymmetric binuclear structure. Great amount of intermolecular hydrogen-bonding and π-π* stacking interactions were formed in these complex structures. The DNA-binding properties of complexes were investigated by electronic absorption spectra and viscosity measurements. The DNA binding constants Kb/(L mol-1) were 1.71 × 104 (1), 2.62 × 104 (2) and 1.59 × 104 (3) at 298 K. The complexes could quench the intrinsic fluorescence of bovine serum albumin (BSA) strongly through static quenching. The protein binding constants Ka/(L mol-1) were 7.27 × 104 (1), 4.55 × 104 (2) and 7.87 × 104 L mol-1 (3) and binding site was one. The complexes bind more tightly with DNA and BSA than with ligands. Complexes 1 and 3 had stronger inhibition ratios than Na2(DCA) against human hepatoma cells (SMMC-7721) lines and human gastric cancer cells (MGC80-3) lines in vitro. Complex 3 showed the strongest antiproliferative activity against SMMC-7721 (IC50 = 29.46 ± 2.12 μmol L-1) and MGC80-3 (IC50 = 27.02 ± 2.38 μmol L-1), which shows potential in anti-cancer drug development.

Binding Selectivity of Methanobactin from Methylosinus trichosporium OB3b for Copper(I), Silver(I), Zinc(II), Nickel(II), Cobalt(II), Manganese(II), Lead(II), and Iron(II)

NASA Astrophysics Data System (ADS)

McCabe, Jacob W.; Vangala, Rajpal; Angel, Laurence A.

2017-12-01

Methanobactin (Mb) from Methylosinus trichosporium OB3b is a member of a class of metal binding peptides identified in methanotrophic bacteria. Mb will selectively bind and reduce Cu(II) to Cu(I), and is thought to mediate the acquisition of the copper cofactor for the enzyme methane monooxygenase. These copper chelating properties of Mb make it potentially useful as a chelating agent for treatment of diseases where copper plays a role including Wilson's disease, cancers, and neurodegenerative diseases. Utilizing traveling wave ion mobility-mass spectrometry (TWIMS), the competition for the Mb copper binding site from Ag(I), Pb(II), Co(II), Fe(II), Mn(II), Ni(II), and Zn(II) has been determined by a series of metal ion titrations, pH titrations, and metal ion displacement titrations. The TWIMS analyses allowed for the explicit identification and quantification of all the individual Mb species present during the titrations and measured their collision cross-sections and collision-induced dissociation patterns. The results showed Ag(I) and Ni(II) could irreversibly bind to Mb and not be effectively displaced by Cu(I), whereas Ag(I) could also partially displace Cu(I) from the Mb complex. At pH ≈ 6.5, the Mb binding selectivity follows the order Ag(I)≈Cu(I)>Ni(II)≈Zn(II)>Co(II)>>Mn(II)≈Pb(II)>Fe(II), and at pH 7.5 to 10.4 the order is Ag(I)>Cu(I)>Ni(II)>Co(II)>Zn(II)>Mn(II)≈Pb(II)>Fe(II). Breakdown curves of the disulfide reduced Cu(I) and Ag(I) complexes showed a correlation existed between their relative stability and their compact folded structure indicated by their CCS. Fluorescence spectroscopy, which allowed the determination of the binding constant, compared well with the TWIMS analyses, with the exception of the Ni(II) complex. [Figure not available: see fulltext.

Binding Selectivity of Methanobactin from Methylosinus trichosporium OB3b for Copper(I), Silver(I), Zinc(II), Nickel(II), Cobalt(II), Manganese(II), Lead(II), and Iron(II).

PubMed

McCabe, Jacob W; Vangala, Rajpal; Angel, Laurence A

2017-12-01

Methanobactin (Mb) from Methylosinus trichosporium OB3b is a member of a class of metal binding peptides identified in methanotrophic bacteria. Mb will selectively bind and reduce Cu(II) to Cu(I), and is thought to mediate the acquisition of the copper cofactor for the enzyme methane monooxygenase. These copper chelating properties of Mb make it potentially useful as a chelating agent for treatment of diseases where copper plays a role including Wilson's disease, cancers, and neurodegenerative diseases. Utilizing traveling wave ion mobility-mass spectrometry (TWIMS), the competition for the Mb copper binding site from Ag(I), Pb(II), Co(II), Fe(II), Mn(II), Ni(II), and Zn(II) has been determined by a series of metal ion titrations, pH titrations, and metal ion displacement titrations. The TWIMS analyses allowed for the explicit identification and quantification of all the individual Mb species present during the titrations and measured their collision cross-sections and collision-induced dissociation patterns. The results showed Ag(I) and Ni(II) could irreversibly bind to Mb and not be effectively displaced by Cu(I), whereas Ag(I) could also partially displace Cu(I) from the Mb complex. At pH ≈ 6.5, the Mb binding selectivity follows the order Ag(I)≈Cu(I)>Ni(II)≈Zn(II)>Co(II)>Mn(II)≈Pb(II)>Fe(II), and at pH 7.5 to 10.4 the order is Ag(I)>Cu(I)>Ni(II)>Co(II)>Zn(II)>Mn(II)≈Pb(II)>Fe(II). Breakdown curves of the disulfide reduced Cu(I) and Ag(I) complexes showed a correlation existed between their relative stability and their compact folded structure indicated by their CCS. Fluorescence spectroscopy, which allowed the determination of the binding constant, compared well with the TWIMS analyses, with the exception of the Ni(II) complex. Graphical abstract ᅟ.

Synthesis, crystallographic and spectral studies of homochiral cobalt(II) and nickel(II) complexes of a new terpyridylaminoacid ligand

NASA Astrophysics Data System (ADS)

Wang, Xing; Gao, Chang-Qing; Gao, Zhi-Yang; Wu, Ben-Lai; Niu, Yun-Yin

2018-04-01

Based on a chiral terpyridylaminoacid ligand, a series of homochiral Co(II) and Ni(II) complexes, namely, [Co(H2L)(HL)]·Cl·(PF6)2·2H2O (1), [Ni(H2L)(HL)]·Cl·(PF6)2 (2), [Co2(L)2(CH3OH)(H2O)]·(PF6)2·CH3OH (3), [Ni2(L)2(CH3OH)2]·(PF6)2·2CH3OH (4), [Co2(L)2(N3)2]·3H2O (5), and [Ni2(L)2(SCN)2]·4H2O (6) have been successfully synthesized and characterized by elemental analysis, TGA, spectroscopic methods (IR, CD and electronic absorption spectra) and single-crystal X-ray diffraction structural analysis (HL = (S)-2-((4-([2,2':6‧,2″-terpyridin]-4‧-yl)benzyl)amino)-4-methylpentanoic acid). In the acidic reaction conditions, one protonated (H2L)+ and one zwitterionic HL only used their terpyridyl groups to chelate one metal ion Co(II) or Ni(II), forming chiral mononuclear cationic complexes 1 or 2. But in the basic and hydro(solvo)thermal reaction conditions, deprotonated ligands (L)‒ acting as bridges used their terpyridyl and amino acid groups to link with two Co(II) or Ni(II) ions, fabricating chiral dinuclear metallocyclic complexes 3-6. Those chiral mononuclear and dinuclear complexes whose chirality originates in the homochiral ligand HL further self-assemble into higher-dimensional homochiral supramolecular frameworks through intermolecular hydrogen-bonding and π···π interactions. Notably, the coordination mode, hydrogen-bonding site, and existence form of HL ligand can be controlled by the protonation of its amino group, and the architectural diversity of those supramolecular frameworks is adjusted by pH and counter anions. Very interestingly, the 3D porous supramolecular frameworks built up from the huge chiral mononuclear cationic complexes 1 and 2 have novel helical layers only formed through every right-handed helical chain intertwining with two adjacent same helical chains, and the 2D supramolecular helicate 5 consists of two types of left-handed helical chains.

Synthesis, characterization and properties of some divalent metal(II) complexes: Their electrochemical, catalytic, thermal and antimicrobial activity studies

NASA Astrophysics Data System (ADS)

Tümer, Mehmet; Ekinci, Duygu; Tümer, Ferhan; Bulut, Akif

2007-07-01

In this study, we synthesized the amine compound 2-(2-aminoethyliminomethyl)phenol (H 3A) as the starting material, and then we prepared the polydentate Schiff base ligands from the reactions of the amine compound (H 3A) with phtaldialdehyde (H 2L), 4-methyl-2,6-di-formlyphenol (H 3L 1) and 4- t-butyl-2,6-di-formylphenol (H 3L 2) in the ethanol solution. Moreover, the complexes Cd(II), Cu(II), Co(II), Ni(II), Zn(II) and Sn(II) of the ligands H 2L, H 3L 1 and H 3L 2 have been prepared. All compounds have been characterized by the analytical and spectroscopic methods. In addition, the magnetic susceptibility and molar conductance measurements have been made. The catalytic properties of the mono- and binuclear Co(II) and Cu(II) complexes have been studied on the 3,5-di- tert-butylcatechol (3,5-DTBC) and ascorbic acid (aa) as a substrate. The oxidative C-C coupling properties of the Co(II) and Cu(II) complexes have been investigated on the sterically hindered 2,6-di- tert-butylphenol (dtbp). The antimicrobial activity properties of the ligands and their mono- and binuclear complexes have been studied against the bacteria and fungi. The results have been compared to the antibacterial and fungi drugs. The TGA curves show that the decomposition takes place in three steps for all complexes. Electrochemical properties of the complexes Cu(II) and Ni(II) have been investigated for the first time in acetonitrile by cyclic voltammetry.

Synthesis, spectral and quantum chemical studies and use of (E)-3-[(3,5-bis(trifluoromethyl)phenylimino)methyl]benzene-1,2-diol and its Ni(II) and Cu(II) complexes as an anion sensor, DNA binding, DNA cleavage, anti-microbial, anti-mutagenic and anti-cancer agent

NASA Astrophysics Data System (ADS)

Ünver, Hüseyin; Boyacıoğlu, Bahadır; Zeyrek, Celal Tuğrul; Yıldız, Mustafa; Demir, Neslihan; Yıldırım, Nuray; Karaosmanoğlu, Oğuzhan; Sivas, Hülya; Elmalı, Ayhan

2016-12-01

We report the synthesis of a novel Schiff base (E)-3-[(3,5-bis(trifluoromethyl) phenylimino)methyl] benzene-1,2-diol from the reaction of 2,3-dihydroxybenzaldehyde with 3,5-bis(trifluoromethyl)aniline, and its Ni(II) and Cu(II) complexes. The molecular structure of the Schiff base was experimentally determined using X-ray single-crystal data and was compared to the structure predicted by theoretical calculations using density functional theory (DFT), Hartree-Fock (HF) and Möller-Plesset second-order perturbation (MP2). In addition, nonlinear optical (NLO) effects of the compound was predicted using DFT. The antimicrobial activities of the compounds were investigated for their minimum inhibitory concentration. UV-Vis spectroscopy studies of the interactions between the compounds and calf thymus DNA (CT-DNA) showed that the compounds interacts with CT-DNA via intercalative binding. A DNA cleavage study showed that the Cu(II) complex cleaved DNA without any external agents. The compounds inhibited the base pair mutation in the absence of S9 with high inhibition rate. In addition, in vitro cytotoxicity of the Ni(II) complex towards HepG2 cell line was assayed by the MTT method. Also, the colorimetric response of the Schiff base in DMSO to the addition of equivalent amount of anions (F-, Br-, I-, CN-, SCN-, ClO4-, HSO4-, AcO-, H2PO4-, N3- and OH-) was investigated. In this regard, while the addition of F-, CN-, AcO- and OH- anions into the solution containing Schiff base resulted in a significant color change, the addition of Br-, I-, SCN-, ClO4-, HSO4-, H2PO4- and N3- anions resulted in no color change. The most discernable color change in the Schiff base was caused by CN-, which demonstrated that the ligand can be used to selectively detect CN-.

p-halo N4-phenyl substituted thiosemicarbazones: Crystal structure, supramolecular architecture, characterization and bio-assay of their Co(III) and Ni(II) complexes

NASA Astrophysics Data System (ADS)

Kotian, Avinash; Kumara, Karthik; Kamat, Vinayak; Naik, Krishna; Kokare, Dhoolesh G.; Nevrekar, Anupama; Lokanath, Neratur Krishnappagowda; Revankar, Vidyanand K.

2018-03-01

In the present work, three potential metal ion chelating ligands, p-halo N4-phenyl substituted thiosemicarbazones are synthesized and characterized. The molecular structure of all (E)-4-(4-halophenyl)-1-(3-hydroxyiminobutan-2-ylidene) thiosemicarbazones (halo = F/Cl/Br) are determined by single crystal X-ray diffraction method. All the molecules have crystallized in monoclinic crystal system with P21/n space group. The ligands show Csbnd H⋯S and Nsbnd H⋯S intermolecular interactions, which are responsible to form the supramolecular self-assemblies through R22(8), R22(12) and R22(14) ring motifs. Hirshfeld surface analysis is carried out to explore the intermolecular interactions. A series of Co(III) and Ni(II) mononuclear transition metal complexes derived from these ligands have been synthesized and characterized by various spectro-analytical methods. The metal to ligand stoichiometry has been found to be 1:2 in all the complexes. The synthesized compounds have been investigated for their in vitro antimicrobial potencies. The compounds are found to be more active than the standard used, in the case of E. coli and A. niger. Additionally, they are also screened for their in vitro antitubercular activity.

Interaction of a Ni(II) tetraazaannulene complex with elongated fullerenes as simple models for carbon nanotubes.

PubMed

Henao-Holguín, Laura Verónica; Basiuk, Vladimir A

2015-06-01

Nickel(II) complex of 5,14-dihydro-6,8,15,17-tetramethyldibenzo[b,i][1,4,8,11] tetraazacyclotetradecine (NiTMTAA), which can be employed for noncovalent functionalization of carbon nanotubes (CNTs), represents a more complex and interesting case in terms of structure of the resulting nanohybrids, as compared to the related materials functionalized with porphyrins and phthalocyanines. Due to its saddle shape, the NiTMTAA molecule adsorbed can adopt different, energetically non-equivalent orientations with respect to CNT, depending on whether CH3 or C6H4 groups contact the latter. The main goal of the present work was to provide information on the interactions of NiTMTAA with simple single-walled CNT (SWNT) models accessible for dispersion-corrected DFT calculations. For reasons of comparison, we employed three such functionals: M06-2X and LC-BLYP as implemented in Gaussian 09 package, and PBE-G as implemented in Materials Studio 6.0. In order to roughly estimate the effect of nanotube chirality on the interaction strenght, we considered two short closed-end SWNT models (also referred to as 'elongated fullerenes'), one armchair and one zigzag, derived from C60 and C80 hemispheres. In addition, we calculated similar complexes with C60, as well as I h and D 5h isomers of C80. The results were analyzed in terms of optimized geometries, formation energies, HOMO-LUMO gap energies, and intermolecular separations. Graphical Abstract Interaction of Ni(II) tetraazaannulene complex with elongated fullerenes.

Spectral studies, thermal investigation and biological activity of some metal complexes derived from (E)-N‧-(1-(4-aminophenyl)ethylidene)morpholine-4-carbothiohydrazide

NASA Astrophysics Data System (ADS)

El-Samanody, El-Sayed A.; Polis, Magdy W.; Emara, Esam M.

2017-09-01

A new series of biologically active Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) complexes derived from the novel thiosemicarbazone ligand; (E)-N‧-(1-(4-aminophenyl)ethylidene)morpholine-4-carbothiohydrazide (HL) were synthesized. The mode of bonding of the ligand and the geometrical structures of its metal complexes were achieved by different analytical and spectral methods. The ligand coordinated with metal ions in a neutral bidentate fashion through the thione sulfur and azomethine nitrogen atoms. All metal complexes adopted octahedral geometry, except Cu(II) complexes (3, 6, 7) which have a square planar structure. The general thermal decomposition pathways of the ligand along with its metal complexes were explained. The thermal stability of the complexes is controlled by the number of outer and inner sphere water molecules, ionic radii and the steric hindrance. The activation thermodynamic parameters; (activation energy (E*), enthalpy of activation (ΔH*), entropy of activation (ΔS*) and Gibbs free energy (ΔG*)) along with order of reaction (n) were estimated from DTG curves. The ESR spectra of Cu(II) complexes indicated that (dx2-y2)1 is the ground state with covalence character of metal-ligand bonds. The molluscicidal and biochemical effects of the ligand and its Ni(II); Cu(II) complexes (2; 3, 5, 7) along with their combinations with metaldehyde were screened in vitro on the mucous gland of Eobania vermiculata. The tested compounds exhibited a significant toxicity against the tested animals and have almost the same toxic effect of metaldehyde which increases the mucous secretion of the snails and leads to death.

Studies on Some Biologically Cobalt(II), Copper(II) and Zinc(II) Complexes With ONO, NNO and SNO Donor Pyrazinoylhydrazine-Derived Ligands

PubMed Central

Praveen, Marapaka; Sherazi, Syed K. A.

1998-01-01

Biologically active complexes of Co(II), Ni(II), Cu(II) and Zn(II) with novel ONO, NNO and SNO donor pyrazinoylhydrazine-derived compounds have been prepared and characterized on the basis of analytical data and various physicochemical studies. Distorted octahedral structures for all the complexes have been proposed. The synthesized ligands and their complexes have been screened for their antibacterial activity against bacterial species Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Klebsiella pneumonae. The activity data show the metal complexes to be more active than the parent free ligands against one or more bacterial species. PMID:18475857

A remarkable member of the polyoxometalates: the eight-nickel-capped alpha-keggin polyoxoazonickelate.

PubMed

Dong, Lanjun; Huang, Rudan; Wei, Yongge; Chu, Wei

2009-08-17

The eight-nickel-capped polyoxoazonickelate, [Ni(20)(OH)(24)(MMT)(12)(SO(4))](NO(3))(2).6H(2)O (1; MMT = 2-mercapto-5-methyl-1,3,4-thiadiazole), has been synthesized, which has an alpha-Keggin structure with eight nickel caps. In this structure, the polyatom is the late transition metal Ni(II); the central heteroatom is S, and the organic terminal ligand becomes the primary part of the Keggin structure. This is a Keplerate-type cluster, which shows a central Ni(II)(12) cuboctahedron formed by the 12 Ni(II) centers of the classical alpha-Keggin core and a Ni(II)(8) hexahedron formed by the eight nickel caps.

Adsorption of Ni(II) onto Chemically Modified Spent Grated Coconut (Cocos Nucifera)

NASA Astrophysics Data System (ADS)

Hamzah, F. I.; Khalid, K.; Hanafiah, M. A. K. M.

2017-06-01

A new adsorbent of plant waste origin from coconut processing food factory was explored for removing Ni(II) from aqueous solutions. Several parameters such as pH, dosage, concentration and contact time were studied to obtain optimum conditions for treatment of Ni(II) contaminated wastewater. Spent grated coconut (Cocos nucifera) treated with sulfuric acid (SSGC) showed good adsorption capacity for Ni(II) ion. The amount adsorbed was affected by solution pH with the highest value achieved at pH 5. Other optimum conditions found were; dosage of 0.02 g, and 60 min of equilibrium time. Ni(II) adsorption obeyed the pseudo-second order kinetic model which suggested that chemisorption mechanism occurred in the adsorption process. The equilibrium data presented a better fitting to the Langmuir isotherm model, an indication that monolayer adsorption occurred onto a homogeneous surface. The maximum adsorption capacity, qmax was 97.09 mg g-1, thus SSGC can be classified as good and comparable with other plant waste adsorbents.

Comparative study on kinetic adsorption of Cu(II), Cd(II) and Ni(II) ions from aqueous solutions using activated sludge and dried sludge

NASA Astrophysics Data System (ADS)

Ong, Soon-An; Toorisaka, Eiichi; Hirata, Makoto; Hano, Tadashi

2013-03-01

The adsorption of Cu(II), Cd(II) and Ni(II) ions from aqueous solutions by activated sludge and dried sludge was investigated under laboratory conditions to assess its potential in removing metal ions. The adsorption behavior of metal ions onto activated sludge and dried sludge was analyzed with Weber-Morris intra-particle diffusion model, Lagergren first-order model and pseudo second-order model. The rate constant of intra-particle diffusion on activated sludge and dried sludge increased in the sequence of Cu(II) > Ni(II) > Cd(II). According to the regression coefficients, it was observed that the kinetic adsorption data can fit better by the pseudo second-order model compared to the first-order Lagergren model with R 2 > 0.997. The adsorption capacities of metal ions onto activated sludge and dried sludge followed the sequence Ni(II) ≈ Cu(II) > Cd(II) and Cu(II) > Ni(II) > Cd(II).

Synthesis, characterization, nucleic acid interactions and photoluminescent properties of methaniminium hydrazone Schiff base and its Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) complexes

NASA Astrophysics Data System (ADS)

Sennappan, M.; Murali Krishna, P.; Hosamani, Amar A.; Hari Krishna, R.

2018-07-01

An environmental benign and efficient reaction was carried out via amine exchange and condensation reaction in water and methanol mixture (3:1) and absence of catalyst between 1-[3-(2-hydroxy benzylidene)amine)phenyl]ethanone and benzhydrazide yields methaniminium hydrazone Schiff base in high yield. The prepared ligand was structurally characterized by using single crystal XRD, elemental analysis and spectroscopy (UV-Vis, FT-IR, LC-MS and NMR) techniques. The crystal data indicates the ligand crystallizes in orthorhombic system with Pna21 space group. Further, the ligand was used in synthesis of mononuclear Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) complexes and were characterized by elemental analysis, magnetic moment and spectroscopy (UV-Vis, FT-IR and ESR) studies. The spectral data showed that ligand is coordinated to the metal ion through azomethine nitrogen and methaniminium nitrogen. The DNA binding absorption titrations reveals that, ligand, L and its metal complexes, 1-6 are avid binders to CT- DNA. The apparent binding constant values of compounds are in the order of 106 M-1. The nuclease activity of ligand, L and its metal complexes, 1-6 were investigated by gel electrophoresis method using pUC18 DNA. The photoluminescent properties of the methaniminium hydrazone ligand, L and its various metal complexes, 1-6 were investigated. The emission spectra of both ligand (L) and metal complexes (1-6) exhibits emission in the range of blue to red.

Pharmacologically significant complexes of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) of novel Schiff base ligand, (E)-N-(furan-2-yl methylene) quinolin-8-amine: Synthesis, spectral, XRD, SEM, antimicrobial, antioxidant and in vitro cytotoxic studies

NASA Astrophysics Data System (ADS)

Shakir, M.; Hanif, Summaiya; Sherwani, Mohd. Asif; Mohammad, Owais; Al-Resayes, Saud I.

2015-07-01

A novel series of metal complexes of the types, [ML2(H2O)2]Cl2 and [ML2]Cl2 [M = Mn(II), 1; Co(II), 2; Ni(II), 3; Cu(II), 4; and Zn(II), 5] were synthesized by the interaction of ligand, L (E)-N-(furan-2-yl methylene) quinolin-8-amine, derived from the condensation of 2-furaldehyde and 8-aminoquinoline. The synthesized ligand and its metal complexes were characterized on the basis of results obtained from elemental analysis, ESI-MS, XRD, SEM, TGA/DTA, FT-IR, UV-Vis, magnetic moment and 1H and 13C NMR spectroscopic studies. EPR parameters were recorded in case of complex 4. The comparative in-vitro antimicrobial activities against various pathogens with reference to known antibiotics and antioxidant activity against standard control at variable concentrations revealed that the metal complexes show enhanced antimicrobial and free radical scavenging activities in general as compared to free ligand. However, the complexes 1 and 5 have shown best antioxidant activity among all the metal complexes. Furthermore, comparative in-vitro antiproliferative activity on ligand and its metal chelates performed on MDA-MB-231 (breast carcinoma), KCL22 (blood lymphoid carcinoma), HeLa (cervical carcinoma) cell lines and normal cells (PBMC) revealed that metal chelates show moderate to good activity as compared to ligand where as complex 1 seems to be the most promising one possessing a broad spectrum of activity against all the selected cancer cell lines with IC50 < 2.10 μM.

Kinetic and thermodynamic studies of the Co(II) and Ni(II) ions removal from aqueous solutions by Ca-Mg phosphates.

PubMed

Ivanets, A I; Srivastava, V; Kitikova, N V; Shashkova, I L; Sillanpää, M

2017-03-01

The aim of this work was to study the sorption kinetics and thermodynamics of Co(II) and Ni(II) from aqueous solutions by sorbents on the basis of hydrogen (PD-1) and tertiary (PD-2) Ca-Mg phosphates depending on the solution temperature and sorbents chemical composition. Kinetic studies of adsorption of Co(II) and Ni(II) ions onto samples of phosphate sorbents were performed in batch experiment at the temperatures 288, 303, 318 and 333 K. The sorbent dose was fixed at 10 g L -1 , initial pH value 2.6, and contact time varied from 5 to 600 min. The kinetics of Co(II) and Ni(II) adsorption were analyzed by using pseudo-first order, pseudo-second order and intraparticle diffusion models. Thermodynamic parameters (ΔG°, ΔH° and ΔS°) for the sorption of Co(II) and Ni(II) were determined using the Gibbs-Helmholtz equation. The calculated kinetic parameters and corresponding correlation coefficients revealed that Co(II) and Ni(II) uptake process followed the pseudo-second order rate expression. Thermodynamic studies confirmed the spontaneous and endothermic nature of removal process which indicate that sorption of Co(II) and Ni(II) ions onto both phosphate sorbents is favoured at higher temperatures and has the chemisorptive mechanism. The data thus obtained would be useful for practical application of the low cost and highly effective Ca-Mg phosphate sorbents. Copyright © 2016 Elsevier Ltd. All rights reserved.

Binding ability of impromidine, a potent H2 agonist of histamine

NASA Astrophysics Data System (ADS)

Anouar, A.; Lhadi, E.; Decock, P.; Kozlowskyinst4, H.

1999-09-01

Impromidine (fig.1) is a potent and selective histamine H2 receptor agonist and its structure comprises a strongly basic guanidine group containing two different imidazole-containing side chains. The present work deals with the study of coordination equilibria between impromidine and Cu(II) and Ni(II) in aqueous solution at 25 circC. Potentiometric, UV-Visible and EPR studies on Cu(II) complexes with impromidine have shown that this anti-ulcerogenic drug is a very potent chelating agent. This drug is found to be a very effective ligand for Ni(II) ions also. The effective coordination of impromidine to metal ions may have significant biological implications. L'impromidine est un agoniste H2 de l'histamine, sa structure possède un groupement guanidinique de forte basicité et dont l'environne ment des deux groupements imidazoliques est différent. Le présent travail consiste en l'étude de la coordination de l'impromidine avec le Cu(II) et le Ni(II) en milieu aqueux à 25 circC. La potentiométrie, LíUV-Visible et la RPE montrent que le cuivre se coordine très fortement avec l'impromidine. Nous avons trouvé que ce médicament se coordine aussi fortement avec le nickel(II). La coordination de l'impromidine avec les métaux pourrait avoir des applications importantes en médecine.

Adsorption of Pb(II), Cu(II), Cd(II), Zn(II), Ni(II), Fe(II), and As(V) on bacterially produced metal sulfides.

PubMed

Jong, Tony; Parry, David L

2004-07-01

The adsorption of Pb(II), Cu(II), Cd(II), Zn(II), Ni(II), Fe(II) and As(V) onto bacterially produced metal sulfide (BPMS) material was investigated using a batch equilibrium method. It was found that the sulfide material had adsorptive properties comparable with those of other adsorbents with respect to the specific uptake of a range of metals and, the levels to which dissolved metal concentrations in solution can be reduced. The percentage of adsorption increased with increasing pH and adsorbent dose, but decreased with increasing initial dissolved metal concentration. The pH of the solution was the most important parameter controlling adsorption of Cd(II), Cu(II), Fe(II), Ni(II), Pb(II), Zn(II), and As(V) by BPMS. The adsorption data were successfully modeled using the Langmuir adsorption isotherm. Desorption experiments showed that the reversibility of adsorption was low, suggesting high-affinity adsorption governed by chemisorption. The mechanism of adsorption for the divalent metals was thought to be the formation of strong, inner-sphere complexes involving surface hydroxyl groups. However, the mechanism for the adsorption of As(V) by BPMS appears to be distinct from that of surface hydroxyl exchange. These results have important implications to the management of metal sulfide sludge produced by bacterial sulfate reduction.

Two new Ni(II) supramolecular complexes based on ethyl isonicotinate and ethyl nicotinate for removal of acid blue 92 dye

NASA Astrophysics Data System (ADS)

Etaiw, Safaa El-din H.; Marie, Hassan

2018-03-01

Two new luminescent supramolecular complexes (SC); [Ni(EIN)4(NCS)2] SC1 and [Ni2(EN)8(NCS)4] SC2, (EIN = ethyl isonicotinate, EN = ethyl nicotinate), have been synthesized by self-assembly method and structurally characterized by X-ray single crystal, FT-IR and UV-Vis spectra, PXRD, elemental and thermogravimetric analyses. Both SC1 and SC2 are monoclinic crystals however, they have different asymmetric units. Ni(II) atoms in both SC are isostructural and have similar hexa-coordinate environment. The structures of SC1 and SC2 consist of parallel polymeric 1D-chains, extended in two and three dimensional supramolecular frameworks by intermolecular hydrogen bonding interactions. SC1 and SC2 are luminescent materials which can be used in applications as molecular sensing systems. SC1 and SC2 were used as heterogeneous catalysts for degradation of acid blue 92 (AB-92) under sun light irradiation. The fluorescence measurements of terephthalic acid technique as a probe molecule were used to determine the •OH radicals. Also the radicals trapping experiments using isopropanol alcohol (IPA) as radical scavenger were discussed. In addition a mechanism of degradation was proposed and discussed.

Ternary metal complexes of guaifenesin drug: Synthesis, spectroscopic characterization and in vitro anticancer activity of the metal complexes.

PubMed

Mahmoud, W H; Mahmoud, N F; Mohamed, G G; El-Sonbati, A Z; El-Bindary, A A

2015-01-01

The coordination behavior of a series of transition metal ions named Cr(III), Fe(III), Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) with a mono negative tridentate guaifenesin ligand (GFS) (OOO donation sites) and 1,10-phenanthroline (Phen) is reported. The metal complexes are characterized based on elemental analyses, IR, (1)H NMR, solid reflectance, magnetic moment, molar conductance, UV-vis spectral studies, mass spectroscopy, ESR, XRD and thermal analysis (TG and DTG). The ternary metal complexes were found to have the formulae of [M(GFS)(Phen)Cl]Cl·nH2O (M=Cr(III) (n=1) and Fe(III) (n=0)), [M(GFS)(Phen)Cl]·nH2O (M=Mn(II) (n=0), Zn(II) (n=0) and Cu(II) (n=3)) and [M(GFS)(Phen)(H2O)]Cl·nH2O (M=Co(II) (n=0), Ni(II) (n=0) and Cd(II) (n=4)). All the chelates are found to have octahedral geometrical structures. The ligand and its ternary chelates are subjected to thermal analyses (TG and DTG). The GFS ligand, in comparison to its ternary metal complexes also was screened for their antibacterial activity on gram positive bacteria (Bacillus subtilis and Staphylococcus aureus), gram negative bacteria (Escherichia coli and Neisseria gonorrhoeae) and for in vitro antifungal activity against (Candida albicans). The activity data show that the metal complexes have antibacterial and antifungal activity more than the parent GFS ligand. The complexes were also screened for its in vitro anticancer activity against the Breast cell line (MFC7) and the results obtained show that they exhibit a considerable anticancer activity. Copyright © 2015 Elsevier B.V. All rights reserved.

Synthesis and characterization of Ni(II) complex with 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-7,14-dienium bromide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yusoff, Latifah M.; Yusoff, Siti Fairus M.; Ismail, Wafiuddin

Nickel(II) complex have been synthesized by treating a 14-membered ring tetraaza macrocyclic compound, 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-7,14-dienium, bromide (Me{sub 6}N{sub 4}H{sub 4})Br{sub 2} with nickel acetate in metanol. The complex was characterized using elemental analysis, Fourier Transform Infrared (FTIR), Ultraviolet-Visible (UV-Vis), and single crystal diffraction (X-ray). The nickel atom coordinates through four nitrogen atoms in the ligand. Square planar geometry has been proposed for this complex.

The influence of Ni(II) on brushite structure stabilization

NASA Astrophysics Data System (ADS)

Guerra-López, J. R.; Güida, J. A.; Ramos, M. A.; Punte, G.

2017-06-01

Brushite samples doped with Ni(II) in different concentrations, from 5% to 20%, were prepared in aqueous solution at pH = 7 and at two temperatures: 25 and 37 °C. The solid samples were characterized by chemical analysis, infrared spectroscopy (FTIR) and x-ray powder diffraction (XRPD). Chemical analysis has shown Ni(II) almost complete incorporation to the solid phase up to 15%. X-ray diffraction patterns have allowed to identify brushite phase with almost no modification of the line breadth and only small shifts of lines positions with increasing Ni(II) incorporation up to 15%. For larger Ni(II) concentration, in solution, a mixture of phases has been detected. Infrared spectra have supported diffraction results. For Ni(II) 20% and over the characteristic bands of HPO42- anions tend to vanish, and the typical shaped PO43- bands are observed. These results have allowed to establish that the presence of low levels of Ni in the synthetic process not only helps brushite formation; but, also prevents brushite from apatite conversion and, in addition, preserves brushite crystallinity. According to these findings, it is possible to propose that nickel traces present in the urinary system might be a trigger to brushite stone formation and/or growth, rather than the expected brushite conversion to hydroxyapatite. This outcome would explain the recurrent detection of difficult to treat brushite stones, observed in the last three decades.

Synthesis, spectral and thermal studies of some transition metal mixed ligand complexes: Modeling of equilibrium composition and biological activity

NASA Astrophysics Data System (ADS)

Neelakantan, M. A.; Sundaram, M.; Nair, M. Sivasankaran

2011-09-01

Several mixed ligand Ni(II), Cu(II) and Zn(II) complexes of 2-amino-3-hydroxypyridine (AHP) and imidazoles viz., imidazole (him), benzimidazole (bim), histamine (hist) and L-histidine (his) have been synthesized and characterized by elemental and spectral (vibrational, electronic, 1H NMR and EPR) data as well as by magnetic moment values. On the basis of elemental analysis and molar conductance values, all the complexes can be formulated as [MAB]Cl except histidine complexes as MAB. Thermogravimetric studies reveal the presence of coordinated water molecules in most of the complexes. From the magnetic measurements and electronic spectral data, octahedral structure was proposed for Ni(II) and Cu(II)-AHP-his, tetrahedral for Cu(II)-AHP-him/bim/hist, but square planar for the Cu(II)-AHP complex. The g∥/ A∥ calculated supports tetrahedral environment around the Cu(II) in Cu(II)-AHP-him/bim/hist and distorted octahedral for Cu(II)-AHP-his complexes. The morphology of the reported metal complexes was investigated by scanning electron micrographs (SEM). The potentiometric study has been performed in aqueous solution at 37 °C and I = 0.15 mol dm -3 NaClO 4. MABH, MAB and MAB 2 species has been identified in the present systems. Proton dissociation constants of AHP and stability constants of metal complexes were determined using MINIQUAD-75. The most probable structure of the mixed ligand species is discussed based upon their stability constants. The in vitro biological activity of the complexes was tested against the Gram positive and Gram negative bacteria, fungus and yeast. The oxidative DNA cleavage studies of the complexes were performed using gel electrophoresis method. Cu(II) complexes have been found to promote DNA cleavage in presence of biological reductant such as ascorbate and oxidant like hydrogen peroxide.

Synthesis, characterization and biological approach of metal chelates of some first row transition metal ions with halogenated bidentate coumarin Schiff bases containing N and O donor atoms.

PubMed

Prabhakara, Chetan T; Patil, Sangamesh A; Toragalmath, Shivakumar S; Kinnal, Shivashankar M; Badami, Prema S

2016-04-01

The impregnation of halogen atoms in a molecule is an emerging trend in pharmaceutical chemistry. The presence of halogens (Cl, Br, I and F) increases the lipophilic nature of molecule and improves the penetration of lipid membrane. The presence of electronegative halogen atoms increases the bio- activity of core moiety. In the present study, Co(II), Ni(II) and Cu(II) complexes are synthesised using Schiff bases (HL(I) and HL(II)), derived from 8-formyl-7-hydroxy-4-methylcoumarin/3-chloro-8-formyl-7-hydroxy-4-methylcoumarin with 2,4-difluoroaniline/o-toluidine respectively. The synthesized compounds were characterized by spectral (IR, NMR, UV-visible, Mass, ESI-MS, ESR), thermal, fluorescence and molar conductivity studies. All the synthesized metal complexes are completely soluble in DMF and DMSO. The non-electrolytic nature of the metal complexes was confirmed by molar conductance studies. Elemental analysis study suggest [ML2(H2O)2] stoichiometry, here M=Co(II), Ni(II) and Cu(II), L=deprotonated ligand. The obtained IR data supports the binding of metal ion to Schiff base. Thermal study suggests the presence of coordinated water molecules. Electronic spectral results reveal six coordinated geometry for the synthesized metal complexes. The Schiff bases and their metal complexes were evaluated for antibacterial (Pseudomonas aureginosa and Proteus mirabilis), antifungal (Aspergillus niger and Rhizopus oryzae), anthelmintic (Pheretima posthuma) and DNA cleavage (Calf Thymus DNA) activities. Copyright © 2016 Elsevier B.V. All rights reserved.

Gas-phase noncovalent functionalization of carbon nanotubes with a Ni(II) tetraaza[14]annulene complex

NASA Astrophysics Data System (ADS)

Basiuk, Vladimir A.; Henao-Holguín, Laura Verónica; Álvarez-Zauco, Edgar; Bassiouk, María; Basiuk, Elena V.

2013-04-01

The noncovalent functionalization of carbon nanotubes (CNTs) with aromatic polyazamacrocyclic compounds, based on π-π-interactions, keeps the intrinsic electronic structure of CNTs totally intact and allows for combining unique properties of the two interacting components. In addition to porphyrins and phthalocyanines, there are other, simpler compounds exhibiting similar properties, potentially useful for photovoltaic, catalytic and electrochemical applications: for example, tetraaza[14]annulenes. Many of them are highly thermally stable, which makes it possible to employ physical vapor deposition for the preparation of macrocycle-nanotube hybrids. One of such compounds is Ni(II) complex of 5,7,12,14-tetramethyldibenzo-1,4,8,11-tetraazacyclotetradeca-3,5,7,10,12,14-hexaene (also called Ni(II)-tetramethyldibenzotetraaza[14]annulene, or NiTMTAA for simplicity). In the present work, we attempted the noncovalent functionalization of both single-walled and multi-walled CNTs with NiTMTAA in the gas phase at two selected temperatures of 220 and 270 °C, which does not require the use of organic solvents and therefore can be considered as ecologically friendly. The nanohybrids obtained were characterized by means of scanning and transmission electron microscopy, energy dispersive X-ray, Fourier-transform infrared and Raman spectroscopy, as well as thermogravimetric analysis. An additional insight into the structure of adsorption complexes of NiTMTAA on CNTs was provided from density functional theory and molecular mechanics calculations.

The n-propyl 3-azido-2,3-dideoxy-β-D-arabino-hexopyranoside: Syntheses, crystal structure, physical properties and stability constants of their complexes with Cu(II), Ni(II) and VO(II)

NASA Astrophysics Data System (ADS)

Barabaś, Anna; Madura, Izabela D.; Marek, Paulina H.; Dąbrowska, Aleksandra M.

2017-11-01

The structure, conformation and configuration of the n-propyl 3-azido-2,3-dideoxy-β-D-arabino-hexopyranoside (BAra-nPr) were determined by 1H NMR, 13C NMR, and IR spectroscopy, as well as by optical rotation. The crystal structure was confirmed by single-crystal X-ray diffraction studies at room temperature. The compound crystallizes in P21 space group symmetry of the monoclinic system. The molecule has a 4C1 chair conformation with azide group in the equatorial position both in a solution as well as in the crystal. The spatial arrangement of azide group is compared to other previously determined azidosugars. The hydrogen bonds between the hydroxyl group of sugar molecules lead to a ribbon structure observed also for the ethyl homolog. The packing of ribbons is dependent on the alkyl substituent length and with the elongation changes from pseudohexagonal to lamellar. Acidity constants for the n-propyl 3-azido-2,3-dideoxy-β-D-arabino-hexopyranoside (BAra-nPr) in an aqueous solution were evaluated by the spectrophotometric and potentiometric titrations methods. Title compound exhibit blue absorption with the maximum wavelengths in the range of 266 nm and 306 nm. Based on these measurements we showed equilibria existing in a particular solution and a distribution of species which have formed during the titration. We also investigated interactions between Cu(II), Ni(II) and VO(II) and title compound (as ligand L) during complexometric titration. On these bases we identified that in [CuII-BAra-nPr]2+ the ratio of the ligand L to metal ion M(II) was 3:1, while in [NiII-BAra-nPr]2+ and [VOII-BAra-nPr]2+ complexes 2:1 ratios were found. The cumulative stability constants (as log β) occurring in an aqueous solution for the complexes of BAra-nPr with Cu(II), Ni(II) and VO(IV) were 14.57; 11.71 and 4.20, respectively.

Neutral Ni(II), Pd(II) and Pt(II) ONS-pincer complexes of 5-acetylbarbituric-4N-dimethylthiosemicarbazone: synthesis, characterization and properties.

PubMed

Castiñeiras, Alfonso; Fernández-Hermida, Nuria; García-Santos, Isabel; Gómez-Rodríguez, Lourdes

2012-11-21

Octahedral 1:1 Ni(II) and square-planar 1:1 Pd(II) and Pt(II) complexes of formulae [Ni(HAcb4DM)(AcO)(H2O)2]·H2O (1), [Pd(HAcb4DM)Cl]·5H2O (2) and [Pt(HAcb4DM)Cl]·3H2O (3), where H2Acb4DM = 5-acetylbarbituric-4N-dimethylthiosemicarbazone (H2 denoting its two dissociable protons, one enolic and one thiolic), have been synthesized and characterized by elemental analysis and by 1H and 13C NMR, UV-vis, and IR spectroscopy. Crystallisation of compounds 1–3 from DMSO afforded complexes of formulae [Ni(HAcb4DM)2]·2H2O (1a), [Pd(Acb4DM)(DMSO)]·DMSO (2a) and [Pt(Acb4DM)(DMSO)]·DMSO (3a), the molecular and crystal structures of which were determined by X-ray diffractometry. The thiosemicarbazone in 1a coordinates to the metal ions in an ONS-tridentate manner in the O-enolate/S-thione form, but in complexes 2a and 3a the thiosemicarbazone binds Pd(II) or Pt(II) as an ONS-pincer ligand in the O-enolate/S-thiolate form. The 195Pt NMR spectrum of 3 shows a signal at −2950 ppm along with two new signals at −3348 and −2731 ppm, indicating the presence of solvolysis products. The catalytic activity of complex 2a has been explored in aryl–aryl Suzuki cross-coupling reactions. H2Acb4DM and complexes 2 and 3 were screened for in vitro cytotoxicity against a human tumour cell line (HeLa-229), with the clinically employed drug cisplatin as a reference.

Synthesis, spectroscopic, biological activity and thermal characterization of ceftazidime with transition metals

NASA Astrophysics Data System (ADS)

Masoud, Mamdouh S.; Ali, Alaa E.; Elasala, Gehan S.; Kolkaila, Sherif A.

2018-03-01

Synthesis, physicochemical characterization and thermal analysis of ceftazidime complexes with transition metals (Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II)) were discussed. It's obtained that ceftazidime act as bidentate ligand. From magnetic measurement and spectral data, octahedral structures were proposed for all complexes except for cobalt, nickel and mercury had tetrahedral structural. Hyper chemistry program confirmed binding sites of ceftazidime. Ceftazidime complexes show higher activity than ceftazidime for some strains. From TG and DTA curves the thermal decomposition mechanisms of ceftazidime and their metal complexes were suggested. The thermal decomposition of the complexes ended with the formation of metal oxides as a final product except in case of Hg complex.

Binaphthyl-containing Schiff base complexes with carboxyl groups for dye sensitized solar cell: An experimental and theoretical study

NASA Astrophysics Data System (ADS)

Tsaturyan, Arshak; Machida, Yosuke; Akitsu, Takashiro; Gozhikova, Inna; Shcherbakov, Igor

2018-06-01

We report on synthesis and characterization of binaphthyl containing Schiff base Ni(II), Cu(II), and Zn(II) complexes as promising photosensitizers for dye-sensitized solar cells (DSSC). Based on theoretical and experimental data, the possibility of their application in DSSC was confirmed. To our knowledge, we find dye performance of complex is steric and rigid structure widely spread to efficiency. The spatial and electronic structures of the complexes were studied by means of the quantum chemical modeling using DFT and TD-DFT approaches. The adsorption energies of the complexes on TiO2 cluster were calculated and appeared to be very close in value. The Zn(II) complex has the biggest value of molar extinction.

Synthesis and characterization of hydroxyapatite nanoparticles impregnated on apple pomace to enhanced adsorption of Pb(II), Cd(II), and Ni(II) ions from aqueous solution.

PubMed

Chand, Piar; Pakade, Yogesh B

2015-07-01

Hydroxyapatite nanoparticles were synthesized, characterized, and impregnated onto apple pomace surface (HANP@AP) for efficient removal of Pb(II), Cd(II), and Ni(II) ions from water. HANP@AP was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), transmission electron microscope (TEM), X-ray diffraction (XRD), and surface area analysis. Batch sorption studies were carried out to investigate the influence of different parameters as amount of dose (g), pH, time (min), and initial concentration (mg L(-1)) on adsorption process. Experimental kinetic data followed pseudo-second-order model and equilibrium data well fitted to Langmuir adsorption model with maximum adsorption capacities of 303, 250, and 100 mg g(-1) for Pb(II), Cd(II), and Ni(II) ions, respectively. Competitive adsorption of Pb(II), Cd(II), and Ni(II) ions in presences of each other was studied to evaluate the removal efficiency of HANP@AP against multi metal-loaded water. HANP@AP was successfully applied to real industrial wastewater with 100 % removal of all three metal ions even at high concentration. HANP@AP could be recycled for four, four, and three cycles in case of Pb(II), Cd(II) and Ni(II), respectively. The study showed that HANP@AP is fast, cost effective, and environmental friendly adsorbent for removal of Pb(II), Cd(II), and Ni(II) ions from real industrial wastewater.

Development of a reduced-graphene-oxide based superparamagnetic nanocomposite for the removal of nickel (II) from an aqueous medium via a fluorescence sensor platform.

PubMed

Nandi, Debabrata; Saha, Indranil; Ray, Suprakas Sinha; Maity, Arjun

2015-09-15

Reduced-graphene-oxide based superparamagnetic nanocomposite (GC) was fabricated and applied for the remediation of Ni(II) from an aqueous medium. The as-prepared GC was extensively characterized by Raman, TEM, AFM, SEM-EDX, SQUID, and BET analyses. Quantitative immobilization of Ni(II) in an aqueous solution by the fluorescent sensor platform of GC was explored at varying pH, doses, contact times, and temperatures. The pseudo-second-order kinetics equation governed the overall sorption process at optimized pH of 5 (±0.2). The superior monolayer sorption capacity was 228mgg(-1) at 300K. Negative ΔG(0) indicated the spontaneous sorption nature, whereas the positive ΔH(0) resulted from an increase in entropy (positive ΔS(0)) at the solid-liquid interface during the endothermic reaction. The lower enthalpy agreed with the relatively high regeneration (approximately 91%) of the GC by 0.1M HCl, because of the formation of stable tetrahedral complex. The physisorption was well corroborated by calculated sorption energy (EDR ∼7kJmol(-1)) and the nature of the Stern-Volmer plot of the fluorescence-quenching data with reaction time. The GC played a pivotal role as a static fluorescent sensor platform (fluorophore) for Ni(II) adsorption. Magnetic property also indicated that GC could be easily separated from fluids by exploiting its superparamagnetic property. Copyright © 2015 Elsevier Inc. All rights reserved.

Electronic structure of transition metal-cysteine complexes from X-ray absorption spectroscopy.

PubMed

Leung, Bonnie O; Jalilehvand, Farideh; Szilagyi, Robert K

2008-04-17

The electronic structures of HgII, NiII, CrIII, and MoV complexes with cysteine were investigated by sulfur K-edge X-ray absorption near-edge structure (XANES) spectroscopy and density functional theory. The covalency in the metal-sulfur bond was determined by analyzing the intensities of the electric-dipole allowed pre-edge features appearing in the XANES spectra below the ionization threshold. Because of the well-defined structures of the selected cysteine complexes, the current work provides a reference set for further sulfur K-edge XAS studies of bioinorganic active sites with transition metal-sulfur bonds from cysteine residues as well as more complex coordination compounds with thiolate ligands.

Synthesis, crystal structures, molecular docking and urease inhibition studies of Ni(II) and Cu(II) Schiff base complexes

NASA Astrophysics Data System (ADS)

Sangeeta, S.; Ahmad, K.; Noorussabah, N.; Bharti, S.; Mishra, M. K.; Sharma, S. R.; Choudhary, M.

2018-03-01

[Ni(L)2] 1 and [Cu(L)2] 2 [HL = 2-((E)-(2-methoxyphenylimino)methyl)-4,6-dichlorophenol] Schiff base complexes have been successfully synthesized and were characterized by FT-IR, UV-Vis, fluorescence spectroscopy and thermogravimetric analysis. The crystal structures of the two complexes were determined through X-ray crystallography. Its inhibitory activity against Helicobacter pylori urease was evaluated in vitro and showed strong inhibitory activity against H. pylori urease compared with acetohydroxamic acid (IC50 = 42.12 μmolL-1), which is a positive reference. A docking analysis using the AutoDock 4.0 program could explain the inhibitory activity of the complex against urease.

Performance of Spent Mushroom Farming Waste (SMFW) Activated Carbon for Ni (II) Removal

NASA Astrophysics Data System (ADS)

Desa, N. S. Md; Ghani, Z. Ab; Talib, S. Abdul; Tay, C. C.

2016-07-01

The feasibility of a low cost agricultural waste of spent mushroom farming waste (SMFW) activated carbon for Ni(II) removal was investigated. The batch adsorption experiments of adsorbent dosage, pH, contact time, metal concentration, and temperature were determined. The samples were shaken at 125 rpm, filtered and analyzed using ICP-OES. The fifty percent of Ni(II) removal was obtained at 0.63 g of adsorbent dosage, pH 5-6 (unadjusted), 60 min contact time, 50 mg/L Ni(II) concentration and 25 °C temperature. The evaluated SMFW activated carbon showed the highest performance on Ni(II) removal compared to commercial Amberlite IRC86 resin and zeolite NK3. The result indicated that SMFW activated carbon is a high potential cation exchange adsorbent and suitable for adsorption process for metal removal. The obtained results contribute toward application of developed SMFW activated carbon in industrial pilot study.

Modeling the active site of [NiFe] hydrogenases and the [NiFeu] subsite of the C-cluster of carbon monoxide dehydrogenases: low-spin iron(II) versus high-spin iron(II).

PubMed

Weber, Katharina; Erdem, Özlen F; Bill, Eckhard; Weyhermüller, Thomas; Lubitz, Wolfgang

2014-06-16

A series of four [S2Ni(μ-S)2FeCp*Cl] compounds with different tetradentate thiolate/thioether ligands bound to the Ni(II) ion is reported (Cp* = C5Me5). The {S2Ni(μ-S)2Fe} core of these compounds resembles structural features of the active site of [NiFe] hydrogenases. Detailed analyses of the electronic structures of these compounds by Mössbauer and electron paramagnetic resonance spectroscopy, magnetic measurements, and density functional theory calculations reveal the oxidation states Ni(II) low spin and Fe(II) high spin for the metal ions. The same electronic configurations have been suggested for the Cred1 state of the C-cluster [NiFeu] subsite in carbon monoxide dehydrogenases (CODH). The Ni-Fe distance of ∼3 Å excludes a metal-metal bond between nickel and iron, which is in agreement with the computational results. Electrochemical experiments show that iron is the redox active site in these complexes, performing a reversible one-electron oxidation. The four complexes are discussed with regard to their similarities and differences both to the [NiFe] hydrogenases and the C-cluster of Ni-containing CODH.

Oxoaporphine Metal Complexes (CoII, NiII, ZnII) with High Antitumor Activity by Inducing Mitochondria-Mediated Apoptosis and S-phase Arrest in HepG2

PubMed Central

Qin, Jiao-Lan; Shen, Wen-Ying; Chen, Zhen-Feng; Zhao, Li-Fang; Qin, Qi-Pin; Yu, Yan-Cheng; Liang, Hong

2017-01-01

Three new oxoaporphine Co(II), Ni(II) and Zn(II) complexes 1–3 have been synthesized and fully characterized. 1–3 have similar mononuclear structures with the metal and ligand ratio of 1:2. 1–3 exhibited higher cytotoxicity than the OD ligand and cisplatin against HepG2, T-24, BEL-7404, MGC80–3 and SK-OV-3/DDP cells, with IC50 value of 0.23−4.31 μM. Interestingly, 0.5 μM 1–3 significantly caused HepG2 arrest at S-phase, which was associated with the up-regulation of p53, p21, p27, Chk1 and Chk2 proteins, and decrease in cyclin A, CDK2, Cdc25A, PCNA proteins. In addition, 1–3 induced HepG2 apoptosis via a caspase-dependent mitochondrion pathway as evidenced by p53 activation, ROS production, Bax up-regulation and Bcl-2 down-regulation, mitochondrial dysfunction, cytochrome c release, caspase activation and PARP cleavage. Furthermore, 3 inhibited tumor growth in HepG2 xenograft model, and displayed more safety profile in vivo than cisplatin. PMID:28436418

Syntheses, crystal structures and Hirshfeld surface analysis of a coordination polymer of Cu(II) chlorido and a tris-octahedral complex of Ni(II) containing isonicotinoylhydrazone blockers

NASA Astrophysics Data System (ADS)

Mahmoudi, Ghodrat; Chowdhury, Habibar; Ghosh, Barindra K.; Lofland, Samuel E.; Maniukiewicz, Waldemar

2018-05-01

One-pot reactions of pre-assigned molar ratios of appropriate metal (II) salts and HL1 (2-acetylpyridine nicotinoylhydrazone) or HL2 (2-acetylpyridine isonicotinoylhydrazone) in MeOH solutions at room temperature afford 1D coordination polymeric chain [Cu(μ-L1) (Cl)]n (1) and a mononuclear complex [Ni(L2)2] (2). The compounds (1) and (2) were characterized using elemental analyses, spectral and other physicochemical methods. Single crystal X-ray diffraction measurements for (1) and (2) have been made to define the molecular aggregates and crystalline architectures. In (1), each copper (II) center adopts a distorted square pyramidal geometry with a CuN3OCl chromophore linked through μ-L1 to form the 1D polymeric chain. While in (2) each Ni(II) cation is six-coordinate with octahedral structure having NiN4O2 chromophore containing two L2 units each functioning as a classical tridentate (N,N,O) chelator. Different weak non-covalent interactions promote dimensionalities in the compounds. A Hirshfeld surface analysis was employed to gain additional insight into interactions responsible for packing of (1) and (2). Magnetic susceptibility measurement of (1) in the 4-300 K range reveals simple paramagnetism.

Synthesis and structure of 1,3-dimethyl-5-(p-sulfonamide-phenylazo)-6-aminouracil and its Ni(II) complex: Topological insights and investigation for noncovalent interactions

NASA Astrophysics Data System (ADS)

Debnath, Diptanu; Roy, Subhadip; Purkayastha, Atanu; Bauzá, Antonio; Choudhury, Rupasree; Ganguly, Rakesh; Frontera, Antonio; Misra, Tarun Kumar

2017-08-01

The azo-derivative, 1,3-dimethyl-5-(p-sulfonamide-phenylazo)-6-aminouracil (HL) containing 6-aminouracil (a biomolecule) and sulfonamide functionality (commonly found in sulfa-drugs), and its Ni(II) complex, NiIIL2 were synthesized. Single-crystal X-ray diffraction studies show that the ligand (HL) consists of an E conformation about the azo-linkage with a nearly planar geometry and the complex possesses distorted square planar geometry. The H-bonded underlying networks of HL and NiIIL2 were topologically classified revealing distinct topological types, namely tts and hxl, respectively. Moreover, topology of molecular packings in HL and NiIIL2 has also been discussed. Density functional theory (DFT) calculations, at the M06-2X/def2TZVP level of theory, are employed to characterize a great variety of non-covalent interactions that explicitly show the importance of antiparallel stacking interactions established by π--π+ interactions and H-bonds in the self-assembled dimmers in HL and lp-π/C-H⋯π interactions in NiIIL2. The results of NMR and UV-vis spectroscopies evidence that the ligand exists in hydrazone-imine-keto (B) tautomeric form in solution. The ligand absorption bands consist of the overlapping bands of π→π* and n→π* transitions. The complex experiences electronic transitions that consist of basically ILCT in character with some sort of participation of the atomic d-orbitals of the nickel. The pKa value of the ligand is found to be 4.09.

Synthesis and characterization of Cu(II), Co(II) and Ni(II) complexes of a number of sulfadrug azodyes and their application for wastewater treatment

NASA Astrophysics Data System (ADS)

El-Baradie, K.; El-Sharkawy, R.; El-Ghamry, H.; Sakai, K.

2014-03-01

The azodye ligand (HL1) was synthesized from the coupling of sulfaguanidine diazonium salt with 2,4-dihydroxy-benzaldehyde while the two ligands, HL2 and HL3, were prepared by the coupling of sulfadiazine diazonium salt with salicylaldehyde (HL2) and 2,4-dihydroxy-benzaldehyde (HL3). The prepared ligands were characterized by elemental analysis, IR, 1H NMR and mass spectra. Cu(II), Co(II) and Ni(II) complexes of the prepared ligands have been synthesized and characterized by various spectroscopic techniques like IR, UV-Visible as well as magnetic and thermal (TG and DTA) measurements. It was found that all the ligands behave as a monobasic bidentate which coordinated to the metal center through the azo nitrogen and α-hydroxy oxygen atoms in the case of HL1 and HL3. HL2 coordinated to the metal center through sulfonamide oxygen and pyrimidine nitrogen. The applications of the prepared complexes in the oxidative degradation of indigo carmine dye exhibited good catalytic activity in the presence of H2O2 as an oxidant. The reactions followed first-order kinetics and the rate constants were determined. The degradation reaction involved the catalytic action of the azo-dye complexes toward H2O2 decomposition, which can lead to the generation of HOrad radicals as a highly efficient oxidant attacking the target dye. The detailed kinetic studies and the mechanism of these catalytic reactions are under consideration in our group.

Ni(II) removal from aqueous solutions using cone biomass of Thuja orientalis.

PubMed

Malkoc, Emine

2006-09-21

The biomass of terrestrial-plant materials has high removal capacities for a number of heavy metal ions. The Ni(II) biosorption capacity of the cone biomass of Thuja orientalis was studied in the batch mode. The biosorption equilibrium level was determined as a function of contact time, pH, temperature, agitation speed at several initial metal ion and adsorbent concentrations. The removal of Ni(II) from aqueous solutions increased with adsorbent concentration, temperature and agitation speed of the solution were increased. The biosorption process was very fast; 90% of biosorption occurred within 3 min and equilibrium was reached at around 7 min. It is found that the biosorption of Ni(II) on the cone biomass was correlated well (R2 > 0.99) with the Langmuir equation as compared to Freundlich, BET Temkin and D-R isotherm equation under the concentration range studied. According to Langmuir isotherm, the monolayer saturation capacity (Q(o)) is 12.42 mg g(-1). The pseudo-first-order, pseudo-second-order and intraparticle diffusion kinetic models were applied to test the experimental data for initial Ni(II) and cone biomass concentrations. The pseudo-second-order kinetic model provided the best correlation of the used experimental data compared to the pseudo-first-order and intraparticle diffusion kinetic models. The activation energy of biosorption (E(a)) was determined as 36.85 kJ mol(-1) using the Arrhenius equation. This study indicated that the cone biomass of T. orientalis can be used as an effective and environmentally friendly adsorbent for the treatment of Ni(II) containing aqueous solutions.

Synthesis, spectral studies and biological evaluation of 2-aminonicotinic acid metal complexes

NASA Astrophysics Data System (ADS)

Nawaz, Muhammad; Abbasi, Muhammad Waseem; Hisaindee, Soleiman; Zaki, Muhammad Javed; Abbas, Hira Fatima; Mengting, Hu; Ahmed, M. Arif

2016-05-01

We synthesized 2-aminonicotinic acid (2-ANA) complexes with metals such as Co(II), Fe(III), Ni(II), Mn(II), Zn(II), Ag(I),Cr(III), Cd(II) and Cu(II) in aqueous media. The complexes were characterized and elucidated using FT-IR, UV-Vis, a fluorescence spectrophotometer and thermo gravimetric analysis (TGA). TGA data showed that the stoichiometry of complexes was 1:2 metal/ligand except for Ag(I) and Mn(II) where the ratio was 1:1. The metal complexes showed varied antibacterial, fungicidal and nematicidal activities. The silver and zinc complexes showed highest activity against Bacillus subtilis and Bacillus licheniformis respectively. Fusarium oxysporum was highly susceptible to nickel and copper complexes whereas Macrophomina phaseolina was completely inert to the complexes. The silver and cadmium complexes were effective against the root-knot nematode Meloidogyne javanica.

Nickel(II) complexes of tripodal 4N ligands as catalysts for alkane oxidation using m-CPBA as oxidant: ligand stereoelectronic effects on catalysis.

PubMed

Balamurugan, Mani; Mayilmurugan, Ramasamy; Suresh, Eringathodi; Palaniandavar, Mallayan

2011-10-07

Several mononuclear Ni(II) complexes of the type [Ni(L)(CH(3)CN)(2)](BPh(4))(2) 1-7, where L is a tetradentate tripodal 4N ligand such as N,N-dimethyl-N',N'-bis(pyrid-2-ylmethyl)ethane-1,2-diamine (L1), N,N-diethyl-N',N'-bis(pyrid-2-ylmethyl)ethane-1,2-diamine (L2), N,N-dimethyl-N'-(1-methyl-1H-imidazol-2-ylmethyl)-N'-(pyrid-2-ylmethyl)ethane-1,2-diamine (L3), N,N-dimethyl-N',N'-bis(1-methyl-1H-imidazol-2-ylmethyl)ethane-1,2-diamine (L4), N,N-dimethyl-N',N'-bis(quinolin-2-ylmethyl)ethane-1,2-diamine (L5), tris(benzimidazol-2-ylmethyl)amine (L6) and tris(pyrid-2-ylmethyl)amine (L7), have been isolated and characterized using CHN analysis, UV-Visible spectroscopy and mass spectrometry. The single-crystal X-ray structures of the complexes [Ni(L1)(CH(3)CN)(H(2)O)](ClO(4))(2) 1a, [Ni(L2)(CH(3)CN)(2)](BPh(4))(2) 2, [Ni(L3)(CH(3)CN)(2)](BPh(4))(2) 3 and [Ni(L4)(CH(3)CN)(2)](BPh(4))(2) 4 have been determined. All these complexes possess a distorted octahedral coordination geometry in which Ni(II) is coordinated to four nitrogen atoms of the tetradentate ligands and two CH(3)CN (2, 3, 4) or one H(2)O and one CH(3)CN (1a) are located in cis positions. The Ni-N(py) bond distances (2.054(2)-2.078(3) Å) in 1a, 2 and 3 are shorter than the Ni-N(amine) bonds (2.127(2)-2.196(3) Å) because of sp(2) and sp(3) hybridizations of the pyridyl and tertiary amine nitrogens respectively. In 3 the Ni-N(im) bond (2.040(5) Å) is shorter than the Ni-N(py) bond (2.074(4) Å) due to the stronger coordination of imidazole compared with the pyridine donor. In dichloromethane/acetonitrile solvent mixture, all the Ni(ii) complexes possess an octahedral coordination geometry, as revealed by the characteristic ligand field bands in the visible region. They efficiently catalyze the hydroxylation of alkanes when m-CPBA is used as oxidant with turnover number (TON) in the range of 340-620 and good alcohol selectivity for cyclohexane (A/K, 5-9). By replacing one of the pyridyl donors in TPA by a weakly coordinating -NMe(2) or -NEt(2) donor nitrogen atom the catalytic activity decreases slightly with no change in the selectivity. In contrast, upon replacing the pyridyl nitrogen donor by the strongly σ-bonding imidazolyl or sterically demanding quinolyl/benzimidazolyl nitrogen donor, both the catalytic activity and selectivity decrease, possibly due to destabilization of the intermediate [(4N)(CH(3)CN)Ni-O˙](+) radical species. Adamantane is selectively (3°/2°, 12-17) oxidized to 1-adamantanol, 2-adamantanol and 2-adamantanone while cumene is selectively oxidized to 2-phenyl-2-propanol. In contrast to cyclohexane oxidation, the incorporation of sterically hindering quinolyl/benzimidazolyl donors around Ni(ii) leads to a high 3°/2° bond selectivity for adamantane oxidation. A linear correlation between the metal-ligand covalency parameter (β) and the turnover number has been observed.

Physicochemical properties of sorbents based on silica gel modified by 1-phenylazo-2-naphtholic complexes of transition metals

NASA Astrophysics Data System (ADS)

Makarycheva, A. I.; Slizhov, Yu. G.

2017-09-01

Gas chromatography sorbents based on Silokhrom C80 and modified by 1-phenylazo-2-naphtholic complexes of 3 d metals (Co(II), Ni(II), Cu(II)) are obtained. Their structural, chromatographic, and sorption characteristics are investigated. It is found that modifying them with 1-phenylazo-2-naphthols of transition metals has a considerable effect on the chromatographic polarity and selectivity of sorption materials. The prospects for the practical application of the obtained sorbents are demonstrated by experiments on the gas chromatographic separation of mixtures of different classes of organic compounds.

Structural Investigation of Dinuclear Clusters Incorporated in Polyoxotungstates

NASA Astrophysics Data System (ADS)

Nagy, C.; Rusu, D.; Somesan, C.; Filip, S.; Rusu, M.; David, L.

2011-10-01

The new K10[M2Bi2W20O70]ṡH2O (M = Mn(II), Co(II), Ni(II), Cu(II)) sandwich-type complex have been investigated by spectroscopic (FT-IR, UV-VIS, ESR) methods. The main goal was to obtain information about the metal ions coordination to the trilacunary regions of Keggin polioxoanion ligands, the local symmetry around the metal ions and the presence of possible metal-metal couplings.

Sequential determination of nickel and cadmium in tobacco, molasses and refill solutions for e-cigarettes samples by molecular fluorescence.

PubMed

Talio, María Carolina; Alesso, Magdalena; Acosta, Mariano; Wills, Verónica S; Fernández, Liliana P

2017-11-01

In this work, a new procedure was developed for separation and preconcentration of nickel(II) and cadmium(II) in several and varied tobacco samples. Tobacco samples were selected considering the main products consumed by segments of the population, in particular the age (youth) and lifestyle of the consumer. To guarantee representative samples, a randomized strategy of sampling was used. In the first step, a chemofiltration on nylon membrane is carried out employing eosin (Eo) and carbon nanotubes dispersed in sodium dodecylsulfate (SDS) solution (phosphate buffer pH 7). In this condition, Ni(II) was selectively retained on the solid support. After that, the filtrate liquid with Cd(II) was re-conditioned with acetic acid /acetate buffer solution (pH 5) and followed by detection. A spectrofluorimetric determination of both metals was carried out, on the solid support and the filtered aqueous solution, for Ni(II) and Cd(II), respectively. The solid surface fluorescence (SSF) determination was performed at λ em = 545nm (λ ex = 515nm) for Ni(II)-Eo complex and the fluorescence of Cd(II)-Eo was quantified in aqueous solution using λ em = 565nm (λ ex = 540nm). The calibration graphs resulted linear in a range of 0.058-29.35μgL -1 for Ni(II) and 0.124-56.20μgL -1 for Cd(II), with detection limits of 0.019 and 0.041μgL -1 (S/N = 3). The developed methodology shows good sensitivity and adequate selectivity, and it was successfully applied to the determination of trace amounts of nickel and cadmium present in tobacco samples (refill solutions for e-cigarettes, snuff used in narguille (molasses) and traditional tobacco) with satisfactory results. The new methodology was validated by ICP-MS with adequate agreement. The proposed methodology represents a novel fluorescence application to Ni(II) and Cd(II) quantification with sensitivity and accuracy similar to atomic spectroscopies, introducing for the first time the quenching effect on SSF. Copyright © 2017 Elsevier B.V. All rights reserved.

Synthesis, spectroscopic characterization and antimicrobial studies of Co(II), Ni(II), Cu(II) and Zn(II) complexes with Schiff bases derived from 5-bromo-salicylaldehyde

NASA Astrophysics Data System (ADS)

Kursunlu, Ahmed Nuri; Guler, Ersin; Sevgi, Fatih; Ozkalp, Birol

2013-09-01

In this study, the new Schiff base ligands derived from condensation of amine and 5-bromo-salicylaldehyde were characterized. All compounds, the Schiff bases and the metal complexes, were characterized by elemental analyzes, FT-IR, 1H NMR, 13C NMR and magnetic susceptibility measurements. The synthesized ligands, along with their metal (II) complexes, were screened for their in vitro antibacterial activity against four Gram-negative (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Salmonella enteritidis) and four Gram-positive (Streptococcus pyogones, Bacillus cereus, Staphylococcus aureus and Methicillin-resistant S. aureus) bacterial strains by using disc diffusion and broth microdilution techniques.

A Novel Nanocomposite as an Efficient Adsorbent for the Rapid Adsorption of Ni(II) from Aqueous Solution

PubMed Central

Wang, Ximing; Chen, Zhangjing

2017-01-01

A sulfhydryl-lignocellulose/montmorillonite (SLT) nanocomposite was prepared using a chemical intercalation reaction. The SLT nanocomposite was characterized by Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), and Transmission Electron Microscopy (TEM), the results demonstrated that an intercalated-exfoliated nanostructure was formed in the SLT nanocomposite. Batch experiments were conducted to optimize parameters such as SLT nanocomposite dosage, the initial concentration of Ni(II), solution pH, temperature, and time. The results indicated that the attractive adsorption capacity reached 1134.08 mg/g with 0.05 g of SLT at an initial concentration of Ni(II) of 700 mg/L, solution pH of 5.5, adsorption temperature of 50 °C, and adsorption time of 40 min, meanwhile, the Ni(II) adsorption capacity significantly decreased with the increase in ionic strength. The pseudo-second order kinetic model could describe the whole adsorption process well, and the isotherm adsorption equilibrium conformed to the Freundlich model. The adsorption mechanism of SLT was also discussed by means of FTIR and Energy-Dispersive X-Ray (EDX). Dramatically, the introduction of sulfhydryl achieves the increased activated functional groups content of SLT nanocomposite, leading to remarkably higher adsorption amount on Ni(II). The desorption capacity of SLT was dependent on parameters such as HNO3 concentration, desorption temperature, and ultrasonic desorption time. The satisfactory desorption capacity and desorption efficiency of 458.21 mg/g and 40.40% were obtained at an HNO3 concentration, desorption temperature, and ultrasonic desorption time of 0.4 mol/L, 40 °C, and 30 min, respectively. The regeneration studies showed that the adsorption capacity of SLT was consistent for four cycles without any appreciable loss and confirmed that the SLT was reusable. Owing to such outstanding features, the novel SLT nanocomposite proved the great potential in adsorption for Ni(II) removal from aqueous solution, and exhibited an extremely significant amount of Ni(II), compared to pristine lignocellulose/montmorillonite and the conventional spent adsorbents. PMID:28937606

Synthesis, spectral studies and biological evaluation of 2-aminonicotinic acid metal complexes.

PubMed

Nawaz, Muhammad; Abbasi, Muhammad Waseem; Hisaindee, Soleiman; Zaki, Muhammad Javed; Abbas, Hira Fatima; Mengting, Hu; Ahmed, M Arif

2016-05-15

We synthesized 2-aminonicotinic acid (2-ANA) complexes with metals such as Co(II), Fe(III), Ni(II), Mn(II), Zn(II), Ag(I),Cr(III), Cd(II) and Cu(II) in aqueous media. The complexes were characterized and elucidated using FT-IR, UV-Vis, a fluorescence spectrophotometer and thermo gravimetric analysis (TGA). TGA data showed that the stoichiometry of complexes was 1:2 metal/ligand except for Ag(I) and Mn(II) where the ratio was 1:1. The metal complexes showed varied antibacterial, fungicidal and nematicidal activities. The silver and zinc complexes showed highest activity against Bacillus subtilis and Bacillus licheniformis respectively. Fusarium oxysporum was highly susceptible to nickel and copper complexes whereas Macrophomina phaseolina was completely inert to the complexes. The silver and cadmium complexes were effective against the root-knot nematode Meloidogyne javanica. Copyright © 2016 Elsevier B.V. All rights reserved.

Synthesis, spectroscopic characterization, DNA interaction and antibacterial study of metal complexes of tetraazamacrocyclic Schiff base

NASA Astrophysics Data System (ADS)

Shakir, Mohammad; Khanam, Sadiqa; Firdaus, Farha; Latif, Abdul; Aatif, Mohammad; Al-Resayes, Saud I.

The template condensation reaction between benzil and 3,4-diaminotoulene resulted mononuclear 12-membered tetraimine macrocyclic complexes of the type, [MLCl2] [M = Co(II), Ni(II), Cu(II) and Zn(II)]. The synthesized complexes have been characterized on the basis of the results of elemental analysis, molar conductance, magnetic susceptibility measurements and spectroscopic studies viz. FT-IR, 1H and 13C NMR, FAB mass, UV-vis and EPR. An octahedral geometry has been envisaged for all these complexes, while a distorted octahedral geometry has been noticed for Cu(II) complex. Low conductivity data of all these complexes suggest their non-ionic nature. The interactive studies of these complexes with calf thymus DNA showed that the complexes are avid binders of calf thymus DNA. The in vitro antibacterial studies of these complexes screened against pathogenic bacteria proved them as growth inhibiting agents.

Novel method of vulnerability assessment of simple landfills area using the multimedia, multipathway and multireceptor risk assessment (3MRA) model, China.

PubMed

Yuan, Ying; He, Xiao-Song; Xi, Bei-Dou; Wei, Zi-Min; Tan, Wen-Bing; Gao, Ru-Tai

2016-11-01

Vulnerability assessment of simple landfills was conducted using the multimedia, multipathway and multireceptor risk assessment (3MRA) model for the first time in China. The minimum safe threshold of six contaminants (benzene, arsenic (As), cadmium (Cd), hexavalent chromium [Cr(VI)], divalent mercury [Hg(II)] and divalent nickel [Ni(II)]) in landfill and waste pile models were calculated by the 3MRA model. Furthermore, the vulnerability indexes of the six contaminants were predicted based on the model calculation. The results showed that the order of health risk vulnerability index was As > Hg(II) > Cr(VI) > benzene > Cd > Ni(II) in the landfill model, whereas the ecology risk vulnerability index was in the order of As > Hg(II) > Cr(VI) > Cd > benzene > Ni(II). In the waste pile model, the order of health risk vulnerability index was benzene > Hg(II) > Cr(VI) > As > Cd and Ni(II), whereas the ecology risk vulnerability index was in the order of Hg(II) > Cd > Cr(VI) > As > benzene > Ni(II). These results indicated that As, Hg(II) and Cr(VI) were the high risk contaminants for the case of a simple landfill in China; the concentration of these in soil and groundwater around the simple landfill should be strictly monitored, and proper mediation is also recommended for simple landfills with a high concentration of contaminants. © The Author(s) 2016.

Spectral and in vitro antimicrobial properties of 2-oxo-4-phenyl-6-styryl-1,2,3,4-tetrahydro-pyrimidine-5-carboxylic acid transition metal complexes

NASA Astrophysics Data System (ADS)

Dhankar, Raksha P.; Rahatgaonkar, Anjali M.; Chorghade, Mukund S.; Tiwari, Ashutosh

2-oxo-4-phenyl-6-styryl-1,2,3,4-tetrahydro-pyrimidine-5-carboxylic acid (ADP) was complexed with acetates of Mn(II), Ni(II), Cu(II) and Zn(II). The structures of the ligand and its metal complexes were characterized by microanalysis, IR, NMR, UV-vis spectroscopy, magnetic susceptibility and TGA-DTA analyses. Octahedral and square planar geometries were suggested for the complexes in which the central metal ion coordinated with sbnd O donors of ligand and acetate ions. Each ligand binds the metal using carboxylate oxygens. The ligand and complexes were evaluated for their antimicrobial activities against different species of pathogenic bacteria and fungi. The present novel pyrimidine containing complexes could constitute a new group of antibacterial and antifungal agents.

Preparation, spectral, X-ray powder diffraction and computational studies and genotoxic properties of new azo-azomethine metal chelates

NASA Astrophysics Data System (ADS)

Bitmez, Şirin; Sayin, Koray; Avar, Bariş; Köse, Muhammet; Kayraldız, Ahmet; Kurtoğlu, Mükerrem

2014-11-01

A new tridentate azo-azomethine ligand, N‧-[{2-hydroxy-5-[(4-nitrophenyl)diazenyl]phenyl}methylidene]benzohydrazidemonohydrate, (sbH·H2O) (1), is prepared by condensation of benzohydrazide and 2-hydroxy-5-[(4-nitrophenyl)diazenyl]benzaldehyde (a) with treatment of a solution of diazonium salt of p-nitroaniline and 2-hydroxybenzaldehyde in EtOH. The five coordination compounds, [Co(sb)2]·4H2O (2), [Ni(sb)2]·H2O (3), [Cu(sb)2]·4H2O (4), [Zn(sb)2]·H2O (5) and [Cd(sb)2]·H2O (6) are prepared by reacting the Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) ions with the ligand. The structures of the compounds are elucidated from the elemental analyses data and spectroscopic studies. It is found the ligand acts as a tridentate bending through phenolic and carbonyl oxygens and nitrogen atom of the Cdbnd Nsbnd group similar to the most of salicylaldimines. Comparison of the infrared spectra of the ligand and its metal complexes confirm that azo-Schiff base behaves as a monobasic tridentate ligand towards the central metal ion with an ONO donor sequence. Upon complexation with the ligand, the Cd(II), and Zn(II) ions form monoclinic structures, while Co(II), Cu(II) and Ni(II) ions form orthorhombic structures. Quantum chemical calculations are performed on tautomers and its metal chelates by using DFT/B3LYP method. Most stable tautomer is determined as tautomer (1a). The geometrical parameters of its metal chelates are obtained as theoretically. The NLO properties of tautomer (1a) and its metal complexes are investigated. Finally, the ligand and its metal complexes are assessed for their genotoxicity.

Activated biochar: Preparation, characterization and electroanalytical application in an alternative strategy of nickel determination.

PubMed

Kalinke, Cristiane; Oliveira, Paulo Roberto; Oliveira, Geovane Arruda; Mangrich, Antonio Sálvio; Marcolino-Junior, Luiz H; Bergamini, Márcio F

2017-08-29

This work reports for the first time the use of chemically activated biochar as electrode modifier for nickel determination. The biochar activation was performed by refluxing with HNO 3 , which promoted a higher nickel preconcentration compared to unmodified and modified biochar precursor electrodes. Morphological and structural characterization revealed the increase of surface acid groups, surface area and porosity of biochar after activation. Nickel determination was investigated adopting an alternative voltammetric methodology based on monitoring the Ni(II)/Ni(III) redox couple. In the proposed method, it was not necessary to use a complexing agent and the biochar itself was responsible for the analyte preconcentration. A linear response for Ni(II) concentration range from 1.0 to 30 μmol L -1 and a limit of detection of 0.25 μmol L -1 were obtained. The method was successfully applied for Ni(II) determination in spiked samples of bioethanol fuel and discharge water, with recoveries values between 103 and 109%. Copyright © 2017 Elsevier B.V. All rights reserved.

Importance of reduced sulfur for the equilibrium chemistry and kinetics of Fe(II), Co(II) and Ni(II) supplemented to semi-continuous stirred tank biogas reactors fed with stillage.

PubMed

Shakeri Yekta, Sepehr; Lindmark, Amanda; Skyllberg, Ulf; Danielsson, Asa; Svensson, Bo H

2014-03-30

The objective of the present study was to assess major chemical reactions and chemical forms contributing to solubility and speciation of Fe(II), Co(II), and Ni(II) during anaerobic digestion of sulfur (S)-rich stillage in semi-continuous stirred tank biogas reactors (SCSTR). These metals are essential supplements for efficient and stable performance of stillage-fed SCSTR. In particular, the influence of reduced inorganic and organic S species on kinetics and thermodynamics of the metals and their partitioning between aqueous and solid phases were investigated. Solid phase S speciation was determined by use of S K-edge X-ray absorption near-edge spectroscopy. Results demonstrated that the solubility and speciation of supplemented Fe were controlled by precipitation of FeS(s) and formation of the aqueous complexes of Fe-sulfide and Fe-thiol. The relatively high solubility of Co (∼ 20% of total Co content) was attributed to the formation of compounds other than Co-sulfide and Co-thiol, presumably of microbial origin. Nickel had lower solubility than Co and its speciation was regulated by interactions with FeS(s) (e.g. co-precipitation, adsorption, and ion substitution) in addition to precipitation/dissolution of discrete NiS(s) phase and formation of aqueous Ni-sulfide complexes. Copyright © 2014 Elsevier B.V. All rights reserved.

Assessment of electrokinetic removal of heavy metals from soils by sequential extraction analysis.

PubMed

Reddy, K R; Xu, C Y; Chinthamreddy, S

2001-06-29

Electrokinetic remediation of metal-contaminated soils is strongly affected by soil-type and chemical species of contaminants. This paper investigates the speciation and extent of migration of heavy metals in soils during electrokinetic remediation. Laboratory electrokinetic experiments were conducted using two diverse soils, kaolin and glacial till, contaminated with chromium as either Cr(III) or Cr(VI). Initial total chromium concentrations were maintained at 1000mg/kg. In addition, Ni(II) and Cd(II) were used in concentrations of 500 and 250mg/kg, respectively. The contaminated soils were subjected to a voltage gradient of 1 VDC/cm for over 200h. The extent of migration of contaminants after the electric potential application was determined. Sequential extractions were performed on the contaminated soils before and after electrokinetic treatment to provide an understanding of the distribution of the contaminants in the soils. The initial speciation of contaminants was found to depend on the soil composition as well as the type and amounts of different contaminants present. When the initial form of chromium was Cr(III), exchangeable and soluble fractions of Cr, Ni, and Cd ranged from 10 to 65% in kaolin; however, these fractions ranged from 0 to 4% in glacial till. When the initial form of chromium was Cr(VI), the exchangeable and soluble fractions of Cr, Ni and Cd ranged from 66 to 80% in kaolin. In glacial till, however, the exchangeable and soluble fraction for Cr was 38% and Ni and Cd fractions were 2 and 10%, respectively. The remainder of the contaminants existed as the complex and precipitate fractions. During electrokinetic remediation, Cr(VI) migrated towards the anode, whereas Cr(III), Ni(II) and Cd(II) migrated towards the cathode. The speciation of contaminants after electrokinetic treatment showed that significant change in exchangeable and soluble fractions occurred. In kaolin, exchangeable and soluble Cr(III), Ni(II), and Cd(II) decreased near the anode and increased near the cathode, whereas exchangeable and soluble Cr(VI) decreased near the cathode and increased near the anode. In glacial till, exchangeable and soluble Cr(III), Ni(II), and Cd(II) were low even before electrokinetic treatment and no significant changes were observed after the electrokinetic treatment. However, significant exchangeable and soluble Cr(VI) that was present in glacial till prior to electrokinetic treatment decreased to non-detectable levels near the cathode and increased significantly near the anode. In both kaolin and glacial till, low migration rates occurred as a result of contaminants existing as immobile complexes and precipitates. The overall contaminant removal efficiency was very low (less than 20%) in all tests.

Uptake of Nickel by Synthetic Mackinawite

EPA Science Inventory

The uptake of aqueous Ni(II) by synthetic mackinawite (FeS) was examined in anaerobic batch experiments at near-neutral pH (5.2 to 8.4). Initial molar ratios of Ni(II) to FeS ranged from 0.008 to 0.83 and maximum Ni concentrations in mackinawite, expressed as the cation mol fract...

Polyethylene imine modified hydrochar adsorption for chromium (VI) and nickel (II) removal from aqueous solution.

PubMed

Shi, Yuanji; Zhang, Tao; Ren, Hongqiang; Kruse, Andrea; Cui, Ruofan

2018-01-01

An adsorbent hydrochar was synthesized from corn cobs and modified with polyethylene imine (PEI). The hydrochars before and after modification were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis. FTIR and XPS revealed that the PEI was grafted onto the hydrochar via ether and imine bonds formed with glutaraldehyde. The maximum adsorption capacities for Cr(VI) (33.663mg/g) and Ni(II) (29.059mg/g) on the modified hydrochars were 365% and 43.7% higher, respectively, than those on the unmodified hydrochar. A pseudo-second-order model described the adsorption of Ni(II) and Cr(VI) on all the adsorbents. The adsorption of Cr(VI) was endothermic, spontaneous, increased disorder, and obeyed the Langmuir model. By contrast, the adsorption of Ni(II) was exothermic, spontaneous, decreased disorder, and obeyed the Freundlich model. XPS confirmed that the adsorption sites and mechanisms for Ni(II) and Cr(VI) on the modified hydrochars were different. Copyright © 2017 Elsevier Ltd. All rights reserved.

Toxicology and metabolism of nickel compounds. Progress report, December 1, 1974--November 30, 1975. [97433ONE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sunderman, F.W. Jr.

1975-08-15

The toxicology and metabolism of nickel compounds (NiCl/sub 2/, Ni/sub 3/S/sub 2/, NiS, and Ni powder) were investigated in rats and hamsters. The new knowledge has included: demonstration that hyperglucagonemia is primarily responsible for the acute hyperglycemic effect of parenteral Ni(II) in rats; demonstration that parenteral injection of Ni(II) in rats produces acute nephropathy with proteinuria and amino aciduria, and with ultrastructural lesions of renal glomeruli and tubules; confirmation of the inhibitory effect of manganese upon the carcinogenicity of Ni/sub 3/S/sub 2/ after intramuscular injection in rats, and elucidation of the effects of manganese upon the rates of excretion ofmore » nickel, and upon the acute histological reactions produced by Ni/sub 3/S/sub 2/; discovery that the antidotal efficacy of triethylenetetramine (TETA) in acute Ni(II) poisoning in rats is substantially greater than that of other chelating agents, including ..cap alpha..-lipoic acid, diethyldithiocarbamate, d-penicillamine, and glycylglycyl-L-histidine-N-methylamide; observation that the acute renal toxicity of Ni(II) is suppressed by administration of TETA, but that the hyperglycemic and hyperglucagonemic responses to Ni(II) are not prevented by TETA; confirmation that marked erythrocytosis is induced in rats by a single intrarenal injection of Ni/sub 3/S/sub 2/, and elucidation of the time-response and dose-response relationships for the Ni-induced erythrocytosis. (auth)« less

Multisurface modeling of Ni bioavailability to wheat (Triticum aestivum L.) in various soils.

PubMed

Zhao, Xiaopeng; Jiang, Yang; Gu, Xueyuan; Gu, Cheng; Taylor, J Anita; Evans, Les J

2018-07-01

Continual efforts have been made to determine a simple and universal method of estimating heavy metal phytoavailability in terrestrial systems. In the present study, a mechanism-based multi-surface model (MSM) was developed to predict the partition of Ni(II) in soil-solution phases and its bioaccumulation in wheat (Triticum aestivum L.) in 19 Chinese soils with a wide range of soil properties. MSM successfully predicted the Ni(II) dissolution in 0.01 M CaCl 2 extracting solution (R 2  = 0.875). The two-site model for clay fraction improved the prediction, particularly for alkaline soils, because of the additional consideration of edge sites. More crucially, the calculated dissolved Ni(II) was highly correlated with the metal accumulation in wheat (R 2  = 0.820 for roots and 0.817 for shoots). The correlation coefficients for the MSM and various chemical extraction methods have the following order: soil pore water > MSM ≈ diffuse gradient technique (DGT) > soil total Ni > 0.43 M HNO 3  > 0.01 M CaCl 2 . The results suggested that the dissolved Ni(II) calculated using MSM can serve as an effective indicator of the bioavailability of Ni(II) in various soils; hence, MSM can be used as an supplement for metal risk prediction and assessment besides chemical extraction techniques. Copyright © 2018 Elsevier Ltd. All rights reserved.

Study of the heavy metal phytoextraction capacity of two forage species growing in an hydroponic environment.

PubMed

Bonfranceschi, Barros A; Flocco, C G; Donati, E R

2009-06-15

Sorghum and alfalfa are two important forage crops. We studied their capacity for accumulating heavy metals in hydroponic experiments. Cadmium, nickel (as divalent cations) and chromium (trivalent and hexavalent) were added individually to the nutrient solution in a range of concentrations from 1 to 80 mg/l. Cr(III) was complexed with EDTA to increase its bioavailability. In alfalfa the increases in the concentration of Cr(III) and Cr(VI) favoured translocation of the metals to the upper parts of the plants, while with Ni(II) the level of translocated metal remained almost unchanged. In sorghum, both Cr(VI) and Ni(II) produced similar results to those in alfalfa, but increases in the concentrations of Cd(II) and Cr(III) in the solution lead to a higher accumulation of the metal at the root level. The concentrations referred to the dry biomass of alfalfa were 500 mg/kg (aerial parts) and 1500 mg/kg (roots) of Cr(III), simultaneously enhancing plant growth. Sorghum captured 500 and 1100 mg/kg (in aerial parts) and 300 and 2000 mg/kg (in roots) for Ni(II) and Cd(II) respectively, without significant damage to its biomass. The results show that alfalfa and sorghum can not only grow in the presence of high heavy metal concentration but also capture and translocate them to the aerial parts; because of these results special attention should be given to these crop plants for their possible use in phytoremediation of large contaminated areas but especially to avoid the possible introduction of the metals accumulated in aerial parts into the food chain when those plants grow in contaminated areas.

{μ-2-[(3-Amino-2,2-dimethyl-prop-yl)imino-meth-yl]-6-meth-oxy-phenolato-1:2κ(5)O(1),O(6):N,N',O(1)}{2-[(3-amino-2,2-dimethyl-prop-yl)imino-meth-yl]-6-meth-oxy-phenolato-1κ(3)N,N',O(1)}-μ-azido-1:2κ(2)N:N-azido-2κN-methanol-2κO-dinickel(II).

PubMed

Ghaemi, Akbar; Rayati, Saeed; Fayyazi, Kazem; Ng, Seik Weng; Tiekink, Edward R T

2012-08-01

Two distinct coordination geometries are found in the binuclear title complex, [Ni(2)(C(13)H(19)N(2)O(2))(2)(N(3))(2)(CH(3)OH)], as one Schiff base ligand is penta-dentate, coordinating via the anti-cipated oxide O, imine N and amine N atoms (as for the second, tridentate, ligand) but the oxide O is bridging and coordination also occurs through the meth-oxy O atom. The Ni(II) atoms are linked by a μ(2)-oxide atom and one end of a μ(2)-azide ligand, forming an Ni(2)ON core. The coordination geometry for the Ni(II) atom coordinated by the tridentate ligand is completed by the meth-oxy O atom derived from the penta-dentate ligand, with the resulting N(3)O(3) donor set defining a fac octa-hedron. The second Ni(II) atom has its cis-octa-hedral N(4)O(2) coordination geometry completed by the imine N and amine N atoms of the penta-dentate Schiff base ligand, a terminally coordinated azide N and a methanol O atom. The arrangement is stabilized by an intra-molecular hydrogen bond between the methanol H and the oxide O atom. Linear supra-molecular chains along the a axis are formed in the crystal packing whereby two amine H atoms from different amine atoms hydrogen bond to the terminal N atom of the monodentate azide ligand.

Spectroscopic and computational studies of a trans-mu-1,2-disulfido-bridged dinickel species, [{(tmc)Ni}(2)(S(2))](OTf)(2): comparison of end-on disulfido and peroxo bonding in (Ni(II))(2) and (Cu(II))(2) species.

PubMed

Van Heuvelen, Katherine M; Kieber-Emmons, Matthew T; Riordan, Charles G; Brunold, Thomas C

2010-04-05

A powerful means of enhancing our understanding of the structures and functions of enzymes that contain nickel-sulfur bonds, such as Ni superoxide dismutase, acetyl-coenzyme A synthase/carbon monoxide dehydrogenase, [NiFe] hydrogenase, and methyl-CoM reductase, involves the investigation of model compounds with similar structural and/or electronic properties. In this study, we have characterized a trans-mu-1,2-disulfido-bridged dinickel(II) species, [{(tmc)Ni}(2)(S(2))](2+) (1, tmc = 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane) by using electronic absorption, magnetic circular dichroism (MCD), and resonance Raman (rR) spectroscopic techniques, as well as density functional theory (DFT) and time-dependent DFT computational methods. Our computational results, validated on the basis of the experimental MCD data and previously reported (1)H NMR spectra, reveal that 1 is best described as containing two antiferromagnetically coupled high-spin Ni(II) centers. A normal coordinate analysis of the rR vibrational data was performed to quantify the core bond strengths, yielding force constants of k(Ni-S) = 2.69 mdyn/A and k(S-S) = 2.40 mdyn/A. These values provide a useful basis for a comparison of metal-S/O bonding in 1 and related Ni(2)(O(2)), Cu(2)(O(2)), and Cu(2)(S(2)) dimers. In both the disulfido and the peroxo species, the lower effective nuclear charge of Ni(II) as compared to Cu(II) results in a decreased covalency, and thus relatively weaker metal-S/O bonding interactions in the Ni(2) dimers than in the Cu(2) complexes.

D-Amino acid oxidase bio-functionalized platforms: Toward an enhanced enzymatic bio-activity

NASA Astrophysics Data System (ADS)

Herrera, Elisa; Valdez Taubas, Javier; Giacomelli, Carla E.

2015-11-01

The purpose of this work is to study the adsorption process and surface bio-activity of His-tagged D-amino acid oxidase (DAAO) from Rhodotorula gracilis (His6-RgDAAO) as the first step for the development of an electrochemical bio-functionalized platform. With such a purpose this work comprises: (a) the His6-RgDAAO bio-activity in solution determined by amperometry, (b) the adsorption mechanism of His6-RgDAAO on bare gold and carboxylated modified substrates in the absence (substrate/COO-) and presence of Ni(II) (substrate/COO- + Ni(II)) determined by reflectometry, and (c) the bio-activity of the His6-RgDAAO bio-functionalized platforms determined by amperometry. Comparing the adsorption behavior and bio-activity of His6-RgDAAO on these different solid substrates allows understanding the contribution of the diverse interactions responsible for the platform performance. His6-RgDAAO enzymatic performance in solution is highly improved when compared to the previously used pig kidney (pk) DAAO. His6-RgDAAO exhibits an amperometrically detectable bio-activity at concentrations as low as those expected on a bio-functional platform; hence, it is a viable bio-recognition element of D-amino acids to be coupled to electrochemical platforms. Moreover, His6-RgDAAO bio-functionalized platforms exhibit a higher surface activity than pkDAAO physically adsorbed on gold. The platform built on Ni(II) modified substrates present enhanced bio-activity because the surface complexes histidine-Ni(II) provide with site-oriented, native-like enzymes. The adsorption mechanism responsible of the excellent performance of the bio-functionalized platform takes place in two steps involving electrostatic and bio-affinity interactions whose prevalence depends on the degree of surface coverage.

Direct Measurement of the Supernova Rate in Starburst Galaxies

NASA Technical Reports Server (NTRS)

Bregman, Jesse D.; Temi, Pasquale; Rank, David; DeVincenzi, Donald L. (Technical Monitor)

1999-01-01

Supernovae play a key role in the dynamics, structure, and chemical evolution of galaxies. The massive stars that end their lives as supernovae live for short times. Many are still associated with dusty star formation regions when they explode, making them difficult to observe at visible wavelengths. In active star forming regions (galactic nuclei and starburst regions), dust extintion is especially severe. Thus, determining the supernova rate in the active star forming regions of galaxies, where the supernova rate can be one or two orders of magnitude higher than the average, has proven to be difficult. From observations of SN1987A, we know that the [NiII] 6.63 micron emission line was the strongest line in the infrared spectrum for a period of a year and a half after the explosion. Since dust extintion is much less at 6.63 pm than at visible wavelengths (A(sub 6.63)/A(sub V) = 0.025), the NiII line can be used as a sensitive probe for the detection of recent supernovae. We have observed a sample of starburst galaxies at 6.63 micron using ISOCAM to search for the NiII emission line characteristic of recent supernovae. We did not detect any NiII line emission brighter than a 5sigma limit of 5 mJy. We can set upper limits to the supernova rate in our sample, scaled to the rate in M82, of less than 0.3 per year at the 90% confidence level using Bayesian methods. Assuming that a supernova would have a NiII with the same luminosity as observed in SN1987A, we find less than 0.09 and 0.15 per year at the 50% and 67% confidence levels. These rates are somewhat less if a more normal type II supernovae has a NiII line luminosity greater than the line in SN1987A.

Spectral and thermal study of the ternary complexes of nickel with sulfasalazine and some amino acids

NASA Astrophysics Data System (ADS)

Soliman, Ahmed A.

2006-12-01

The ternary complexes of Ni(II) with sulfasalazine (H 3SS) as a primary ligand and alanine (ala), aspartic acid (asp), histidene (hist), methionine (meth) and serine (ser) amino acids as secondary ligands have been synthesized. Characterization of the complexes was based on elemental analyses, IR, UV-vis, mass spectra, magnetic moment and thermal analysis (TG). The isolated complexes were found to have the general formula [M(HSS)(AA)]4H 2O (AA = ala, asp, hist, meth, or ser amino acid) where nickel is tetra-coordinated. The thermal stability of the complexes was studied and the weight losses for the decomposition of the complexes were calculated and correlated with the mass fragmentation pattern. In most cases, the amino acid moiety is removed along with the Schiff base moiety leaving NiO as a metallic residue. The metallic residue was confirmed by powder XRD measurements.

Synthesis, spectroscopic and thermal studies of transition metal complexes derived from benzil and diethylenetriamine

NASA Astrophysics Data System (ADS)

Khan, Sadaf; Nami, Shahab A. A.; Siddiqi, K. S.

2007-10-01

A macrocyclic ligand, bdta (where bdta = 3,6,9,12,15,18-hexaaza-1,2,10,11-tetraphenyl-2,9,11,18-tetraenecyclododecane) has been prepared by cyclocondensation of benzil with diethylenetriamine which efficiently encapsulates transition as well as pseudo-transition metal ions leading to the formation of M(bdta)Cl 2 type complexes [where M = Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II)]. The analytical, spectroscopic and magnetic moment data suggests an octahedral geometry for all the complexes. EPR spectra of Mn(II) and Cu(II) show considerable exchange interaction in the complex. They are non-conducting in DMSO. The TGA profile of the ligand and its complexes are identical and consists of two discreet stages. The voltammogram of Cu-complex exhibits a quasi-reversible one-electron transfer wave for Cu(II)/Cu(I) couple.

Synthesis, spectroscopic and thermal studies of transition metal complexes derived from benzil and diethylenetriamine.

PubMed

Khan, Sadaf; Nami, Shahab A A; Siddiqi, K S

2007-10-01

A macrocyclic ligand, bdta (where bdta=3,6,9,12,15,18-hexaaza-1,2,10,11-tetraphenyl-2,9,11,18-tetraenecyclododecane) has been prepared by cyclocondensation of benzil with diethylenetriamine which efficiently encapsulates transition as well as pseudo-transition metal ions leading to the formation of M(bdta)Cl2 type complexes [where M=Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II)]. The analytical, spectroscopic and magnetic moment data suggests an octahedral geometry for all the complexes. EPR spectra of Mn(II) and Cu(II) show considerable exchange interaction in the complex. They are non-conducting in DMSO. The TGA profile of the ligand and its complexes are identical and consists of two discreet stages. The voltammogram of Cu-complex exhibits a quasi-reversible one-electron transfer wave for Cu(II)/Cu(I) couple.

Ligational behaviour of lomefloxacin drug towards Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Th(IV) and UO(2)(VI) ions: synthesis, structural characterization and biological activity studies.

PubMed

Abd el-Halim, Hanan F; Mohamed, Gehad G; el-Dessouky, Maher M I; Mahmoud, Walaa H

2011-11-01

Nine new mononuclear Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Th(IV) and UO(2)(VI) complexes of lomefloxacin drug were synthesized. The structures of these complexes were elucidated by elemental analyses, IR, XRD, UV-vis, (1)H NMR as well as conductivity and magnetic susceptibility measurements and thermal analyses. The dissociation constants of lomefloxacin and stability constants of its binary complexes have been determined spectrophotometrically in aqueous solution at 25±1°C and at 0.1 M KNO(3) ionic strength. The discussion of the outcome data of the prepared complexes indicate that the lomefloxacin ligand behaves as a neutral bidentate ligand through OO coordination sites and coordinated to the metal ions via the carbonyl oxygen and protonated carboxylic oxygen with 1:1 (metal:ligand) stoichiometry for all complexes. The molar conductance measurements proved that the complexes are electrolytes. The powder XRD study reflects the crystalline nature for the investigated ligand and its complexes except Mn(II), Zn(II) and UO(2)(II). The geometrical structures of these complexes are found to be octahedral. The thermal behaviour of these chelates is studied where the hydrated complexes lose water molecules of hydration in the first steps followed by decomposition of the anions, coordinated water and ligand molecules in the subsequent steps. The activation thermodynamic parameters are calculated using Coats-Redfern and Horowitz-Metzger methods. A comparative study of the inhibition zones of the ligand and its metal complexes indicates that metal complexes exhibit higher antibacterial effect against one or more bacterial species than the free LFX ligand. The antifungal and anticancer activities were also tested. The antifungal effect of almost metal complexes is higher than the free ligand. LFX, [Co(LFX)(H(2)O)(4)]·Cl(2) and [Zn(LFX)(H(2)O)(4)]·Cl(2) were found to be very active with IC50 values 14, 11.2 and 43.1, respectively. While, other complexes had been found to be inactive at lower concentration than 100 μg/ml. Copyright © 2011 Elsevier B.V. All rights reserved.

Square-antiprismatic eight-coordinate complexes of divalent first-row transition metal cations: a density functional theory exploration of the electronic-structural landscape.

PubMed

Conradie, Jeanet; Patra, Ashis K; Harrop, Todd C; Ghosh, Abhik

2015-02-16

Density functional theory (in the form of the PW91, BP86, OLYP, and B3LYP exchange-correlation functionals) has been used to map out the low-energy states of a series of eight-coordinate square-antiprismatic (D2d) first-row transition metal complexes, involving Mn(II), Fe(II), Co(II), Ni(II), and Cu(II), along with a pair of tetradentate N4 ligands. Of the five complexes, the Mn(II) and Fe(II) complexes have been synthesized and characterized structurally and spectroscopically, whereas the other three are as yet unknown. Each N4 ligand consists of a pair of terminal imidazole units linked by an o-phenylenediimine unit. The imidazole units are the strongest ligands in these complexes and dictate the spatial disposition of the metal three-dimensional orbitals. Thus, the dx(2)-y(2) orbital, whose lobes point directly at the coordinating imidazole nitrogens, has the highest orbital energy among the five d orbitals, whereas the dxy orbital has the lowest orbital energy. In general, the following orbital ordering (in order of increasing orbital energy) was found to be operative: dxy < dxz = dyz ≤ dz(2) < dx(2)-y(2). The square-antiprism geometry does not lead to large energy gaps between the d orbitals, which leads to an S = 2 ground state for the Fe(II) complex. Nevertheless, the dxy orbital has significantly lower energy relative to that of the dxz and dyz orbitals. Accordingly, the ground state of the Fe(II) complex corresponds unambiguously to a dxy(2)dxz(1)dyz(1)dz(2)(1)dx(2)-y(2)(1) electronic configuration. Unsurprisingly, the Mn(II) complex has an S = 5/2 ground state and no low-energy d-d excited states within 1.0 eV of the ground state. The Co(II) complex, on the other hand, has both a low-lying S = 1/2 state and multiple low-energy S = 3/2 states. Very long metal-nitrogen bonds are predicted for the Ni(II) and Cu(II) complexes; these bonds may be too fragile to survive in solution or in the solid state, and the complexes may therefore not be isolable. Overall, the different exchange-correlation functionals provided a qualitatively consistent and plausible picture of the low-energy d-d excited states of the complexes.

A Paper-Based Analytical Device Based on Combination of Thin Film Microextraction and Reflection Scanometry for Sensitive Colorimetric Determination of Ni(II) in Aqueous Matrix.

PubMed

Allafchian, Ali Reza; Farajmand, Bahman; Koupaei, Amin Javaheri

2018-04-01

In this research, the thin film microextraction method was applied for the extraction of Ni(II) ion from aqueous matrixes. Chemically modified cellulosic filter paper with phosphorus was used as a thin film extractor. After extraction, the thin film was treated with a solution of dimethylglyoxime. The colored film was captured by flatbed scanner and the absorbance of the images was extracted by some suitable software. Under the optimum conditions and at the pH 7.0, with the sample volume of 100 mL, the stirring rate of 800 rpm, and the extraction time of 50 min, the calibration curve was obtained in the range of 0.05-5 mg/L Ni(II) (R 2  = 0.989). Limit and relative standard deviation were achieved to be 18 µg/L and less than 6.7%, respectively. Relative recoveries were obtained in the range of 87%-105%. Finally, the proposed method was found to be simple and cost-effective, with adequate analytical performance for the rapid detection of Ni(II) in river and wastewater samples.

Site preference of alloying elements in DO22-Ni3V phase: Phase-field and first-principles study

NASA Astrophysics Data System (ADS)

Zhang, Ding-Ni; Shangguan, Qian-Qian; Liu, Fu; Zhang, Ming-Yi

2015-07-01

Site preference of alloying elements in DO22-Ni3V phase was investigated using phase-field and first-principles method. The concentrations of alloying elements on sublattices of DO22-Ni3V phase were quantitatively studied using phase-field model based on microscopic diffusion equations. The phase-field computation results demonstrate that the concentration differences of alloying elements on the NiI and NiII site are attributed to the coordination environment difference. Host atoms Ni and substitutional ternary additions Al prefer to occupy NiI site. Antisite atoms V show site preference on the NiII site. Further reason of site preference of alloying elements on the two different Ni sites were studied using first-principles method to calculate the electronic structure of DO22-Ni3V phase. Calculation of density of states, orbitals population and charge population of the optimized Ni3V structure found that the electronic structures of NiI and NiII sites are different. Electronic structure difference, which is caused by coordination environment difference, is the essential reason for site selectivity behaviors of alloying elements on NiI and NiII sites.

Trithiocyanurate complexes of iron, manganese and nickel and their anticholinesterase activity.

PubMed

Kopel, Pavel; Dolezal, Karel; Langer, Vratislav; Jun, Daniel; Adam, Vojtech; Kuca, Kamil; Kizek, Rene

2014-04-08

The complexes of Fe(II), Mn(II) and Ni(II) with a combination of a Schiff base, nitrogen-donor ligand or macrocyclic ligand and trithiocyanuric acid (ttcH3) were prepared and characterized by elemental analysis and spectroscopies. Crystal and molecular structures of the iron complex of composition [Fe(L1)](ttcH2)(ClO4)·EtOH·H2O (1), where L1 is Schiff base derived from tris(2-aminoethyl)amine and 2-pyridinecarboxaldehyde, were solved. It was found that the Schiff base is coordinated to the central iron atom by six nitrogens forming deformed octahedral arrangement, whereas trithiocyanurate(1-) anion, perchlorate and solvent molecules are not coordinated. The X-ray structure of the Schiff base sodium salt is also presented and compared with the iron complex. The anticholinesterase activity of the complexes was also studied.

Synthesis, characterization and biological activity of some transition metals with Schiff base derived from 2-thiophene carboxaldehyde and aminobenzoic acid.

PubMed

Mohamed, Gehad G; Omar, M M; Hindy, Ahmed M M

2005-12-01

Metal complexes of Schiff base derived from 2-thiophene carboxaldehyde and 2-aminobenzoic acid (HL) are reported and characterized based on elemental analyses, IR, 1H NMR, solid reflectance, magnetic moment, molar conductance and thermal analysis (TGA). The ligand dissociation as well as the metal-ligand stability constants were calculated pH metrically at 25 degrees C and ionic strength mu=0.1 (1M NaCl). The complexes are found to have the formulae [M(HL)2](X)n.yH2O (where M=Fe(III) (X=Cl, n=3, y=3), Co(II) (X=Cl, n=2, y=1.5), Ni(II) (X=Cl, n=2, y=1) and UO2(II) (X=NO3, n=2, y=0)) and [M(L)2] (where M=Cu(II) (X=Cl) and Zn(II) (X=AcO)). The molar conductance data reveal that Fe(III) and Co(II), Ni(II) and UO2(II) chelates are ionic in nature and are of the type 3:1 and 2:1 electrolytes, respectively, while Cu(II) and Zn(II) complexes are non-electrolytes. IR spectra show that HL is coordinated to the metal ions in a terdentate manner with ONS donor sites of the carboxylate O, azomethine N and thiophene S. From the magnetic and solid reflectance spectra, it is found that the geometrical structure of these complexes are octahedral. The thermal behaviour of these chelates shows that the hydrated complexes losses water molecules of hydration in the first step followed immediately by decomposition of the anions and ligand molecules in the subsequent steps. The activation thermodynamic parameters, such as, E*, DeltaH*, DeltaS* and DeltaG* are calculated from the DrTG curves using Coats-Redfern method. The synthesized ligands, in comparison to their metal complexes also were screened for their antibacterial activity against bacterial species, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus pyogones and Fungi (Candida). The activity data show that the metal complexes to be more potent/antibacterial than the parent Schiff base ligand against one or more bacterial species.

Synthesis, characterization and biological activity of some transition metals with Schiff base derived from 2-thiophene carboxaldehyde and aminobenzoic acid

NASA Astrophysics Data System (ADS)

Mohamed, Gehad G.; Omar, M. M.; Hindy, Ahmed M. M.

2005-12-01

Metal complexes of Schiff base derived from 2-thiophene carboxaldehyde and 2-aminobenzoic acid (HL) are reported and characterized based on elemental analyses, IR, 1H NMR, solid reflectance, magnetic moment, molar conductance and thermal analysis (TGA). The ligand dissociation as well as the metal-ligand stability constants were calculated pH metrically at 25 °C and ionic strength μ = 0.1 (1 M NaCl). The complexes are found to have the formulae [M(HL) 2](X) n· yH 2O (where M = Fe(III) (X = Cl, n = 3, y = 3), Co(II) (X = Cl, n = 2, y = 1.5), Ni(II) (X = Cl, n = 2, y = 1) and UO 2(II) (X = NO 3, n = 2, y = 0)) and [M(L) 2] (where M = Cu(II) (X = Cl) and Zn(II) (X = AcO)). The molar conductance data reveal that Fe(III) and Co(II), Ni(II) and UO 2(II) chelates are ionic in nature and are of the type 3:1 and 2:1 electrolytes, respectively, while Cu(II) and Zn(II) complexes are non-electrolytes. IR spectra show that HL is coordinated to the metal ions in a terdentate manner with ONS donor sites of the carboxylate O, azomethine N and thiophene S. From the magnetic and solid reflectance spectra, it is found that the geometrical structure of these complexes are octahedral. The thermal behaviour of these chelates shows that the hydrated complexes losses water molecules of hydration in the first step followed immediately by decomposition of the anions and ligand molecules in the subsequent steps. The activation thermodynamic parameters, such as, E*, Δ H*, Δ S* and Δ G* are calculated from the DrTG curves using Coats-Redfern method. The synthesized ligands, in comparison to their metal complexes also were screened for their antibacterial activity against bacterial species, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus pyogones and Fungi (Candida). The activity data show that the metal complexes to be more potent/antibacterial than the parent Schiff base ligand against one or more bacterial species.

On the ortho-positronium quenching reactions promoted by Fe(II), Fe(III), Co(III), Ni(II), Zn(II) and Cd(II) cyanocomplexes

NASA Astrophysics Data System (ADS)

Fantola Lazzarini, Anna L.; Lazzarini, Ennio

The o-Ps quenching reactions promoted in aqueous solutions by the following six cyanocomplexes: [Fe(CN) 6] 4-; [Co(CN) 6] 3-; [Zn(CN) 4] 2-; [Cd(CN) 6] 2-; [Fe(CN) 6] 3-; [Ni(CN) 4] 2- were investigated. The first four reactions probably consist in o-Ps addition across the CN bond, their rate constants at room temperature, Tr, being ⩽(0.04±0.02) × 10 9 M -1 s -1, i.e. almost at the limit of experimental errors. The rate constant of the fifth reaction, in o-Ps oxydation, at Tr is (20.3±0.4) × 10 9 M -1 s -1. The [Ni(CN) 4] 2-k value at Tr, is (0.27±0.01) × 10 9 M -1 s -1, i.e. 100 times less than the rate constants of o-Ps oxydation, but 10 times larger than those of the o-Ps addition across the CN bond. The [Ni(CN) 4] 2- reaction probably results in formation of the following positronido complex: [Ni(CN) 4Ps] 2-. However, it is worth noting that the existence of such a complex is only indirectly deduced. In fact it arises from comparison of the [Ni(CN) 4] 2- rate constant with those of the Fe(II), Zn(II), Cd(II), and Co(III) cyanocomplexes, which, like the Ni(II) cyanocomplex, do not promote o-Ps oxydation or spin exchange reactions.

Controlling the Chiral Inversion Reaction of the Metallopeptide Ni-Asparagine-Cysteine-Cysteine with Dioxygen

PubMed Central

Glass, Amanda M.; Krause, Mary E.; Laurence, Jennifer S.; Jackson, Timothy A.

2014-01-01

Synthetically generated metallopeptides have the potential to serve a variety of roles in biotechnology applications, but the use of such systems is often hampered by the inability to control secondary reactions. We have previously reported that the NiII complex of the tripeptide LLL-asparagine-cysteine-cysteine, LLL-NiII-NCC, undergoes metal-facilitated chiral inversion to DLD-NiII-NCC, which increases the observed superoxide scavenging activity. However, the mechanism for this process remained unexplored. Electronic absorption and circular dichroism studies of the chiral inversion reaction of NiII-NCC reveal a unique dependence on dioxygen. Specifically, in the absence of dioxygen, the chiral inversion is not observed, even at elevated pH, whereas the addition of O2 initiates this reactivity and concomitantly generates superoxide. Scavenging experiments using acetaldehyde are indicative of the formation of carbanion intermediates, demonstrating that inversion takes place by deprotonation of the alpha carbons of Asn1 and Cys3. Together, these data are consistent with the chiral inversion being dependent on the formation of a NiIII-NCC intermediate from NiII-NCC and O2. The data further suggest that the anionic thiolate and amide ligands in NiII-NCC inhibit Cα–H deprotonation for the NiII oxidation state, leading to a stable complex in the absence of O2. Together, these results offer insights into the factors controlling reactivity in synthetic metallopeptides. PMID:22928993

Catalytic reduction of pralidoxime in pharmaceuticals by macrocyclic Ni(II) compounds derived from orthophthalaldehyde.

PubMed

Reddy, P Muralidhar; Prasad, Adapa V S S; Rohini, Rondla; Ravinder, Vadde

2008-08-01

Efficient catalytic method for the reduction of pralidoxime to its amine derivative by macrocyclic Ni(II) compounds has been developed. Ten macrocyclic Schiff base Ni(II) compounds were synthesized via non-template synthesis by treating the corresponding macrocycles with nickel chloride in 1:1 ratio. The resulting compounds were characterized by elemental, IR, (1)H NMR, (13)C NMR, mass, electronic spectra, conductance, magnetic, thermal studies and their structures have been proposed. These compounds were used as catalysts for the reduction of pralidoxime to its amino derivative. The reduced pralidoxime was also characterized by spectral analysis and catalytic cycle has been established. The reduced product was determined spectrophotometrically by treating with ninhydrin reagent and the percent yields were found to be in the range of 75.12-82.36%.

Synthesis, spectral, thermal and antimicrobial studies of transition metal complexes of 14-membered tetraaza[N4] macrocyclic ligand

NASA Astrophysics Data System (ADS)

Shankarwar, Sunil G.; Nagolkar, Bhagwat B.; Shelke, Vinod A.; Chondhekar, Trimbak K.

2015-06-01

A series of metal complexes of Mn(II), Co(II), Ni(II), Cu(II), have been synthesized with newly synthesized biologically active macrocyclic ligand. The ligand was synthesized by condensation of β-diketone 1-(4-chlorophenyl)-3-(2-hydroxyphenyl)propane-1,3-dione and o-phenylene diamine. All the complexes were characterized by elemental analysis, molar conductivity, magnetic susceptibility, thermal analysis, X-ray diffraction, IR, 1H-NMR, UV-Vis spectroscopy and mass spectroscopy. From the analytical data, stoichiometry of the complexes was found to be 1:2 (metal:ligand). Thermal behavior (TG/DTA) and kinetic parameters suggest more ordered activated state in complex formation. All the complexes are of high spin type and six coordinated. On the basis of IR, electronic spectral studies and magnetic behavior, an octahedral geometry has been assigned to these complexes. The antibacterial and antifungal activities of the ligand and its metal complexes, has been screened in vitro against Staphylococcus aureus, Escherichia coli and Aspergillus niger, Trichoderma respectively.

The Synthesis and Characterization of a Group of Transition Metal Octabutoxynaphthalocyanines and the Absorption and Emission Properties of the Co, Rh, Ir, Ni, Pd and Pt Members of This Group

PubMed Central

Kim, Junhwan; Soldatova, Alexandra V.; Rodgers, Michael A. J.; Kenney, Malcolm E.

2013-01-01

The synthesis and photophysical properties of new metallo-octabutoxynaphthalocyanines with Rh(III), Ir(III), and Pt(II) are reported. Various metals were inserted into the metal-free octabutoxynaphthalocyanine and the resultant metal complexes were fully characterized by NMR, UV-vis spectroscopy, and mass spectrometry. The absorption and emission properties of these new complexes were also examined and compared to those of Co(II), Ni(II), and Pd(II) octabutoxynaphthalocyanines. The results provide useful information to understand the effect of these transition metals on the properties of this macrocyclic ring. PMID:23745014

Access to Formally Ni(I) States in a Heterobimetallic NiZn System

PubMed Central

Uyeda, Christopher

2014-01-01

Heterobimetallic NiZn complexes featuring metal centers in distinct coordination environments have been synthesized using diimine-dioxime ligands as binucleating scaffolds. A tetramethylfuran-containing ligand derivative enables a stable one-electron-reduced S = 1/2 species to be accessed using Cp2Co as a chemical reductant. The resulting pseudo-square planar complex exhibits spectroscopic and crystallographic characteristics of a ligand-centered radical bound to a Ni(II) center. Upon coordination of a π-acidic ligand such as PPh3, however, a five-coordinate Ni(I) metalloradical is formed. The electronic structures of these reduced species provide insight into the subtle effects of ligand structure on the potential and reversibility of the NiII/I couple for complexes of redox-active tetraazamacrocycles. PMID:25614786

Glutamate Ligation in the Ni(II)- and Co(II)-Responsive Escherichia coli Transcriptional Regulator, RcnR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carr, Carolyn E.; Musiani, Francesco; Huang, Hsin-Ting

Escherichia coli RcnR (resistance to cobalt and nickel regulator, EcRcnR) is a metal-responsive repressor of the genes encoding the Ni(II) and Co(II) exporter proteins RcnAB by binding to PRcnAB. The DNA binding affinity is weakened when the cognate ions Ni(II) and Co(II) bind to EcRcnR in a six-coordinate site that features a (N/O)5S ligand donor-atom set in distinct sites: while both metal ions are bound by the N terminus, Cys35, and His64, Co(II) is additionally bound by His3. On the other hand, the noncognate Zn(II) and Cu(I) ions feature a lower coordination number, have a solvent-accessible binding site, and coordinatemore » protein ligands that do not include the N-terminal amine. A molecular model of apo-EcRcnR suggested potential roles for Glu34 and Glu63 in binding Ni(II) and Co(II) to EcRcnR. The roles of Glu34 and Glu63 in metal binding, metal selectivity, and function were therefore investigated using a structure/function approach. X-ray absorption spectroscopy was used to assess the structural changes in the Ni(II), Co(II), and Zn(II) binding sites of Glu → Ala and Glu → Cys variants at both positions. The effect of these structural alterations on the regulation of PrcnA by EcRcnR in response to metal binding was explored using LacZ reporter assays. These combined studies indicate that while Glu63 is a ligand for both metal ions, Glu34 is a ligand for Co(II) but possibly not for Ni(II). The Glu34 variants affect the structure of the cognate metal sites, but they have no effect on the transcriptional response. In contrast, the Glu63 variants affect both the structure and transcriptional response, although they do not completely abolish the function of EcRcnR. The structure of the Zn(II) site is not significantly perturbed by any of the glutamic acid variations. The spectroscopic and functional data obtained on the mutants were used to calculate models of the metal-site structures of EcRcnR bound to Ni(II), Co(II), and Zn(II). The results are interpreted in terms of a switch mechanism, in which a subset of the metal-binding ligands is responsible for the allosteric response required for DNA release.« less

Arrested 1,2-hydrogen migration from silicon to nickel upon oxidation of a three-coordinate Ni(I) silyl complex.

PubMed

Iluc, Vlad M; Hillhouse, Gregory L

2010-09-01

Reaction of the dimeric Ni(I) chloride complex [(dtbpe)NiCl](2) (1) with dimesitylsilyl potassium affords the three-coordinate Ni(I) silyl complex (dtbpe)Ni(SiHMes(2)) (2). Alternatively, 2 can be prepared by an oxidative-addition reaction of Mes(2)Si(H)OTf (Tf = CF(3)SO(3)) with the nickel(0) complex [(dtbpe)Ni](2)(mu-C(6)H(6)) (3), with (dtbpe)Ni(OTf) (4) formed as an easily separable byproduct. The one-electron oxidation of 2 by ferrocenium affords diamagnetic [(dtbpe)Ni(mu-H)SiMes(2)][BAr(F)(4)] (5), a Ni(II) complex formed by partial 1,2-H migration from silicon to nickel and featuring an unusual 3-center, 2-electron bonding motif between Ni, Si, and the bridging H. Complex 5 was also obtained from Mes(2)SiH(2) activation by the neopentyl complex salt [(dtbpe)Ni(CH(2)CMe(3))][BAr(F)(4)] (6) with elimination of neopentane.

Process development for recovery of vanadium and nickel from an industrial solid waste by a leaching-solvent extraction technique.

PubMed

Barik, S P; Park, K H; Nam, C W

2014-12-15

A process for recovering V(V) and Ni(II) from an industrial solid waste using sulfuric acid leaching, solvent extraction, precipitation and crystallization has been developed. The leaching parameters investigated were time, temperature and H2SO4 concentration. To quantify the linear and interaction coefficients a 2(3) full factorial experimental design was used. Regression equations for the extraction of V(V) and Ni(II) were determined and the adequacy of these equations was tested by Student's t-Test. More than 98% of both V(V) and Ni(II) were extracted in 90 min using 1.35 M H2SO4 at 40 °C. In addition, solvent extraction of V(V) with LIX 84-I in kerosene from the acidic leach liquor bearing 10.922 g/L V(V) and 18.871 g/L of Ni(II) was investigated. V(V) was extracted selectively using 40% LIX 84-I followed by stripping with NH4OH solution. McCabe-Thiele plots at O:A = 2:3 with 40% LIX 84-I and O:A = 3:1 with 15% (v/v) NH4OH showed two and three theoretical stages are needed for quantitative extraction and stripping of V(V), respectively. Ni(II) was selectively recovered from the V(V) free raffinate by adding ammonium oxalate at 60 °C. The purity of different products such as ammonium vanadate, nickel oxalate and nickel oxide obtained during the processes were analyzed and confirmed from the XRD studies. Copyright © 2014 Elsevier Ltd. All rights reserved.

Tris(5,6-dimethyl-1H-benzimidazole-κN(3))(pyridine-2,6-dicarboxyl-ato-κ(3)O(2),N,O(6))nickel(II).

PubMed

Li, Yue-Hua; Li, Feng-Feng; Liu, Xin-Hua; Zhao, Ling-Yan

2012-06-01

The title mononuclear complex, [Ni(C(7)H(3)NO(4))(C(9)H(10)N(2))(3)], shows a central Ni(II) atom which is coordinated by two carboxyl-ate O atoms and the N atom from a pyridine-2,6-dicarboxyl-ate ligand and by three N atoms from different 5,6-dimethyl-1H--benzimidazole ligands in a distorted octa-hedral geometry. The crystal structure shows intermolecular N-H⋯O hydrogen bonds.

Extraction and separation of Co(II) and Ni(II) from acidic sulfate solutions using Aliquat 336.

PubMed

Nayl, A A

2010-01-15

Extraction and separation of Co(II) and Ni(II) from acidic sulfate solutions by solvent extraction technique were studied using different forms of Aliquat 336 diluted with kerosene. The extraction percent of each metal ion was found to increase with increasing pH and extractant concentration. Co(II) was preferentially extracted by different forms of Aliquat 336 over Ni(II) under the same extraction conditions. From analysis of the experimental results, the extraction mechanism of R(4)N-forms was proposed with Co(II). It was found that the highest separation factor (S(Co/Ni)) value of 606.7 was obtained with 0.36 M R(4)N-SCN in kerosene from 2.0M H(2)SO(4) solution at pH 4.8 and shaking time of 20 min. Stripping of the two metal ions from the organic phase was also investigated. Based on the experimental results, a separation method was developed and tested to separate high purity Co(II), Ni(II) and Ln(III) from Ni-MH batteries leached by 2.0M H(2)SO(4). Based on the experimental results, a flow sheet was developed and tested and 0.34 g Co, 1.39 g Ln and 5.2g Ni were obtained from the leaching process.

Spectral, optical and cytotoxicity studies on 2-isonicotinoyl-N-phenylhydrazine-1-carboxamide(H3L) and some of its metal complexes

NASA Astrophysics Data System (ADS)

Hosny, Nasser M.; Hassan, Nader Y.; Mahmoud, Heba M.; Abdel-Rhman, Mohamed H.

2018-03-01

The ligand 2-isonicotinoyl-N-phenylhydrazine-1-carboxamide (H3L) and its metal complexes with Co(II), Ni(II), Cu(II) and Zn(II) acetates have been synthesized. The isolated compounds have been characterized by elemental analyses, FT-IR, 1H NMR, 13C NMR, ESR, mass, electronic spectra, electrical conductivity, effective magnetic moments and thermal analyses. The free organic ligand exists in the keto form, but in the metal complexes, it coordinates in the enol form. Four coordinated species were suggested for all the isolated metal complexes. The measured optical band gap values confirmed the presence of direct electronic transition and the semi-conductivity of the compounds. The ligand and its Zn(II) complex were examined as cytotoxic agent against HCT-116 and HePG-2. The ligand showed very strong cytotoxic effect against HePG-2, but moderate cytotoxicity against HCT-116. Zn(II) complex showed weak cytotoxicity against the two cell lines.

Design and synthesis of metal complexes of (2E)-2-[(2E)-3-phenylprop-2-en-1-ylidene]hydrazinecarbothioamide and their photocatalytic degradation of methylene blue.

PubMed

Krishna, P Murali; Reddy, N B Gopal; Kottam, Nagaraju; Yallur, B C; Katreddi, Hussain Reddy

2013-01-01

The photocatalytic degradation has been considered to be an efficient process for the degradation of organic pollutants, which are present in the effluents released by industries. The photocatalytic bleaching of cationic dye methylene blue was carried out spectrometrically on irradiation of UV light using Cu(II), Ni(II), and Co(II) complexes of (2E)-2-[(2E)-3-phenylprop-2-en-1-ylidene]hydrazinecarbothioamide (HL). The effects of pH and metal ion were studied on the efficiency of the reaction. Cu(II) complex shows better catalytic activity and the highest percentage degradation (~88.8%) of methylene blue was observed at pH 12. A tentative mechanism has also been proposed for the photocatalytic degradation of methylene blue.

Observations of localized NiII emission in M82: Evidence for supernovae activity in the molecular cloud east of the nucleus

NASA Technical Reports Server (NTRS)

Rank, David M.; Temi, Pasquale; Bregman, Jesse D.; Dunham, Edward W.; Harker, David

1995-01-01

Narrow band images of M82 at wavelengths of 6.63 microns (NiII) and 6.8 microns (continuum) are discussed in terms of new evidence for supernova activity in the nuclear region of the M82 starburst galaxy. Data were recorded using a 128x128 Si:Ga array in an infrared camera on the KAO Southern Expedition in April '94.

Structure of the Ni(II) complex of Escherichia coli peptide deformylase and suggestions on deformylase activities depending on different metal(II) centres.

PubMed

Yen, Ngo Thi Hai; Bogdanović, Xenia; Palm, Gottfried J; Kühl, Olaf; Hinrichs, Winfried

2010-02-01

Crystal structures of polypeptide deformylase (PDF) of Escherichia coli with nickel(II) replacing the native iron(II) have been solved with chloride and formate as metal ligands. The chloro complex is a model for the correct protonation state of the hydrolytic hydroxo ligand and the protonated status of the Glu133 side chain as part of the hydrolytic mechanism. The ambiguity that recently some PDFs have been identified with Zn(2+) ion as the active-site centre whereas others are only active with Fe(2+) (or Co(2+), Ni(2+) is discussed with respect to Lewis acid criteria of the metal ion and substrate activation by the CD loop.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yao, Shuang; Yi, Fei-Yan; Li, Guanghua

Two coordination polymers [Co{sub 2}(TA)(4,4′-bipy){sub 2}(H{sub 2}O){sub 2}]·H{sub 2}O (1) and [Ni{sub 2}(TA)(4,4′-bipy){sub 2}(H{sub 2}O){sub 4}]·3H{sub 2}O (2) were prepared by hydrothermal reactions of MCl{sub 2}·6H{sub 2}O (M = Co, Ni) with a V-shaped ligand TDPA (3,3′,4,4′-thiodiphthalic anhydride) and a I-shaped N-donor co-ligand (4,4′-bipy). They were characterized by elemental analyses, thermogravinetric analyses, and magnetic behavior. As is expected, TDPA hydrolyzes into the corresponding tetra-carboxylate acid H{sub 4}TA (3,3′,4,4′-thiodiphthalic acid) during the reactions. Co{sub 2} dimer and Ni mononuclear center are connected into two-dimensional (2D) layers by H{sub 4}TA and 4,4′-bipy bridge in 1 and 2, respectively. The most amazing featuremore » is that 1 and 2 exhibit interesting spin-canting metamagnetism and weak ferromagnetic behavior, respectively, with the critical Néel temperature of T{sub N} =4 K for 1 and T{sub N} =13 K for 2, based on variable temperature magnetic susceptibility measurements. In low mono- or dinuclear metal system, such magnetic behaviors have rare been observed. Furthermore, complex 1 will be a potential metamagnet material. - Graphical abstract: Two Co(II) and Ni(II) coordination polymers were synthesized by hydrothermal reactions from a V-shape ligand (3,3′,4,4′-thiodiphthalic anhydride) and a I-shape ligand (4,4′-bipy), which were characterized by single crystal X-ray diffraction, elemental analyses, thermogravinetric analyses, and magnetic behavior, and exhibit interesting spin-canting metamagnetism and weak ferromagnetic behavior, respectively. - Highlights: • Two Co(II) and Ni(II) coordination polymers were successfully synthesized. • Co(II) coordination polymer shows an interesting spin-canting metamagnetism. • Ni(II) coordination polymer exhibits a weak ferromagnetic behavior.« less

Ni(II)-tetrahedral complexes: Characterization, antimicrobial properties, theoretical studies and a new family of charge-transfer transitions

NASA Astrophysics Data System (ADS)

Sarı, Nurşen; Şahin, Songül Çiğdem; Öğütcü, Hatice; Dede, Yavuz; Yalcin, Soydan; Altundaş, Aliye; Doğanay, Kadir

2013-04-01

A new amine containing selenium and their five imine, (SeSchX)(X: -H, F, Cl, Br, CH3), and Ni (II) complexes, [Ni(SeSchX)(H2O)2]Cl/[Ni(SeSchCl)(H2O)Cl], were synthesized. The compounds were characterized by means of elemental analyses, 13C and 1H NMR (for imine), FT-IR, UV-Visible spectroscopy, TGA/DTA and elemental analyses. [Ni(SeSchCl)(H2O)Cl] complex from Ni(II) complexes changes color from yellow to orange in the range pH 5-7. [Ni(SeSchCl)(H2O)Cl] complex has ligand-to-metal charge-transfer (LMCT) transitions in the basic medium. Excitation characteristics and energetic of [Ni(SeSchCl)(H2O)Cl] complex, examined via TD-DFT calculations, reveals transitions of LMCT and π → π* character that matches the experimental values. [Ni(SeSchCl)(H2O)Cl] complex showed the highest antibacterial activity when compared to other complexes reported in this work.

Effect of pyoverdine supply on cadmium and nickel complexation and phytoavailability in hydroponics.

PubMed

Ferret, C; Cornu, J Y; Elhabiri, M; Sterckeman, T; Braud, A; Jezequel, K; Lollier, M; Lebeau, T; Schalk, I J; Geoffroy, V A

2015-02-01

Siderophores are chelators with a high selectivity for Fe(III) and a good affinity for divalent metals, including Cd(II) and Ni(II). Inoculation with siderophore-producing bacteria (SPB) has thus been proposed as an alternative to chelator supply in phytoremediation. Accurate assessments of the potential of this association require a dissection of the interaction of siderophores with metals at the soil-root interface. This study focuses on pyoverdine (Pvd), the main siderophore produced by Pseudomonas aeruginosa. We first assessed the ability of Pvd to coordinate Ni(II). The stability constant of Pvd-Ni(II) (log K (L'Ni) = 10.9) was found to be higher than that of Pvd-Cd(II) (log K (L'Cd) = 8.2). We then investigated the effect of a direct supply of Pvd on the mobilization, speciation, and phytoavailability of Cd and Ni in hydroponics. When supplied at a concentration of 50 μM, Pvd selectively promoted Ni mobilization from smectite. It decreased plant Ni and Cd contents and the free ionic fractions of these two metals, consistent with the free ion activity model. Pvd had a more pronounced effect for Ni than for Cd, as predicted from its coordination properties. Inoculation with P. aeruginosa had a similar effect on Ni phytoavailability to the direct supply of Pvd.

Dinuclear metallacycles with single M-O(H)-M bridges [M = Fe(II), Co(II), Ni(II), Cu(II)]: effects of large bridging angles on structure and antiferromagnetic superexchange interactions.

PubMed

Reger, Daniel L; Pascui, Andrea E; Foley, Elizabeth A; Smith, Mark D; Jezierska, Julia; Ozarowski, Andrew

2014-02-17

The reactions of M(ClO4)2·xH2O and the ditopic ligands m-bis[bis(1-pyrazolyl)methyl]benzene (Lm) or m-bis[bis(3,5-dimethyl-1-pyrazolyl)methyl]benzene (Lm*) in the presence of triethylamine lead to the formation of monohydroxide-bridged, dinuclear metallacycles of the formula [M2(μ-OH)(μ-Lm)2](ClO4)3 (M = Fe(II), Co(II), Cu(II)) or [M2(μ-OH)(μ-Lm*)2](ClO4)3 (M = Co(II), Ni(II), Cu(II)). With the exception of the complexes where the ligand is Lm and the metal is copper(II), all of these complexes have distorted trigonal bipyramidal geometry around the metal centers and unusual linear (Lm*) or nearly linear (Lm) M-O-M angles. For the two solvates of [Cu2(μ-OH)(μ-Lm)2](ClO4)3, the Cu-O-Cu angles are significantly bent and the geometry about the metal is distorted square pyramidal. All of the copper(II) complexes have structural distortions expected for the pseudo-Jahn-Teller effect. The two cobalt(II) complexes show moderate antiferromagnetic coupling, -J = 48-56 cm(-1), whereas the copper(II) complexes show very strong antiferromagnetic coupling, -J = 555-808 cm(-1). The largest coupling is observed for [Cu2(μ-OH)(μ-Lm*)2](ClO4)3, the complex with a Cu-O-Cu angle of 180°, such that the exchange interaction is transmitted through the dz(2) and the oxygen s and px orbitals. The interaction decreases, but it is still significant, as the Cu-O-Cu angle decreases and the character of the metal orbital becomes increasingly d(x(2)-y(2)). These intermediate geometries and magnetic interactions lead to spin Hamiltonian parameters for the copper(II) complexes in the EPR spectra that have large E/D ratios and one g matrix component very close to 2. Density functional theory calculations were performed using the hybrid B3LYP functional in association with the TZVPP basis set, resulting in reasonable agreement with the experiments.

Adsorption and Desorption of Nickel(II) Ions from Aqueous Solution by a Lignocellulose/Montmorillonite Nanocomposite

PubMed Central

Zhang, Xiaotao; Wang, Ximing

2015-01-01

A new and inexpensive lignocellulose/montmorillonite (LNC/MMT) nanocomposite was prepared by a chemical intercalation of LNC into MMT and was subsequently investigated as an adsorbent in batch systems for the adsorption-desorption of Ni(II) ions in an aqueous solution. The optimum conditions for the Ni(II) ion adsorption capacity of the LNC/MMT nanocomposite were studied in detail by varying parameters such as the initial Ni(II) concentration, the solution pH value, the adsorption temperature and time. The results indicated that the maximum adsorption capacity of Ni(II) reached 94.86 mg/g at an initial Ni(II) concentration of 0.0032 mol/L, a solution pH of 6.8, an adsorption temperature of 70°C, and adsorption time of 40 min. The represented adsorption kinetics model exhibited good agreement between the experimental data and the pseudo-second-order kinetic model. The Langmuir isotherm equation best fit the experimental data. The structure of the LNC/MMT nanocomposite was characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM), whereas the adsorption mechanism was discussed in combination with the results obtained from scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and Fourier-transform infrared spectroscopy analyses (FTIR). The desorption capacity of the LNC/MMT nanocomposite depended on parameters such as HNO3 concentration, desorption temperature, and desorption time. The satisfactory desorption capacity of 81.34 mg/g was obtained at a HNO3 concentration, desorption temperature, and desorption time of 0.2 mol/L, 60 ºC, and 30 min, respectively. The regeneration studies showed that the adsorption capacity of the LNC/MMT nanocomposite was consistent for five cycles without any appreciable loss in the batch process and confirmed that the LNC/MMT nanocomposite was reusable. The overall study revealed that the LNC/MMT nanocomposite functioned as an effective adsorbent in the detoxification of Ni(II)-contaminated wastewater. PMID:25647398

Synthesis, Crystal Structures, Magnetic Properties, and Theoretical Investigation of a New Series of NiII-LnIII-WV Heterotrimetallics: Understanding the SMM Behavior of Mixed Polynuclear Complexes.

PubMed

Vieru, Veacheslav; Pasatoiu, Traian D; Ungur, Liviu; Suturina, Elizaveta; Madalan, Augustin M; Duhayon, Carine; Sutter, Jean-Pascal; Andruh, Marius; Chibotaru, Liviu F

2016-12-05

The polynuclear compounds containing anisotropic metal ions often exhibit efficient barriers for blocking of magnetization at fairly arbitrary geometries. However, at variance with mononuclear complexes, which usually become single-molecule magnets (SMM) under the sole requirement of a highly axial crystal field at the metal ion, the factors influencing the SMM behavior in polynuclear complexes, especially, with weakly axial magnetic ions, still remain largely unrevealed. As an attempt to clarify these conditions, we present here the synthesis, crystal structures, magnetic behavior, and ab initio calculations for a new series of Ni II -Ln III -W V trimetallics, [(CN) 7 W(CN)Ni(H 2 O)(valpn)Ln(H 2 O) 4 ]·H 2 O (Ln = Y 1, Eu 2, Gd 3, Tb 4, Dy 5, Lu 6). The surprising finding is the absence of the magnetic blockage even for compounds involving strongly anisotropic Dy III and Tb III metal ions. This is well explained by ab initio calculations showing relatively large transversal components of the g-tensor in the ground exchange Kramers doublets of 1 and 4 and large intrinsic tunneling gaps in the ground exchange doublets of 3 and 5. In order to get more insight into this behavior, another series of earlier reported compounds with the same trinuclear [W V Ni II Ln III ] core structure, [(CN) 7 W(CN)Ni(dmf)(valdmpn)Ln(dmf) 4 ]·H 2 O (Ln = Gd III 7, Tb III 8a, Dy III 9, Ho III 10), [(CN) 7 W(CN)Ni(H 2 O)(valdmpn)Tb(dmf) 2.5 (H 2 O) 1.5 ]·H 2 O·0.5dmf 8b, and [(CN) 7 W(CN)Ni(H 2 O)(valdmpn)Er(dmf) 3 (H 2 O) 1 ]·H 2 O·0.5dmf 11, has been also investigated theoretically. In this series, only 8b exhibits SMM behavior which is confirmed by the present ab initio calculations. An important feature for the entire series is the strong ferromagnetic coupling between Ni(II) and W(V), which is due to an almost perfect trigonal dodecahedron geometry of the octacyano wolframate fragment. The reason why only 8b is an SMM is explained by positive zero-field splitting on the nickel site, precluding magnetization blocking in complexes with fewer axial Ln ions. Further analysis has shown that, in the absence of ZFS on Ni ion, all compounds in the two series (except those containing Y and Gd) would be SMMs. The same situation arises for perfectly axial ZFS on Ni(II) with the main anisotropy axis parallel to the main magnetic axis of Ln(III) ions. In all other cases the ZFS on Ni(II) will worsen the SMM properties. The general conclusion is that the design of efficient SMMs on the basis of such complexes should involve isotropic or weekly anisotropic metal ions, such as Mn(II), Fe(III), etc., along with strongly axial lanthanides.

General and mild Ni(0)-catalyzed α-arylation of ketones using aryl chlorides.

PubMed

Fernández-Salas, José A; Marelli, Enrico; Cordes, David B; Slawin, Alexandra M Z; Nolan, Steven P

2015-03-02

A general methodology for the α-arylation of ketones using a nickel catalyst has been developed. The new well-defined [Ni(IPr*)(cin)Cl] (1 c) pre-catalyst showed great efficiency for this transformation, allowing the coupling of a wide range of ketones, including acetophenone derivatives, with various functionalised aryl chlorides. This cinnamyl-based Ni-N-heterocyclic carbene (NHC) complex has demonstrated a different behaviour to previously reported NHC-Ni catalysts. Preliminary mechanistic studies suggest a Ni(0)/Ni(II) catalytic cycle to be at play. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Tris(5,6-dimethyl-1H-benzimidazole-κN 3)(pyridine-2,6-dicarboxyl­ato-κ3 O 2,N,O 6)nickel(II)

PubMed Central

Li, Yue-Hua; Li, Feng-Feng; Liu, Xin-Hua; Zhao, Ling-Yan

2012-01-01

The title mononuclear complex, [Ni(C7H3NO4)(C9H10N2)3], shows a central NiII atom which is coordinated by two carboxyl­ate O atoms and the N atom from a pyridine-2,6-dicarboxyl­ate ligand and by three N atoms from different 5,6-dimethyl-1H-­benzimidazole ligands in a distorted octa­hedral geometry. The crystal structure shows intermolecular N—H⋯O hydrogen bonds. PMID:22719301

Exploration of cellular DNA lesion, DNA-binding and biocidal ordeal of novel curcumin based Knoevenagel Schiff base complexes incorporating tryptophan: Synthesis and structural validation

NASA Astrophysics Data System (ADS)

Chandrasekar, Thiravidamani; Raman, Natarajan

2016-07-01

A few novel Schiff base transition metal complexes of general formula [MLCl] (where, L = Schiff base, obtained by the condensation reaction of Knoevenagel condensate of curcumin, L-tryptophan and M = Cu(II), Ni(II), Co(II), and Zn(II)), were prepared by stencil synthesis. They were typified using UV-vis, IR, EPR spectral techniques, micro analytical techniques, magnetic susceptibility and molar conductivity. Geometry of the metal complexes was examined and recognized as square planar. DNA binding and viscosity studies revealed that the metal(II) complexes powerfully bound via an intercalation mechanism with the calf thymus DNA. Gel-electrophoresis technique was used to investigate the DNA cleavage competence of the complexes and they establish to approve the cleavage of pBR322 DNA in presence of oxidant H2O2. This outcome inferred that the synthesized complexes showed better nuclease activity. Moreover, the complexes were monitored for antimicrobial activities. The results exposed that the synthesized compounds were forceful against all the microbes under exploration.

Synthesis, structural and biochemical activity studies of a new hexadentate Schiff base ligand and its Cu(II), Ni(II), and Co(II) complexes

NASA Astrophysics Data System (ADS)

Ekmekcioglu, Pinar; Karabocek, Nevin; Karabocek, Serdar; Emirik, Mustafa

2015-11-01

A new Schiff base ligand (H2L) and its metal complexes have been prepared and characterized by elemental analysis, magnetic moment and spectral studies. The comparative in-vitro antimicrobial activities against various pathogens with reference to known antibiotics activity under the standard control of different concentrations revealed that the metal complexes (6-8) showed enhanced antimicrobial activities in general as compared to free ligand. As an exception, the free ligand showed better activity against Trichoderma. The antifungal activity experiments were performed in triplicate. The order of biochemical activity for metal complexes were observed as in the following. CuL > CoL > NiL, which is exactly same as the order of stability constants of these complexes. Additionally, we performed DFT and TD-DFT calculation for free ligand and Cu(II) complex to support the experimental data. The geometries of the Cu(II) complex have been optimized using the B3LYP level of theory. The theoretical calculations confirm that the copper (II) center exhibits a distorted square pyramidal geometry which is favored by experimental results.

Synthesis and Spectral Characterization of Antifungal Sensitive Schiff Base Transition Metal Complexes

PubMed Central

Sakthivel, A.; Rajasekaran, K.

2007-01-01

New N2O2 donor type Schiff base has been designed and synthesized by condensing acetoacetanilido-4-aminoantipyrine with 2-aminobenzoic acid in ethanol. Solid metal complexes of the Schiff base with Cu(II), Ni(II), Co(II), Mn(II), Zn(II), VO(IV), Hg(II) and Cd(II) metal ions were synthesized and characterized by elemental analyses, magnetic susceptibility, molar conduction, fast atom bombardment (FAB) mass, IR, UV-Vis, and 1H NMR spectral studies. The data show that the complexes have the composition of ML type. The UV-Vis. and magnetic susceptibility data of the complexes suggest a square-planar geometry around the central metal ion except VO(IV) complex which has square-pyramidal geometry. The in vitro antifungal activities of the compounds were tested against fungi such as Aspergillus niger, Aspergillus flavus, Rhizopus stolonifer, Candida albicans, Rhizoctonia bataicola and Trichoderma harizanum. All the metal complexes showed stronger antifungal activities than the free ligand. The minimum inhibitory concentrations (MIC) of the metal complexes were found in the range of 10~31 µg/ml. PMID:24015086

A robust Ni(II) α-diimine catalyst for high temperature ethylene polymerization.

PubMed

Rhinehart, Jennifer L; Brown, Lauren A; Long, Brian K

2013-11-06

Sterically demanding Ni(II) α-diimine precatalysts were synthesized utilizing 2,6-bis(diphenylmethyl)-4-methyl aniline. When activated with methylaluminoxane, the catalyst NiBr2(ArN═C(Me)-C(Me)═NAr) (Ar = 2,6 bis(diphenylmethyl)-4-methylbenzene) was highly active, produced well-defined polyethylene at temperatures up to 100 °C (Mw/Mn = 1.09-1.46), and demonstrated remarkable thermal stability at temperatures appropriate for industrially used gas-phase polymerizations (80-100 °C).

Comparison of nickel biosorption properties of living and dead Rhizopus arrhizus biosorbent

NASA Astrophysics Data System (ADS)

Silah, Hülya; Gül, Ülküye Dudu

2017-04-01

The passive removal of commonly used heavy metal Ni(II), from aqueous solutions by inexpensive biomaterial, fungi Rhizopus arrhizus biomass, termed biosorption, was studied in this study. The effects of biomass type (living and dead) and pH (2-6) on metal removal by fungus were investigated. The dead biomass (44.2%) exhibited higher uptake ability of Ni(II) than living biomass (40.5%) at 100 mg/L heavy metal after 6 h. Optimal pH for biosorption was 6.

Synthesis, characterization, antimicrobial, DNA-cleavage and antioxidant activities of 3-((5-chloro-2-phenyl-1H-indol-3-ylimino)methyl)quinoline-2(1H)-thione and its metal complexes

NASA Astrophysics Data System (ADS)

Vivekanand, B.; Mahendra Raj, K.; Mruthyunjayaswamy, B. H. M.

2015-01-01

Schiff base 3-((5-chloro-2-phenyl-1H-indol-3-ylimino)methyl)quinoline-2(1H)-thione and its Cu(II), Co(II), Ni(II), Zn(II) and Fe(III), complexes have been synthesized and characterized by elemental analysis, UV-Visible, IR, 1H NMR, 13C NMR and mass spectra, molar conductance, magnetic susceptibility, ESR and TGA data. The ligand and its metal complexes have been screened for their antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa, antifungal activity against Aspergillus niger and Aspergillus flavus in minimum inhibition concentration (MIC) by cup plate method respectively, antioxidant activity using 1,1-diphenyl-2-picryl hydrazyl (DPPH), which was compared with that of standard drugs vitamin-C and vitamin-E and DNA cleavage activity using calf-thymus DNA.

A Ni(iii) complex stabilized by silica nanoparticles as an efficient nanoheterogeneous catalyst for oxidative C-H fluoroalkylation.

PubMed

Khrizanforov, Mikhail N; Fedorenko, Svetlana V; Strekalova, Sofia O; Kholin, Kirill V; Mustafina, Asiya R; Zhilkin, Mikhail Ye; Khrizanforova, Vera V; Osin, Yuri N; Salnikov, Vadim V; Gryaznova, Tatyana V; Budnikova, Yulia H

2016-07-26

We have developed Ni(III)-doped silica nanoparticles ([(bpy)xNi(III)]@SiO2) as a recyclable, low-leaching, and efficient oxidative functionalization nanocatalyst for aromatic C-H bonds. The catalyst is obtained by doping the complex [(bpy)3Ni(II)] on silica nanoparticles along with its subsequent electrooxidation to [(bpy)xNi(III)] without an additional oxidant. The coupling reaction of arenes with perfluoroheptanoic acid occurs with 100% conversion of reactants in a single step at room temperature under nanoheterogeneous conditions. The catalyst content is only 1% with respect to the substrates under electrochemical regeneration conditions. The catalyst can be easily separated from the reaction mixture and reused a minimum of five times. The results emphasize immobilization on the silica support and the electrochemical regeneration of Ni(III) complexes as a facile route for developing an efficient nanocatalyst for oxidative functionalization.

Synthesis and characterization of ligational behavior of curcumin drug towards some transition metal ions: Chelation effect on their thermal stability and biological activity

NASA Astrophysics Data System (ADS)

Refat, Moamen S.

2013-03-01

Complexes of Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) with curcumin ligand as antitumor activity were synthesized and characterized by elemental analysis, conductometry, magnetic susceptibility, UV-Vis, IR, Raman, ESR, 1H-NMR spectroscopy, X-ray diffraction analysis of powdered samples and thermal analysis, and screened for antimicrobial activity. The IR spectral data suggested that the ligand behaves as a monobasic bidentate ligand towards the central metal ion with an oxygen's donor atoms sequence of both sbnd OH and Cdbnd O groups under keto-enol structure. From the microanalytical data, the stoichiometry of the complexes 1:2 (metal:ligand) was found. The ligand and their metal complexes were screened for antibacterial activity against Escherichia Coli, Staphylococcus aureus, Bacillus subtilis and Pseudomonas aeruginosa and fungicidal activity against Aspergillus flavus and Candida albicans.

Exploring DNA binding and nucleolytic activity of few 4-aminoantipyrine based amino acid Schiff base complexes: A comparative approach

NASA Astrophysics Data System (ADS)

Raman, N.; Sakthivel, A.; Pravin, N.

A series of novel Co(II), Cu(II), Ni(II) and Zn(II) complexes were synthesized from Schiff base(s), obtained by the condensation of 4-aminoantipyrine with furfural and amino acid (glycine(L1)/alanine(L2)/valine(L3)) and respective metal(II) chloride. Their structural features and other properties were explored from the analytical and spectral methods. The binding behaviors of the complexes to calf thymus DNA were investigated by absorption spectra, viscosity measurements and cyclic voltammetry. The intrinsic binding constants for the above synthesized complexes are found to be in the order of 102 to 105 indicating that most of the synthesized complexes are good intercalators. The binding constant values (Kb) clearly indicate that valine Schiff-base complexes have more intercalating ability than alanine and glycine Schiff-base complexes. The results indicate that the complexes bind to DNA through intercalation and act as efficient cleaving agents. The in vitro antibacterial and antifungal assay indicates that these complexes are good antimicrobial agents against various pathogens. The IC50 values of [Ni(L1)2] and [Zn(L1)2] complexes imply that these complexes have preferable ability to scavenge hydroxyl radical.

Solid-phase extraction of some heavy metal ions on a double-walled carbon nanotube disk and determination by flame atomic absorption spectrometry.

PubMed

Karatepe, Aslihan; Soylak, Mustafa; Elçi, Latif

2011-01-01

A new preconcentration method was developed for the determination of trace amounts of Cu(II), Fe(III), Pb(II), Ni(II), and Cd(II) on a double-walled carbon nanotube disk. 4-(2-Thiazolylazo) resorcinol was used as a complexing reagent. The effects of parameters, including pH of the solutions, amounts of complexing reagent, eluent type, sample volume, flow rates of solutions, and matrix ions were examined for quantitative recoveries of the studied analyte ions. The retained metal ions were eluted by 2 M HNO3. The LOD values for the analytes were in the range of 0.7-4.4 microg/mL. Natural water samples and standard reference materials were analyzed by the presented method.

Sorption kinetics of zinc and nickel on modified chitosan.

PubMed

Tripathi, Nimisha; Choppala, Girish; Singh, Raj S; Srivastava, Prashant; Seshadri, Balaji

2016-09-01

This study was conducted to evaluate the effect of equilibration time on adsorption of zinc [Zn(II)] and nickel [Ni(II)] on pure and modified chitosan beads. The initial adsorption of Zn(II) was high on molybdenum (Mo)-impregnated chitosan beads (MoCB) during the initial 60 min. However, after 240 min, Zn(II) adsorption occurred more on single super phosphate chitosan beads (SSPCB), followed by monocalcium phosphate chitosan beads (MCPCB), untreated pure chitosan beads (UCB), and MoCB. Similarly, Ni(II) adsorption was greatest on MoCB during the initial 60 min. At the conclusion of the experiment (at 240 min), the greatest adsorption was occurred on MCPCB, followed by MoCB, UCB, and SSPCB. Chemical sorption and intra-particle diffusion were probably the dominant processes responsible for Zn(II) and Ni(II) sorption onto chitosan beads. The results demonstrated that modified chitosan beads were effective in adsorbing Zn and Ni and hence, could be used for the removal of these toxic metals from soil.

Nickel(II) Inhibits Tet-Mediated 5-Methylcytosine Oxidation by High Affinity Displacement of the Cofactor Iron(II).

PubMed

Yin, Ruichuan; Mo, Jiezhen; Dai, Jiayin; Wang, Hailin

2017-06-16

Ten-eleven translocation (Tet) family proteins are Fe(II)- and 2-oxoglutarate-dependent dioxygenases that regulate the dynamics of DNA methylation by catalyzing the oxidation of DNA 5-methylcytosine (5mC). To exert physiologically important functions, redox-active iron chelated in the catalytic center of Tet proteins directly involves the oxidation of the multiple substrates. To understand the function and interaction network of Tet dioxygenases, it is interesting to obtain high affinity and a specific inhibitor. Surprisingly, here we found that natural Ni(II) ion can bind to the Fe(II)-chelating motif (HXD) with an affinity of 7.5-fold as high as Fe(II). Consistently, we further found that Ni(II) ion can displace the cofactor Fe(II) of Tet dioxygenases and inhibit Tet-mediated 5mC oxidation activity with an estimated IC 50 of 1.2 μM. Essentially, Ni(II) can be used as a high affinity and selective inhibitor to explore the function and dynamics of Tet proteins.

Metal based pharmacologically active complexes of Cu(II), Ni(II) and Zn(II): synthesis, spectral, XRD, antimicrobial screening, DNA interaction and cleavage investigation.

PubMed

Raman, Natarajan; Mahalakshmi, Rajkumar; Arun, T; Packianathan, S; Rajkumar, R

2014-09-05

The present contribution reports a thorough characterization of newly obtained metallointercalators incorporating Schiff bases, formed by the condensation of N-acetoacetyl-o-toluidine with 1-amino-4-nitrobenzene (L(1))/1-amino-4-chlorobenzene (L(2)) as main ligand and 1,10-phenanthroline as co-ligand respectively. The characterization of newly formed metallointercalators has been done by (1)H NMR, UV-Vis, IR, EPR spectroscopy and molar conductivity studies. X-ray powder diffraction illustrates that they are crystalline nature. Binding interaction of these complexes with calf thymus (CT-DNA) has been investigated by emission, absorption, viscosity, cyclic voltammetry and differential pulse voltammetry. DNA binding experiments results reveal that the synthesized complexes interact with DNA through intercalative mode. The in vitro antibacterial and antifungal assay indicate that these complexes are good antimicrobial agents against various pathogens. The DNA cleavage exhibits that they act as efficient cleaving agents. Copyright © 2014 Elsevier B.V. All rights reserved.

Antioxidant, electrochemical, thermal, antimicrobial and alkane oxidation properties of tridentate Schiff base ligands and their metal complexes

NASA Astrophysics Data System (ADS)

Ceyhan, Gökhan; Çelik, Cumali; Uruş, Serhan; Demirtaş, İbrahim; Elmastaş, Mahfuz; Tümer, Mehmet

2011-10-01

In this study, two Schiff base ligands (HL 1 and HL 2) and their Cu(II), Co(II), Ni(II), Pd(II) and Ru(III) metal complexes were synthesized and characterized by the analytical and spectroscopic methods. Alkane oxidation activities of the metal complexes were studied on cyclohexane as substrate. The ligands and their metal complexes were evaluated for their antimicrobial activity against Corynebacterium xerosis, Bacillus brevis, Bacillus megaterium, Bacillus cereus, Mycobacterium smegmatis, Staphylococcus aureus, Micrococcus luteus and Enterococcus faecalis (as Gram-positive bacteria) and Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, Yersinia enterocolitica, Klebsiella fragilis, Saccharomyces cerevisiae, and Candida albicans (as Gram-negative bacteria). The antioxidant properties of the Schiff base ligands were evaluated in a series of in vitro tests: 1,1-diphenyl-2-picrylhydrazyl (DPPH rad ) free radical scavenging and reducing power activity of superoxide anion radical generated non-enzymatic systems. Electrochemical and thermal properties of the compounds were investigated.

Synthesis and synergistic antifungal activities of a pyrazoline based ligand and its copper(II) and nickel(II) complexes with conventional antifungals.

PubMed

Ali, Imran; Wani, Waseem A; Khan, Amber; Haque, Ashanul; Ahmad, Aijaz; Saleem, Kishwar; Manzoor, Nikhat

2012-08-01

A pyrazoline based ligand; (5-(4-chlorophenyl)-3-phenyl-4, 5-dihydro-1H-pyrazole-1-carbothioamide) has been synthesized by Claisen-Schmidt condensation of acetophenone with p-chlorobenzaldehyde, followed by sodium hydroxide assisted cyclization of the resulting chalcone with thiosemicarbazide. Metal ion complexes of the synthesized ligand were prepared with Cu(II) and Ni(II) metal ions, separately and respectively. Ligand and the metal complexes were characterized by elemental analysis, FT-IR, UV-Vis, (1)HNMR, ESI-MS and (13)CNMR spectroscopic techniques. Molar conductance measurements in DMSO suggested non-electrolytic nature of the complexes. Tetragonally distorted octahedral geometry for copper and octahedral geometry for the nickel complexes was proposed on the basis of UV-Vis spectroscopic studies and magnetic moment measurements. The complexes were investigated for their ability to kill human fungal pathogen Candida by determining MICs (Minimum inhibitory concentrations), inhibition in solid media and ability to produce a possible synergism with conventional most clinically practiced antifungals by disc diffusion assay and FICI (fractional inhibitory concentration index). Copyright © 2012 Elsevier Ltd. All rights reserved.

Spectroscopic studies and antibacterial activities of some new 16-membered octaazamacrocyclic complexes derived from thiocarbohydrazide and pentane-2,4-dione

NASA Astrophysics Data System (ADS)

Singh, D. P.; Kumar, Krishan; Chopra, Rimpi Mehani ne'e.

2011-02-01

A series of macrocyclic complexes of the type [M(C 12H 20N 8S 2)X 2]; where M = Co(II), Ni(II), Cu(II), Zn(II); X = Cl -, NO 3-, CH 3COO - has been synthesized by template condensation of thiocarbohydrazide and pentane-2,4-dione in the presence of divalent metal salts in methanolic medium. The complexes have been characterized with the help of elemental analyses, conductance measurements, magnetic measurements, electronic, NMR, IR, EPR and MS spectral studies. The low value of molar conductance indicates them to be non-electrolytes. On the basis of various studies a distorted octahedral geometry may be proposed for all of these complexes. These metal complexes were also tested for their in vitro antibacterial activities against some Gram-positive bacterial strains, i.e., Bacillus subtilis, Bacillus stearothermophilus and two Gram-negative bacterial strains, i.e., Escherichia coli, Pseudomonas putida. The results obtained were compared with standard antibiotics, Chloramphenicol and Streptomycin and found that some of the synthesized complexes show good antibacterial activities as compared to the standard antibiotics.

Co(II) and Ni(II) complexes based on anthraquinone-1,4,5,8-tetracarboxylic acid (H4AQTC): canted antiferromagnetism and slow magnetization relaxation in {[Co2(AQTC)(H2O)6]·6H2O}.

PubMed

Yan, Wei-Hong; Bao, Song-Song; Huang, Jian; Ren, Min; Sheng, Xiao-Li; Cai, Zhong-Sheng; Lu, Chang-Sheng; Meng, Qing-Jin; Zheng, Li-Min

2013-06-21

Three coordination polymers {[Co2(AQTC)(H2O)6]·6H2O}n (1), {[M2(AQTC)(bpym)(H2O)6]·6H2O}n (M = Co(2), Ni(3)) have been synthesized and structurally characterized, where H4AQTC is anthraquinone-1,4,5,8-tetracarboxylic acid and bpym is 2,2'-bipyrimidine. Complex 1 features a 3-D structure, where layers of Co2(AQTC) are cross-linked by Co-H2O chains. Complexes 2 and 3 are isostructural and display 1-D chain structures. The chains are connected through hydrogen-bonding interactions to form 3-D supramolecular structures. Magnetic properties of these complexes are investigated. Compound 1 shows canted antiferromagnetism and slow relaxation below 4.0 K. For complexes 2 and 3, dominant antiferromagnetic interactions are observed. The luminescent properties of the three complexes are investigated as well.

Novel Cu(I)-selective chelators based on a bis(phosphorothioyl)amide scaffold.

PubMed

Amir, Aviran; Ezra, Alon; Shimon, Linda J W; Fischer, Bilha

2014-08-04

Bis(dialkyl/aryl-phosphorothioyl)amide (BPA) derivatives are versatile ligands known by their high metal-ion affinity and selectivity. Here, we synthesized related chelators based on bis(1,3,2-dithia/dioxaphospholane-2-sulfide)amide (BTPA/BOPA) scaffolds targeting the chelation of soft metal ions. Crystal structures of BTPA compounds 6 (N(-)R3NH(+)) and 8 (NEt) revealed a gauche geometry, while BOPA compound 7 (N(-)R3NH(+)) exhibited an anti-geometry. Solid-state (31)P magic-angle spinning NMR spectra of BTPA 6-Hg(II) and 6-Zn(II) complexes imply a square planar or tetrahedral geometry of the former and a distorted tetrahedral geometry of the latter, while both BTPA 6-Ni(II) and BOPA 7-Ni(II) complexes possibly form a polymeric structure. In Cu(I)-H2O2 system (Fenton reaction conditions) BTPA compounds 6, 8, and 10 (NCH2Ph) were identified as most potent antioxidants (IC50 32, 56, and 29 μM, respectively), whereas BOPA analogues 7, 9 (NEt), and 11 (NCH2Ph) were found to be poor antioxidants. In Fe(II)-H2O2 system, IC50 values for both BTPA and BOPA compounds exceeded 500 μM indicating high selectivity to Cu(I) versus the borderline Fe(II)-ion. Neither BTPA nor BOPA derivatives showed radical scavenging properties in H2O2 photolysis, implying that inhibition of the Cu(I)-induced Fenton reaction by both BTPA and BOPA analogues occurred predominantly through Cu(I)-chelation. In addition, NMR-monitored Cu(I)- and Zn(II)-titration of BTPA compounds 8 and 10 showed their high selectivity to a soft metal ion, Cu(I), as compared to a borderline metal ion, Zn(II). In summary, lipophilic BTPA analogues are promising highly selective Cu(I) ion chelators.

Scanning tunneling microscopy, orbital-mediated tunneling spectroscopy, and ultraviolet photoelectron spectroscopy of metal(II) tetraphenylporphyrins deposited from vapor.

PubMed

Scudiero, L; Barlow, D E; Mazur, U; Hipps, K W

2001-05-02

Thin films of vapor-deposited Ni(II) and Co(II) complexes of tetraphenylporphyrin (NiTPP and CoTPP) were studied supported on gold and embedded in Al-Al(2)O(3)-MTPP-Pb tunnel diodes, where M = Ni or Co. Thin films deposited onto polycrystalline gold were analyzed by ultraviolet photoelectron spectroscopy (UPS) using He I radiation. Scanning tunneling microscopy (STM) and orbital-mediated tunneling spectroscopy (STM-OMTS) were performed on submonolayer films of CoTPP and NiTPP supported on Au(111). Inelastic electron tunneling spectroscopy (IETS) and OMTS were measured in conventional tunnel diode structures. The highest occupied pi molecular orbital of the porphyrin ring was seen in both STM-OMTS and UPS at about 6.4 eV below the vacuum level. The lowest unoccupied pi molecular orbital of the porphyrin ring was observed by STM-OMTS and by IETS-OMTS to be located near 3.4 eV below the vacuum level. The OMTS spectra of CoTPP had a band near 5.2 eV (below the vacuum level) that was attributed to transient oxidation of the central Co(II) ion. That is, it is due to electron OMT via the half-filled d(z)(2) orbital present in Co(II) of CoTPP. The NiTPP OMTS spectra show no such band, consistent with the known difficulty of oxidation of the Ni(II) ion. The STM-based OMTS allowed these two porphyrin complexes to be easily distinguished. The present work is the first report of the observation of STM-OMTS, tunnel junction OMTS, and UPS of the same compounds. Scanning tunneling microscope-based orbital-mediated tunneling provides more information than UPS or tunnel junction-based OMTS and does so with molecular-scale resolution.

Spectroscopic characteristic (FT-IR, 1H, 13C NMR and UV-Vis) and theoretical calculations (MEP, DOS, HOMO-LUMO, PES, NBO analysis and keto-enol tautomerism) of new tetradentate N,N‧-bis(4-hydroxysalicylidene)-1,4-phenylenediamine ligand as chelating agent for the synthesis of dinuclear Co(II), Ni(II), Cu(II) and Zn(II) complexes

NASA Astrophysics Data System (ADS)

Rajaei, Iman; Mirsattari, Seyed Nezamoddin

2018-07-01

The synthesis and characterization of a novel symmetrical Schiff base ligand N,Nʹ-bis(4-hydroxysalicylidene)-1,4-phenylenediamine (BHSP) was presented in this study and characterized by FT-IR, NMR (1H and 13C) and UV-Vis spectroscopy experimentally and theoretically. Also a series of binuclear Co(II), Ni(II), Cu(II) and Zn(II) complexes of BHSP ligand have been synthesized by conventional sequential route in 1:1 equivalent of L:M ratio and characterized by routine physicochemical characterizations. The molecular geometry and vibrational frequencies of the BHSP in the ground state were calculated by using density functional theory (DFT) B3LYP method invoking 6-31G(d,p) and 6-31++G(d,p) basis sets. To study different conformations of the molecule, potential energy surface (PES) scan investigations were performed. The energetic behavior of the ligand compound (BHSP) in solvent media has been examined using B3LYP method with the 6-31G(d,p) and 6-31++G(d,p) basis sets by applying the polarized continuum model (PCM). In addition, DFT calculations of the BHSP ligand, molecular electrostatic potential (MEP), contour map, natural bond orbital (NBO) analysis, frontier molecular orbitals (FMO) analysis, NMR analysis and TD-DFT calculations were conducted. The calculated properties are in agreement with the available experimental data and closely related molecule BSP. The calculated results show that the optimized geometry can well reproduce the crystal structural parameters.

Synthesis and characterization of new complexes of nickel (II), palladium (II) and platinum(II) with derived sulfonamide ligand: Structure, DFT study, antibacterial and cytotoxicity activities

NASA Astrophysics Data System (ADS)

Bouchoucha, Afaf; Zaater, Sihem; Bouacida, Sofiane; Merazig, Hocine; Djabbar, Safia

2018-06-01

The synthesis, characterization and biological study of new nickel (II), palladium (II), and platinum (II) complexes with sulfamethoxazole ligand used in pharmaceutical field, were reported. [MLCl2].nH2O is the general formula obtained for Pd(II) and Pt(II) complexes. These complexes have been prepared and characterized by elemental analysis, FTIR, 1HNMR spectral, magnetic measurements, UV-Visible spectra, and conductivity. The DFT calculation was applied to optimize the geometric structure of the Pd(II) and Pt(II) complexes. A new single-crystal X-ray structure of the Ni(II) complex has been determined. It crystallized in monoclinic system with P 21/c space group and Z = 8. The invitro antibacterial activity of ligand and complexes against Escherichia coli, P. aeruginosa, Klebsiella pneumoniae, S. aureus, Bacillus subtilis species has been carried out and compared using agar-diffusion method. The Pd(II) and Pt(II) complexes showed a remarkable inhibition against bacteria tested. The invitro cytotoxicity assay of the complexes against three cell lines chronic myelogenous leukaemia (K562), human colon adenocarcinoma (HT-29) and breast cancer (MCF-7) was also reported.

Alkylation of a bioinspired high spin Ni(II)N{sub 3}S{sub 2} complex with bifunctional reagents

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chohan, B. S., E-mail: bsc12@psu.edu

2013-12-15

Crystal structures of two S-alkylated complexes generated from the reaction of iodoacetamide and iodoethanol with an air and moisture sensitive high spin Ni(II) pentacoordinate triaminodithiolate complex, 1 are determined by X-ray structure analysis. Crystals of complex 2, [NiC{sub 16}H{sub 31}N{sub 5}O{sub 2}S{sub 2}]I{sub 2}, are triclinic, sp. gr. P-bar1 , Z = 2. Crystals of complex 3, [NiC{sub 16}H{sub 28}N{sub 3}O{sub 2}S{sub 2}]I{sub 2}, are monoclinic, sp. gr. P2{sub 1}/c, Z = 4. Structures of complexes 2 and 3 are very similar: one of the S-acetamide (2) or S-ethanol (3) groups coordinates to the Ni center through the oxygen atom formingmore » N{sub 3}S{sub 2}O hexacoordination; the other group remains unbound to the Ni and left dangling. Crystal packing shows that complexes 2 and 3 interact with the iodide counterions, and that only complex 2 interact with neighboring molecules; some of these close intermolecular contacts include H-bonding interactions.« less

Fe (III), Co(II), Ni(II), Cu(II) and Zn(II) complexes of schiff bases based-on glycine and phenylalanine: Synthesis, magnetic/thermal properties and antimicrobial activity

NASA Astrophysics Data System (ADS)

Sevgi, Fatih; Bagkesici, Ugur; Kursunlu, Ahmed Nuri; Guler, Ersin

2018-02-01

Zinc (II), copper (II), nickel (II), cobalt (II) and iron (III) complexes of Schiff bases (LG, LP) derived from 2-hydroxynaphthaldehyde with glycine and phenylalanine were reported and characterized by 1H NMR, 13C NMR, elemental analyses, melting point, FT-IR, magnetic susceptibility and thermal analyses (TGA). TGA data show that iron and cobalt include to the coordinated water and metal:ligand ratio is 1:2 while the complex stoichiometry for Ni (II), Cu (II) and Zn (II) complexes is 1:1. As expected, Ni (II) and Zn (II) complexes are diamagnetic; Cu (II), Co (II) and Fe (III) complexes are paramagnetic character due to a strong ligand of LG and LP. The LG, LP and their metal complexes were screened for their antimicrobial activities against five Gram-positive (Staphylococcus aureus, Methicillin resistant Staphylococcus aureus (MRSA), Bacillus cereus, Streptococcus mutans and Enterococcus faecalis) and three Gram-negative (Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa) and one fungi (Candida albicans) by using broth microdilution techniques. The activity data show that ligands and their metal complexes exhibited moderate to good activity against Gram-positive bacteria and fungi.

A Novel Micellar Electrokinetic Chromatographic Method for Separation of Metal-DDTC Complexes

PubMed Central

Mallah, Arfana; Memon, Saima Q.; Solangi, Amber R.; Memon, Najma; Abbassi, Kulsoom; Khuhawar, Muhammad Yar

2012-01-01

Micellar electrokinetic chromatography (MEKC) was examined for the separation and determination of Mo(VI), Cr(VI), Ni(II), Pd(II), and Co(III) as diethyl dithiocarbamate (DDTC) chelates. The separation was achieved from fused silica capillary (52 cm × 75 μm id) with effective length 40 cm, background electrolyte (BGE) borate buffer pH 9.1 (25 mM), CTAB 30% (100 mM), and 1% butanol in methanol (70 : 30 : 5 v/v/v) with applied voltage of −10 kV using reverse polarity. The photodiode array detection was achieved at 225 nm. The linear calibration for each of the element was obtained within 0.16–10 μg/mL with a limit of detection (LOD) 0.005–0.0167 μg/mL. The separation and determination was repeatable with relative standard deviation (RSD) within 2.4–3.3% (n = 4) in terms of migration time and peak height/peak area. The method was applied for the determination of Mo(VI) from potatoes and almond, Ni(II) from hydrogenated vegetable oil, and Co(III) from pharmaceutical preparations with RSD within 3.9%. The results obtained were checked by standard addition and rechecked by atomic absorption spectrometry. PMID:22649320

Advanced asymmetric synthesis of (1R,2S)-1-amino-2-vinylcyclopropanecarboxylic acid by alkylation/cyclization of newly designed axially chiral Ni(II) complex of glycine Schiff base.

PubMed

Kawashima, Aki; Shu, Shuangjie; Takeda, Ryosuke; Kawamura, Akie; Sato, Tatsunori; Moriwaki, Hiroki; Wang, Jiang; Izawa, Kunisuke; Aceña, José Luis; Soloshonok, Vadim A; Liu, Hong

2016-04-01

Asymmetric synthesis of (1R,2S)-1-amino-2-vinylcyclopropanecarboxylic acid (vinyl-ACCA) is in extremely high demand due to the pharmaceutical importance of this tailor-made, sterically constrained α-amino acid. Here we report the development of an advanced procedure for preparation of the target amino acid via two-step SN2 and SN2' alkylation of novel axially chiral nucleophilic glycine equivalent. Excellent yields and diastereoselectivity coupled with reliable and easy scalability render this method of immediate use for practical synthesis of (1R,2S)-vinyl-ACCA.

Efficient removal of nickel(II) from high salinity wastewater by a novel PAA/ZIF-8/PVDF hybrid ultrafiltration membrane.

PubMed

Li, Ting; Zhang, Weiming; Zhai, Shu; Gao, Guandao; Ding, Jie; Zhang, Wenbin; Liu, Yang; Zhao, Xin; Pan, Bingcai; Lv, Lu

2018-06-15

The development of highly efficient membranes, especially those aimed at the removal of trace (ppm, 10 -6 ) heavy metals from high salinity wastewater, is one of the principal challenges in the wastewater treatment field. In this study, a new metal-organic frameworks-based hybrid ultrafiltration membrane (PAA/ZIF-8/PVDF membrane) was prepared, which outperformed some other adsorption materials and owned the first and highest reported nickel ion (Ni(II)) adsorption capacity (219.09 mg/g) in high salinity ([Na + ] = 15000 mg/L) wastewater. Novel and highly efficient hybrid ultrafiltration membrane was facilely fabricated by physically immobilizing zeolitic imidazolate framework-8 (ZIF-8) particles onto the surface of trimesoyl chloride (TMC)-modified polyvinylidene fluoride (PVDF) membrane under the protection of polyacrylic acid (PAA) layer, and possessed a relatively high water flux of ∼460 L m -2 h -1 . The XPS studies revealed that the Ni(II) uptake was mainly attributed to the specific hydrogen bonding interaction between Ni(II) and hydroxyl on ZIF-8 frameworks as well as the electrostatic adsorption by carboxyl groups in PAA layer. Especially, compared to PAA, ZIF-8 could selectively bind with Ni(II) effectively, which was almost not affected by concentrated sodium ion. The filtration study showed that the membrane with an area of 12.56 cm 2 could treat 5.76 L of Ni(II)-contained high salinity wastewater ([Ni(II) = 2 mg/L, [Na + ] = 15000 mg/L) to meet the maximum contaminant level of 0.1 mg/L Ni(II). Moreover, the hybrid membrane can be regenerated several times by HCl-NaCl solution (pH = 5.5) for repeated use under direct current electric field. Thus, the newly developed ZIF-8 hybrid ultrafiltration membrane showed a promising potential for heavy metals containing wastewater treatment. This work provides a worthy reference for designing highly efficient ultrafiltration membranes modified by metal-organic frameworks. Copyright © 2018 Elsevier Ltd. All rights reserved.

Application of mucilage from Dicerocaryum eriocarpum plant as biosorption medium in the removal of selected heavy metal ions.

PubMed

Jones, Bassey O; John, Odiyo O; Luke, Chimuka; Ochieng, Aoyi; Bassey, Bridget J

2016-07-15

The ability of mucilage from Dicerocaryum eriocarpum (DE) plant to act as biosorption medium in the removal of metals ions from aqueous solution was investigated. Functional groups present in the mucilage were identified using Fourier transform infrared spectroscopy (FTIR). Mucilage was modified with sodium and potassium chlorides. This was aimed at assessing the biosorption efficiency of modified mucilage: potassium mucilage (PCE) and sodium mucilage (SCE) and comparing it with non-modified deionised water mucilage (DCE) in the uptake of metal ions. FTIR results showed that the functional groups providing the active sites in PCE and SCE and DCE include: carboxyl, hydroxyl and carbonyl groups. The chloride used in the modification of the mucilage did not introduce new functional groups but increased the intensity of the already existing functional groups in the mucilage. Results from biosorption experiment showed that DE mucilage displays good binding affinity with metals ions [Zn(II), Cd(II) Ni(II), Cr(III) and Fe(II)] in the aqueous solution. Increase in the aqueous solution pH, metal ions initial concentration and mucilage concentration increased the biosorption efficiency of DE mucilage. The maximum contact time varied with each species of metal ions. Optimum pH for [Zn(II), Cd(II) Ni(II) and Fe(II)] occurred at pH 4 and pH 6 for Cr(III). Kinetic models result fitted well to pseudo-second-order with a coefficient values of R(2) = 1 for Cd(II), Ni(II), Cr(III), Fe(II) and R(2) = 0.9974 for Zn(II). Biosorption isotherms conforms best with Freundlich model for all the metal ions with correlation factors of 0.9994, 0.9987, 0.9554, 0.9621 and 0.937 for Zn(II), Ni(II), Fe(II), Cr(III) and Cd(II), respectively. Biosorption capacity of DE mucilage was 0.010, 2.387, 4.902, 0688 and 0.125 for Zn(II), Cr(III), Fe(II), Cd(II) and Ni(II) respectively. The modified mucilage was found to be highly efficient in the removal of metal ions than the unmodified mucilage. Copyright © 2016 Elsevier Ltd. All rights reserved.

Synthesis, characterization and anticancer activity of new Schiff bases bearing neocryptolepine

NASA Astrophysics Data System (ADS)

Emam, Sanaa M.; El Sayed, Ibrahim E. T.; Ayad, Mohamed I.; Hathout, Heba M. R.

2017-10-01

The synthesis of new Shiff base ligands denoted L1, HL2 and HL3 starting from the appropriate aminoneocryptolepine and salicaldehyde were described. The chelation abilities of L1, HL2 and HL3 ligands towards Co(II), Ni(II), Cu(II) and Pd(II) salts have been studied. A series of square planar complexes containing Cu(II) salts, PdCl2 and octahedral chelates containing NiCl2, CoCl2 salts (2 and 7) have been isolated. Also, the pentacoordinated Co(II) complex [Co(L1)2Cl]·Cl.0.5H2O·1.25EtOH (1) has been prepared. The mode of bonding and geometrical structure of complexes has been confirmed by elemental analyses and different spectroscopic methods together with thermal, magnetic moment studies, molecular modeling and X-ray diffraction. Furthermore, the synthesized ligands, in comparison to some of their metal complexes were screened for their anticancer activity against colorectal adenocarcinoma (HT-29) cells. The results showed that Co(II) complexes (1 and 7) exhibited higher anticancer activity when compared to the corresponding ligands.

Synthesis, spectral, thermal and optical properties of Schiff-base complexes derived from 2(E)-2-((z)-4-hydroxypent-3-en-2-ylideneamino)-5-guanidinopentanoic acid and acetylacetone

NASA Astrophysics Data System (ADS)

Hosny, Nasser Mohammed; Hussien, Mostafa A.; Radwan, Fatima M.; Nawar, Nagwa

2017-09-01

New metal complexes derived from the in situ reaction of Cu(II), Co(II), Ni(II) and Zn(II) acetates with the Schiff-base ligand (H2L) resulted from the condensation of 2-amino-5-guanidinopentanoic acid (arginine) and acetylacetone have been synthesized. The resulting complexes have been characterized by, elemental analyses, ES-MS, IR, Raman spectra, UV-Vis., 1HNMR, ESR, thermal analyses (TGA and DTG) and magnetic measurements. The results showed that, The Schiff-base ligand acts as bi-negative tridentate coordinating via azomethine nitrogen, enolic carbonyl oxygen and carboxylate oxygen after displacement of hydrogen. The thermodynamic parameters E∗, ΔH, ΔG and ΔS of the isolated complexes have been calculated. The optical band gap (Eg) values of Cu, Co, Ni and Zn were found to be 3.3, 3.4, 3.7 and 4.3 eV, respectively, arising from direct transitions. Optical band gap measurements indicate the semi-conductivity nature of these complexes.

New 15-membered tetraaza (N4) macrocyclic ligand and its transition metal complexes: Spectral, magnetic, thermal and anticancer activity

NASA Astrophysics Data System (ADS)

El-Boraey, Hanaa A.; EL-Gammal, Ohyla A.

2015-03-01

Novel tetraamidemacrocyclic 15-membered ligand [L] i.e. naphthyl-dibenzo[1,5,9,12]tetraazacyclopentadecine-6,10,11,15-tetraoneand its transition metal complexes with Fe(II), Co(II), Ni(II), Cu(II), Ru(III) and Pd(II) have been synthesized and characterized by elemental analysis, spectral, thermal as well as magnetic and molar conductivity measurements. On the basis of analytical, spectral (IR, MS, UV-Vis, 1H NMR and EPR) and thermal studies distorted octahedral or square planar geometry has been proposed for the complexes. The antitumor activity of the synthesized ligand and some complexes against human breast cancer cell lines (MCF-7) and human hepatocarcinoma cell lines (HepG2) has been studied. The complexes (IC50 = 2.27-2.7, 8.33-31.1 μg/mL, respectively) showed potent antitumor activity, towards the former cell lines comparable with their ligand (IC50 = 13, 26 μg/mL, respectively). The results show that the activity of the ligand towards breast cancer cell line becomes more pronounced and significant when coordinated to the metal ion.

New 14-membered octaazamacrocyclic complexes of divalent transition metal ions with their antimicrobial and spectral studies

NASA Astrophysics Data System (ADS)

Singh, D. P.; Kumar, Krishan; Sharma, Chetan

2010-01-01

A novel series of macrocyclic complexes of the type [M(C 18H 14N 10S 2)X 2]; where M = Co(II), Ni(II), Cu(II), Zn(II) and Cd(II); X = Cl -, NO 3-, CH 3COO - has been synthesized by [2+2] condensation of thiocarbohydrazide and isatin in the presence of divalent metal salts in methanolic medium. The complexes have been characterized with the help of elemental analyses, conductance measurements, magnetic measurements, electronic, NMR and infrared spectral studies. The low value of molar conductance indicates them to be non-electrolytes. On the basis of various studies a distorted octahedral geometry may be proposed for all of these complexes. These metal complexes were also tested for their in vitro antimicrobial activities against some Gram-positive bacteria viz. Staphylococcus aureus, Bacillus subtilis, and some Gram-negative bacteria Escherichia coli, Pseudomonas aeruginosa and some fungal strains Aspergillus niger, Aspergillus flavus (molds), Candida albicans, Saccharomyces cerevisiae (yeasts). The results obtained were compared with standard antibiotic: Ciprofloxacin and the standard antifungal drug: Amphotericin-B.

Synthesis, spectral characterization and DNA binding of Schiff-base metal complexes derived from 2-amino-3-hydroxyprobanoic acid and acetylacetone

NASA Astrophysics Data System (ADS)

Hosny, Nasser Mohammed; Hussien, Mostafa A.; Radwan, Fatima M.; Nawar, Nagwa

2014-11-01

Four new metal complexes derived from the reaction of Cu(II), Co(II), Ni(II) and Zn(II) acetates with the Schiff-base ligand (H3L) resulted from the condensation of the amino acid 2-amino-3-hydroxyprobanoic acid (serine) and acetylacetone have been synthesized and characterized by, elemental analyses, ES-MS, IR, UV-Vis., 1H NMR, 13C NMR, ESR, thermal analyses (TGA and DTG) and magnetic measurements. The results showed that the Schiff-base ligand acts as bi-negative tridentate through the azomethine nitrogen, the deprotonated carboxylate oxygen and the enolic carbonyl oxygen. The optical band gaps measurements indicated the semi-conducting nature of these complexes. Molecular docking was used to predict the binding between the Schiff base ligand with the receptor of prostate cancer mutant H874Y. The interactions between the Cu(II) complex and calf thymus DNA (CT-DNA) have been studied by UV spectra. The results confirm that the Cu(II) complex binds to CT-DNA in an intercalative mode.

Spectroscopic and biological activities studies of bivalent transition metal complexes of Schiff bases derived from condensation of 1,4-phenylenediamine and benzopyrone derivatives.

PubMed

Sherif, Omaima E; Abdel-Kader, Nora S

2014-01-03

Many tools of analysis such as elemental analyses, infrared, ultraviolet-visible, electron spin resonance (ESR) and thermal analysis, as well as conductivity and magnetic susceptibility measurements were used to elucidate the structures of the newly prepared Co(II), Ni(II) and Cu(II) complexes with Schiff bases derived from the condensation of 1,4-phenylenediamine with 6-formyl-7-hydroxy-5-methoxy-2-methylbenzo-pyran-4-one (H2L) or 5,7-dihydroxy-6-formyl-2-methylbenzopyran-4-one (H4L). The data showed that all formed complexes are 1:1 or 2:2 (M:L) and non-electrolyte chelates. The Co(II) and Cu(II) complexes of the two Schiff bases were screened for antibacterial activities by the disk diffusion method. The antibacterial activity was screened using Escherichia coli and Staphylococcus capitis but the antifungal activity was examined by using Aspergillus flavus and Candida albicans. The Results showed that the tested complexes have antibacterial, except CuH4L, but not antifungal activities. Copyright © 2013 Elsevier B.V. All rights reserved.

C-H Activation of Benzene by a Photoactivated Ni(II)(azide): Formation of a Transient Nickel Nitrido Complex.

PubMed

Vreeken, Vincent; Siegler, Maxime A; de Bruin, Bas; Reek, Joost N H; Lutz, Martin; van der Vlugt, Jarl Ivar

2015-06-08

Photochemical activation of nickel-azido complex 2 [Ni(N3)(PNP)] (PN(H)P=2,2'-di(isopropylphosphino)-4,4'-ditolylamine) in neat benzene produces diamagnetic complex 3 [Ni(Ph)(PN(P)N(H))], which is crystallographically characterized. DFT calculations support photoinitiated N2-loss of the azido complex to generate a rare, transient Ni(IV) nitrido species, which bears significant nitridyl radical character. Subsequent trapping of this nitrido through insertion into the Ni-P bond generates a coordinatively unsaturated Ni(II) imidophosphorane P=N donor. This species shows unprecedented reactivity toward 1,2-addition of a C-H bond of benzene to form 3. The structurally characterized chlorido complex 4 [Ni(Cl)(PN(P)N(H))] is generated by reaction of 3 with HCl or by direct photolysis of 2 in chlorobenzene. This is the first report of aromatic C-H bond activation by a trapped transient nitrido species of a late transition metal. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Investigating the pharmacodynamic and magnetic properties of pyrophosphate-bridged coordination complexes

NASA Astrophysics Data System (ADS)

Ikotun, Oluwatayo (Tayo) F.

The multidentate nature of pyrophosphate makes it an attractive ligand for complexation of metal cations. The participation of pyrophosphate in a variety of biological pathways and its metal catalyzed hydrolysis has driven our investigation into its coordination chemistry. We have successfully synthesized a library of binuclear pyrophosphate bridge coordination complexes. The problem of pyrophosphate hydrolysis to phosphate in the presence of divalent metal ions was overcome by incorporating capping ligands such as 1,10-phenanthroline and 2,2'-bipyridine prior to the addition of the pyrophosphate. The magnetic properties of these complexes was investigated and magneto-structural analysis was conducted. The biological abundance of pyrophosphate and the success of metal based drugs such as cisplatin, prompted our investigation of the cytotoxic properties of M(II) pyrophosphate dimeric complexes (where M(II) is CoII, CuII, and NiII) in adriamycin resistant human ovarian cancer cells. Thess compounds were found to exhibit toxicity in the nanomolar to picomolar range. We conducted in vitro stability studies and the mechanism of cytoxicity was elucidated by performing DNA mobility and binding assays, enzyme inhibition assays, and in vitro oxidative stress studies.

Spectroscopic, cyclic voltammetric and biological studies of transition metal complexes with mixed nitrogen-sulphur (NS) donor macrocyclic ligand derived from thiosemicarbazide

NASA Astrophysics Data System (ADS)

Chandra, Sulekh; Gupta, Lokesh Kumar; Sangeetika

2005-11-01

The complexation of new mixed thia-aza-oxa macrocycle viz., 2,12-dithio-5,9,14,18-tetraoxo-7,16-dithia-1,3,4,10,11,13-hexaazacyclooctadecane containing thiosemicarba-zone unit with a series of transition metals Co(II), Ni(II) and Cu(II) has been investigated, by different spectroscopic techniques. The structural features of the ligand have been studied by EI-mass, 1H NMR and IR spectral techniques. Elemental analyses, magnetic moment susceptibility, molar conductance, IR, electronic, and EPR spectral studies characterized the complexes. Electronic absorption and IR spectra of the complexes indicate octahedral geometry for chloro, nitrato, thiocyanato or acetato complexes. The dimeric and neutral nature of the sulphato complexes are confirmed from magnetic susceptibility and low conductance values. Electronic spectra suggests square-planar geometry for all sulphato complexes. The redox behaviour was studied by cyclic voltammetry, show metal-centered reduction processes for all complexes. The complexes of copper show both oxidation and reduction process. The redox potentials depend on the conformation of central atom in the macrocyclic complexes. Newly synthesized macrocyclic ligand and its transition metal complexes show markedly growth inhibitory activity against pathogenic bacterias and plant pathogenic fungi under study. Most of the complexes have higher activity than that of the metal free ligand.

2,4-Dinitrophenylhydrazine functionalized sodium dodecyl sulfate-coated magnetite nanoparticles for effective removal of Cd(II) and Ni(II) ions from water samples.

PubMed

Sobhanardakani, Soheil; Zandipak, Raziyeh

2015-07-01

2,4-Dinitrophenylhydrazine immobilized on sodium dodecyl sulfate (SDS)-coated magnetite and was used for removal of Cd(II) and Ni(II) ions from aqueous solution. The prepared product was characterized by X-ray diffraction (XRD) analysis, Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM). The size of the nanoparticles according to SEM was obtained around 20-35 nm. In batch tests, the effects of pH, contact time, initial metal concentration, and temperature were studied. The kinetic and equilibrium data were modeled with recently developed models. The adsorption kinetics and isotherms were well fitted by the fractal-like pseudo-second-order model and Langmuir-Freundlich model, respectively. Maximum adsorption capacity by this adsorbent is 255.1 mg g(-1) for Cd(II) ion and 319.6 mg g(-1) for Ni(II) ion at pH 7.0 and 25 °C. The method was successfully applied to the removal of metal cations in real samples (tap water, river water, and petrochemical wastewater).

Dye-doped nanostructure polypyrrole film for electrochemically switching solid-phase microextraction of Ni(II) and ICP-OES analysis of waste water.

PubMed

Shamaeli, Ehsan; Alizadeh, Naader

2012-01-01

A nanostructure fiber based on conducting polypyrrole synthesized by an electrochemical method has been developed, and used for electrochemically switching solid-phase microextraction (ES-SPME). The ES-SPME was prepared by the doping of eriochrome blue in polypyrrole (PPy-ECB) and used for selectively extracting the Ni(II) cation in the presence of some transition and heavy metal ions. The cation-exchange behavior of electrochemically prepared polypyrrole on stainless-steel with and without eriochrome blue (ECB) dye was characterized using ICP-OES analysis. The effects of the scan rate for electrochemical synthesis, uptake and the release potential on the extraction behavior of the PPy-ECB conductive fiber were studied. Uptake and release time profiles show that the process of electrically switched cation exchange could be completed within 250 s. The results of the present study point concerning the possibility of developing a selective extraction process for Ni(II) from waste water was explored using such a nanostructured PPy-ECB film through an electrically switched cation exchange. 2012 © The Japan Society for Analytical Chemistry

Dual shell-like magnetic clusters containing Ni(II) and Ln(III) (Ln = La, Pr, and Nd) ions.

PubMed

Kong, Xiang-Jian; Ren, Yan-Ping; Long, La-Sheng; Zheng, Zhiping; Nichol, Gary; Huang, Rong-Bin; Zheng, Lan-Sun

2008-04-07

Dual shell-like nanoscopic magnetic clusters featuring a polynuclear nickel(II) framework encapsulating that of lanthanide ions (Ln = La, Pr, and Nd) were synthesized using Ni(NO3)(2).6H2O, Ln(NO3)(3).6H2O, and iminodiacetic acid (IDA) under hydrothermal conditions. Structurally established by crystallographic studies, these clusters are [La20Ni30(IDA)30(CO3)6(NO3)6(OH)30(H2O)12](CO3)(6).72H2O (1), [Ln20Ni21(C4H5NO4)21(OH)24(C2H2O3)6(C2O4)3(NO3)9(H2O)12](NO3)9.nH2O [C2H2O3 is the alkoxide form of glycolate; Ln = Pr (2), n = 42; Nd (3), n = 50], and {[La4Ni5Na(IDA)5(CO3)(NO3)4(OH)5(H2O)5][CO3].10H2O} infinity (4). Carbonate, oxalate, and glycolate are products of hydrothermal decomposition of IDA. Compositions of these compounds were confirmed by satisfactory elemental analyses. It has been found that the cluster structure is dependent on the identity of the lanthanide ion as well as the starting Ln/Ni/IDA ratio. The cationic cluster of 1 features a core of the Keplerate type with an outer icosidodecahedron of Ni(II) ions encaging a dodecahedral kernel of La(III). Clusters 2 and 3, distinctly different from 1, are isostructural, possessing a core of an outer shell of 21 Ni(II) ions encapsulating an inner shell of 20 Ln(III) ions. Complex 4 is a three-dimensional assembly of cluster building blocks connected by units of Na(NO3)/La(NO3)3; the structure of the building block resembles closely that of 1, with a hydrated La(III) ion internalized in the decanuclear cage being an extra feature. Magnetic studies indicated ferromagnetic interactions in 1, while overall antiferromagnetic interactions were revealed for 2 and 3. The polymeric, three-dimensional cluster network 4 displayed interesting ferrimagnetic interactions.

Synthesis, characterization and solid state electrical properties of 1-D coordination polymer of the type [CuxNi1-x(dadb)·yH2O]n

NASA Astrophysics Data System (ADS)

Prasad, R. L.; Kushwaha, A.; Shrivastava, O. N.

2012-12-01

New heterobimetallic complexes [CuxNi1-x(dadb)·yH2O]n {where dadb=2,5-Diamino-3,6-dichloro-1,4-benzoquinone (1); x=1 (2), 0.5 (4), 0.25 (5), 0.125 (6), 0.0625 (7) and 0 (3); y=2; n=degree of polymerization} were synthesized and characterized. Heterobimetallic complexes show normal magnetic moments, whereas, monometallic complexes exhibit magnetic moments less than the value due to spin only. Thermo-gravimetric analysis shows that degradation of the ligand dadb moiety is being controlled by the electronic environment of the Cu(II) ions in preference over Ni(II) in heterobimetallic complexes. Existence of the mixed valency/non-integral oxidation states of copper and nickel metal ions in the complex 4 has been attributed from magnetic moment and ESR spectral results. Solid state dc electrical conductivity of all the complexes was investigated. Monometallic complexes were found to be semiconductors, whereas heterobimetallic coordination polymer 4 was found to exhibit metallic behaviour. Existence of mixed valency/ non-integral oxidation state of metal ions seems to be responsible for the metallic behaviour.

Adsorption of Cu(II), Hg(II), and Ni(II) ions by modified natural wool chelating fibers.

PubMed

Monier, M; Ayad, D M; Sarhan, A A

2010-04-15

The graft copolymerization of ethyl acrylate (EA) onto natural wool fibers initiated by potassium persulphate and Mohr's salt redox initiator system in limited aqueous medium was carried out in heterogeneous media. Ester groups of the grafted copolymers were partially converted into hydrazide function groups followed by hydrazone formation through reaction with isatin. Also the application of the modified fibers for metal ion uptake was studied using Cu(II), Hg(II) and Ni(II). The modified chelating fibers were characterized using FTIR spectroscopy, SEM and X-ray diffraction. 2009 Elsevier B.V. All rights reserved.

Zn(II), Ni(II), Cu(II) and Pb(II) complexes of tridentate asymmetrical Schiff base ligands: Synthesis, characterization, properties and biological activity

NASA Astrophysics Data System (ADS)

Şahin, Mustafa; Koçak, Nuriye; Erdenay, Damla; Arslan, Uğur

2013-02-01

New asymmetrical tridentate Schiff base ligands were synthesized using 1,2-phenylenediamine, 4-methyl-1,2-phenylenediamine, 2-hydroxy-1-napthaldehyde, 9-anthracenecarboxaldehyde. Schiff base ligands and their metal complexes were synthesised and characterized by using FT-IR, 1H NMR, 13C NMR, UV-Vis, XRD, ESR, elemental analysis and fluorescence studies. The antimicrobial activity of the ligands and their metal complexes were studied against Staphylococcus aureus ATCC 29213, S. aureus ATCC 25923, Streptococcus mutans RSHM 676, Enterococcus faecalis ATCC 29212, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853. The determination of the antibacterial activity was done using the broth microdilution methods. In general, it has been determined that the studied compounds have MIC values similar to Gram-positive and Gram-negative bacteria. It has been found that Ni, Pb, Zn derivatives of HL1A and ZnL2A has lower MIC values than ampicillin for P. aeruginosa ATCC 27853 strain.

Metal-Metal Interactions in Heterobimetallic Complexes with Dinucleating Redox-Active Ligands.

PubMed

Broere, Daniël L J; Modder, Dieuwertje K; Blokker, Eva; Siegler, Maxime A; van der Vlugt, Jarl Ivar

2016-02-12

The tuning of metal-metal interactions in multinuclear assemblies is a challenge. Selective P coordination of a redox-active PNO ligand to Au(I) followed by homoleptic metalation of the NO pocket with Ni(II) affords a unique trinuclear Au-Ni-Au complex. This species features two antiferromagnetically coupled ligand-centered radicals and a double intramolecular d(8)-d(10) interaction, as supported by spectroscopic, single-crystal X-ray diffraction, and computational data. A corresponding cationic dinuclear Au-Ni analogue with a stronger d(8)-d(10) interaction is also reported. Although both heterobimetallic structures display rich electrochemistry, only the trinuclear Au-Ni-Au complex facilitates electrocatalytic C-X bond activation of alkyl halides in its doubly reduced state. Hence, the presence of a redox-active ligand framework, an available coordination site at gold, and the nature of the nickel-gold interaction appear to be essential for this reactivity. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Functionalized Derivatives of Benzo-Crown Ethers. Part 4. Antifungal Macrocyclic Supramolecular Complexes of Transition Metal Ions Acting as Lanosterol-14-α-Demethylase Ihibitors

PubMed Central

Barboiu, Mihai; Scozzafava, Andrea; Guran, Cornelia; Diaconescu, Paula; Bojin, Mihaela; Iluc, Vlad; Cot, Louis

1999-01-01

Poly- and mononuclear metal complexes of 2,3,11,12-bis[4-(10-aminodecylcarbonyl)]benzo-18- crown-6 (L) and Cu(II); Ni(II); Co(II) and Cr(III) have been synthesized and characterized by standard physico-chemical procedures. In the newly prepared complexes the crown moiety oxygen atoms of the macrocyclic host did not generally interact with metal ions, whereas the two amino groups of the ligand always did. Several of the newly synthesized compounds act as effective antifungal agents against Aspergillus and Candida spp., some of them showing activities comparable to ketoconazole, with minimum inhibitory concentrations in the range of 0.3−0.5 μg/mL. The mechanism of antifungal action of these coordination compounds is probably connected to an inhibition of lanosterol-14-α-demethylase, a metallo-enzyme playing a key role in sterol biosynthesis in fungi, bacteria and eukariotes. PMID:18475888

In-Situ Immobilization of Ni Complex on Amine-Grafted SiO₂ for Ethylene Polymerization.

PubMed

Lee, Sang Yun; Ko, Young Soo

2018-02-01

The results on the In-Situ synthesis of Ni complex on amine-grafted SiO2 and its ethylene polymerization were explained. SiO2/2NS/(DME)NiBr2 and SiO2/3NS/(DME)NiBr2(Ni(II) bromide ethylene glycol dimethyl ether) catalysts were active for ethylene polymerization. The highest activity was shown at the polymerization temperature of 25 °C, and SiO2/2NS/(DME)NiBr2 exhibited higher activity than SiO2/3NS/(DME)NiBr2. The PDI values of SiO2/2NS/(DME)NiBr2 were in the range of 8~18. The aminosilane compounds and Ni were evenly grafted and distributed in the silica. It was proposed that DME ligand was mostly removed during the supporting process, and only NiBr2 was complexed with the amine group of 2NS based on the results of FT-IR and ethylene polymerization.

Synthesis, spectral characterization, molecular modeling, biological activity and potentiometric studies of 4-amino-5-mercapto-3-methyl-S-triazole Schiff's base complexes

NASA Astrophysics Data System (ADS)

Alaghaz, Abdel-Nasser M. A.; Zayed, Mohamed E.; Alharbi, Suliman A.

2015-03-01

The Schiff's base derived from condensation of s-triazole (4-amino-5-mercapto-3-methyl-S-triazole) with pyridine-2-aldehyde and their corresponding Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes have been synthesized. The isolated solid complexes were characterized by elemental analyses, molar conductance, spectral (IR, UV-Vis, 1H NMR, mass), magnetic moment and thermal measurements. The IR spectral data suggest that the ligand coordinate in a tridentate manner (SNN) via the one thiol (SH), one pyridine ring and the azomethine (Cdbnd N) groups. The data show that the complexes have composition of ML2 type. The activation of thermodynamic parameters are calculated using Coats-Redfern, Horowitz-Metzger (HM), and Piloyan-Novikova (PN). The octahedral geometry of the complexes is confirmed using DFT method from DMOL3 calculations and ligand field parameters. Protonation constants of Schiff base and stability constants of their binary metal complexes have been determined potentiometrically in 50% DMSO-water media at 25 °C and ionic strength 0.10 M potassium nitrate. The biological activity of these compounds against various fungi has been investigated.

Simulation of water solutions of Ni 2+ at infinite dilution

NASA Astrophysics Data System (ADS)

Natália, M.; Cordeiro, D. S.; Ignaczak, Anna; Gomes, José A. N. F.

1993-10-01

A new ab initio pair potential is developed to describe the nickel—water interactions in Ni(II) aqueous solutions. Results of Monte Carlo simulations for the Ni(II)(H 2O) 200 system are presented for this pair potential with and without three-body classical polarization terms (the water—water interaction is described by the ab initio MCY potential). The structure of the solution around Ni(II) is discussed in terms of radial distribution functions, coordination numbers and thermal ellipsoids. The results show that the three-body terms have a non-negligible effect on the simulated solution. In fact, the experimental coordination number of six is reproduced with the full potential while a higher value is predicted when the simple pairwise-additive potential is used. The equilibrium NiO distance for the first hydration shell is also dependent on the use of the three-body terms. Comparison of our distribution functions with those obtained by neutron-diffraction experiments shows a reasonable quantitative agreement. Statistical pattern recognition analysis has also been applied to our simulations in order to better understand the local thermal motion of the water molecules around the metal ion. In this way, thermal ellipsoids have been computed (and graphically displayed) for each atom of the water molecules belonging to the Ni(II) first hydration shell. This analysis revealed that the twisting and bending motions are greater than the radial motion, and that the hydrogens have a higher mobility than the oxygens. In addition, a thermodynamic perturbation method has been incorporated in our Monte Carlo procedure in order to compute the free energy of hydration for the Ni(II) ion. Agreement between these results and the experimental ones is also sufficiently reasonable to demonstrate the feasibility of this new potential for the nickel—water interactions.

Syntheses, crystal structures, anticancer activities of three reduce Schiff base ligand based transition metal complexes

NASA Astrophysics Data System (ADS)

Chang, Hui-Qin; Jia, Lei; Xu, Jun; Zhu, Tao-Feng; Xu, Zhou-Qing; Chen, Ru-Hua; Ma, Tie-Liang; Wang, Yuan; Wu, Wei-Na

2016-02-01

Three nickel(II) complexes, [Ni2(L1)2(tren)2(H2O)](ClO4)3 (1), [NiL2(tren)2](ClO4)·2.5H2O (2), [NiL2(tren)2]I·1.5H2O·CH3OH (3) based on amino acid reduced Schiff ligands are synthesized and characterized by physico-chemical and spectroscopic methods. The results show that in all complexes, the amino acid ligand is deprotonated and acts as an anionic ligand. In the dinuclear complex 1, each Ni(II) atom has a distorted octahedron geometry while with different coordination environment. However, the complexes 2 and 3 are mononuclear, almost with the same coordination environment. Furthermore, in vitro experiments are carried out, including MTT assay, Annexin V/PI flow cytometry and western blotting, to assess whether the complexes have antitumor effect. And the results show that all the three complexes have moderate anticancer activity towards human hepatic cancer (HepG2), human cervical cancer (HeLa) and human prostate (PC3) cell lines, in a concentration dependent way. The complex 1 exhibit higher cytotoxicity than the other two complexes and can induce human hepatic cancer cell (HepG2) to cell apoptosis by activating caspase 3.

Aqua­{6,6′-dimeth­oxy-2,2′-[ethane-1,2-diylbis(nitrilo­methyl­idyne)]diphenolato}nickel(II)

PubMed Central

Guo, Zhenghua; Li, Lianzhi; Xu, Tao; Li, Jinghong; Wang, Daqi

2009-01-01

The title complex, [Ni(C18H18N2O4)(H2O)], lies on a mirror plane with the NiII ion coordinated by two N and two O atoms of a tetra­dentate Schiff base ligand and one water O atom in a distorted square-pyramidal enviroment. The –CH2–CH2– group of the ligand is disordered equally over two sites about the mirror plane. The dihedral angle between the mean planes of the two symmetry-related chelate rings is 37.16 (6)°. In the crystal structure, inter­molecular O—H⋯O hydrogen bonds link complex mol­ecules into one-dimensional chains along [100] and these chains are linked, in turn, by very weak inter­molecular C—H⋯O hydrogen bonds into a two-dimensional network. PMID:21577698

A novel coordination polymer of Ni(II) based on 1,3,5-benzenetricarboxylic acid synthesis, characterization, crystal structure, thermal study, and luminescent properties

NASA Astrophysics Data System (ADS)

Saheli, Sania; Rezvani, Alireza

2017-01-01

A new metal-organic framework (MOF) formulated as [Ni(H2btc)(OH)(H2O)2] (1) (H3btc = 1,3,5-benzenetricarboxylic acid) was synthesized using the hydrothermal technique. The complex 1 was characterized by elemental analysis, infrared spectroscopy, and powder X-ray diffraction in addition to single crystal X-ray diffraction. X-ray crystal structural analysis displayed that the compound belonged to the monoclinic space group P21/n with cell parameters a = 6.8658(14) Å, b = 18.849(4) Å, c = 8.5608(17) Å. In the title complex, ligand is linked to metal centers through two μ-oxo bridges and forming a 2D layer which is led to form an interesting geometry. The thermal stability and fluorescence property of 1 have also been investigated.

Synthesis, Characterization, Electrochemical Studies, and In Vitro Antibacterial Activity of Novel Thiosemicarbazone and Its Cu(II), Ni(II), and Co(II) Complexes

PubMed Central

Khan, Salman A.; Asiri, Abdullah M.; Al-Amry, Khalid; Malik, Maqsood Ahmad

2014-01-01

Metal complexes were prepared by the reaction of thiosemicarbazone with CuCl2, NiCl2, CoCl2, Cu(OAc)2, Ni(OAc)2, and Co(OAc)2. The thiosemicarbazone coordinates to metal through the thionic sulfur and the azomethine nitrogen. The thiosemicarbazone was obtained by the thiosemicarbazide with 3-acetyl-2,5-dimethylthiophene. The identities of these compounds were elucidated by IR, 1H, 13C-NMR, and GC-MS spectroscopic methods and elemental analyses. The antibacterial activity of these compounds was first tested in vitro by the disc diffusion assay against two Gram-positive and two Gram-negative bacteria, and then the minimum inhibitory concentration (MIC) was determined by using chloramphenicol as reference drug. The results showed that compound 1.1 is better inhibitor of both types of tested bacteria as compared to chloramphenicol. PMID:24523641

Bis(diethylenetriamine-kappa3N)nickel(II) 5-amino-1,3,4-thiadiazole-2-sulfonamidate chloride monohydrate.

PubMed

Liu-Gonzalez, M; Sanz-Ruiz, F; Chufán, E E; Pedregosa, J C; Borras-Tortonda, J

2001-10-01

In the X-ray crystal structure of the title complex, [Ni(C(4)H(13)N(3))(2)](C(2)H(3)N(4)O(2)S(2))Cl.H(2)O, the coordination polyhedron is composed of non-centrosymmetric [Ni(diethylenetriamine)(2)](2+) cations in which the triamine ligands coordinate to the metal centre as tridentate ligands in a facial position. The Ni(II) ions are linked to six N atoms in an octahedral arrangement, slightly compressed in one extreme. The sulfonamide behaves as a counter-ion instead of as a ligand. Important information about the deprotonated sulfonamide group conformation has been obtained.

Layered transition metal carboxylates: efficient reusable heterogeneous catalyst for epoxidation of olefins.

PubMed

Sen, Rupam; Bhunia, Susmita; Mal, Dasarath; Koner, Subratanath; Miyashita, Yoshitaro; Okamoto, Ken-Ichi

2009-12-01

Layered metal carboxylates [M(malonato)(H(2)O)(2)](n) (M = Ni(II) and Mn(II)) that have a claylike structure have been synthesized hydrothermally and characterized. The interlayer separation in these layered carboxylates is comparable to that of the intercalation distance of the naturally occurring clay materials or layered double hydroxides (LDHs). In this study, we have demonstrated that, instead of intercalating the metal complex into layers of the clay or LDH, layered transition metal carboxylates, [M(malonato)(H(2)O)(2)](n), as such can be used as a recyclable heterogeneous catalyst in olefin epoxidation reaction. Metal carboxylates [M(malonato)(H(2)O)(2)](n) exhibit excellent catalytic performance in olefin epoxidation reaction.

A radical pathway in catecholase activity with nickel(II) complexes of phenol based "end-off" compartmental ligands.

PubMed

Ghosh, Totan; Adhikary, Jaydeep; Chakraborty, Prateeti; Sukul, Pradip K; Jana, Mahendra Sekhar; Mondal, Tapan Kumar; Zangrando, Ennio; Das, Debasis

2014-01-14

Seven dinuclear and one dinuclear based dicyanamide bridged polymeric Ni(II) complexes of phenol based compartmental ligands (HL(1)-HL(4)) have been synthesized with the aim to investigate their catecholase-like activity and to evaluate the most probable mechanistic pathway involved in this process. The complexes have been characterized by routine physicochemical studies as well as by X-ray single crystal structure analyses namely [Ni2(L(2))(SCN)3(H2O)(CH3OH)] (), [Ni2(L(4))(SCN)3(CH3OH)2] (), [Ni2(L(2))(SCN)2(AcO)(H2O)] (), [Ni2(L(4))(SCN)(AcO)2] (), [Ni2(L(2))(N3)3(H2O)2] (), [Ni2(L(4))(N3)3(H2O)2] (), [Ni2(L(1))(AcO)2(N(CN)2)]n () and [Ni2(L(3))(AcO)2(N(CN)2)] (), [SCN = isothiocyanate, AcO = acetate, N3 = azide, and N(CN)2 = dicyanamide anion; L(1-4) = 2,6-bis(R2-iminomethyl)-4-R1-phenolato, where R1 = methyl and tert-butyl, R2 = N,N-dimethyl ethylene for L(1-2) and R1 = methyl and tert-butyl, R2 = 2-(N-ethyl) pyridine for L(3-4)]. A UV-vis spectrophotometric study using 3,5-di-tert butylcatechol (3,5-DTBC) reveals that all the complexes are highly active in catalyzing the aerobic oxidation of (3,5-DTBC) to 3,5-di-tert-butylbenzoquinone (3,5-DTBQ) in methanol medium with the formation of hydrogen peroxide. An EPR study confirms the generation of radicals during the catalysis. Cyclic voltammetric studies of the complexes in the presence and absence of 3,5-DTBC have been performed. Reduction of Ni(II) to Ni(I) and that of the imine bond of the ligand system have been detected at ∼-1.0 V and ∼-1.5 V, respectively. Coulometric separation of the species at -1.5 V followed by the EPR study at 77 K confirms the species as an organic radical and thus most probably reduced imine species. Spectroelectrochemical analysis at -1.5 V clearly indicates the oxidation of 3,5-DTBC and thus suggests that the radical pathway is supposed to be responsible for the catecholase-like activity exhibited by the nickel complexes. The ligand centred radical generation has further been verified by density functional theory calculation.

Selective adsorption of Pb(II), Cd(II), and Ni(II) ions from aqueous solution using chitosan-MAA nanoparticles.

PubMed

Heidari, Aghdas; Younesi, Habibollah; Mehraban, Zahra; Heikkinen, Harri

2013-10-01

Chitosan-MAA nanoparticles (CS-MAA) with an average size of 10-70 nm were prepared by polymerizing chitosan with methacrylic acid in aqueous solution. The physicochemical properties of nanoparticles were investigated using Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), dynamic light scattering (DLS) and nuclear magnetic resonance (NMR). The adsorption of Pb(II), Cd(II) and Ni(II) from aqueous solution on CS-MAA was studied in a batch system. The effects of the solution pH, initial metal concentration, contact time, and dosage of the adsorbent on the adsorption process were examined. The experimental data were analyzed using the pseudo-second-order kinetic equations and the Langmuir, Freundlich and Redlish-Peterson isotherms. The maximum adsorption capacity was 11.30, 1.84, and 0.87 mg/g for Pb(II), Cd(II) and Ni(II) ions, respectively, obtained by the Langmuir isotherm. However, the adsorption isotherm was better explained by the Freundlich rather than by the Langmuir model, as the high correlation coefficients (R(2)>0.99) were obtained at a higher confidence level. Copyright © 2013 Elsevier B.V. All rights reserved.

Oxidative Stress Level in the Testes of Mice and Rats during Nickel Intoxication

PubMed Central

Murawska-Ciałowicz, Eugenia; Bal, Wojciech; Januszewska, Lidia; Zawadzki, Marcin; Rychel, Joanna; Zuwała-Jagiełło, Jolanta

2012-01-01

The genotioxic and carcinogenic effect of nickel probably results from its capacity to produce reactive oxygen species (ROS) and disturb the redox balance. The aim of the study was to find out if rats lacking spermatic protamine 2 are less susceptible to Ni(II) than mice. Consequently, the levels of malondialdehyde + 4 hydroxynonenal (MDA+4HDA) − markers of lipid peroxidation, as well as the level of reduced glutathione (GSH) were measured within the rat and mouse testes. Our results showed that the levels of lipid peroxidation markers were elevated in testicular homogenates of intoxicated mice without any changes in rats. GSH level was lower in the group of intoxicated mice comparing to the control without statistically significant changes in rats' homogenates. Moreover, the level of GSH in the testes of intoxicated mice was lower than in rats. On the basis of our results, it appears that Ni(II) can initiate oxidative stress in the testes of mice but not of rats and can reduce GSH level. Consequently, the antioxidative defense of the testes is reduced. Ni(II) that causes oxidative stress in the testes may also contribute to infertility. PMID:22448131

Removal of copper and nickel from water using nanocomposite of magnetic hydroxyapatite nanorods

NASA Astrophysics Data System (ADS)

Thanh, Dong Nguyen; Novák, Pavel; Vejpravova, Jana; Vu, Hong Nguyen; Lederer, Jaromír; Munshi, Tasnim

2018-06-01

A nanocomposite of magnetic hydroxyapatite was synthesized and tested as an adsorbent for the removal of copper (Cu (II)) and nickel (Ni(II)) from aqueous solution. The adsorbent was investigated using Transmission Electron Microscopy (TEM), Scanning Electron Microscopy equipped with an Energy Dispersive Spectrometer (SEM/EDS), X-ray powder diffraction (XRD) and the Brunauer-Elmet-Teller nitrogen adsorption technique (BET-N2 adsorption). Batch experiments were carried out to determine and compare the adsorption parameters of Fe3O4 and its composite with hydroxyapatite. It was found that the adsorbent is nanostructured and has a specific surface area of 101.2 m2 g-1. The Langmuir adsorption isotherm was found to be an appropriate model to describe the adsorption processes, showing the adsorption capacities of Cu(II) and Ni(II) of 48.78 mg g-1 and 29.07 mg g-1, respectively. In addition to the high adsorption capacity, the fully-adsorbed material could be easily separated from aqueous media using an external magnetic field. These results suggested that the utilization of new hydroxyapatite - Fe3O4 nanocomposite for the removal of Cu(II) and Ni(II) is a promising method in water technology.

Adsorption and co-adsorption of graphene oxide and Ni(II) on iron oxides: A spectroscopic and microscopic investigation.

PubMed

Sheng, Guodong; Huang, Chengcai; Chen, Guohe; Sheng, Jiang; Ren, Xuemei; Hu, Baowei; Ma, Jingyuan; Wang, Xiangke; Huang, Yuying; Alsaedi, Ahmed; Hayat, Tasawar

2018-02-01

Graphene oxide (GO) may strongly interact with toxic metal ions and mineral particles upon release into the soil environment. We evaluated the mutual effects between GO and Ni (Ni(II)) with regard to their adsorption and co-adsorption on two minerals (goethite and hematite) in aqueous phase. Results indicated that GO and Ni could mutually facilitate the adsorption of each other on both goethite and hematite over a wide pH range. Addition of Ni promoted GO co-adsorption mainly due to the increased positive charge of minerals and cation-π interactions, while the presence of GO enhanced Ni co-adsorption predominantly due to neutralization of positive charge and strong interaction with oxygen-containing functional groups on adsorbed GO. Increasing adsorption of GO and Ni on minerals as they coexist may thus reduce their mobility in soil. Extended X-ray absorption fine structure (EXAFS) spectroscopy data revealed that GO altered the microstructure of Ni on minerals, i.e., Ni formed edge-sharing surface species (at R Ni-Fe ∼3.2 Å) without GO, while a GO-bridging ternary surface complexes (at R Ni-C ∼2.49 Å and R Ni-Fe ∼4.23 Å) was formed with GO. These findings improved the understanding of potential fate and toxicity of GO as well as the partitioning processes of Ni ions in aquatic and soil environments. Copyright © 2017 Elsevier Ltd. All rights reserved.

Composition, Characterization and Antibacterial activity of Mn(II), Co(II),Ni(II), Cu(II) Zn(II) and Cd(II) mixed ligand complexes Schiff base derived from Trimethoprim with 8-Hydroxy quinoline

NASA Astrophysics Data System (ADS)

Numan, Ahmed T.; Atiyah, Eman M.; Al-Shemary, Rehab K.; Ulrazzaq, Sahira S. Abd

2018-05-01

New Schiff base ligand 2-((4-amino-5-(3, 4, 5-trimethoxybenzyl) pyrimidin-2-ylimino) (phenyl)methyl)benzoic acid] = [HL] was synthesized using microwave irradiation trimethoprim and 2-benzoyl benzoic acid. Mixed ligand complexes of Mn((II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) are reacted in ethanol with Schiff base ligand [HL] and 8-hydroxyquinoline [HQ] then reacted with metal salts in ethanol as a solvent in (1:1:1) ratio. The ligand [HL] is characterized by FTIR, UV-Vis, melting point, elemental microanalysis (C.H.N), 1H-NMR, 13C-NMR, and mass spectra. The mixed ligand complexes are characterized by infrared spectra, electronic spectra, (C.H.N), melting point, atomic absorption, molar conductance and magnetic moment measurements. These measurements indicate that the ligand [HL] coordinates with metal (II) ion in a tridentate manner through the oxygen and nitrogen atoms of the ligand, octahedral structures are suggested for these complexes. Antibacterial activity of the ligands [HL], [HQ] and their complexes are studied against (gram positive) and (gram negative) bacteria.

Novel thiourea derivative and its complexes: Synthesis, characterization, DFT computations, thermal and electrochemical behavior, antioxidant and antitumor activities

NASA Astrophysics Data System (ADS)

Yeşilkaynak, Tuncay; Muslu, Harun; Özpınar, Celal; Emen, Fatih Mehmet; Demirdöğen, Ruken Esra; Külcü, Nevzat

2017-08-01

A novel thiourea derivative, N-((2-chloropyridin-3-yl)carbamothioyl) thiophene-2-carboxamide,C11H8ClN3OS2 (HL) and its Co(II), Ni(II) and Cu(II) complexes (ML2 type) were prepared and characterized by elemental analysis, FT-IR,1H NMR and HR-MS methods. The crystal structure of HL was also investigated by single crystal X-ray diffraction study. The HL crystallizes in the orthorhombic crystal system with P 21 21 21 space group, Z = 4, a = 3.8875(3) Å, b = 14.6442(13) Å, c = 21.8950(19) Å. The [ML2] complex structures were optimized by using B97D/TZVP level. Molecular orbitals of HL ligand were calculated at the same level. Thermal and electrochemical behaviors of the complexes were investigated. Anticancer and antioxidant activities of the complexes were also investigated. Antioxidant activities were determined by using DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2‧-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) assays. Anticancer activities were studied via MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay in MCF-7 (Michigan Cancer Foundation-7) breast cancer cells.

Transition metal complexes of a new 15-membered [N5] penta-azamacrocyclic ligand with their spectral and anticancer studies

NASA Astrophysics Data System (ADS)

El-Boraey, Hanaa A.; Serag El-Din, Azza A.

2014-11-01

Novel penta-azamacrocyclic 15-membered [N5] ligand [L] i.e. 1,5,8,12-tetetraaza-3,4: 9,10-dibenzo-6-ethyl-7-methyl-1,12-(2,6-pyrido)cyclopentadecan-5,7 diene-2,11-dione and its transition metal complexes with Co(II), Ni(II), Cu(II), Ru(III) and Pd(II) have been synthesized and structurally characterized by elemental analysis, spectral, thermal as well as magnetic and molar conductivity measurements. On basis of IR, MS, UV-Vis 1H NMR and EPR spectral studies an octahedral geometry has been proposed for all complexes except Co(II), Cu(II) nitrate complexes and Pd(II) chloride complex that adopt tetrahedral, square pyramidal and square planar geometries, respectively. The antitumor activity of the synthesized ligand and some complexes against human breast cancer cell lines (MCF-7) and human hepatocarcinoma cell lines (HepG2) has been studied. The complexes (IC50 = 2.04-9.7, 2.5-3.7 μg/mL) showed potent antitumor activity comparable with their ligand (IC50 = 11.7, 3.45 μg/mL) against the above mentioned cell lines, respectively. The results evidently show that the activity of the ligand becomes more pronounced and significant when coordinated to the metal ion.

Synthesis and characterization of a series of transition metal complexes with a new symmetrical polyoxaaza macroacyclic Schiff base ligand: X-ray crystal structure of cobalt(II) and nickel(II) complexes and their antibacterial properties

NASA Astrophysics Data System (ADS)

Keypour, Hassan; Shayesteh, Maryam; Rezaeivala, Majid; Chalabian, Firoozeh; Valencia, Laura

2013-01-01

A new symmetrical [N4O2] hexadentate Schiff base ligand, (E)-N-(pyridin-2-ylmethylene)-2-(3-(2-((E)-pyridin-2-lmethyleneamino)phenoxy)naphthalen-2-yloxy)benzenamine, abbreviated to L, and its complexes of Ni(II), Cu(II), Zn(II), Co(II), Cd(II) and Mn(II) have been synthesized in the presence of metal ions. The complexes were structurally characterized by elemental analyses, IR, UV-Vis, NMR and molar conductivity. The crystal structures of two complexes, [NiL(ONO2)2]·2H2O and [CoLCl2]CH3OH·0.5H2O, have been determined by a single crystal X-ray diffraction study. In these complexes, the ligand is coordinated in a neutral form via pyridine and azomethine nitrogen atoms. The metal ions complete their six coordination with two coordinated nitrate or chloride ions, forming a distorted octahedral geometry. The synthesized compounds have antibacterial activity against the three Gram-positive bacteria: Enterococcus faecalis, Bacillus cereus and Staphylococcus epid and also against the three Gram-negative bacteria: Citrobacter freundii, Enterobacter aerogenes and Salmonella typhi. The activity data show that the complexes are more potent antibacterials than the parent Schiff base.

Spectral characterization, crystal structures and biological activities of iminodiacetate ternary complexes

NASA Astrophysics Data System (ADS)

Shahid, M.; Anjuli; Tasneem, Sana; Mantasha, I.; Ahamad, M. Naqi; Sama, Farasha; Fatma, Kehkeshan; Siddiqi, Zafar A.

2017-10-01

The ternary complexes with stoichiometry [M(imda)(bipy)]·6H2O (M = Cu) and [M(imda)(bipy)(H2O)]·4H2O (M = Ni, Co and Mn) where H2imda = iminodiacetic acid and bipy = 2,2‧-bipyridine, are prepared and characterized to exploit as novel antimicrobial agents and SOD mimics. The chemical structures were elucidated by IR, FAB-Mass, 1H, 13C NMR, EPR and spectral techniques. Single crystal X-ray and spectral studies of the complexes (1) and (2) have confirmed a square pyramidal geometry around Cu(II) ion while a saturated six coordinate (distorted octahedral) geometry around the Ni(II), Co(II) and Mn(II) ions due to the additional coordination from water. A supramolecular network is formed by extensive H-bonding in complex (1). The supramolecular assembly in complex (1) is additionally consolidated via the existence of unusual cyclic hexameric water clusters. The antimicrobial activities for the present complexes have been examined against Escherichia coli (K-12), Bacillus subtilis (MTC-121), Staphylococcus aureus (IOASA-22), Salmonella typhymurium (MTCC-98), Candida albicans, Aspergillus fumigatus and Penicillium marneffei. The superoxide dismutase (SOD) activity of the Cu(II) complex (1) is also assessed employing nitrobluetetrazolium (NBT) assay.

Citrate, in collaboration with a guanidinium ion, as a generator of cubane-like complexes with a range of metal cations: synthesis, structures, and magnetic properties of [C(NH2)3]8[(M(II))4(cit)4].8H2O (M = Mg, Mn, Fe, Co, Ni, and Zn; cit = Citrate).

PubMed

Hudson, Timothy A; Berry, Kevin J; Moubaraki, Boujemaa; Murray, Keith S; Robson, Richard

2006-05-01

Aqueous reaction mixtures containing citric acid, guanidinium carbonate, and a range of metal cations (Mg2+, Mn2+, Fe2+, Co2+, Ni2+, and Zn2+) at room temperature give crystalline products of composition [C(NH2)3]8[(M(II))4(cit)4].8H2O (cit = citrate). In all cases, the crystals are suitable for single-crystal X-ray diffraction studies, which reveal that the compounds are isostructural (space group P4(2)/n; a approximately 16.2 A, and c approximately 11.5 A). As was intended, cubane-like [M4(cit)4]8- complex anions are present. The individual citrate units are chiral, but each cubane unit contains two of one hand and two of the other, related around an S4 axis. The cubane units are involved in no less than 40 H-bonding interactions with guanidinium cations and lattice water molecules. Detailed susceptibility and magnetization studies show that the intracluster magnetic coupling within the Mn(II), Fe(II), Co(II), and Ni(II) cubanes is very weak in all cases with J values of -0.82, -0.43, and -0.09 cm(-1) for the Mn, Fe, and Co species, respectively. A two-J model gave the best agreement with the susceptibility and high-field magnetization data for the Ni(II) case, over the whole temperature range studied, and the sign of the parameters, J12 = -0.3 cm(-1) and J13 = +2.97 cm(-1), correlated with the two Ni-(mu3-O)-Ni angles observed in the cluster structure. All members of the 3d-block [M4(cit)4]8- family have spin ground states, ST, of zero, with the higher ST levels just a few reciprocal centimeters away in energy.

Synthesis and Adsorption Properties of 4-Vinylpyridine and Styrene Copolymer In Situ Immobilized on Silica Surface

NASA Astrophysics Data System (ADS)

Yanovska, E. S.; Vretik, L. O.; Nikolaeva, O. A.; Polonska, Y.; Sternik, D.; Kichkiruk, O. Yu.

2017-03-01

Copolymer of 4-vinylpyridine with styrene was in situ immobilized on silica gel surface via the heterogeneous radical polymerization. Anchorage of the copolymer on the surface layer was confirmed by IR spectroscopy. The quantity of copolymer on the silica gel surface was evaluated as 25.73 wt.% by TG and DSC-MS analysis. "Islet" location of polymer layer on the silica surface was confirmed by the scanning electron microscopy. A high adsorption activity of silica gel with immobilized copolymer towards microquantitatives of Cu(II), Cd(II), Pb(II), Fe(III), and Ni(II) ions in steady state conditions as well as of Ni(II) ions in dynamic regime was found.

Synthesis and Adsorption Properties of 4-Vinylpyridine and Styrene Copolymer In Situ Immobilized on Silica Surface.

PubMed

Yanovska, E S; Vretik, L O; Nikolaeva, O A; Polonska, Y; Sternik, D; Kichkiruk, O Yu

2017-12-01

Copolymer of 4-vinylpyridine with styrene was in situ immobilized on silica gel surface via the heterogeneous radical polymerization. Anchorage of the copolymer on the surface layer was confirmed by IR spectroscopy. The quantity of copolymer on the silica gel surface was evaluated as 25.73 wt.% by TG and DSC-MS analysis. "Islet" location of polymer layer on the silica surface was confirmed by the scanning electron microscopy. A high adsorption activity of silica gel with immobilized copolymer towards microquantitatives of Cu(II), Cd(II), Pb(II), Fe(III), and Ni(II) ions in steady state conditions as well as of Ni(II) ions in dynamic regime was found.

Synthesis, structure, DNA/BSA binding and antibacterial studies of NNO tridentate Schiff base metal complexes

NASA Astrophysics Data System (ADS)

Sakthi, Marimuthu; Ramu, Andy

2017-12-01

A new salicylaldehyde derived 2,4-diiodo-6-((2-phenylaminoethylimino)methyl)phenol Schiff base(L) and its transition metal complexes of the type MLCl where, M = Cu(II), Ni(II), Co(II), Mn(II) and Zn(II) have been synthesized. The coordination mode of Schiff base holding NNO donor atoms with metal ions was well investigated by elemental analysis, ESI-mass as well as IR, UV-vis, CV and NMR spectral studies. The binding efficiency and mode of these complexes with biological macromolecules viz., herring sperm DNA (HS- DNA) and bovine serum albumin (BSA) have been explored through various spectroscopic techniques. The characteristic changes in absorption, emission and, circular dichroism spectra of the complexes with DNA indicate the noticeable interaction between them. From the all spectral information complexes could interact with DNA via non-intercalation mode of binding. The hyperchromisim in absorption band and hypochromisim in emission intensity of BSA with different complex concentrations shown significant information, and the binding affinity value has been predicted from Stern-Volmer plots. Further, all the complexes could cleave the circular plasmid pUC19 DNA efficiently by using an activator H2O2. The ligand and all metal(II) complexes showed good antibacterial activities. The molecular docking studies of the complexes with DNA were performed in order to make a comparison and conclusion with spectral technic results.

Effects of metal on the biochemical properties of Helicobacter pylori HypB, a maturation factor of [NiFe]-hydrogenase and urease.

PubMed

Sydor, Andrew M; Liu, Jenny; Zamble, Deborah B

2011-03-01

The biosyntheses of the [NiFe]-hydrogenase and urease enzymes in Helicobacter pylori require several accessory proteins for proper construction of the nickel-containing metallocenters. The hydrogenase accessory proteins HypA and HypB, a GTPase, have been implicated in the nickel delivery steps of both enzymes. In this study, the metal-binding properties of H. pylori HypB were characterized, and the effects of metal binding on the biochemical behavior of the protein were examined. The protein can bind stoichiometric amounts of Zn(II) or Ni(II), each with nanomolar affinity. Mutation of Cys106 and His107, which are located between two major GTPase motifs, results in undetectable Ni(II) binding, and the Zn(II) affinity is weakened by 2 orders of magnitude. These two residues are also required for the metal-dependent dimerization observed in the presence of Ni(II) but not Zn(II). The addition of metals to the protein has distinct impacts on GTPase activity, with zinc significantly reducing GTP hydrolysis to below detectable levels and nickel only slightly altering the k(cat) and K(m) of the reaction. The regulation of HypB activities by metal binding may contribute to the maturation of the nickel-containing enzymes.

On the biosorption, by brown seaweed, Lobophora variegata, of Ni(II) from aqueous solutions: equilibrium and thermodynamic studies.

PubMed

Basha, Shaik; Jaiswar, Santlal; Jha, Bhavanath

2010-09-01

The biosorption equilibrium isotherms of Ni(II) onto marine brown algae Lobophora variegata, which was chemically-modified by CaCl(2) were studied and modeled. To predict the biosorption isotherms and to determine the characteristic parameters for process design, twenty-three one-, two-, three-, four- and five-parameter isotherm models were applied to experimental data. The interaction among biosorbed molecules is attractive and biosorption is carried out on energetically different sites and is an endothermic process. The five-parameter Fritz-Schluender model gives the most accurate fit with high regression coefficient, R (2) (0.9911-0.9975) and F-ratio (118.03-179.96), and low standard error, SE (0.0902-0.0.1556) and the residual or sum of square error, SSE (0.0012-0.1789) values to all experimental data in comparison to other models. The biosorption isotherm models fitted the experimental data in the order: Fritz-Schluender (five-parameter) > Freundlich (two-parameter) > Langmuir (two-parameter) > Khan (three-parameter) > Fritz-Schluender (four-parameter). The thermodynamic parameters such as DeltaG (0), DeltaH (0) and DeltaS (0) have been determined, which indicates the sorption of Ni(II) onto L. variegata was spontaneous and endothermic in nature.

New Cu (II), Co(II) and Ni(II) complexes of chalcone derivatives: Synthesis, X-ray crystal structure, electrochemical properties and DFT computational studies

NASA Astrophysics Data System (ADS)

Tabti, Salima; Djedouani, Amel; Aggoun, Djouhra; Warad, Ismail; Rahmouni, Samra; Romdhane, Samir; Fouzi, Hosni

2018-03-01

The reaction of nickel(II), copper(II) and cobalt(II) with 4-hydroxy-3-[(2E)-3-(1H-indol-3-yl)prop-2-enoyl]-6-methyl-2H-pyran-2-one (HL) leads to a series of new complexes: Ni(L)2(NH3), Cu(L)2(DMF)2 and Co(L)2(H2O). The crystal structure of the Cu(L)2(DMF)2 complex have been determined by X-ray diffraction methods. The Cu(II) lying on an inversion centre is coordinated to six oxygen atoms forming an octahedral elongated. Additionally, the electrochemical behavior of the metal complexes were investigated by cyclic voltammetry at a glassy carbon electrode (GC) in CH3CN solutions, showing the quasi-reversible redox process ascribed to the reduction of the MII/MI couples. The X-ray single crystal structure data of the complex was matched excellently with the optimized monomer structure of the desired compound; Hirschfeld surface analysis supported the packed crystal lattice 3D network intermolecular forces. HOMO/LUMO energy level and the global reactivity descriptors quantum parameters are also calculated. The electrophilic and nucleophilic potions in the complex surface are theoretically evaluated by molecular electrostatic potential and Mulliken atomic charges analysis.

Structural, spectral and biological studies of binuclear tetradentate metal complexes of N 3O Schiff base ligand synthesized from 4,6-diacetylresorcinol and diethylenetriamine

NASA Astrophysics Data System (ADS)

Emara, Adel A. A.

2010-09-01

The binuclear Schiff base, H 2L, ligand was synthesized by reaction of 4,6-diacetylresorcinol with diethylenetriamine in the molar ratio 1:2. The coordination behavior of the H 2L towards Cu(II), Ni(II), Co(II), Zn(II), Fe(III), Cr(III), VO(IV) and UO 2(VI) ions has been investigated. The elemental analyses, magnetic moments, thermal studies and IR, electronic, 1H NMR, ESR and mass spectra were used to characterize the isolated ligand and its metal complexes. The ligand acts as dibasic with two N 3O-tetradentate sites and can coordinate with two metal ions to form binuclear complexes. The bonding sites are the nitrogen atoms of the azomethine and amine groups and the oxygen atoms of the phenolic groups. The metal complexes exhibit either square planar, tetrahedral, square pyramid or octahedral structures. The Schiff base ligand and its metal complexes were tested against four pathogenic bacteria ( Staphylococcus aureus and Streptococcus pyogenes) as Gram-positive bacteria, and ( Pseudomonas fluorescens and Pseudomonas phaseolicola) as Gram-negative bacteria and two pathogenic fungi ( Fusarium oxysporum and Aspergillus fumigatus) to assess their antimicrobial properties. Most of the complexes exhibit mild antibacterial and antifungal activities against these organisms.

Highly planar diarylamine-fused porphyrins and their remarkably stable radical cations† †Electronic supplementary information (ESI) available. CCDC 1469154–1469160. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c6sc02721k Click here for additional data file. Click here for additional data file.

PubMed Central

Fukui, Norihito; Cha, Wonhee; Shimizu, Daiki; Oh, Juwon

2017-01-01

Oxidative fusion reactions of meso-phenoxazino Ni(ii) porphyrin were found to be temperature dependent, giving rise to either a doubly phenylene-fused product at room temperature or a singly phenoxazine-fused product at 70 °C. The latter was further oxidized to a doubly phenoxazine-fused Ni(ii) porphyrin, which was subsequently converted to the corresponding free base porphyrin and Zn(ii) porphyrin. Compared to previously reported diphenylamine-fused porphyrins that displayed a molecular twist, doubly phenoxazine-fused porphyrins exhibited distinctly different properties owing to their highly planar structures, such as larger fluorescence quantum yields, formation of an offset face-to-face dimer both in solution and the solid state, and the generation of a mixed-valence π-radical cation dimer upon electrochemical oxidation. One-electron oxidation of the phenoxazine-fused Ni(ii) porphyrin with Magic Blue gave the corresponding radical cation, which was certainly stable and could be isolated by separation over a silica gel column but slowly chlorinated at the reactive β-positions in the solid state. This finding led to us to examine β,β′-dichlorinated phenoxazine-fused and diphenylamine-fused Ni(ii) porphyrins, which, upon treatment with Magic Blue, provided remarkably stable radical cations to an unprecedented level. It is actually possible to purify these radical cations by silica gel chromatography, and they can be stored for over 6 months without any sign of deterioration. Moreover, they exhibited no degradation even after the CH2Cl2 solution was washed with water. However, subtle structural differences (planar versus partly twisted) led to different crystal packing structures and solid-state magnetic properties. PMID:28451165

The Effects of Select Histidine to Cysteine Mutations on Transcriptional Regulation by E. coli RcnR‡

PubMed Central

Higgins, Khadine A.; Hu, Heidi Q.; Chivers, Peter T.; Maroney, Michael J.

2013-01-01

The RcnR metalloregulator represses the transcription of the Co(II) and Ni(II) exporter, RcnAB. Previous studies have shown that Co(II) and Ni(II) bind to RcnR in six-coordinate sites, resulting in de-repression. Here, the roles of His60, His64, and His67 in specific metal recognition are examined. His60 and His64 correspond to ligands that are important for Cu(I) binding in the homologous Cu(I)-responsive metalloregulator, CsoR. These residues are known to be functionally important in RcnR transcriptional regulation. XAS was used to examine the structure of bound cognate and non-cognate metal ions, and lacZ reporter assays were used to assess the transcription of rcnA in response to metal binding in the three His → Cys mutations, H60C, H64C and H67C. These studies confirm that both Ni(II) and Co(II) use His64 as a ligand. H64C-RcnR is also the only known mutation that retains a Co(II) response while eliminating the response to Ni(II) binding. XAS data indicate that His60 and His67 are potential Co(II) ligands. The effects of the mutations of His60, His64, and His67 residues on the structures of the non-cognate metal ions (Zn(II) and Cu(I)) reveals that these residues have distinctive roles in binding non-cognate metals. None of the His → Cys mutants in RcnR confer any response to Cu(I) binding, including H64C-RcnR, where the ligands involved in Cu(I) binding in CsoR are present. These data indicate that while the secondary, tertiary and quaternary structures of CsoR and RcnR are quite similar, small changes in primary sequence reveal that the specific mechanisms involved in metal recognition are quite different. PMID:23215580

Coordination Polymers Containing 1,3-Phenylenebis-((1H-1,2,4-triazol-1-yl)methanone) Ligand: Synthesis and ε-Caprolactone Polymerization Behavior.

PubMed

Bello-Vieda, Nestor J; Murcia, Ricardo A; Muñoz-Castro, Alvaro; Macías, Mario A; Hurtado, John J

2017-11-10

The reaction of isophthaloyl dichloride with 1 H -1,2,4-triazole afforded the new ligand 1,3-phenylenebis(1,2,4-triazole-1-yl)methanone ( 1 ). A series of Co(II), Cu(II), Zn(II) and Ni(II) complexes were synthesized using 1 and then characterized by melting point analysis, elemental analysis, theoretical calculations, thermogravimetric analysis, X-ray powder diffraction, nuclear magnetic resonance, infrared and Raman spectroscopy. Experimental and computational studies predict the formation of coordination polymers (CPs). The cobalt and copper CPs and zinc(II) complex were found to be good initiators for the ring-opening polymerization of ε-caprolactone (CL) under solvent-free conditions. ¹H-NMR analysis showed that the obtained polymers of CL were mainly linear and had terminal hydroxymethylene groups. Differential scanning calorimetry showed that the obtained polycaprolactones had high crystallinity, and TGA showed that they had decomposition temperatures above 400 °C. These results provide insight and guidance for the design of metal complexes with potential applications in the polymerization of CL.

Effects of 3d-4f magnetic exchange interactions on the dynamics of the magnetization of Dy(III)-M(II)-Dy(III) trinuclear clusters.

PubMed

Pointillart, Fabrice; Bernot, Kevin; Sessoli, Roberta; Gatteschi, Dante

2007-01-01

[{Dy(hfac)(3)}(2){Fe(bpca)(2)}] x CHCl(3) ([Dy(2)Fe]) and [{Dy(hfac)(3)}(2){Ni(bpca)(2)}]CHCl(3) ([Dy(2)Ni]) (in which hfac(-)=1,1,1,5,5,5-hexafluoroacetylacetonate and bpca(-)=bis(2-pyridylcarbonyl)amine anion) were synthesized and characterized. Single-crystal X-ray diffraction shows that [Dy(2)Fe] and [Dy(2)Ni] are linear trinuclear complexes. Static magnetic susceptibility measurements reveal a weak ferromagnetic exchange interaction between Ni(II) and Dy(III) ions in [Dy(2)Ni], whereas the use of the diamagnetic Fe(II) ion leads to the absence of magnetic exchange interaction in [Dy(2)Fe]. Dynamic susceptibility measurements show a thermally activated behavior with the energy barrier of 9.7 and 4.9 K for the [Dy(2)Fe] and [Dy(2)Ni] complexes, respectively. A surprising negative effect of the ferromagnetic exchange interaction has been found and has been attributed to the structural conformation of these trinuclear complexes.

Six complexes based on bis(imidazole/benzimidazole-1-yl)pyridazine ligands: Syntheses, structures and properties

NASA Astrophysics Data System (ADS)

Wang, Xin-Fang; Du, Ceng-Ceng; Zhou, Sheng-Bin; Wang, Duo-Zhi

2017-01-01

Herein we reported six new Ni(II)/Cu(II)/Zn(II) complexes, namely, [Ni(L1)4(OH)2] (1), [Cu(L1)4(OH)2] (2), [Cu(L1)2(SiF6)]n (3), {[Cu(L2)(HCOO)2]·H2O·CH3OH}n (4), [Ni(L2)2(NO3)2]n (5) and {[Zn(L2)Cl2]·DMF}n (6) (L1 = 3,6-bis(imidazole-1-yl)pyridazine, L2 = 3,6-bis(benzimidazole-1-yl)pyridazine), which were characterized by single-crystal X-ray diffraction, elemental analysis, IR, PXRD. These complexes have been successfully constructed under interface diffusion process, heating reflux or hydrothermal conditions. The structures of 1 and 2 are mononuclear complexes. Complex 3 exhibits a 6-connected 3D topology network with the Schläfli symbol of (412·63). In complex 4, two Cu(II) were connected through two HCOO- anions to form dinuclear structure unit, which is arranged into a 1D ladder-like structure by μ2-L2 ligands. Complexes 5 and 6 are 1D zigzag chains connected by L2 ligands, but the Ni(II) ion is six-coordinated in 5 and the Zn(II) ion is four-coordinated in 6. Moreover, the solid-state luminescence property and UV-vis diffuse reflection spectrum of complex 6 have been investigated and discussed.

Screening the efficient biological prospects of triazole allied mixed ligand metal complexes

NASA Astrophysics Data System (ADS)

Utthra, Ponnukalai Ponya; Kumaravel, Ganesan; Raman, Natarajan

2017-12-01

Triazole appended mixed ligand complexes (1-8) of the general formula [ML (bpy/phen)2]Cl2, where M = Cu(II), Co(II), Ni(II) and Zn(II), L = triazole appended Schiff base (E)sbnd N-(4-nitrobenzylidene)-1H-1,2,4-triazol-3-amine and bpy/phen = 2,2‧-bipyridine/1,10-phenanthroline, have been synthesized. The design and synthesis of this elaborate ligand has been performed with the aim of increasing stability and conjugation of 1,2,4 triazole, whose Schiff base derivatives are known as biologically active compounds thereby exploring their DNA binding affinity and other biological applications. The compounds have been comprehensively characterized by elemental analysis, spectroscopic methods (IR, UV-Vis, EPR, 1H and 13C NMR spectroscopy), ESI mass spectrometry and magnetic susceptibility measurements. The complexes were found to exhibit octahedral geometry. The complexes 1-8 were subjected to DNA binding techniques evaluated using UV-Vis absorption, CV, CD, Fluorescence spectroscopy and hydrodynamic measurements. Complex 5 showed a Kb value of 3.9 × 105 M-1. The DNA damaging efficacy for the complexes was observed to be high compared to the ligand. The antimicrobial screening of the compounds against bacterial and fungal strains indicates that the complexes possess excellent antimicrobial activity than the ligand. The overall biological activity of the complexes with phen as a co-ligand possessed superior potential than the ligand.

Synthesis, characterization and biocidal activities of heterobimetallic complexes having tin(IV) as a padlock

NASA Astrophysics Data System (ADS)

Husain, Ahmad; Nami, Shahab A. A.; Siddiqi, K. S.

2010-04-01

A mononuclear precursor complex, [(CH 3) 2Sn(tpdtc)] and several of its heterobimetallic derivatives of the type, [(CH 3) 2Sn(tpdtc)]MCl 2 have been synthesized by the simple addition reaction of transition metal chlorides, MCl 2· nH 2O where tpdtc = tetraethylenepentamine bis(dithiocarbamate) anion, M = Fe(II), Co(II), Ni(II), Cu(II) and Zn(II). The synthesized complexes have been systematically characterized by the physicochemical and spectroscopic techniques. A square-pyramidal geometry has been proposed for all the transition metal atoms with chloride ions occupying the axial while the three nitrogen atoms occupying the equatorial positions. A symmetrical bidentate coordination has been observed for the dithiocarbamato moiety leading to the formation of 18 member cavity. The thermal studies reveal that the mononuclear complex decomposes in three stages while its heterobimetallic analog exhibits a simple two-stage profile. The conductivity measurement data (1 mmol solution) implies a non-electrolytic behavior for all the complexes as evident by their low conductivity values obtained at room temperature. The heterobimetallic complexes have also been tested against the bacterial ( Escherichia coli and Pseudomonas aeruginosa) and antifungal strains ( Aspergillus niger and Fusarium oxysporum). All the complexes were found to be active against the test organisms and maximum activity was found for [(CH 3) 2Sn(tpdtc)]CuCl 2 complex.

Studies on DNA binding behaviour of biologically active transition metal complexes of new tetradentate N2O2 donor Schiff bases: inhibitory activity against bacteria.

PubMed

Sobha, S; Mahalakshmi, R; Raman, N

2012-06-15

A series of Cu(II), Ni(II) and Zn(II) complexes of the type ML have been synthesized with Schiff bases derived from o-acetoacetotoluidide, 2-hydroxybenzaldehyde and o-phenylenediamine/1,4-diaminobutane. The complexes are insoluble in common organic solvents but soluble in DMF and DMSO. The measured molar conductance values in DMSO indicate that the complexes are non-electrolytic in nature. All the six metal complexes have been fully characterized with the help of elemental analyses, molecular weights, molar conductance values, magnetic moments and spectroscopic data. The analytical data helped to elucidate the structure of the metal complexes. The Schiff bases are found to act as tetradentate ligands using N(2)O(2) donor set of atoms leading to a square-planar geometry for the complexes around all the metal ions. The binding properties of metal complexes with DNA were investigated by absorption spectra, viscosity measurements and cyclic voltammetry. Detailed analysis reveals that the metal complexes intercalate into the DNA base stack as intercalators. All the metal complexes cleave the pUC19 DNA in presence of H(2)O(2.) The Schiff bases and their complexes have been screened for their antibacterial activity against five bacterial strains (Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus epidermidis, Klebsiella pneumoniae) by disk diffusion method. All the metal complexes have potent biocidal activity than the free ligands. Copyright © 2012 Elsevier B.V. All rights reserved.

Spectral, biological screening of metal chelates of chalcone based Schiff bases of N-(3-aminopropyl) imidazole.

PubMed

Kalanithi, M; Rajarajan, M; Tharmaraj, P; Sheela, C D

2012-02-15

Tridentate chelate complexes of Co(II), Ni(II), Cu(II) and Zn(II) have been synthesized from the chalcone based ligands 2-[1-(3-(1H-imidazol-1-yl)propylimino)-3-(phenylallyl)]phenol(HL(1)), 2-[1-(3-(1H-imidazol-1-yl)propylimino)-3-p-tolylallyl]phenol(HL(2)), 2-[1-(3-(1H-imidazol-1-yl)propylimino)-3-4-nitrophenylallyl]phenol(HL(3)). Microanalytical data, UV-vis spectrophotometric method, magnetic susceptibility measurements, IR, 1H NMR, Mass, and EPR techniques were used to characterize the structure of chelates. The electronic absorption spectra and magnetic susceptibility measurements suggest a distorted square planar geometry for the copper(II) ion. The other metal complexes show distorted tetrahedral geometry. The coordination of the ligands with metal(II) ions was further confirmed by solution fluorescence spectrum. The antimicrobial activity of the ligands and metal(II) complexes against the species Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Candida albigans and Aspergillus niger has been carried out and compared. The electrochemical behavior of copper(II) complex is studied by cyclic voltammetry. Copyright © 2011 Elsevier B.V. All rights reserved.

Isolation and Characterization of FORMATE/NI(CYCLAM)^{2+} Complexes with Cryogenic Ion Vibrational Predissociation

NASA Astrophysics Data System (ADS)

Wolk, Arron B.; Fournier, Joseph A.; Wolke, Conrad T.; Johnson, Mark A.

2013-06-01

Transition metal-based organometallic catalysts are a promising means of converting CO_{2} to transportable fuels. Ni(cyclam)^{2+}(cyclam = 1,4,8,11-tetraazacyclotetradecane), a Ni^{II} complex ligated by four nitrogen centers, has shown promise as a catalyst selective for CO_{2} reduction in aqueous solutions. The cyclam ligand has four NH hydrogen bond donors that can adopt five conformations, each offering distinct binding motifs for coordination of CO_{2} close to the metal center. To probe the ligand conformation and the role of hydrogen bonding in adduct binding, we extract Ni(cyclam)^{2+} complexes with the formate anion and some of its analogs from solution using electrospray ionization, and characterize their structures using cryogenic ion vibrational predissociation spectroscopy. Using the signature vibrational features of the embedded carboxylate anion and the NH groups as reporters, we compare the binding motifs of oxalate, benzoate, and formate anions to the Ni(cyclam)^{2+} framework. Finally, we comment on possible routes to generate the singly charged Ni(cyclam)^{+} complex, a key intermediate that has been invoked in the catalytic CO_{2} reduction cycle, but has never been isolated through ion processing techniques.

Synthesis of Optode Thin Layer using Sol Gel Hybrid of Trietoxysiloxane monomer and 3-(Trimethoxysilyl) Propilamine with Ionophore 4-(2-Pyridilazo)-1,3-Benzenadiol (PAR)

NASA Astrophysics Data System (ADS)

Wahyuningsih, S.; Rahmawati, F.; Kamal, S.; Slamet, S.; Yunianto, M.; Rahmawati, P.; Aini, F. N.

2018-03-01

Optode (Optical sensors) is one of the modern chemical sensors in the field of analytical chemistry that has utilized of inorganic polymers. The optode based on MLCT (Metal to Ligand Charge Transfer) (or MMLL’CT, Mixing Metal-Ligand to Ligand Charge Transfer) or LMCT (Ligand to Metal Charge Transfer) phenomenons have beed generated from oktyltrietxysilane, aminopropyltrimethoxysilane and 4-(2-pyrydilazo) resorcinol (abbreviated as OTES-APTS-PAR) for Cu(II), Cr(III), Ni(II), Fe(III), Cd(II), and Zn(II) ions target. The syntheses of thin layer optode were performed by sol gel method followed by evaporation in glass substrat. The formation of 4-(2-pyrydilazo) resorcinol complexes with ions target have gained strong absorption spectras in visible region because of charge transfer phenomenons. The optical sensor of OTES-APTS-PAR was analysed thermal properties using Differential Thermal Analysis (DTA). DTA thermogram showed a glass transition peaks at a temperature of 315.5 °C. Fourier transform Infrared (FTIR) spectras have showed that the optode materials consisted NH aryl groups indicated IR absorption at 1577.7 cm-1 and also –CH aromatic at 1469.0 cm-1. Synthesized optode materials have strong broad visible absorption with the maximum wavelengths (λmax) = 405 nm and 508.5 nm, respectively. This material have excellent optical responds to several metal ions such as Cu(II), Cr(III), Ni(II), Fe(III), Cd(II), and Zn(II) that was showed from huge Δλmax and the increase of Ktotal

Synthesis, characterization and analytical applications of Ni(II)-ion imprinted polymer

NASA Astrophysics Data System (ADS)

Singh, D. K.; Mishra, Shraddha

2010-10-01

Ion recognition-based separation techniques have received much attention because of their high selectivity for target ions. In this study, we have prepared a novel ion imprinted polymer (IIP) to remove nickel ions with high selectivity. The imprinted polymer was prepared by copolymerization of 2-hydroxy ethyl methacrylate (HEMA) with nickel vinylbenzoate complex in the presence of ethylene glycol dimethacrylate (EGDMA) as a crosslinker. The polymerization was carried out in bulk with free radical initiation using 2-methoxy ethanol as a solvent and porogen. The adsorbed nickel was completely eluted with 15 mL of 1 M HCl. Control polymer was also prepared by similar experimental conditions without using imprint ion. The above synthesized polymers were characterized by surface area measurements, FT-IR, microanalysis and SEM analysis. The adsorption capacity of IIP and CP was found to be 1.51 and 0.65 mmol g -1, respectively. The optimal pH for quantitative enrichment was 6.5. Nature of eluent, eluent concentration and eluent volume were also studied. The relative selectivity factor ( αr) values of Ni(II)/Zn(II), Ni(II)/Cu(II) and Ni(II)/Co(II) were 78.6, 111.1 and 91.6, respectively. Five replicate determinations of 30 μg L -1 of Ni(II) gave a mean absorbance of 0.067 with a relative standard deviation of 1.06%. The lowest concentration determined by GTA-AAS below which the recovery becomes non-quantitative is 6 μg L -1. IIP was tested for removal of Ni(II) from sea water sample.

X-ray absorption spectroscopic evidence for binding of the competitive inhibitor 2-mercaptoethanol to the nickel sites of Jack bean urease. A new Ni-Ni interaction in the inhibited enzyme

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clark, P.A.; Wilcox, D.E.; Scott, R.A.

The enzyme Jack bean urease has been identified as the first nickel-containing metalloenzyme to catalyze the hydrolysis of urea to carbon dioxide and ammonia. Competitive inhibitors such as 2-mercaptoethanol (2-ME) have been shown to dramatically affect the ground-state electronic properties of the urease Ni(II) ions. Results of preliminary structural investigations using x-ray absorption spectroscopy of the nickel salts of urease in its native and 2-ME bound forms are presented. The binding of 2-ME to Ni(II) through the thiolate sulfur is confirmed by the results of this study. 17 refs., 2 figs., 2 tabs.

Pentanuclear Cyanide-Bridged Complexes with High Spin Ground States S=6 and 9: Characterization and Magnetic Properties

NASA Astrophysics Data System (ADS)

Marvilliers, Arnaud; Hortholary, Cédric; Rogez, Guillaume; Audière, Jean-Paul; Rivière, Eric; Cano Boquera, Joan; Paulsen, Carley; Villar, Vincent; Mallah, Talal

2001-07-01

Two pentanuclear complexes are obtained from the reaction of hexacyanochromate(III) with one to two molar equivalents of [Ni(H2O)6]2+ and bidentate organic ligands that chelate the metal ion, leaving two coordination sites in cis positions. Even though the crystal structure was not solved, the full characterization supports the formation of pentanuclear discrete species. [Cr(CN)6]2[Ni(HIM2-py)2]3·7H2O, 1, has a ground spin state S=6 owing to the ferromagnetic interaction between CrIII (S=3/2) and NII (S=1). The presence of six organic radicals that couple ferromagnetically with NiII in [Cr(CN)6]2[Ni(IM2-py)2]3·7H2O, 2, leads to an S=9 ground state. A.c. susceptibility measurements below 2K indicate the occurrence of an antiferromagnetic order at 1.5 K in 2.

Tuning the spin ground state in heterononanuclear nickel(II)-copper(II) cylinders with a triangular metallacyclophane core.

PubMed

Dul, Marie-Claire; Ferrando-Soria, Jesús; Pardo, Emilio; Lescouëzec, Rodrigue; Journaux, Yves; Ruiz-García, Rafael; Cano, Joan; Julve, Miguel; Lloret, Francesc; Fabelo, Oscar; Pasán, Jorge; Ruiz-Pérez, Catalina

2010-12-20

Two new heterometallic Ni(II)(n)Cu(II)((9-n)) complexes [n = 1 (2) and 2 (3)] have been synthesized following a multicomponent self-assembly process from a n:(3 - n):2:6 stoichiometric mixture of Ni(2+), Cu(2+), L(6-), and [CuL'](2+), where L and L' are the bridging and blocking ligands 1,3,5-benzenetris(oxamate) and N,N,N',N'',N''-pentamethyldiethylenetriamine, respectively. Complexes 2 and 3 possess a unique cyclindrical architecture formed by three oxamato-bridged trinuclear linear units connected through two 1,3,5-substituted benzenetris(amidate) bridges, giving a triangular metallacyclophane core. They behave as a ferromagnetically coupled trimer of two (2)/one (3) S = (1)/(2) Cu(II)(3) plus one (2)/two (3) S = 0 Ni(II)Cu(II)(2) linear units with overall S = 1 Ni(II)Cu(II)(8) (2) and S = (1)/(2) Ni(II)(2)Cu(II)(7) (3) ground states.

Synthesis, Characterization and Biological Evaluation of Transition Metal Complexes Derived from N, S Bidentate Ligands

PubMed Central

Md Yusof, Enis Nadia; Ravoof, Thahira Begum S. A.; Tiekink, Edward R. T.; Veerakumarasivam, Abhimanyu; Crouse, Karen Anne; Mohamed Tahir, Mohamed Ibrahim; Ahmad, Haslina

2015-01-01

Two bidentate NS ligands were synthesized by the condensation reaction of S-2-methylbenzyldithiocarbazate (S2MBDTC) with 2-methoxybenzaldehyde (2MB) and 3-methoxybenzaldehyde (3MB). The ligands were reacted separately with acetates of Cu(II), Ni(II) and Zn(II) yielding 1:2 (metal:ligand) complexes. The metal complexes formed were expected to have a general formula of [M(NS)2] where M = Cu2+, Ni2+, and Zn2+. These compounds were characterized by elemental analysis, molar conductivity, magnetic susceptibility and various spectroscopic techniques. The magnetic susceptibility measurements and spectral results supported the predicted coordination geometry in which the Schiff bases behaved as bidentate NS donor ligands coordinating via the azomethine nitrogen and thiolate sulfur. The molecular structures of the isomeric S2M2MBH (1) and S2M3MBH (2) were established by X-ray crystallography to have very similar l-shaped structures. The Schiff bases and their metal complexes were evaluated for their biological activities against estrogen receptor-positive (MCF-7) and estrogen receptor-negative (MDA-MB-231) breast cancer cell lines. Only the Cu(II) complexes showed marked cytotoxicity against the cancer cell lines. Both Schiff bases and other metal complexes were found to be inactive. In concordance with the cytotoxicity studies, the DNA binding studies indicated that Cu(II) complexes have a strong DNA binding affinity. PMID:25988384

Synthesis and spectral studies on metal complexes of s-triazine based ligand and non linear optical properties

NASA Astrophysics Data System (ADS)

Shanmugakala, R.; Tharmaraj, P.; Sheela, C. D.

2014-11-01

A series of transition metal complexes of type [ML] and [ML2]Cl2 (where M = Cu(II), Ni(II), Co(II) have synthesized from 2-phenylamino-4,6-dichloro-s-triazine and 3,5-dimethyl pyrazole; their characteristics have been investigated by means of elemental analyses, magnetic susceptibility, molar conductance, IR, UV-Vis, Mass, NMR and ESR spectra. The electrochemical behavior of copper(II) complexes we have studied, by using cyclic voltammetry. The ESR spectra of copper(II) complexes are recorded at 300 K and 77 K and their salient features are appropriately reported. Spectral datas, we found, show that the ligand acts as a neutral tridentate, and coordinates through the triazine ring nitrogen and pyrazolyl ring nitrogen atoms to the metal ion. Evident from our findings, the metal(II) complexes of [ML] type exhibit square pyramidal geometry, and that of [ML2]Cl2 exhibit octahedral geometry. The in vitro antimicrobial activities of the ligand and its complexes are evaluated against Bacillus subtilis, Micrococcus luteus, Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus mutans, Escherichia coli, Enterobacter aerogenes, Klebsiella pneumoniae, Proteus vulgaris, Cryptococcus neoformans, Pseudomonas aeruginosa, Salmonella typhi, Serratia marcescens, Shigella flexneri, Vibrio cholera, Vibris parahaemolyticus, Aspergillus niger, Candida albicans and Penicillium oxalicum by well-diffusion method. The second harmonic generation efficiency of the ligand and its complexes are determined and compared with urea and KDP.

Preparation of thiol-functionalized activated carbon from sewage sludge with coal blending for heavy metal removal from contaminated water.

PubMed

Li, Juan; Xing, Xing; Li, Jiao; Shi, Mei; Lin, Aijun; Xu, Congbin; Zheng, Jianzhong; Li, Ronghua

2018-03-01

Sewage sludge produced from wastewater treatment is a pressing environmental issue. Mismanagement of the massive amount of sewage sludge would threat our valuble surface and shallow ground water resources. Use of activated carbon prepared from carbonization of these sludges for heavy metal removal can not only minimize and stabilize these hazardous materials but also realize resources reuse. In this study, thiol-functionalized activated carbon was synthesized from coal-blended sewage sludge, and its capacity was examined for removing Cu(II), Pb(II), Cd(II) and Ni(II) from water. Pyrolysis conditions to prepare activated carbons from the sludge and coal mixture were examined, and the synthesized material was found to achieve the highest BET surface area of 1094 m 2 /g under 500 °C and 30 min. Batch equilibrium tests indicated that the thiol-functionalized activated carbon had a maximum sorption capacity of 238.1, 96.2, 87.7 and 52.4 mg/g for Pb(II), Cd(II), Cu(II) and Ni(II) removal from water, respectively. Findings of this study suggest that thiol-functionalized activated carbon prepared from coal-blended sewage sludge would be a promising sorbent material for heavy metal removal from waters contaminated with Cu(II), Pb(II), Cd(II) and Ni(II). Copyright © 2017 Elsevier Ltd. All rights reserved.

Synthesis, spectral, thermal and antimicrobial studies on cobalt(II), nickel(II), copper(II), zinc(II) and palladium(II) complexes containing thiosemicarbazone ligand

NASA Astrophysics Data System (ADS)

El-Sawaf, Ayman K.; El-Essawy, Farag; Nassar, Amal A.; El-Samanody, El-Sayed A.

2018-04-01

The coordination characteristic of new N4-morpholinyl isatin-3-thiosemicarbazone (HL) towards Co(II), Ni(II), Cu(II), Zn(II) and Pd(II) has been studies. The structures of the complexes were described by elemental analyses, molar conductivity, magnetic, thermal and spectral (IR, UV-Vis, 1H and 13C NMR and ESR) studies. On the basis of analytical and spectral studies the ligand behaves as monobasic tridentate ONS donor forming two five membered rings towards cobalt, copper and palladium and afforded complexes of the kind [M(L)X], (Mdbnd Co, Cu or Pd; Xdbnd Cl, Br or OAc). Whereas the ligand bound to NiCl2 as neutral tridentate ONS donor and with ZnCl2 as neutral bidentate NS donor. The newly synthesized thiosemicarbazone ligand and some of its complexes were examined for antimicrobial activity against 2 gram negative bacterial strains (Escherichia coli Pseudomonas and aeruginosa), 2 gram positive bacterial strains (Streptococcus pneumoniae and Staphylococcus aureus)} and two Pathogenic fungi (Aspergillus fumigatus and Candida albicans). All metal complexes possess higher antimicrobial activity comparing with the free thiosemicarbazone ligand. The high potent activities of the complexes may arise from the coordination and chelation, which tends to make metal complexes act as more controlling and potent antimicrobial agents, thus hindering the growing of the microorganisms. The antimicrobial results also show that copper bromide complex is better antimicrobial agent as compared to the Schiff base and its metal complexes.

The metamorphosis of heterometallic trinuclear antiferromagnetic complexes into nano-sized superparamagnetic spinels.

PubMed

Vasylenko, Inna V; Gavrylenko, Konstiantyn S; Il'yin, Vladimir G; Golub, Vladimir; Goloverda, Galina; Kolesnichenko, Vladimir; Addison, Anthony W; Pavlishchuk, Vitaly V

2010-05-15

Thermal decomposition of the trinuclear heterometallic oxoacetates [Fe(2)M(μ(3)-O)(CH(3)COO)(6)(H(2)O)(3)] has been used as a single-precursor method for synthesis of the spinel-structured ternary oxides MFe(2)O(4) (M = Mn(II), Co(II), and Ni(II)). This facile process occurring at 320 °C results in the formation of nanocrystalline, (7-20 nm) highly pure stoichiometric ferrites in quantitative yield. The magnetic properties of these nanoparticulate ferrites were studied in the 10-300 K temperature range, revealing superparamagnetic behaviour for the Ni and Mn particles and ferromagnetic behavior for the Co ones at room temperature. Their blocking temperatures follow the order: CoFe(2)O(4) > MnFe(2)O(4) > NiFe(2)O(4).

Copper(II)-rubeanic acid coprecipitation system for separation-preconcentration of trace metal ions in environmental samples for their flame atomic absorption spectrometric determinations.

PubMed

Soylak, Mustafa; Erdogan, Nilgun D

2006-09-21

A simple and facile preconcentration procedure based on the coprecipitation of trace heavy metal ions with copper(II)-rubeanic acid complex has been developed. The analytical parameters including pH, amounts of rubeanic acid, sample volume, etc. was investigated for the quantitative recoveries of Pb(II), Fe(III), Cd(II), Au(III), Pd(II) and Ni(II). No interferic effects were observed from the concomitant ions. The detection limits for analyte ions by 3 sigma were in the range of 0.14 microg/l for iron-3.4 microg/l for lead. The proposed coprecipitation method was successfully applied to water samples from Palas Lake-Kayseri, soil and sediment samples from Kayseri and Yozgat-Turkey.

FT-IR and FT-Raman spectra of cimetidine and its metallocomplexes

NASA Astrophysics Data System (ADS)

Barańska, M.; Proniewicz, L. M.

1999-11-01

We present vibrational spectra of three stable, well-reproducible, polymorphic forms of cimetidine ( cim), a drug which is a powerful histamine H 2-receptor antagonist used in the treatment of peptic ulcer and the Zollinger-Ellison syndrome. Assignments of Raman and IR bands are made using semiempirical methods: MNDO, AM1 and PM3. We also describe the synthesis of Me( cim) 2(ClO 4) 2, where Me=Cu(II), Cd(II), Co(II) and Ni(II), and present their vibrational data. We show that the obtained complexes are isostructural, however a metal ion that occupies a center of octahedral unit introduces some distortions that can be seen in the spectra. We also make tentative assignment of metal-ligand stretching modes observed in low frequency range.

Modulation of the electronic structure and the Ni–Fe distance in heterobimetallic models for the active site in [NiFe]hydrogenase

PubMed Central

Zhu, Wenfeng; Marr, Andrew C.; Wang, Qiang; Neese, Frank; Spencer, Douglas J. E.; Blake, Alexander J.; Cooke, Paul A.; Wilson, Claire; Schröder, Martin

2005-01-01

Reaction of the mononuclear Ni(II) thiolate complexes [Ni(L)] [L, L1, H2L1, bis(2-mercaptoethyl)-1,2-dimercaptoethane; L2, H2L2, N,N′-dimethyl-N,N′-bis(2-mercaptoethyl)-bis(aminoethyl)sulfide] with [FeCp(CO)2I] gives the dithiolate-bridged heterobimetallic species, [Ni(L1)FeCp(CO)]PF6, 1, and [Ni(L2)FeCp]I, 2, respectively. Binding of a Fe(CO)3 fragment via reaction of square-planar [Ni(pdt)(dppe)] (dppe, 1,2-diphenylphosphinoethane; pdt2–, 1,3-propanedithiolate) with Fe3(CO)12 or [Fe(CO)3(BDA)] (BDA, benzylidene acetone) affords diamagnetic [(dppe)Ni(μ-pdt)Fe(CO)3], 3, in which the Ni(II) center is bound tetrahedrally to two thiolate S-donors and to two P-donors. The complex [(dppe)Ni(μ-pdt)Fe(CO)3], 3, reacts in solution via rearrangement to afford [(OC)Ni(μ-dppe)(μ-pdt)Fe(CO)2], 4, in which one P-donor of dppe is bound to Ni and the other to Fe, and a CO ligand has transferred from Fe to Ni. Additionally, the syntheses of 3 and 4 afford the side products [(dppe)Ni(CO)2] and [(OC)3Fe(pdt)Fe(CO)3] together with the trinuclear species [(dppe)(CO)Fe(μ-CO)(μ-pdt)Fe(μ-pdt)Fe(CO)3], 5. Reaction of [Ni(pdt)(dppe)] with [FeCp(CO)2I] in CH2Cl2 affords two products [(dppe)Ni(μ-pdt)FeCp(CO)]PF6, 6, and [(dppe)Ni(pdt)(μ-I)Ni(dppe)]PF6, 7. The complexes 2, 3, and 4 show Ni–Fe distances of 2.539(4), 2.4666(6), and 2.4777(7) Å, respectively, with relatively acute dihedral angles of 79.5–81.8° for the Ni–S2-Fe bridge, thus mimicking the shortened Ni...Fe distance (2.5 Å) and the acute dihedral angle of the Ni–S2–Fe moiety observed in certain active forms of [NiFe]hydrogenase. The role of direct Ni–Fe bonding in these complexes is discussed and linked to electronic structure calculations on [(dppe)Ni(pdt)Fe(CO)3], 3, which confirm the presence of a bent Ni(dz2)-Fe(dz2) σ-bond in a singlet ground state. PMID:16352727

Synthesis, crystal structures and Hirshfeld surface analyses of two new Salen type nickel/sodium heteronuclear complexes

NASA Astrophysics Data System (ADS)

Mahlooji, Niloofar; Behzad, Mahdi; Tarahhomi, Atekeh; Maroney, Michael; Rudbari, Hadi Amiri; Bruno, Giuseppe; Ghanbari, Bahram

2016-04-01

Two new heteronuclear Nickel(II)/Sodium(I) complexes of a side-off compartmental Schiff base ligand were synthesized and characterized by spectroscopic methods. Crystal structures of both of the complexes were also obtained. The Schiff base ligand was synthesized from the condensation of meso-1,2-diphenyl-1,2-ethylenediamine with 2-hydroxy-3-methoxybenzaldehyde. In both of the complexes the Ni(II) ion is coordinated to the inner N2O2 coordination sphere with square-planar geometry and the Na(I) ion is coordinated to the outer O2 O2‧ coordination sphere. In Complex (1) with general formula [Ni(L)Na(CH3OH)(ClO4)] the sodium ion is seven coordinated while in (2) with general formula [{Ni(L)Na(OH2)}2(μ-Ni(CN)4)] the sodium ion is six coordinated. Intermolecular interactions in two studied complexes were analyzed using 3D Hirshfeld surfaces and corresponding 2D fingerprint plots. This analysis showed that the H … H and C … H/H … C contacts for both structures (altogether 67.5% of total Hirshfeld surface area for (1) and 77.6% for (2)) and the O … H/H … O (24.2%) for (1) and the N … H/H … N (8.1%) contacts for (2) were the characteristic intermolecular contacts in the related crystal structures.

Synthesis of metal complexes involving Schiff base ligand with methylenedioxy moiety: spectral, thermal, XRD and antimicrobial studies.

PubMed

Sundararajan, M L; Jeyakumar, T; Anandakumaran, J; Karpanai Selvan, B

2014-10-15

Metal complexes of Zn(II), Cd(II), Ni(II), Cu(II), Fe(III), Co(II), Mn(II) Hg(II), and Ag(I) have been synthesized from Schiff base ligand, prepared by the condensation of 3,4-(methylenedioxy)aniline and 5-bromo salicylaldehyde. All the compounds have been characterized by using elemental analysis, molar conductance, FT-IR, UV-Vis, (1)H NMR, (13)C NMR, mass spectra, powder XRD and thermal analysis (TG/DTA) technique. The elemental analysis suggests the stoichiometry to be 1:1 (metal:ligand). The FT-IR, (1)H NMR, (13)C NMR and UV-Vis spectral data suggest that the ligand coordinate to the metal atom by imino nitrogen and phenolic oxygen as bidentate manner. Mass spectral data further support the molecular mass of the compounds and their structure. Powder XRD indicates the crystalline state and morphology of the ligand and its metal complexes. The thermal behaviors of the complexes prove the presence of lattice as well as coordinated water molecules in the complexes. Melting point supports the thermal stability of all the compounds. The in vitro antimicrobial effects of the synthesized compounds were tested against five bacterial and three fungal species by well diffusion method. Antioxidant activities have also been performed for all the compounds. Metal complexes show more biological activity than the Schiff base. Copyright © 2014 Elsevier B.V. All rights reserved.

Fluconazole and its interaction with metal (II) complexes: SEM, Spectroscopic and antifungal studies.

PubMed

Ali, Mohsin; Ahmed, Mansoor; Ahmed, Shakil; Ali, Syed Imran; Perveen, Samina; Mumtaz, Majid; Haider, Syed Moazzam; Nazim, Urooj

2017-01-01

The human digestive tract contains some 100 trillion cells and thousands of species of micro-organisms may be present as normal flora of this tract as well as other mucocutaneous junctions of the body. Candida specie is the most common organism residing in these areas and can easily invade the internal tissues in cases of loss of host defenses. Modifications of previously existing antifungal agents may provide new options to fight against these species. Inorganic compounds of different antifungals are under investigations. Present study report six complexes of fluconazole with Cu (II)), Fe(II), Cd(II), Co(II), Ni(II) and Mn(II) have been synthesized and characterized by elemental analysis, IR, UV and H-NMR. The elemental analysis and spectroscopic data were found in agreement with the expected values as the metal to ligand value was 1:2 ratios with two chlorides in coordination sphere. The morphology of each complex was studied using scanning electron microscope and compared with fluconazole molecule the flaky-slab rock like particles of pure fluconazole was also observed as reported earlier. However, the complexes of fluconazole were showed different morphology in their micrograph. Fluconazole and its complex derivatives have also been screened in vitro for their antifungal activity against Candida albican and Aspergillus niger by MIC method. The complexes showed varied activity ranging from 2-20%.

A preconcentration method for indirect determination of acrylamide from chips, crackers and cereal-based baby foods using flame atomic absorption spectrometry.

PubMed

Altunay, Nail; Gürkan, Ramazan; Orhan, Ulaş

2016-12-01

Acrylamide is a toxic species for human health, and is a Maillard reaction product which forms spontaneously in heat treatment process of foods. Therefore, a simple, fast and cost-effective method was developed for the indirect determination of acrylamide in processed foods particularly consumed by children. The method is based on ion-pairing of acrylamide with fluorescein (F 2- ) in presence of Ni(II) ions at pH 9.0, and then extraction of the formed ternary complex into micellar phase of poly(ethyleneglycol-mono-p-nonylphenylether) (PONPE 7.5) before analysis by flame atomic absorption spectrometry (FAAS). The ultrasonic-assisted cloud point extraction (UA-CPE) has been used for the preconcentration of acrylamide in the samples prior to its FAAS detection. The matrix matched calibration curve is linear in range of 0.3-150µgkg -1 under optimal reagent conditions (1.75mL of 0.1molL -1 ammonia buffer at pH 9.0, 2.2mgL -1 Ni(II), 4.0×10 -4 molL -1 F 2- , 0.4% (w/v) NH 4 Cl and 0.7% (v/v) PONPE 7.5) with sensitivity enhancement of 160-fold. The proposed method has been validated by assessment of the following parameters; the limits of detection (LOD) and quantification (LOQ) (0.08µgkg -1 and 0.28µgkg -1 , respectively) with a relative standard deviation (RSD%) lower than 6.3%, and extractive recovery higher than 95% for acrylamide spiked at levels of 5 and 25µgkg -1 . The method was successfully applied to the indirect determination of acrylamide in the processed foods and two CRMs with satisfactory results. Copyright © 2016 Elsevier B.V. All rights reserved.

Impact of Weak Agostic Interactions in Nickel Electrocatalysts for Hydrogen Oxidation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klug, Christina M.; O’Hagan, Molly; Bullock, R. Morris

To understand how H2 binding and oxidation is influenced by [Ni(PR2NR'2)2]2+ PR2NR'2 catalysts with H2 binding energies close to thermoneutral, two [Ni(PPh2NR'2)2]2+ (R = Me or C14H29) complexes with phenyl substituents on phosphorous and varying alkyl chain lengths on the pendant amine were studied. In the solid state, [Ni(PPh2NMe2)2]2+ exhibits an anagostic interaction between the Ni(II) center and the α-CH3 of the pendant amine, and DFT and variable-temperature 31P NMR experiments suggest than the anagostic interaction persists in solution. The equilibrium constants for H2 addition to these complexes was measured by 31P NMR spectroscopy, affording free energies of H2 additionmore » (ΔG°H2) of –0.8 kcal mol–1 in benzonitrile and –1.6 to –2.3 kcal mol–1 in THF. The anagostic interaction contributes to the low driving force for H2 binding by stabilizing the four-coordinate Ni(II) species prior to binding of H2. The pseudo-first order rate constants for H2 addition at 1 atm were measured by variable scan rate cyclic voltammetry, and were found to be similar for both complexes, less than 0.2 s–1 in benzonitrile and 3 –6 s–1 in THF. In the presence of exogenous base and H2 , turnover frequencies of electrocatalytic H2 oxidation were measured to be less than 0.2 s–1 in benzonitrile and 4 –9 s–1 in THF. These complexes are slower electrocatalysts for H2 oxidation than previously studied [Ni(PR2NR'2)2]2+ complexes due to a competition between H2 binding and formation of the anagostic interaction. However, the decrease in catalytic rate is accompanied by a beneficial 130 mV decrease in overpotential. This research was supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the U.S. Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences. Computational resources were provided at the National Energy Research Scientific Computing Center (NERSC) at Lawrence Berkeley National Laboratory. Mass spectrometry experiments were performed in the William R. Wiley Environmental Molecular Sciences Laboratory, a DOE national scientific user facility sponsored by the DOE’s Office of Biological and Environmental Research and located and the Pacific Northwest National Laboratory (PNNL). The authors thank Dr. Rosalie Chu for mass spectroscopy analysis. PNNL is operated by Battelle for DOE.« less

Synthesis, interaction with DNA and bovine serum albumin of the transition metal complexes of demethylcantharate and 2-aminobenzothiazole

NASA Astrophysics Data System (ADS)

Zhang, Fan; Lin, Qiu-Yue; Li, Shi-Kun; Zhao, Yu-Ling; Wang, Peng-Peng; Chen, Miao-Miao

2012-12-01

Four new transition metal complexes (Habtz)2[M(DCA)2]·6H2O (M = Co(II) (1), Ni(II) (2), Cu(II) (3), Zn(II) (4); DCA = demethylcantharate, 7-oxabicyclo [2.2.1]heptane-2,3-dicarboxylate, C8H8O5; Habtz = 2-aminobenzothiazole acid, C7H7N2S) were synthesized and characterized by elemental analysis, molar conductance, infrared spectra and thermogravimetric analysis. The coordination number of complex was six. The X-ray diffraction analysis indicated that complex 3 crystallized in the triclinic crystal system with P1¯ space group. The DNA-binding properties of the complexes were investigated by electronic absorption spectra, fluorescence spectra, viscosity measurements. Title complexes could bind to DNA via partial intercalative mode. The Kb of the complexes were 5.33 × 104 (1), 7.04 × 104 (2), 9.91 × 104 (3) and 5.03 × 104 L mol-1 (4). The results of agarose gel electrophoresis showed that Cu(II) complex could cleave pBR322 plasmid DNA via radical-based mechanism. The complexes could quench the intrinsic fluorescence of bovine serum albumin (BSA) through a static quenching with the binding constants Ka of 1.11 × 104 (1), 1.24 × 106 (2), 8.42 × 105 (3) and 1.75 × 104 L mol-1 (4). The complexes had intense antiproliferative activities against human hepatoma cell lines (SMMC7721) and human gastric cancer cells (MGC80-3) lines in vitro. Cu(II) complex had the strongest activity against human gastric cancer cells.

Phosphine-functionalized NHC Ni(ii) and Ni(0) complexes: synthesis, characterization and catalytic properties.

PubMed

Rull, S G; Rama, R J; Álvarez, E; Fructos, M R; Belderrain, T R; Nicasio, M C

2017-06-13

Two families of nickel complexes bearing chelating diphenylphosphine-functionalized NHC ligands [Ni II (ArNHCPPh 2 )(allyl)]Cl 1a (Ar = Mes); 1b, (Ar = 2,6-iPr 2 -C 6 H 3 ) and [Ni 0 (ArNHCPPh 2 )(alkene)] 2a (Ar = 2,6-iPr 2 -C 6 H 3 , alkene = styrene); 2b (Ar = 2,6-iPr 2 -C 6 H 3 , alkene = diethyl fumarate) have been prepared and fully characterized. VT-NMR experiments in solution reveal that the allyl derivatives 1a-b are stereochemically nonrigid. The solid-state structure of the Ni 0 derivative 2b is also reported. These complexes display interesting catalytic properties in various cross-coupling reactions. The precatalyst [Ni 0 (ArNHCPPh 2 )(styrene)] 2a was found to be the most active system. The bulkiness of the N-substituent on the imidazole ring and the low oxidation state of the metal center in 2a accounted for its enhanced catalytic performance. This system catalyzed effectively the coupling of (hetero)aryl chlorides with a range of nucleophiles including Grignard reagents, boronic acids, secondary amines and indoles.

The binuclear nickel center in the A-cluster of acetyl-CoA synthase (ACS) and two biomimetic dinickel complexes studied by X-ray absorption and emission spectroscopy

NASA Astrophysics Data System (ADS)

Schrapers, P.; Mebs, S.; Ilina, Y.; Warner, D. S.; Wörmann, C.; Schuth, N.; Kositzki, R.; Dau, H.; Limberg, C.; Dobbek, H.; Haumann, M.

2016-05-01

Acetyl-CoA synthase (ACS) is involved in the bacterial carbon oxide conversion pathway. The binuclear nickel sites in ACS enzyme and two biomimetic synthetic compounds containing a Ni(II)Ni(II) unit (1 and 2) were compared using XAS/XES. EXAFS analysis of ACS proteins revealed similar Ni-N/O/S bond lengths and Ni-Ni/Fe distances as in the crystal structure in oxidized ACS, but elongated Ni-ligand bonds in reduced ACS, suggesting more reduced nickel species. The XANES spectra of ACS and the dinickel complexes showed overall similar shapes, but less resolved pre-edge and edge features in ACS, attributed to more distorted square-planar nickel sites in particular in reduced ACS. DFT calculation of pre-edge absorption and Kβ2,5 emission features reproduced the experimental spectra of the synthetic complexes, was sensitive even to the small geometry differences in 1 and 2, and indicated low-spin Ni(II) sites. Comparison of nickel sites in proteins and biomimetic compounds is valuable for deducing structural and electronic differences in response to ligation and redox changes.

Thermolysis synthesis of pure phase NiO from novel sonochemical synthesized Ni(II) nano metal-organic supramolecular architecture.

PubMed

Hanifehpour, Younes; Morsali, Ali; Mirtamizdoust, Babak; Joo, Sang Woo; Soltani, Behzad

2017-07-01

Nano-structures of a new supramolecular coordination compound of divalent nickel with the pyrazol (pzH) containing the terminal azide anions, [Ni(pzH) 2 (N 3 ) 2 ] (1), with discrete molecular architecture (DMA) in solid state was synthesized via sonochemical method. The new nanostructure was characterized by scanning electron microscopy, X-ray powder diffraction, IR, and elemental analysis. Compound 1 was structurally characterized by single crystal X-ray diffraction and the single-crystal X-ray data shows that the coordination number of Ni (II) ions is six, (NiN 6 ), with four N-donor atoms from neutral "pzH" ligands and two N-donors from two terminal azide anions. The supramolecular features in these complexes are guided and controlled by weak directional intermolecular interactions. The structure of the title complex was optimized by density functional theory calculations. Calculated structural parameters and IR spectra for the title complex are consistent with the crystal structure. The NiO nanoparticles were obtained by thermolysis of 1 at 180°C with oleic acid as a surfactant. Copyright © 2017 Elsevier B.V. All rights reserved.

Synthesis, characterization and anti-microbial activity of phenylurea-formaldehyde resin (PUF) and its polymer metal complexes (PUF-Mn(II)

NASA Astrophysics Data System (ADS)

Ahamad, Tansir; Alshehri, Saad M.

2012-10-01

Phenylurea-formaldehyde polymer (PUF) was synthesized via polycondensation of phenylurea and formaldehyde in basic medium, its polymer-metal complexes [PUF-M(II)] were prepared with Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) ions. PUF and PUF-M(II) were characterized with magnetic moment measurements, elemental and spectral (UV-visible, FTIR, 1H-NMR, 13C-NMR and ESR) analysis. The thermal behaviors of all the synthesized polymers were carried out using thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The thermal data revealed that all of the PUF-M(II) showed higher thermal stabilities than the PUF and also ascribed that the PUF-Cu(II) showed better thermal stability than the other PUF-M(II). The kinetic parameters such as activation energy, pre-exponential factor etc., were evaluated for these polymer metal complexes using Coats-Redfern equation. In addition, the antimicrobial activity of the synthesized polymers was tested against several microorganisms using agar well diffusion methods. Among all of the PUF-M(II), the antimicrobial activity of the PUF-Cu(II) showed the highest zone of inhibition because of its higher stability constant and may be used in biomedical applications.

Synthesis of Unsupported d(1)-d(x) Oxido-Bridged Heterobimetallic Complexes Containing V(IV): A New Direction for Metal-to-Metal Charge Transfer.

PubMed

Wu, Xinyuan; Huang, Tao; Lekich, Travis T; Sommer, Roger D; Weare, Walter W

2015-06-01

Heterobimetallic complexes composed only of first-row transition metals [(TMTAA)V(IV)═O→M(II)Py5Me2](OTf)2 (TMTAA = 7,16-dihydro-6,8,15,17-tetramethyldibenzo[b,i][1,4,8,11]tetraazacyclotetradecine; Py5Me2 = 2,6-bis(1,1-bis(2-pyridyl)ethyl)pyridine; M = Mn(II), Fe(II), Co(II), Ni(II), Cu(II); OTf = trifluoromethanesulfonate) have been synthesized through a dative interaction between a terminal oxido and M(II) metal centers. This is the first series of V(IV)═O→M(II) heterobimetallic complexes containing an unsupported oxido bridge. Among these five complexes, only V(IV)═O→Fe(II) (3b) has a clear new absorption band upon formation of the dinuclear species (502 nm, ε = 1700 M(-1) cm(-1)). This feature is assigned to a metal-to-metal charge transfer (MMCT) transition from V(IV) to Fe(II), which forms a V(V)-O-Fe(I) excited state. This assignment is supported by electrochemical data, electronic absorption profiles, and resonance Raman spectroscopy and represents the first report of visible-light induced MMCT in a heterobimetallic oxido-bridged molecule where the electron originates on a d(1) metal center.

Fructose-1,6-bisphosphate aldolase (class II) is the primary site of nickel toxicity in Escherichia coli.

PubMed

Macomber, Lee; Elsey, Scott P; Hausinger, Robert P

2011-12-01

Nickel is toxic to all forms of life, but the mechanisms of cell damage are unknown. Indeed, environmentally relevant nickel levels (8 µM) inhibit wild-type Escherichia coli growth on glucose minimal medium. The same concentration of nickel also inhibits growth on fructose, but not succinate, lactate or glycerol; these results suggest that fructose-1,6-bisphosphate aldolase (FbaA) is a target of nickel toxicity. Cells stressed by 8 µM Ni(II) for 20 min lost 75% of their FbaA activity, demonstrating that FbaA is inactivated during nickel stress. Furthermore, overexpression of fbaA restored growth of an rcnA mutant in glucose minimal medium supplemented with 4 µM Ni(II), thus confirming that FbaA is a primary target of nickel toxicity. This class II aldolase has an active site zinc and a non-catalytic zinc nearby. Purified FbaA lost 80 % of its activity within 2 min when challenged with 8 µM Ni(II). Nickel-challenged FbaA lost 0.8 zinc and gained 0.8 nickel per inactivated monomer. FbaA mutants (D144A and E174A) affecting the non-catalytic zinc were resistant to nickel inhibition. These results define the primary site of nickel toxicity in E. coli as the class II aldolase FbaA through binding to the non-catalytic zinc site. © 2011 Blackwell Publishing Ltd.

Genetic and physiological responses of Bacillus subtilis to metal ion stress.

PubMed

Moore, Charles M; Gaballa, Ahmed; Hui, Monica; Ye, Rick W; Helmann, John D

2005-07-01

Metal ion homeostasis is regulated principally by metalloregulatory proteins that control metal ion uptake, storage and efflux genes. We have used transcriptional profiling to survey Bacillus subtilis for genes that are rapidly induced by exposure to high levels of metal ions including Ag(I), Cd(II), Cu(II), Ni(II) and Zn(II) and the metalloid As(V). Many of the genes affected by metal stress were controlled by known metalloregulatory proteins (Fur, MntR, PerR, ArsR and CueR). Additional metal-induced genes are regulated by two newly defined metal-sensing ArsR/SmtB family repressors: CzrA and AseR. CzrA represses the CadA efflux ATPase and the cation diffusion facilitator CzcD and this repression is alleviated by Zn(II), Cd(II), Co(II), Ni(II) and Cu. CadA is the major determinant for Cd(II) resistance, while CzcD protects the cell against elevated levels of Zn(II), Cu, Co(II) and Ni(II). AseR negatively regulates itself and AseA, an As(III) efflux pump which contributes to arsenite resistance in cells lacking a functional ars operon. Our results extend the range of identified effectors for the As(III)-sensor ArsR to include Cd(II) and Ag(I) and for the Cu-sensor CueR to include Ag(I) and, weakly, Cd(II) and Zn(II). In addition to systems dedicated to metal homeostasis, specific metal stresses also strongly induced pathways related to cysteine, histidine and arginine metabolism.

Bivalent transition metal complexes of o-hydroxyacetophenone [N-(3-hydroxy-2-naphthoyl)] hydrazone: Spectroscopic, antibacterial, antifungal activity and thermogravimetric studies

NASA Astrophysics Data System (ADS)

Zaky, R. R.; Ibrahim, K. M.; Gabr, I. M.

2011-10-01

Schiff base complexes of Cu(II), Ni(II) and Zn(II) with the o-hydroxyacetophenone [N-(3-hydroxy-2-naphthoyl)] hydrazone (H 2o-HAHNH) containing N and O donor sites have been synthesized. Both ligand and its metal complexes were characterized by different physicochemical methods, elemental analysis, molar conductivity ( 1H NMR, 13C NMR, IR, UV-visible, ESR, MS spectra) and also thermal analysis (TG and DTG) techniques. The discussion of the outcome data of the prepared complexes indicates that the ligand behave as a bidentate and/or tridentate ligand. The electronic spectra of the complexes as well as their magnetic moments suggest octahedral geometries for all isolated complexes. The room temperature solid state ESR spectrum of the Cu(II) complex shows d x2- y2 as a ground state, suggesting tetragonally distorted octahedral geometry around Cu(II) centre. The molar conductance measurements proved that the complexes are non-electrolytes. The kinetic thermodynamic parameters such as: E#, Δ H#, Δ G#, Δ S# are calculated from the DTG curves, for the [Ni(H O-HAHNH) 2] and [Zn(H 2 O-HAHNH)(OAc) 2]·H 2O complexes using the Coats-Redfern equation. Also, the antimicrobial properties of all compounds were studied using a wide spectrum of bacterial and fungal strains. The [Cu(H o-HAHNH)(OAc)(H 2O) 2] complex was the most active against all strains, including Aspergillus sp., Stemphylium sp. and Trichoderma sp. Fungi; E. coli and Clostridium sp. Bacteria.

Green synthesis of nano sized transition metal complexes containing heterocyclic Schiff base: Structural and morphology characterization and bioactivity study

NASA Astrophysics Data System (ADS)

Jawoor, Shailaja S.; Patil, Sangamesh A.; Kumbar, Mahantesh; Ramawadgi, Prashant B.

2018-07-01

In the current involvement of our research work in coordination chemistry, novel transition metal complexes were synthesized from regular reflux method and hydrothermal method using Schiff base prepared via condensation of ethyl 2-amino-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxylate with 8-carbaldehyde-7-hydroxy-4-methylcoumarin. All the synthesized compounds were interpreted using different analytical, physicochemical and spectral methods such as magnetic moment measurement, FT-IR, 1H and 13C NMR, GCMS/ESI-MS, UV/Vis spectroscopy and TGA. The size and morphology of the nano metal complexes were determined using atomic force microscope (AFM), field emission scanning electron spectroscopy (FE-SEM) and X-ray powder diffraction (PXRD). The non-electrolytic nature of the metal complexes was confirmed by molar conductance studies. The obtained FT-IR data supports the binding of metal ion to Schiff base. Elemental analysis study suggests [ML2(H2O)2] stoichiometry, here M = Co(II), Ni(II) and Cu(II), L = deprotonated ligand. Electronic spectral results reveal six-coordinated geometry for the synthesized metal complexes. All the tested compounds show good DNA cleavage (Calf Thymus DNA) and in vitro anticancer activity (PA-I cell line), the activity results for the tested compounds are prominent and compound 9 exhibited a little enhanced activity than the other tested compounds.

Spectroscopic and thermal properties of short wavelength metal (II) complexes containing α-isoxazolylazo-β-diketones as co-ligands

NASA Astrophysics Data System (ADS)

Huang, Fuxin; Wu, Yiqun; Gu, Donghong; Gan, Fuxi

2005-10-01

Two new azo dyes of α-isoxazolylazo-β-diketones and their Ni(II) and Cu(II) complexes with blue-violet light wavelength were synthesized using a coupling component, different diazo components and metal (II) ions (Ni 2+ and Cu 2+). Based on the elemental analysis, MS spectra and FT-IR spectral analyses, azo dyes were unequivocally shown to exist as hydrazoketo and azoenol forms which were respectively obtained from the solution forms and from the solid forms. The action of sodium methoxide (NaOMe) on azo dyes in solutions converts hydrazoketo form into azoenol form, so azo dyes are coordinated with metal (II) ions as co-ligands in the azoenol forms. The solubility of all the compounds in common organic solvents such as 2,2,3,3-tetrafluoro-1-propanol (TFP) or chloroform (CHCl 3) and absorption properties of spin-coating thin films were measured. The difference of absorption maxima from the complexes to their ligands was discussed. In addition, the TG analysis of the complexes was also determined, and their thermal stability was evaluated. It is found that these new metal (II) complexes had potential application for high-density digital versatile disc-recordable (HD-DVD-R) system due to their good solubility in organic solvents, reasonable and controllable absorption spectra in blue-violet light region and high thermal stability.

Theoretical investigation, biological evaluation and VEGFR2 kinase studies of metal(II) complexes derived from hydrotris(methimazolyl)borate.

PubMed

Jayakumar, S; Mahendiran, D; Srinivasan, T; Mohanraj, G; Kalilur Rahiman, A

2016-02-01

The reaction of soft tripodal scorpionate ligand, sodium hydrotris(methimazolyl)borate with M(ClO4)2·6H2O [MMn(II), Ni(II), Cu(II) or Zn(II)] in methanol leads to the cleavage of B-N bond followed by the formation of complexes of the type [M(MeimzH)4](ClO4)2·H2O (1-4), where MeimzH=methimazole. All the complexes were fully characterized by spectro-analytical techniques. The molecular structure of the zinc(II) complex (4) was determined by X-ray crystallography, which supports the observed deboronation reaction in the scorpionate ligand with tetrahedral geometry around zinc(II) ion. The electronic spectra of complexes suggested tetrahedral geometry for manganese(II) and nickel(II) complexes, and square-planar geometry for copper(II) complex. Frontier molecular orbital analysis (HOMO-LUMO) was carried out by B3LYP/6-31G(d) to understand the charge transfer occurring in the molecules. All the complexes exhibit significant antimicrobial activity against Gram (-ve) and Gram (+ve) bacterial as well as fungal strains, which are quite comparable to standard drugs streptomycin and clotrimazole. The copper(II) complex (3) showed excellent free radical scavenging activity against DPPH in all concentration with IC50 value of 30μg/mL, when compared to the other complexes. In the molecular docking studies, all the complexes showed hydrophobic, π-π and hydrogen bonding interactions with BSA. The cytotoxic activity of the complexes against human hepatocellular liver carcinoma (HepG2) cells was assessed by MTT assay, which showed exponential responses toward increasing concentration of complexes. Copyright © 2015 Elsevier B.V. All rights reserved.

Binding of nickel /II/ to 5-prime-nucleoside monophosphates and related compounds. [role in origin of life

NASA Technical Reports Server (NTRS)

Orenberg, J. B.; Kjos, K. M.; Winkler, R.; Link, J.; Lawless, J. G.

1982-01-01

The interactions of Ni(II) cation with a representative suite of purine bases and the respective nucleosides and nucleotides have been studied by ultraviolet difference spectroscopy. Apparent association constants were determined for each system at pH 7.0, using computer linear regression coupled with an iteration technique. The specificity of binding of Ni(2+) for the purine nucleotides studied at pH 7.0 was 5-prime-GMP greater than 5-prime-AMP; a similar ordering was also found for the respective nucleosides and bases. In this study binding was not observed for the suite of pyramidines used, although an Ni(2+) -cytidine complex has been observed (Fiskin and Beer, 1965). It was also found that Ni(2+) bound more strongly to the purine 5-prime-nucleotides than to the respective nucleosides and bases. These trends are explained in terms of metal-ligand bonds and available bonding positions on the ligands. A role for metal-ion-nucleotide types of complexes is suggested in the processes that might have given rise to the origin of life.

Catalytic Formylation of Primary and Secondary Amines with CO2 and H2 Using Abundant-Metal Catalysts.

PubMed

Affan, Mohammad A; Jessop, Philip G

2017-06-19

Catalytic hydrogenation of CO 2 is an efficient and selective way to prepare formic acid derivatives, but most of the highly active catalysts used for this purpose require precious metals. In this study, in situ abundant-metal complexes have been evaluated as potential catalysts for CO 2 hydrogenation to prepare formamides, including N-formylmorpholine, 2-ethylhexylformamide, and dimethylformamide, from the corresponding amines. From these initial screening results, the most active catalysts for these reactions were found to be MX 2 /dmpe in situ catalysts (M = Fe(II), Ni(II); X = Cl - , CH 3 CO 2 - , acac - ; dmpe = 1,2-bis(dimethylphosphino)ethane) in DMSO. The optimal reaction conditions were found to be 100-135 °C and a total pressure of 100 bar. Morpholine was formylated with a TON value of up to 18000, which is the highest TON for the hydrogenation of CO 2 to formamides using any abundant-metal-phosphine complex. With an appropriate selection of catalyst and reaction conditions, >90-98% conversion of amine to formamide could be achieved.

Co(II), Ni(II) and Cu(II) complexes of methyl-5-(Phenylthio) benzimidazole-2-carbamate: Molecular structures, spectral and DFT calculations

NASA Astrophysics Data System (ADS)

Mansour, Ahmed M.; El Bakry, Eslam M.; Abdel-Ghani, Nour T.

2016-05-01

[Co(FBZ)2(H2O)]·2NO3·0.5H2O (1), [Ni(FBZ)2X2]·zH2O (X = Cl​-, z = 0.5 (2) and X = CH3COO-, z = 1 (3)) and [Cu(FBZ)2(H2O) (NO3)]·NO3·1.5H2O (4) (FBZ = methyl-5-(Phenylthio) benzimidazole-2-carbamate; Fenbendazole) complexes were synthesized and characterized by elemental analysis, thermal, IR, EPR, UV-Vis, magnetic and conductance measurements. Geometry optimization, molecular electrostatic potential maps and natural bond orbital analysis were carried out at DFT/B3LYP/6-31G∗ level of theory. FBZ behaves as a neutral bidentate ligand via the pyridine-type nitrogen of the benzimidazole moiety and the carbamate group. Three-step ionization with pKa values of 3.38, 4.06 and 10.07 were reported for FBZ. The coordination of FBZ to the metal ions led to an increase in the antibacterial activity against the tested Staphylococcus aureus and Escherichia coli bacteria.

[15]aneN4S: synthesis, thermodynamic studies and potential applications in chelation therapy.

PubMed

Torres, Nuno; Gonçalves, Sandrina; Fernandes, Ana S; Machado, J Franco; de Brito, Maria J Villa; Oliveira, Nuno G; Castro, Matilde; Costa, Judite; Cabral, Maria F

2014-01-03

The purpose of this work was to synthesize and characterize the thiatetraaza macrocycle 1-thia-4,7,10,13-tetraazacyclopentadecane ([15]aneN4S). Its acid-base behaviour was studied by potentiometry at 25 °C and ionic strength 0.10 M in KNO3. The protonation sequence of this ligand was investigated by 1H-NMR titration that also allowed the determination of protonation constants in D2O. Binding studies of [15]aneN4S with Mn2+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Hg2+ and Pb2+ metal ions were further performed under the same experimental conditions. The results demonstrated that this compound has a higher selectivity and thermodynamic stability for Hg2+ and Cu2+, followed by Ni2+. The UV-visible-near IR spectroscopies and magnetic moment data for the Co(II) and Ni(II) complexes indicated a tetragonal distorted coordination geometry for both metal centres. The value of magnetic moment and the X-band EPR spectra of the Cu(II) complex are consistent with a distorted square pyramidal geometry.

Ligational behavior of Schiff bases towards transition metal ion and metalation effect on their antibacterial activity

NASA Astrophysics Data System (ADS)

Devi, Jai; Batra, Nisha; Malhotra, Rajesh

2012-11-01

New Schiff bases pyrazine-2-carboxylicacid (phenyl-pyridin-2-yl-methylene)-hydrazide (Hpch-bp) HL1 and pyrazine-2-carboxylicacid (pyridin-2-ylmethylene)-hydrazide (Hpch-pc) HL2 derived from condensation of pyrazine carboxylic hydrazide (Hpch) with 2-benzoyl pyridine (bp) or pyridine 2-carbaldehyde (pc) and their transition metal complexes of type ML(1-2)2 have been synthesized, where M = Mn(II), Co(II), Ni(II), Cu(II) and Zn(II). Characterization of ligands and their metal complexes was carried out by elemental analysis, conductimetric studies, magnetic susceptibility, spectroscopic techniques (IR, UV-VIS, NMR, ESR, Mass) and thermogravimetric analysis. The physico-chemical studies revealed octahedral geometry or distorted octahedral geometry around metal ion. These azomethine Schiff base ligands acted as tridentate ? coordinating through carbonyl, azomethine and pyridine nitrogen present in the ligand. The thermodynamic and thermal properties of the complexes have been investigated and it was observed on the basis of these studies that thermal stability of complexes follows the order Mn < Zn < Cu < Co < Ni. The ligands and their complexes were tested for in vitro antibacterial activity at different concentrations against bacteria viz. Gram positive Bacillus subtilis, Micrococcus luteus and Gram negative Pseudomonas aeruginosa, Pseudomonas mendocina. A marked enhancement in biocidal activity of the ligands under similar experimental conditions was observed as a consequence of coordination with metal ions. The trend of growth inhibition in the complexes was found to be in the order: Cu > Mn > Ni > Co > Zn.

Gold nanoparticle capture within protein crystal scaffolds.

PubMed

Kowalski, Ann E; Huber, Thaddaus R; Ni, Thomas W; Hartje, Luke F; Appel, Karina L; Yost, Jarad W; Ackerson, Christopher J; Snow, Christopher D

2016-07-07

DNA assemblies have been used to organize inorganic nanoparticles into 3D arrays, with emergent properties arising as a result of nanoparticle spacing and geometry. We report here the use of engineered protein crystals as an alternative approach to biologically mediated assembly of inorganic nanoparticles. The protein crystal's 13 nm diameter pores result in an 80% solvent content and display hexahistidine sequences on their interior. The hexahistidine sequence captures Au25(glutathione)∼17 (nitrilotriacetic acid)∼1 nanoclusters throughout a chemically crosslinked crystal via the coordination of Ni(ii) to both the cluster and the protein. Nanoparticle loading was validated by confocal microscopy and elemental analysis. The nanoparticles may be released from the crystal by exposure to EDTA, which chelates the Ni(ii) and breaks the specific protein/nanoparticle interaction. The integrity of the protein crystals after crosslinking and nanoparticle capture was confirmed by single crystal X-ray crystallography.

Influence of thermal history on the electrochemical properties of Li[Ni0.5Mn1.5]O4

NASA Astrophysics Data System (ADS)

Liu, Guoqiang; Park, Kyu-Sung; Song, Jie; Goodenough, John B.

2013-12-01

The oxygen-stoichiometric spinel Li[Ni0.5Mn1.5]O4 is an insulator with ordered Ni(II) and Mn(IV). Although it delivers 4.7 V versus Li, the ordered phase gives poor performance as the cathode of a Li-ion battery. Here we demonstrate control of the degree of cation order by adjusting the oxygen stoichiometry with thermal history of the synthesis rather than by doping 2M(III) for Ni(II) + Mn(IV) (M = Cr, Mn, Fe, Co, Al, Ga). We report retention of capacity near 100 mAh g-1 at room temperature at 10C/10C charge/discharge rate with little capacity fade; at 55 °C, a capacity fade occurs as a result of reaction with the electrolyte, but it is reduced to a level comparable to that obtained by doping.

Novel mixed ligand complexes of bioactive Schiff base (E)-4-(phenyl (phenylimino) methyl) benzene-1,3-diol and 2-aminophenol/2-aminobenzoic acid: Synthesis, spectral characterization, antimicrobial and nuclease studies

NASA Astrophysics Data System (ADS)

Subbaraj, P.; Ramu, A.; Raman, N.; Dharmaraja, J.

2014-01-01

A novel bidentate Schiff base ligand has been synthesized using 2,4-dihydroxybenzophenone and aniline. Its mixed ligand complexes of MAB type [M = Mn(II), Co(II), Ni(II), Cu(II) and Zn(II); HA = Schiff base and B = 2-aminophenol/2-aminobenzoic acid] have been synthesized and characterized on the basis of spectral data UV-Vis, IR, 1H NMR, FAB-Mass, EPR, SEM and magnetic studies. All the complexes were soluble in DMF and DMSO. Elemental analysis and molar conductance values indicate that the complexes are non-electrolytes. HA binds with M(II) ions through azomethine and deprotonated phenolic group and B binds through the primary amine group and deprotonated phenolic/carboxylic groups. Using FAB-Mass the cleavage pattern of the ligand (HA) has been established. All the complexes adopt octahedral geometry around the metal ions. It has been confirmed with the help of UV-Vis, IR, 1H NMR and FAB-Mass spectral data. DNA binding activities of the complexes 1d and 2d are studied by UV-Vis spectroscopy and cleavage studies of Schiff base ligand and its complexes 1d and 2d have been by agarose gel electrophoresis method. In vitro biological activities of the free ligand (HA) and their metal complexes (1a-1e and 2a-2e) were screened against few bacteria, Escherichia coli, Staphylococcus saphyphiticus, Staphylococcus aureus, Pseudomonas aeruginosa and fungi Aspergillus niger, Enterobacter species, Candida albicans by well diffusion technique.

Synthesis, characterization, molecular docking and biological studies of self assembled transition metal dithiocarbamates of substituted pyrrole-2-carboxaldehyde.

PubMed

Nami, Shahab A A; Ullah, Irfan; Alam, Mahboob; Lee, Dong-Ung; Sarikavakli, Nursabah

2016-07-01

A series of self assembled 3d transition metal dithiocarbamate, M(pdtc) [where M=Mn(II), Fe(II), Co(II), Ni(II) and Cu(II)] have been synthesized and spectroscopically characterized. The bidentate dithiocarbamate ligand Na2pdtc (Disodium-1,4-phenyldiaminobis (pyrrole-1-sulfino)dithioate) was prepared by insertion reaction of carbondisulfide with Schiff base, N,N'-bis-(1H-pyrrol-2-ylmethylene)-benzene-1,4-diamine (L1) in basic medium. The simple substitution reaction between the metal halide and Na2pdtc yielded the title complexes in moderate yields. However, the in situ procedure gives high yield with the formation of single product as evident by TLC. Elemental analysis, IR, (1)H and (13)C NMR spectra, UV-vis., magnetic susceptibility and conductance measurements were done to characterize the complexes, M(pdtc). All the evidences suggest that the complexes have tetrahedral geometry excepting Cu(II) which is found to be square planar. A symmetrical bidentate coordination of the dithiocarbamato moiety has been observed in all the complexes. The conductivity data show that the complexes are non-electrolyte in nature. The anti-oxidant activity of the ligand, Na2pdtc and its transition metal complexes, M(pdtc) have been carried out using DPPH and Cu(pdtc) was found to be most effective. The anti-microbial activity of the Na2pdtc and M(pdtc) complexes have been carried out and on this basis the molecular docking study of the most effective complex, Cu(pdtc) has also been reported. Copyright © 2016 Elsevier B.V. All rights reserved.

Spectroscopic, thermal analysis and DFT computational studies of salen-type Schiff base complexes.

PubMed

Ebrahimi, Hossein Pasha; Hadi, Jabbar S; Abdulnabi, Zuhair A; Bolandnazar, Zeinab

2014-01-03

A new series of metal(II) complexes of Co(II), Ni(II), Cu(II), Zn(II), and Pb(II) have been synthesized from a salen-type Schiff base ligand derived from o-vanillin and 4-methyl-1,2-phenylenediamine and characterized by elemental analysis, spectral (IR, UV-Vis, (1)H NMR, (13)C NMR and EI-mass), molar conductance measurements and thermal analysis techniques. Coats-Redfern method has been utilized to calculate the kinetic and thermodynamic parameters of the metal complexes. The molecular geometry, Mulliken atomic charges of the studied compounds were investigated theoretically by performing density functional theory (DFT) to access reliable results to the experimental values. The theoretical (13)C chemical shift results of the studied compounds have been calculated at the B3LYP, PBEPBE and PW91PW91 methods and standard 6-311+G(d,p) basis set starting from optimized geometry. The comparison of the results indicates that B3LYP/6-311+G(d,p) yields good agreement with the observed chemical shifts. The measured low molar conductance values in DMF indicate that the metal complexes are non-electrolytes. The spectral and thermal analysis reveals that all complexes have octahedral geometry except Cu(II) complex which can attain the square planner arrangement. The presence of lattice and coordinated water molecules are indicated by thermograms of the complexes. The thermogravimetric (TG/DTG) analyses confirm high stability for all complexes followed by thermal decomposition in different steps. Copyright © 2013 Elsevier B.V. All rights reserved.

Interaction between transition metals and phenylalanine: a combined experimental and computational study.

PubMed

Elius Hossain, Md; Mahmudul Hasan, Md; Halim, M E; Ehsan, M Q; Halim, Mohammad A

2015-03-05

Some transition metal complexes of phenylalanine of general formula [M(C9H10NO2)2]; where M=Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) are prepared in aqueous medium and characterized by spectroscopic, thermo-gravimetric (TG) and magnetic susceptibility analysis. Density functional theory (DFT) has been employed calculating the equilibrium geometries and vibrational frequencies of those complexes at B3LYP level of theory using 6-31G(d) and SDD basis sets. In addition, frontier molecular orbital and time-dependent density functional theory (TD-DFT) calculations are performed with CAM-B3LYP/6-31+G(d,p) and B3LYP/SDD level of theories. Thermo-gravimetric analysis confirms the composition of the complexes by comparing the experimental and calculated data for C, H, N and metals. Experimental and computed IR results predict a significant change in vibrational frequencies of metal-phenylalanine complexes compared to free ligand. DFT calculation confirms that Mn, Co, Ni and Cu complexes form square planar structure whereas Zn adopts distorted tetrahedral geometry. The metal-oxygen bonds in the optimized geometry of all complexes are shorter compared to the metal-nitrogen bonds which is consistent with a previous study. Cation-binding energy, enthalpy and Gibbs free energy indicates that these complexes are thermodynamically stable. UV-vis and TD-DFT studies reveal that these complexes demonstrate representative metal-to-ligand charge transfer (MLCT) and d-d transitions bands. TG analysis and IR spectra of the metal complexes strongly support the absence of water in crystallization. Magnetic susceptibility data of the complexes exhibits that all except Zn(II) complex are high spin paramagnetic. Copyright © 2014 Elsevier B.V. All rights reserved.

Simultaneous decomplexation in blended Cu(II)/Ni(II)-EDTA systems by electro-Fenton process using iron sacrificing electrodes.

PubMed

Zhao, Zilong; Dong, Wenyi; Wang, Hongjie; Chen, Guanhan; Tang, Junyi; Wu, Yang

2018-05-15

This research explored the application of electro-Fenton (E-Fenton) technique for the simultaneous decomplexation in blended Cu(II)/Ni(II)-EDTA systems by using iron sacrificing electrodes. Standard discharge (0.3 mg L -1 for Cu and 0.1 mg L -1 for Ni in China) could be achieved after 30 min reaction under the optimum conditions (i.e. initial solution pH of 2.0, H 2 O 2 dosage of 6 mL L -1  h -1 , current density of 20 mA/cm 2 , inter-electrode distance of 2 cm, and sulfate electrolyte concentration of 2000 mg L -1 ). The distinct differences in apparent kinetic rate constants (k app ) and intermediate removal efficiencies corresponding to mere and blended systems indicated the mutual promotion effect toward the decomplexation between Cu(II) and Ni(II). Massive accumulation of Fe(Ⅲ) favored the further removal of Cu(II) and Ni(II) by metal ion substitution. Species distribution results demonstrated that the decomplexation of metal-EDTA in E-Fenton process was mainly contributed to the combination of various reactions, including Fenton reaction together with the anodic oxidation, electro-coagulation (E-coagulation) and electrodeposition. Unlike hypophosphite and citrate, the presence of chlorine ion displayed favorable effects on the removal efficiencies of Cu(II) and Ni(II) at low dosage, but facilitated the ammonia nitrogen (NH 4 + -N) removal only at high dosage. Copyright © 2018 Elsevier B.V. All rights reserved.

Batch and dynamic sorption of Ni(II) ions by activated carbon based on a native lignocellulosic precursor.

PubMed

Nabarlatz, Debora; de Celis, Jorge; Bonelli, Pablo; Cukierman, Ana Lea

2012-04-30

Vinal-derived Activated Carbon (VAC) developed by phosphoric acid activation of sawdust from Prosopis ruscifolia native wood was tested for the adsorption of Ni(II) ions from dilute solutions in both batch and dynamic modes, comparing it with a Commercial Activated Carbon (CAC). Batch experiments were performed to determine adsorption kinetics and equilibrium isotherms for both carbons. It was possible to remove near 6.55 mg Ni g(-1) VAC and 7.65 mg Ni g(-1) CAC after 5 h and 10 h contact time, respectively. A pseudo second order equation fitted well with the kinetics of the process, and Langmuir adsorption model was used to adjust the experimental results concerning the adsorption isotherm. The parameters obtained indicate a stronger interaction between sorbent and sorbate for VAC (K = 26.56 L mmol(-1)) than for CAC (K = 19.54 L mmol(-1)). Continuous experiments were performed in a fixed-bed column packed with the investigated carbons, evaluating the influence of operational parameters such as flow rate, bed height and feed concentration on the breakthrough curves obtained. The breakthrough occurred more slowly for low concentrations of the metal ion in the feed, low flow rates and high bed height. The breakthrough curves were properly represented by Hall's model for both carbon types. Regeneration of the vinal activated carbon in column was tested, obtaining the same breakthrough curve in a new cycle of use. Finally, vinal-derived activated carbon can effectively be used to treat wastewater having until 30 ppm Ni(II). Copyright © 2011 Elsevier Ltd. All rights reserved.

Synthesis of MFe3S4 clusters containing a planar M(II) site (M = Ni, Pd, Pt), a structural element in the C-cluster of carbon monoxide dehydrogenase.

PubMed

Panda, Rashmishree; Berlinguette, Curtis P; Zhang, Yugen; Holm, Richard H

2005-08-10

Synthesis of an analogue of the C-cluster of C. hydrogenoformans carbon monoxide dehydrogenase requires formation of a planar Ni(II) site and attachment of an exo iron atom in the core unit NiFe(4)S(5). The first objective has been achieved by two reactions: (i) displacement of Ph(3)P or Bu(t)()NC at tetrahedral Ni(II) sites of cubane-type [NiFe(3)S(4)](+) clusters with chelating diphosphines, and (ii) metal atom incorporation into a cuboidal [Fe(3)S(4)](0) cluster with a M(0) reactant in the presence of bis(1,2-dimethylphosphino)ethane (dmpe). The isolated product clusters [(dmpe)MFe(3)S(4)(LS(3))](2-) (M = Ni(II) (9), Pd(II) (12), Pt(II) (13); LS(3) = 1,3,5-tris((4,6-dimethyl-3-mercaptophenyl)thio)-2,4,6-tris(p-tolylthio)benzene(3-)) contain the cores [MFe(3)(mu(2)-S)(mu(3)-S)(3)](+) having planar M(II)P(2)S(2) sites and variable nonbonding M...S distances of 2.6-3.4 A. Reaction (i) involves a tetrahedral --> planar Ni(II) structural change between isomeric cubane and cubanoid [NiFe(3)S(4)](+) cores. Based on the magnetic properties of 12 and earlier considerations, the S = (5)/(2) ground state of the cubanoid cluster arises from the [Fe(3)S(4)](-) fragment, whereas the S = (3)/(2) ground state of the cubane cluster is a consequence of antiferromagnetic coupling between the spins of Ni(2+) (S = 1) and [Fe(3)S(4)](-). Other substitution reactions of [NiFe(3)S(4)](+) clusters and 1:3 site-differentiated [Fe(4)S(4)](2+) clusters are described, as are the structures of 12, 13, [(Me(3)P)NiFe(3)S(4)(LS(3))](2-), and [Fe(4)S(4)(LS(3))L'](2-) (L' = Me(2)NC(2)H(4)S(-), Ph(2)P(O)C(2)H(4)S(-)). This work significantly expands our initial report of cluster 9 (Panda et al. J. Am. Chem. Soc. 2004, 126, 6448-6459) and further demonstrates that a planar M(II) site can be stabilized within a cubanoid [NiFe(3)S(4)](+) core.

Plasma-assisted MBE growth kinetics and characterization studies of wide bandgap III-V epitaxial materials

NASA Astrophysics Data System (ADS)

O'Steen, Mark Lee

2000-10-01

Scope and method of study. The purpose of this research was to understand the physics of RF plasma-assisted molecular beam epitaxial growth of GaN epitaxial films and InGaN/GaN superlattice structures grown on Al2O3 (0001) substrates. The techniques used to characterize the RF-MBE grown samples include in situ reflection high energy electron diffraction (RHEED) and optical pyrometry, and ex situ spatially-resolved high resolution X-ray diffraction, spatially-resolved reflectance spectroscopy, atomic force microscopy, and low-temperature photoluminescence (PL) spectroscopy. Findings and conclusions. RF plasma-assisted molecular beam epitaxy (RF-MBE) has been used to grow GaN epitaxial films and InGaN/GaN superlattice structures. The most important growth parameters in the growth of GaN epitaxial films were identified as the substrate temperature, incident N*/Ga flux ratio, and GaN growth rate. The effect of these growth parameters on GaN growth and quality of GaN epitaxial films is discussed. Additionally, an interpretation of the effects of growth conditions on the underlying microscopic growth processes occurring is presented. All of the observed GaN growth results may be understood in terms of these microscopic growth processes. InGaN/GaN superlattice samples are grown to identify and quantitatively access the InGaN growth phenomenology. It is inferred that InN requires a higher N*/III flux ratio than does GaN for stoichiometric growth. At substrate temperatures below 590°C, the In composition of the superlattice samples is nominally constant. However, in the narrow temperature range 590--670°C, the In composition decreases by more than an order-or-magnitude at the lowest N*/III flux ratio of this study. Additionally, the incident N*/III flux ratio is found to strongly influence the In composition as well. Nearly an order-of-magnitude increase in In composition is observed despite only a 20% increase in the N*/III flux ratio at the highest temperature of this study. RHEED and PL measurements support the assessment of the In reduction mechanism as thermally-activated surface-segregation and surface-desorption of In. Implications of these results for device growth are discussed.

Spectral characterization, cyclic voltammetry, morphology, biological activities and DNA cleaving studies of amino acid Schiff base metal(II) complexes

NASA Astrophysics Data System (ADS)

Neelakantan, M. A.; Rusalraj, F.; Dharmaraja, J.; Johnsonraja, S.; Jeyakumar, T.; Sankaranarayana Pillai, M.

2008-12-01

Metal complexes are synthesized with Schiff bases derived from o-phthalaldehyde (opa) and amino acids viz., glycine (gly) L-alanine (ala), L-phenylalanine (pal). Metal ions coordinate in a tetradentate or hexadentate manner with these N 2O 2 donor ligands, which are characterized by elemental analysis, molar conductance, magnetic moments, IR, electronic, 1H NMR and EPR spectral studies. The elemental analysis suggests the stoichiometry to be 1:1 (metal:ligand). Based on EPR studies, spin-Hamiltonian and bonding parameters have been calculated. The g-values calculated for copper complexes at 300 K and in frozen DMSO (77 K) indicate the presence of the unpaired electron in the d orbital. The evaluated metal-ligand bonding parameters showed strong in-plane σ- and π-bonding. X-ray diffraction (XRD) and scanning electron micrography (SEM) analysis provide the crystalline nature and the morphology of the metal complexes. The cyclic voltammograms of the Cu(II)/Mn(II)/VO(II) complexes investigated in DMSO solution exhibit metal centered electroactivity in the potential range -1.5 to +1.5 V. The electrochemical data obtained for Cu(II) complexes explains the change of structural arrangement of the ligand around Cu(II) ions. The biological activity of the complexes has been tested on eight bacteria and three fungi. Cu(II) and Ni(II) complexes show an increased activity in comparison to the controls. The metal complexes of opapal Schiff base were evaluated for their DNA cleaving activities with calf-thymus DNA (CT DNA) under aerobic conditions. Cu(II) and VO(II) complexes show more pronounced activity in presence of the oxidant.

Spectroscopic, structural, electrochemical and computational studies of some new 2-thienyl-containing β-diketonate complexes of cobalt(II), nickel(II) and copper(II)

NASA Astrophysics Data System (ADS)

Ahumada, Guillermo; Fuentealba, Mauricio; Roisnel, Thierry; Kahlal, Samia; Córdova, Ricardo; Carrillo, David; Saillard, Jean-Yves; Hamon, Jean-René; Manzur, Carolina

2017-12-01

In this work, we present the synthesis of the unsymmetrical β-diketone 1-(2-thienyl)-3-(4-fluorophenyl)-propane-1,3-dione (HL) and its corresponding Co(II), Ni(II) and Cu(II) bis(β-diketonato) complexes 1-3, respectively. The four new compounds were isolated in good yields (65-70%), and characterized by mass spectrometry, elemental analysis, FT-IR and UV-Vis spectroscopy and, in the case of HL, by 1H, 13C and 19F NMR spectroscopy. In addition, the molecular identities and the geometries of the β-diketone HL and complex 3 were confirmed by X-ray diffraction analysis. The dicarbonyl derivative HL does exist as the diketo tautomeric form in DMSO solution and as its keto-enol tautomer in the solid-state with the sbnd OH group adjacent to the 4-fluorophenyl unit. The keto-enol isomer was computed to be more stable by 8.2 kcal/mol in free energy at room temperature. In 3, the Cu(II) center adopts a perfect square-planar geometry. Two reduction processes were observed in the cyclovoltammogram of 3 at -1.30 and -1.80 V vs. Fc/Fc+, with copper deposit on the surface of the electrode. DFT and TD-DFT calculations on HL and complex 3 allow rationalizing their stability, bonding and properties.

Synthesis, characterization and anti-microbial activity of phenylurea-formaldehyde resin (PUF) and its polymer metal complexes (PUF-Mn(II).

PubMed

Ahamad, Tansir; Alshehri, Saad M

2012-10-01

Phenylurea-formaldehyde polymer (PUF) was synthesized via polycondensation of phenylurea and formaldehyde in basic medium, its polymer-metal complexes [PUF-M(II)] were prepared with Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) ions. PUF and PUF-M(II) were characterized with magnetic moment measurements, elemental and spectral (UV-visible, FTIR, 1H-NMR, 13C-NMR and ESR) analysis. The thermal behaviors of all the synthesized polymers were carried out using thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The thermal data revealed that all of the PUF-M(II) showed higher thermal stabilities than the PUF and also ascribed that the PUF-Cu(II) showed better thermal stability than the other PUF-M(II). The kinetic parameters such as activation energy, pre-exponential factor etc., were evaluated for these polymer metal complexes using Coats-Redfern equation. In addition, the antimicrobial activity of the synthesized polymers was tested against several microorganisms using agar well diffusion methods. Among all of the PUF-M(II), the antimicrobial activity of the PUF-Cu(II) showed the highest zone of inhibition because of its higher stability constant and may be used in biomedical applications. Copyright © 2012 Elsevier B.V. All rights reserved.

Structural variety of mono- and binuclear transition metal complexes of 3-[(2-hydroxy-benzylidene)-hydrazono]-1-(2-hydroxyphenyl)-butan-1-one: Synthesis, spectral, thermal, molecular modeling, antimicrobial and antitumor studies

NASA Astrophysics Data System (ADS)

Shebl, Magdy; Adly, Omima M. I.; El-Shafiy, Hoda F.; Khalil, Saied M. E.; Taha, A.; Mahdi, Mohammed A. N.

2017-04-01

A new polydentate Schiff base ligand and its metal complexes were synthesized and characterized by elemental analyses, IR, 1H NMR, electronic, ESR and mass spectra, conductivity and magnetic susceptibility measurements as well as thermal analyses. The free ligand was synthesized by condensation of o-acetoacetylphenol with salicylaldehyde hydrazone. The analytical and spectroscopic tools showed that the obtained complexes are mono- and binuclear complexes, which can be generally formulated as: [(L)M2X2(H2O)m]·nZ; M = Cr, Fe, Ni or Cu, X = OAc or NO3, m = 5 or nil and n = 3, 1.5 or 0.5 and Z = EtOH or H2O, [(H2L)2M(X)m].nH2O; M = Mn, Zn, or Cd, X = EtOH, H2O or nil, m = 2 or nil and n = 3.5 or 0, [(HL)2Co2]·0.5H2O and [(H2L)2UO2(H2O)]. The metal complexes displayed octahedral, tetrahedral and square-planar geometrical arrangements, while uranium complex displayed seven-coordinate. Kinetic parameters (Ea, A, ΔH, ΔS and ΔG) of the thermal decomposition stages have been evaluated using Coats-Redfern equations. The molecular structural parameters of the ligand and its metal complexes have been calculated and correlated with the experimental data such as IR. The antimicrobial activity of the ligand and its complexes was screened against some kinds of bacteria and fungi. The antitumor activity of the ligand and its Ni(II) and Cu(II) complexes was investigated against HepG2 cell line.

Synthesis, spectroscopic characterization, in-vitro antibacterial and antiproliferative activities of some metal(II) complexes of 3,4-dihydronaphthalen-1(2H)-one Schiff base

PubMed Central

Osowole, Aderoju Amoke

2012-01-01

The Schiff base, 3-hydroxy-4-{[4-(methylsulfanyl)phenyl]imino}-3,4-dihydronaphthalen-1(2H)-one, and its Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Pd(II) complexes have been synthesized and characterized by microanalysis, conductance, 1H NMR, infrared and electronic spectral measurements. The ligand exists in the ketoimine form in chloroform, and in the enolimine form in the solid state, as shown by 1H NMR and IR spectroscopies. The ligand coordinates to the metal ions in the ratio 1:1, using NO chromophores forming complexes of the type [MLNO3]H2O, with the exception of the Zn(II) and Pd(II) complexes. Electronic measurements are indicative of a four coordinate square-planar geometry for all the complexes, except for the Cu(II) and Zn(II) complexes which assume a tetrahedral geometry. None is an electrolyte in nitromethane. The ligand and the metal complexes are air-stable, but decomposed on heating at 120 °C and in the range 150-156 °C respectively. The antibacterial studies reveal that the Co(II) and the Cu(II) complexes exhibit broad-spectrum activity against Proteus mirabilis, Escherichia coli and Staphylococcus aureus with inhibitory zones range of 14.0-22.0 and 13.0-25.0 mm respectively. The antiproliferative studies show that the Zn(II) complex has the best in-vitro anticancer activity against both HT-29 (colon) carcinoma and MCF-7 (human breast) adenocarcinoma with IC50 values of 6.46 µm and 3.19 µm, which exceeds the activity of Cis-platin by 8 % and 63 % respectively. PMID:27350773

Syntheses, crystal structures and magnetic properties of complexes based on [Ni(L-L)3]2+ complex cations with dimethylderivatives of 2,2‧-bipyridine and TCNQ

NASA Astrophysics Data System (ADS)

Černák, Juraj; Hegedüs, Michal; Váhovská, Lucia; Kuchár, Juraj; Šoltésová, Daniela; Čižmár, Erik; Feher, Alexander; Falvello, L. R.

2018-03-01

From the aqueous-methanolic systems Ni(NO3)2 - LiTCNQ - 5,5‧-dmbpy and Ni(NO3)2 - LiTCNQ - 4,4‧-dmbpy three novel complexes [Ni(5,5‧-dmbpy)3](TCNQ)2 (1), [Ni(4,4‧-dmbpy)3](TCNQ)2 (2) and [Ni(4,4‧-dmbpy)3]2(TCNQ-TCNQ)(TCNQ)2•0.60H2O (3), were isolated in single crystal form. The new compounds were identified using chemical analyses and IR spectroscopy. Single crystal studies of all samples corroborated their compositions and have shown that their ionic structures contain the complex cations [Ni(5,5‧-dmbpy)]2+ (1) or [Ni(4,4‧-dmbpy)]2+ (2 and 3). The anionic parts of the respective crystal structures 1-3 are formed by TCNQṡ- anion-radicals and in 3 also by a σ-dimerized dianion (TCNQ-TCNQ)2- with a C-C distance of 1.663(5) Å. The supramolecular structures are governed by weak hydrogen bonding interactions. The variable-temperature (2-300 K) magnetic studies of 1 and 3 confirmed the presence of magnetically active Ni(II) atoms with S = 1 and TCNQṡ- anion-radicals with S = 1/2 while the (TCNQ-TCNQ)2- dianion is magnetically silent. The magnetic behavior was described by a complex magnetic model assuming strong antiferromagnetic interactions between some TCNQṡ- anion-radicals.

Design, spectral characterization and biological studies of transition metal(II) complexes with triazole Schiff bases

NASA Astrophysics Data System (ADS)

Hanif, Muhammad; Chohan, Zahid H.

2013-03-01

A new series of three biologically active triazole derived Schiff base ligands L1-L3 have been synthesized in equimolar reaction of 3-amino-1H-1,2,4-triazole with pyrrol-2-carboxaldehyde, 4-bromo-thiophene-2-carboxaldehyde, and 5-iodo-2-hydroxy benzaldehyde. The prepared Schiff bases were used for further complex formation reaction with different metal elements like Co(II), Ni(II), Cu(II) and Zn(II) as chlorides by using a molar ratio of ligand:metal as 2:1. The structure and bonding nature of all the compounds were identified by their physical, spectral and analytical data. All the metal(II) complexes possessed an octahedral geometry except the Cu(II) complexes which showed a distorted octahedral geometry. All the synthesized compounds, were studied for their in vitro antibacterial, and antifungal activities, against four Gram-negative (Escherichia coli, Shigella sonnei, Pseudomonas aeruginosa and Salmonella typhi) and two Gram-positive (Bacillus subtilis and Staphylococcus aureus) bacterial strains and against six fungal strains (Trichophyton longifusus, Candida albicans, Aspergillus flavus, Microsporum canis, Fusarium solani and Candida glabrata) by using agar-well diffusion method. It has been shown that all the synthesized compounds showed moderate to significant antibacterial activity against one or more bacterial strains. In vitro Brine Shrimp bioassay was also carried out to investigate the cytotoxic properties of these compounds. The data also revealed that the metal complexes showed better activity than the ligands due to chelation/coordination.

A self-assembled supramolecular optical sensor for NiII, CdII, and CrIII.

PubMed

Resendiz, Marino J E; Noveron, Juan C; Disteldorf, Hendrick; Fischer, Sonja; Stang, Peter J

2004-03-04

A new chromogenic supramolecular sensor for transition metals is reported. It is based on a newly designed phenanthroline-containing molecule that self-assembles via an organometallic "clip" into a supramolecular optical sensor for metals. [reaction: see text

High capacity nickel battery material doped with alkali metal cations

DOEpatents

Jackovitz, John F.; Pantier, Earl A.

1982-05-18

A high capacity battery material is made, consisting essentially of hydrated Ni(II) hydroxide, and about 5 wt. % to about 40 wt. % of Ni(IV) hydrated oxide interlayer doped with alkali metal cations selected from potassium, sodium and lithium cations.

Alkali slurry ozonation to produce a high capacity nickel battery material

DOEpatents

Jackovitz, John F.; Pantier, Earl A.

1984-11-06

A high capacity battery material is made, consisting essentially of hydrated Ni(II) hydroxide, and about 5 wt. % to about 40 wt. % of Ni(IV) hydrated oxide interlayer doped with alkali metal cations selected from potassium, sodium and lithium cations.

New method for the direct determination of dissolved Fe(III) concentration in acid mine waters

USGS Publications Warehouse

To, T.B.; Nordstrom, D. Kirk; Cunningham, K.M.; Ball, J.W.; McCleskey, R. Blaine

1999-01-01

A new method for direct determination of dissolved Fe(III) in acid mine water has been developed. In most present methods, Fe(III) is determined by computing the difference between total dissolved Fe and dissolved Fe(II). For acid mine waters, frequently Fe(II) >> Fe(III); thus, accuracy and precision are considerably improved by determining Fe(III) concentration directly. The new method utilizes two selective ligands to stabilize Fe(III) and Fe(II), thereby preventing changes in Fe reduction-oxidation distribution. Complexed Fe(II) is cleanly removed using a silica-based, reversed-phase adsorbent, yielding excellent isolation of the Fe(III) complex. Iron(III) concentration is measured colorimetrically or by graphite furnace atomic absorption spectrometry (GFAAS). The method requires inexpensive commercial reagents and simple procedures that can be used in the field. Calcium(II), Ni(II), Pb(II), AI(III), Zn(II), and Cd(II) cause insignificant colorimetric interferences for most acid mine waters. Waters containing >20 mg of Cu/L could cause a colorimetric interference and should be measured by GFAAS. Cobalt(II) and Cr(III) interfere if their molar ratios to Fe(III) exceed 24 and 5, respectively. Iron(II) interferes when its concentration exceeds the capacity of the complexing ligand (14 mg/L). Because of the GFAAS elemental specificity, only Fe(II) is a potential interferent in the GFAAS technique. The method detection limit is 2 ??g/L (40 nM) using GFAAS and 20 ??g/L (0.4 ??M) by colorimetry.A new method for direct determination of dissolved Fe(III) in acid mine water has been developed. In most present methods, Fe(III) is determined by computing the difference between total dissolved Fe and dissolved Fe(II). For acid mine waters, frequently Fe(II)???Fe(III); thus, accuracy and precision are considerably improved by determining Fe(III) concentration directly. The new method utilizes two selective ligands to stabilize Fe(III) and Fe(II), thereby preventing changes in Fe reduction-oxidation distribution. Complexed Fe(II) is cleanly removed using a silica-based, reversed-phase adsorbent, yielding excellent isolation of the Fe(III) complex. Iron(III) concentration is measured colorimetrically or by graphite furnace atomic absorption spectrometry (GFAAS). The method requires inexpensive commercial reagents and simple procedures that can be used in the field. Calcium(II), Ni(II), Pb(II), Al(III), Zn(II), and Cd(II) cause insignificant colorimetric interferences for most acid mine waters. Waters containing >20 mg of Cu/L could cause a colorimetric interference and should be measured by GFAAS. Cobalt(II) and Cr(III) interfere if their molar ratios to Fe(III) exceed 24 and 5, respectively. Iron(II) interferes when its concentration exceeds the capacity of the complexing ligand (14 mg/L). Because of the GFAAS elemental specificity, only Fe(II) is a potential interferent in the GFAAS technique. The method detection limit is 2/??g/L (40 nM) using GFAAS and 20 ??g/L (0.4 ??M) by colorimetry.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taha, Mohd F., E-mail: faisalt@petronas.com.my; Shaharun, Maizatul S.; Shuib, Anis Suhaila, E-mail: anisuha@petronas.com.my

An attempt was made to investigate the potential of rice husk-based activated carbon as an alternative low-cost adsorbent for the removal of Ni(II), Zn(II) and Pb(II) ions from single aqueous solution. Rice husk-based activated carbon was prepared via treatment of rice husk with NaOH followed by the carbonization process at 400°C for 2 hours. Three samples, i.e. raw rice husk, rice husk treated with NaOH and rice husk-based activated carbon, were analyzed for their morphological characteristics using field-emission scanning electron microscope/energy dispersive X-ray (FESEM/EDX). These samples were also analyzed for their carbon, hydrogen, nitrogen, oxygen and silica contents using CHNmore » elemental analyzer and FESEM/EDX. The porous properties of rice husk-based activated carbon were determined by Brunauer-Emmett-Teller (BET) surface area analyzer, and its surface area and pore volume were 255 m{sup 2}/g and 0.17 cm{sup 2}/g, respectively. The adsorption studies for the removal of Ni(II), Zn(II) and Pb(II) ions from single metal aqueous solution were carried out at a fixed initial concentration of metal ion (150 ppm) with variation amount of adsorbent (rice husk-based activated carbon) as a function of varied contact time at room temperature. The concentration of each metal ion was analyzed using atomic absorption spectrophotometer (AAS). The results obtained from adsorption studies indicate the potential of rice husk as an economically promising precursor for the preparation of activated carbon for removal of Ni(II), Zn(II) and Pb(II) ions from single aqueous solution. Isotherm and kinetic model analyses suggested that the experimental data of adsorption studies fitted well with Langmuir, Freundlich and second-order kinetic models.« less

Magnetic and low temperature phonon studies of CoCr2O4 powders doped with Fe(III) and Ni(II) ions

NASA Astrophysics Data System (ADS)

Ptak, M.; Mączka, M.; Pikul, A.; Tomaszewski, P. E.; Hanuza, J.

2014-04-01

Extensive temperature-dependent phonon studies and low-temperature magnetic measurements of CoCr2-xFexO4 (for x=0.5, 1 and 2) and Co0.9Ni0.1Cr2O4 polycrystalline powders are presented. The main aim of these studies was to obtain information on phonon and structural properties of these compounds as well as strength of spin-phonon coupling in the magnetically ordered phases. IR and Raman spectra show that doping of CoCr2O4 with Fe(III) ions leads to broadening of bands and appearance of new bands due to the formation of inverted spinel structure. In contrast to this behavior, doping with 10 mol% of Ni(II) ions leads to weak increase of band width only. Magnetization measured as a function of temperature and external magnetic field showed that magnetic properties of Co0.9Ni0.1Cr2O4 sample are similar to those reported for pure CoCr2O4, i.e., partial substitution of Ni(II) for Co(II) leads to slight shift of the ferrimagnetic phase transition at TC and spiral spin order transition at TS towards lower values. The change of crystallization preference induced by incorporation of increasing concentration of Fe(III) ions in the spinel lattice causes significant increase of TC and decrease of TS. The latter transition disappears completely for higher concentrations of Fe(III). The performed temperature-dependent IR studies revealed interesting anomalous behavior of phonons below TC for CoCr1.5Fe0.5O4 and Co0.9Ni0.1Cr2O4, which was attributed to spin-phonon coupling.

Metal selectivity of the E. coli nickel metallochaperone, SlyD

PubMed Central

Kaluarachchi, Harini; Siebel, Judith F.; Kaluarachchi-Duffy, Supipi; Krecisz, Sandra; Sutherland, Duncan E. K.; Stillman, Martin J.; Zamble, Deborah B.

2012-01-01

SlyD is a Ni(II)-binding protein that contributes to nickel homeostasis in Escherichia coli. The C-terminal domain of SlyD contains a rich variety of metal-binding amino acids, suggesting broader metal-binding capabilities, and previous work demonstrated that the protein can coordinate several types of first row transition metals. However, the binding of SlyD to metals other than Ni(II) has not been previously characterized. To further our understanding of the in vitro metal-binding activity of SlyD and how it correlates with the in vivo function of this protein, the interactions between SlyD and the series of biologically relevant transition metals Mn(II), Fe(II), Co(II), Cu(I) and Zn(II) were examined by using a combination of optical spectroscopy and mass spectrometry. SlyD binding to Mn(II) or to Fe(II) ions was not detected but the protein coordinates multiple ions of Co(II), Zn(II) and Cu(I) with appreciable affinities (KD ≤ nM), highlighting the promiscuous nature of this protein. The order of affinities of SlyD for the metals examined is Mn(II), Fe(II) < Co(II) < Ni(II) ~ Zn(II) ≪ Cu(I). Although the purified protein is unable to overcome the large thermodynamic preference for Cu(I) and exclude Zn(II) chelation in the presence of Ni(II), in vivo studies reveal a Ni(II)-specific function for the protein. Furthermore, these latter experiments support a specific role for SlyD as a [NiFe]-hydrogenase enzyme maturation factor. The implications of the divergence between the metal selectivity of SlyD in vitro and the specific activity in vivo are discussed. PMID:22047179

Metal complexes of a new potentially heptadentate(N 7) tripodal Schiff base ligand. Synthesis, NMR studies and ab initio calculations

NASA Astrophysics Data System (ADS)

Salehzadeh, Sadegh; Javarsineh, Seyed Amrollah; Keypour, Hassan

2006-03-01

Tris(3-aminopropyl)amine, 2-pyridinecarboxaldehyde and a number of metal ions were used to prepare metal complexes of a new fully condensed potentially heptadentate(N 7) tripodal Schiff base ligand (L 333). The resulting complexes, [M(L 333)](ClO 4) 2 {M= Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), and Cd(II); L 333=[N(CH 2CH 2CH 2N dbnd6 CH(C 5H 4N)) 3]}, were characterized by microanalysis, IR and electronic spectra in all cases and by NMR spectra in the case of Zn(II) and Cd(II) complexes: these two are both seven-co-ordinate. The 1H NMR, COSY and HMQC spectra of these complexes show two kinds of protons for each methylene group. The COSY spectrum confirms the geminal coupling of the two protons of each methylene group, indicating that the protons are diastereotopic in rigid six-membered rings. In the 1H NMR spectrum of the cadmium complex the signal of the imine proton has two clear satellites peaks ( 3J=41.9 Hz) with intensities in the ratio 1:6:1 due to coupling with neighbouring 111/113Cd. This coupling constant was confirmed by 113Cd NMR spectroscopy. Ab initio studies on [Fe(L 333)] 2+, [Zn(L 333)] 2+ and [Cd(L 333)] 2+ and also on the previously known complex, [Cd(L Me333)] 2+ are also reported. The results show that the shortest bonding interaction between the metal ion and the bridging tertiary nitrogen atom of the ligand is occurs in the Cd(II) complexes.

Preparation, characterization and biological activity of novel metal-NNNN donor Schiff base complexes

NASA Astrophysics Data System (ADS)

Mohamed, Gehad G.; Omar, M. M.; Ibrahim, Amr A.

2010-02-01

Novel Schiff base (H 2L) ligand is prepared via condensation of benzil and triethylenetetraamine. The ligand is characterized based on elemental analysis, mass, IR and 1H NMR spectra. Metal complexes are reported and characterized based on elemental analyses, IR, 1H NMR, solid reflectance, magnetic moment, molar conductance, and thermal analyses (TG, DTG and DTA). 1:1 [M]:[H 2L] complexes are found from the elemental analyses data having the formulae [M(H 2L)Cl 2]· yH 2O (M = Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II)), [Fe(H 2L)Cl 2]Cl·H 2O, [Th(H 2L)Cl 2]Cl 2·3H 2O and [UO 2(H 2L)](CH 3COO) 2·2H 2O. The metal chelates are found to be non-electrolytes except Fe(III), Th(IV) and UO 2(II) complexes are electrolytes. IR spectra show that H 2L is coordinated to the metal ions in a neutral tetradentate manner with 4Ns donor sites of the two azomethine N and two NH groups. The geometrical structures of these complexes are found to be octahedral. The thermal behaviour of these chelates is studied where the hydrated complexes lose water molecules of hydration in the first step followed immediately by decomposition of the anions and ligand molecules in the subsequent steps. The activation thermodynamic parameters are calculated using Coats-Redfern method. The ligand (H 2L), in comparison to its metal complexes, is screened for its antibacterial activity. The activity data show that the metal complexes have antibacterial activity more than the parent Schiff base ligand and cefepime standard against one or more bacterial species.

Novel mixed ligand complexes of bioactive Schiff base (E)-4-(phenyl (phenylimino) methyl) benzene-1,3-diol and 2-aminophenol/2-aminobenzoic acid: synthesis, spectral characterization, antimicrobial and nuclease studies.

PubMed

Subbaraj, P; Ramu, A; Raman, N; Dharmaraja, J

2014-01-03

A novel bidentate Schiff base ligand has been synthesized using 2,4-dihydroxybenzophenone and aniline. Its mixed ligand complexes of MAB type [M=Mn(II), Co(II), Ni(II), Cu(II) and Zn(II); HA=Schiff base and B=2-aminophenol/2-aminobenzoic acid] have been synthesized and characterized on the basis of spectral data UV-Vis, IR, (1)H NMR, FAB-Mass, EPR, SEM and magnetic studies. All the complexes were soluble in DMF and DMSO. Elemental analysis and molar conductance values indicate that the complexes are non-electrolytes. HA binds with M(II) ions through azomethine and deprotonated phenolic group and B binds through the primary amine group and deprotonated phenolic/carboxylic groups. Using FAB-Mass the cleavage pattern of the ligand (HA) has been established. All the complexes adopt octahedral geometry around the metal ions. It has been confirmed with the help of UV-Vis, IR, (1)H NMR and FAB-Mass spectral data. DNA binding activities of the complexes 1d and 2d are studied by UV-Vis spectroscopy and cleavage studies of Schiff base ligand and its complexes 1d and 2d have been by agarose gel electrophoresis method. In vitro biological activities of the free ligand (HA) and their metal complexes (1a-1e and 2a-2e) were screened against few bacteria, Escherichia coli, Staphylococcus saphyphiticus, Staphylococcus aureus, Pseudomonas aeruginosa and fungi Aspergillus niger, Enterobacter species, Candida albicans by well diffusion technique. Copyright © 2013 Elsevier B.V. All rights reserved.

Chemical and biological evaluation of moxifloxacin-benzimidazole mixed ligands complexes: Anti-cancer and anti-oxidant activities

NASA Astrophysics Data System (ADS)

Refaat, Heba M.; Noor El-Din, Doaa A.

2018-07-01

Novel complexes of the formula [M(MOX)(Ben)Cl(H2O)m].nH2O and [Ag(MOX)(Ben)] 3.5H2O; M = Co, Ni, and Zn, n = 1.5, 2 and 1, m = 0 or 2, MOX; Moxifloxacin and Ben; benzimidazole, were synthesized. Their effect on different cancer cells together with bacterial and fungal activity was determined. Formulation of the complexes was based on elemental analyses, different spectrophotometric methods (FT-IR, UV/Vis, NMR), and magnetic studies. FT-IR data indicated that the bonding of the Co(II), Ni(II) and Zn(II) ions with MOX to be achieved through the quinolone and carboxylate oxygen atoms. On the other hand Ag(I) bonded to the MOX through hydro-pyrrolopyridine nitrogen atom. TGA and DTA studies for the metal complexes showed them to possess considerable stability. Thermodynamic parameters ΔE*, ΔS* and ΔH* were evaluated and the appearance of fractional orders suggested that the reactions proceed via complicated mechanisms. The novel mixed ligands complexes were evaluated for their biological activity against the bacterial species (S. aureus) and (E. coli) and the fungal species Aspergillus flavus and Candida albicans. The complexes were found to possess better antibacterial and antifungal activities compared to the Moxifloxacin ligand. The compounds' effects were also screened for their anti-oxidant activity by DPPH method and were tested for their cytotoxicity activity against Breast cancer cell lines (MCF-7), Colon carcinoma cells (HCT) and Hepatocellular carcinoma cells (HepG2) by viability assay method.

Synthesis, crystal structure, antibacterial activity and theoretical studies on a novel mononuclear cobalt(II) complex based on 2,4,6-tris(2-pyridyl)-1,3,5-triazine ligand

NASA Astrophysics Data System (ADS)

Maghami, Mahboobeh; Farzaneh, Faezeh; Simpson, Jim; Ghiasi, Mina; Azarkish, Mohammad

2015-08-01

A cobalt complex was prepared from CoCl2·6H2O and 2,4,6-tris(2-pyridyl)-1,3,5-triazine (tptz) in methanol and designated as [Co(tptz)(CH3OH)Cl2]·CH3OH·0.5H2O (1). It was characterized by several techniques including TGA analysis and FT-IR, UV-Vis and 1H NMR spectral studies. The crystal structure of 1 was determined by single-crystal X-ray diffraction. The Co(II) metal center in 1 is six coordinated with a distorted octahedral geometry. The tptz ligand is tridentate and coordinates to the cobalt through coplanar nitrogen atoms from the triazine and two pyridyl rings. Two chloride anions and a methanol molecule complete the inner coordination sphere of the metal ion. The optimized geometrical parameters obtained by DFT calculation are in good agreement with single XRD data. The in vitro antibacterial activity of various tptz complexes of Co(II), Ni(II), Cu(II), Mn(II) and Rh(III) were evaluated against Gram-positive (Bacillus subtilis, Staphylococcus aureus and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria. Whereas all complexes exhibited good activity in comparison to standard antibacterial drugs, the inhibitory effects of complexes were found to be more than that of the parent ligand. Overall, the obtained results strongly suggest that the cobalt(II) complex is a suitable candidate for counteracting antibiotic resistant microorganisms.

Rapid Adsorption of Heavy Metals by Fe3O4/Talc Nanocomposite and Optimization Study Using Response Surface Methodology

PubMed Central

Kalantari, Katayoon; Ahmad, Mansor B.; Masoumi, Hamid Reza Fard; Shameli, Kamyar; Basri, Mahiran; Khandanlou, Roshanak

2014-01-01

Fe3O4/talc nanocomposite was used for removal of Cu(II), Ni(II), and Pb(II) ions from aqueous solutions. Experiments were designed by response surface methodology (RSM) and a quadratic model was used to predict the variables. The adsorption parameters such as adsorbent dosage, removal time, and initial ion concentration were used as the independent variables and their effects on heavy metal ion removal were investigated. Analysis of variance was incorporated to judge the adequacy of the models. Optimal conditions with initial heavy metal ion concentration of 100, 92 and 270 mg/L, 120 s of removal time and 0.12 g of adsorbent amount resulted in 72.15%, 50.23%, and 91.35% removal efficiency for Cu(II), Ni(II), and Pb(II), respectively. The predictions of the model were in good agreement with experimental results and the Fe3O4/talc nanocomposite was successfully used to remove heavy metals from aqueous solutions. PMID:25050784

Bis[1-meth­oxy-2,2,2-tris­(pyrazol-1-yl-κN 2)ethane]­nickel(II) bis­(tri­fluoro­methane­sulfonate) methanol disolvate

PubMed Central

Lyubartseva, Ganna; Parkin, Sean; Mallik, Uma Prasad

2013-01-01

In the title salt, [Ni(C12H14N6O)2](CF3SO3)2·2CH3OH, the NiII ion is coordinated by six N atoms from two tridentate 1-meth­oxy-2,2,2-tris­(pyrazol-1-yl)ethane ligands in a distorted octa­hedral geometry. The NiII ion is situated on an inversion centre. The Ni—N distances range from 2.0589 (19) to 2.0757 (19) Å, intra-ligand N—Ni—N angles range from 84.50 (8) to 85.15 (8)°, and adjacent inter-ligand N—Ni—N angles range between 94.85 (8) and 95.50 (8)°. In the crystal, O—H⋯O hydrogen bonds between methanol solvent mol­ecules and tri­fluoro­methane­sulfonate anions are observed. PMID:24098170

A one-dimensional nickel(II) coordination polymer containing 2,6-dipicolinate and dipyrido[3,2-a:2',3'-c]phenazine.

PubMed

Ma, Yi; Zhang, Li-Tian; Wang, Xiao-Fang; He, Yong-Ke; Han, Zheng-Bo

2007-12-01

A new coordination polymer, catena-poly[[(dipyrido[3,2-a:2',3'-c]phenazine-kappa(2)N,N')nickel(II)]-mu-2,6-dipicolinato-kappa(4)O(2),N,O(6):O(2')], [Ni(C7H3NO4)(C18H10N4)]n, exhibits a one-dimensional structure in which 2,6-dipicolinate acts as a bridging ligand interconnecting adjacent nickel(II) centers to form a chain structure. The asymmetric unit contains one Ni(II) center, one dipyrido[3,2-a:2',3'-c]phenazine ligand and one 2,6-dipicolinate ligand. Each Ni(II) center is six-coordinated and surrounded by three N atoms and three O atoms from one dipyrido[3,2-a:2',3'-c]phenazine ligand and two different 2,6-dipicolinate ligands, leading to a distorted octahedral geometry. Adjacent chains are linked by pi-pi stacking interactions and weak interactions to form a three-dimensional supramolecular network.

Removal of Heavy Metals by Adsorption onto Activated Carbon Derived from Pine Cones of Pinus roxburghii.

PubMed

Saif, Muhammad Jawwad; Zia, Khalid Mahmood; Fazal-ur-Rehman; Usman, Muhammad; Hussain, Abdullah Ijaz; Chatha, Shahzad Ali Shahid

2015-04-01

Activated carbon derived from cones of Pinus roxburghii (Himalayan Pine) was used as an adsorbent for the removal of copper, nickel and chromium ions from waste water. Surface analysis was carried out to determine the specific surface area and pore size distribution of the pine cone derived activated carbon. Optimal parameters, effect of adsorbent quantity, pH, equilibrium time, agitation speed and temperature were studied. Equilibrium data were evaluated by Langmuir and Freundlich isotherm models. Langmuir isotherm afforded the best fit to the equilibrium data with a maximum adsorption capacity of 14.2, 31.4 and 29.6 mg/g for Cu(II), Ni(II) and Cr(VI) respectively. Maximum adsorption of Cu(II), Ni(II) was observed in the pH range 4.0 to 4.5, whereas the best adsorption of Cr(VI) was observed at pH 2.5. It was found that 180 minutes was sufficient to gain adsorption equilibrium. The adsorption process follows a pseudo-second-order kinetic model.

Rapid adsorption of heavy metals by Fe3O4/talc nanocomposite and optimization study using response surface methodology.

PubMed

Kalantari, Katayoon; Ahmad, Mansor B; Masoumi, Hamid Reza Fard; Shameli, Kamyar; Basri, Mahiran; Khandanlou, Roshanak

2014-07-21

Fe3O4/talc nanocomposite was used for removal of Cu(II), Ni(II), and Pb(II) ions from aqueous solutions. Experiments were designed by response surface methodology (RSM) and a quadratic model was used to predict the variables. The adsorption parameters such as adsorbent dosage, removal time, and initial ion concentration were used as the independent variables and their effects on heavy metal ion removal were investigated. Analysis of variance was incorporated to judge the adequacy of the models. Optimal conditions with initial heavy metal ion concentration of 100, 92 and 270 mg/L, 120 s of removal time and 0.12 g of adsorbent amount resulted in 72.15%, 50.23%, and 91.35% removal efficiency for Cu(II), Ni(II), and Pb(II), respectively. The predictions of the model were in good agreement with experimental results and the Fe3O4/talc nanocomposite was successfully used to remove heavy metals from aqueous solutions.

A Crystal Field Approach to Orbitally Degenerate SMMs: Beyond the Spin-Only Hamiltonian

NASA Astrophysics Data System (ADS)

Bhaskaran, Lakshmi; Marriott, Katie; Murrie, Mark; Hill, Stephen

Single-Molecule Magnets (SMMs) with large magnetization reversal barriers are promising candidates for high-density information storage. Recently, a large uniaxial magnetic anisotropy was observed for a mononuclear trigonal bipyramidal (TBP) [NiIICl3(Me-abco)2] SMM. High-field EPR studies analyzed on the basis of a spin-only Hamiltonian give ¦D¦>400 cm-1, which is close to the spin-orbit coupling parameter λ = 668 cm-1 for NiII, suggesting an orbitally degenerate ground state. The spin-only description is ineffective in this limit, necessitating the development of a model that includes the orbital moment. Here we describe a phenomenological approach that takes into account a full description of crystal field, electron-electron repulsion and spin-orbit coupling effects on the ground state of a NiII ion in a TBP coordination geometry. The model is in good agreement with the high-field EPR experiments, validating its use for spectroscopic studies of orbitally degenerate molecular nanomagnets. This work was supported by the NSF (DMR-1309463).

Octa-akis(4-amino-pyridine)-1κN,2κN-aqua-2κO-μ-carbonato-1:2κO,O':O''-dinickel(II) dichloride penta-hydrate.

PubMed

Fun, Hoong-Kun; Sinthiya, A; Jebas, Samuel Robinson; Ravindran Durai Nayagam, B; Alfred Cecil Raj, S

2008-10-18

In the title compound, [Ni(2)(CO(3))(C(5)H(6)N(2))(8)(H(2)O)]Cl(2)·5H(2)O, one of the the Ni(II) ions is six-coordinated in a distorted octa-hedral geometry, with the equatorial plane defined by four pyridine N atoms from four amino-pyridine ligands, the axial positions being occupied by one water O and a carbonate O atom. The other Ni(II) ion is also six-coordinated, by four other pyridine N atoms from four other amino-pyridine ligands and two carbonate O atoms to complete a distorted octa-hedral geometry. In the crystal structure, mol-ecules are linked into an infinite three-dimensional network by O-H⋯O, N-H⋯Cl, N-H⋯O, O-H⋯N, C-H⋯O, C-H⋯N and C/N-H⋯π inter-actions involving the pyridine rings.

Optical studies of the X-ray transient XTE J2123-058 - II. Phase-resolved spectroscopy

NASA Astrophysics Data System (ADS)

Hynes, R. I.; Charles, P. A.; Haswell, C. A.; Casares, J.; Zurita, C.; Serra-Ricart, M.

2001-06-01

We present time-resolved spectroscopy of the soft X-ray transient XTEJ2123-058 in outburst. A useful spectral coverage of 3700-6700Å was achieved spanning two orbits of the binary, with single-epoch coverage extending to ~9000Å. The optical spectrum approximates a steep blue power law, consistent with emission on the Rayleigh-Jeans tail of a hot blackbody spectrum. The strongest spectral lines are Heii 4686Å and Ciii/Niii 4640Å (Bowen blend) in emission. Their relative strengths suggest that XTEJ2123-058 was formed in the Galactic plane, not in the halo. Other weak emission lines of Heii and Civ are present, and Balmer lines show a complex structure, blended with Heii. Heii 4686-Å profiles show a complex multiple S-wave structure, with the strongest component appearing at low velocities in the lower-left quadrant of a Doppler tomogram. Hα shows transient absorption between phases 0.35 and 0.55. Both of these effects appear to be analogous to similar behaviour in SW Sex type cataclysmic variables. We therefore consider whether the spectral line behaviour of XTEJ2123-058 can be explained by the same models invoked for those systems.

Excited-state absorption in tetrapyridyl porphyrins: comparing real-time and quadratic-response time-dependent density functional theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bowman, David N.; Asher, Jason C.; Fischer, Sean A.

2017-01-01

Threemeso-substituted tetrapyridyl porphyrins (free base, Ni(ii), and Cu(ii)) were investigated for their optical limiting (OL) capabilities using real-time (RT-), linear-response (LR-), and quadratic-response (QR-) time-dependent density functional theory (TDDFT) methods.

Analysis of transition-metal acetylacetonate complexes by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

PubMed

Wyatt, Mark F; Havard, Stephen; Stein, Bridget K; Brenton, A Gareth

2008-01-01

Transition-metal acetylacetonate complexes of the form Metal(acac)(2), where Metal = Fe(II), Co(II), Ni(II), Cu(II), and Zn(II), and Metal(acac)(3), where Metal = V(III), Cr(III), Mn(III), Fe(III), and Co(III), were investigated by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS). The data was acquired using the aprotic, electron transfer matrix, 2-[(2E)-3-(4-tert-butylphenyl)-2-methylprop-2-enylidene]malononitrile (DCTB), and the observation of positive radical ions is shown clearly to depend on the metal element and the oxidation state it occupies. The ionization energy of DCTB was calculated to be 8.08 eV by density functional theory methods, which is notably lower than the experimental value, but within the range of other computational values. This value is very close to those of the analytes, so the existing electron transfer mechanism which is based on the ionization energies of the matrix and analyte, cannot be used predictively. Similarly, the data neither proves nor disproves the validity of the existing electron transfer ionization mechanism, with respect to metal coordination complexes without strong chromophores. In this case, periodic trends may be more useful in explaining the observed species and the prediction of species from sets of similar complexes. The addition of a sodium salt benefits the MALDI-TOFMS characterization of certain compounds studied, but the benefit of the addition of ammonium or silver salts is negligible.

Chitosan-bound pyridinedicarboxylate Ni(II) and Fe(III) complex biopolymer films as waste water decyanidation agents.

PubMed

Adewuyi, Sheriff; Jacob, Julianah Modupe; Olaleye, Oluwatoyin Omolola; Abdulraheem, Taofiq Olanrewaju; Tayo, Jubril Ayopo; Oladoyinbo, Fatai Oladipupo

2016-10-20

Chitosan is a biopolymer with immense structural advantage for chemical and mechanical modifications to generate novel properties, functions and applications. This work depicts new pyridinedicarboxylicacid (PDC) crosslinked chitosan-metal ion films as veritable material for cyanide ion removal from aqueous solution. The PDC-crosslinked chitosan-metal films (PDC-Chit-Ni(II) and PDC-Chit-Fe(III)) were formed by complexing PDC-crosslinked chitosan film with anhydrous nickel(II) and iron(III) chloride salts respectively. The PDC-Chit and its metal films were characterized employing various analytical and spectroscopic techniques. The FT-IR, UV-vis and the XRD results confirm the presence of the metal ions in the metal coordinated PDC-crosslinked chitosan film. The surface morphological difference of PDC-Chit-Ni(II) film before and after decyanidation was explored with scanning electron microscopy. Furthermore, the quantitative amount of nickel(II) and iron(III) present in the complex were determined using Atomic Absorption Spectrophotometer as 32.3 and 37.2μg/g respectively which portends the biopolymer film as a good complexing agent. Removal of cyanide from aqueous solution with PDC-Chit, PDC-Chit-Ni(II) and PDC-Chit-Fe(III) films was studied with batch equilibrium experiments. At equilibrium, decyanidation capacity (DC) followed the order PDC-Chit-Ni (II)≈PDC-Chit-Fe(III)>PDC-Chit. PDC-Chit-Ni(II) film gave 100% CN(-) removal within 40min decyanidation owing to favorable coordination geometry. Copyright © 2016 Elsevier Ltd. All rights reserved.

Influence of mixed thiolate/thioether versus dithiolate coordination on the accessibility of the uncommon +I and +III oxidation states for the nickel ion: an experimental and computational study.

PubMed

Gennari, Marcello; Orio, Maylis; Pécaut, Jacques; Bothe, Eberhard; Neese, Frank; Collomb, Marie-Noëlle; Duboc, Carole

2011-04-18

Sulfur-rich nickel metalloenzymes are capable of stabilizing Ni(I) and Ni(III) oxidation states in catalytically relevant species. In an effort to better understand the structural and electronic features that allow the stabilization of such species, we have investigated the electrochemical properties of two mononuclear N(2)S(2) Ni(II) complexes that differ in their sulfur environment. Complex 1 features aliphatic dithiolate coordination ([NiL], 1), and complex 2I is characterized by mixed thiolate/thioether coordination ([NiL(Me)]I, 2I). The latter results from the methylation of a single sulfur of 1. The X-ray structure of 2I reveals a distorted square planar geometry around the Ni(II) ion, similar to what was previously reported by us for 1. The electrochemical investigation of 1 and 2(+) shows that the addition of a methyl group shifts the potentials of both redox Ni(II)/Ni(I) and Ni(III)/Ni(II) redox couples by about 0.7 and 0.6 V to more positive values. Through bulk electrolyses, only the mononuclear dithiolate [Ni(I)L](-) (1(-)) and the mixed thiolate/thioether [Ni(III)L(Me)](2+) (2(2+)) complexes were generated, and their electronic properties were investigated by UV-vis and EPR spectroscopy. For 1(-) (Ni(I), d(9) configuration) the EPR data are consistent with a d(x(2))(-)(y(2)) based singly occupied molecular orbitals (SOMOs). However, DFT calculations suggest that there is also pronounced radical character. This is consistent with the small g-anisotropy observed in the EPR experiments. The spin population (Mulliken analysis) analysis of 1(-) reveals that the main contribution to the SOMO (64%) is due to the bipyridine unit. Time dependent density functional theory (TD-DFT) calculations attribute the most prominent features observed in the electronic absorption spectrum of 1(-) to metal to ligand charge transfer (MLCT) transitions. Concerning 2(2+), the EPR spectrum displays a rhombic signal with g(x) = 2.236, g(y) = 2.180, and g(z) = 2.039 in CH(3)CN. The g(iso) value is larger than 2.0, which is consistent with metal based oxidation. The unpaired electron (Ni(III), d(7) configuration) occupies a Ni-d(z(2)) based molecular orbital, consistent with DFT calculations. Nitrogen hyperfine structure is observed as a triplet in the g(z) component of the EPR spectrum with A(N) = 51 MHz. This result indicates the coordination of a CH(3)CN molecule in the axial position. DFT calculations confirm that the presence of a fifth ligand in the coordination sphere of the Ni ion is required for the metal-based oxidation process. Finally, we have shown that 1 exhibits catalytic reductive dehalogenation activity below potentials of -2.00 V versus Fc/Fc(+) in CH(2)Cl(2).

Synthesis, spectral, thermal and biological studies of mixed ligand complexes with newly prepared Schiff base and 1,10-phenanthroline ligands

NASA Astrophysics Data System (ADS)

Abd El-Halim, Hanan F.; Mohamed, Gehad G.; Khalil, Eman A. M.

2017-10-01

A series of mixed ligand complexes were prepared from the Schiff base (L1) as a primary ligand, prepared by condensation of oxamide and furan-2-carbaldehyde, and 1,10-phenanthroline (1,10-phen) as a secondary ligand. The Schiff base ligand and its mixed ligand chelates were characterized based on elemental analysis, IR, 1H NMR, thermal analysis, UV-Visible, mass, molar conductance, magnetic moment. X-ray diffraction, solid reflectance and ESR also have been studied. The mixed ligand complexes were found to have the formulae of [M(L1) (1,10-phen)]Clm.nH2O (M = Cr(III) and Fe(III) (m = 3) (n = 0); M = Mn(II), Cu(II) and Cd(II) (m = 2) (n = 0); and M = Co(II) (m = 2) (n = 1), Ni(II) (m = 2) (n = 2) and Zn(II) (m = 2) (n = 3)) and that the geometrical structure of the complexes were octahedral. The parameters of thermodynamic using Coats-Redfern and Horowitz-Metzger equations were calculated. The synthesized Schiff base ligand, 1,10-phenanthroline ligand and Their mixed ligand complexes were also investigated for their antibacterial and antifungal activity against bacterial species (Gram-Ve bacteria: Pseudomonas aeruginosa and Escherichia coli) and (Gram + Ve bacteria: Bacillus subtilis and Streptococcus pneumonia) and fungi (Aspergillus fumigates and Candida albicans). The anticancer activity of the new compounds had been tested against breast (MFC7) and colon (HCT-116) cell lines. The results showed high activity for the synthesized compounds.

Coordination behavior of new bis Schiff base ligand derived from 2-furan carboxaldehyde and propane-1,3-diamine. Spectroscopic, thermal, anticancer and antibacterial activity studies

NASA Astrophysics Data System (ADS)

Mohamed, Gehad G.; Zayed, Ehab M.; Hindy, Ahmed M. M.

2015-06-01

Novel bis Schiff base ligand, [N1,N3-bis(furan-2-ylmethylene)propane-1,3-diamine], was prepared by the condensation of furan-2-carboxaldehyde with propane-1,3-diamine. Its conformational changes on complexation with transition metal ions [Co(II), Ni(II), Cu(II), Mn(II), Cd(II), Zn(II) and Fe(III)] have been studied on the basis of elemental analysis, conductivity measurements, spectral (infrared, 1H NMR, electronic), magnetic and thermogravimetric studies. The conductance data of the complexes revealed their electrolytic nature suggesting them as 1:2 (for bivalent metal ions) and 1:3 (for Fe(III) ion) electrolytes. The complexes were found to have octahedral geometry based on magnetic moment and solid reflectance measurements. Thermal analysis data revealed the decomposition of the complexes in successive steps with the removal of anions, coordinated water and bis Schiff base ligand. The thermodynamic parameters were calculated using Coats-Redfern equation. The Anticancer screening studies were performed on human colorectal cancer (HCT), hepatic cancer (HepG2) and breast cancer (MCF-7) cell lines. The antimicrobial activity of all the compounds was studied against Gram negative (Escherichia coli and Proteus vulgaris) and Gram positive (Bacillus vulgaris and Staphylococcus pyogones) bacteria. It was observed that the coordination of metal ion has a pronounced effect on the microbial activities of the bis Schiff base ligand. All the metal complexes have shown higher antimicrobial effect than the free bis Schiff base ligand.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Jing-Yun, E-mail: jyunwu@ncnu.edu.tw; Tsai, Chi-Jou; Chang, Ching-Yun

A Zn(II)−salicylaldimine complex [Zn(L{sup salpyca})(H{sub 2}O)]{sub n} (1, where H{sub 2}L{sup salpyca}=4-hydroxy-3-(((pyridin-2-yl)methylimino)methyl)benzoic acid), with a one-dimensional (1D) chain structure, has been successfully converted to a discrete Ni(II)−salicylaldimine complex [Ni(L{sup salpyca})(H{sub 2}O){sub 3}] (2) and an infinite Cu(II)−salicylaldimine complex ([Cu(L{sup salpyca})]·3H{sub 2}O){sub n} (3) through a metal-ion exchange induced structural transformation process. However, such processes do not worked by Mn(II) and Co(II) ions. Solid-state structure analyses reveal that complexes 1–3 form comparable coordinative or supramolecular zigzag chains running along the crystallographic [201] direction. In addition, replacing Zn(II) ion by Ni(II) and Cu(II) ions caused changes in coordination environment and sphere ofmore » metal centers, from a 5-coordinate intermediate geometry of square pyramidal and trigonal bipyramidal in 1 to a 6-coordinate octahedral geometry in 2, and to a 4-coordiante square planar geometry in 3. This study shows that metal-ion exchange serves as a very efficient way of forming new coordination complexes that may not be obtained through direct synthesis. - Graphical abstract: A Zn(II)−salicylaldimine zigzag chain has been successfully converted to a Ni(II)−salicylaldimine supramolecular zigzag chain and a Cu(II)−salicylaldimine coordinative zigzag chain through metal-ion exchange induced structural transformations, which is not achieved by Mn(II) and Co(II) ions.« less

Design, spectral characterization and biological studies of transition metal(II) complexes with triazole Schiff bases.

PubMed

Hanif, Muhammad; Chohan, Zahid H

2013-03-01

A new series of three biologically active triazole derived Schiff base ligands L(1)-L(3) have been synthesized in equimolar reaction of 3-amino-1H-1,2,4-triazole with pyrrol-2-carboxaldehyde, 4-bromo-thiophene-2-carboxaldehyde, and 5-iodo-2-hydroxy benzaldehyde. The prepared Schiff bases were used for further complex formation reaction with different metal elements like Co(II), Ni(II), Cu(II) and Zn(II) as chlorides by using a molar ratio of ligand:metal as 2:1. The structure and bonding nature of all the compounds were identified by their physical, spectral and analytical data. All the metal(II) complexes possessed an octahedral geometry except the Cu(II) complexes which showed a distorted octahedral geometry. All the synthesized compounds, were studied for their in vitro antibacterial, and antifungal activities, against four Gram-negative (Escherichia coli, Shigella sonnei, Pseudomonas aeruginosa and Salmonella typhi) and two Gram-positive (Bacillus subtilis and Staphylococcus aureus) bacterial strains and against six fungal strains (Trichophyton longifusus, Candida albicans, Aspergillus flavus, Microsporum canis, Fusarium solani and Candida glabrata) by using agar-well diffusion method. It has been shown that all the synthesized compounds showed moderate to significant antibacterial activity against one or more bacterial strains. In vitro Brine Shrimp bioassay was also carried out to investigate the cytotoxic properties of these compounds. The data also revealed that the metal complexes showed better activity than the ligands due to chelation/coordination. Copyright © 2012 Elsevier B.V. All rights reserved.

Syntheses, crystallographic, mass-spectroscopic determination and antioxidant studies of Co(II), Ni(II) and Cu(II) complexes of a new imidazol based Schiff base.

PubMed

Demir, Serkan; Güder, Aytaç; Yazıcılar, Turan K; Çağlar, Sema; Büyükgüngör, Orhan

2015-01-01

A new imidazole-based Schiff base, 2-((1H-imidazol-4-yl)methyleneamino)benzylalcohol (HL) and corresponding analogous bis(2-((1H-imidazol-4-yl)methyleneimino)benzylalcohol)metal(II) perchlorates (M: Co(1), Ni(2), Cu(3)) have prepared and characterized by elemental analyses, ESI-MS, IR, UV-Vis spectroscopies and conductivity measurements. X-ray single crystal structures of 1 and 2 have been also determined. Elemental analyses, spectroscopic and conductance data of 3 demonstrated similar structural features with these of crystallographically characterized complexes and based upon this relevances, HL ligands are neutrally coordinated to metal(II) ions in tridentate mode and all complexes are isostructural, dicathionic, contain perchlorate anions as complementary ions and, are in octahedral geometry with the formulae of [M(HL)2](ClO4)2 (for 3) and [M(HL)2](ClO4)2·H2O (for 1 and 2). Radical scavenging activities of the complexes have been evaluated by using DPPH, DMPD(+), and ABTS(+) assays. SC50 values (μg/mL) of the complexes and standards on DPPH, DMPD(+), ABTS(+) follow the sequences, BHA (9.06±0.33)>CMPD3 (15.62±0.52)>CMPD2 (17.43±0.29)>Rutin (21.65±0.60)>CMPD1 (25.67±0.51)>Trolox (28.57±0.37), Rutin>BHA>CMPD3>CMPD2>Trolox>CMPD1, and Trolox>BHA>CMPD3>CMPD2>Rutin>CMPD1 respectively. Copyright © 2015 Elsevier B.V. All rights reserved.

Synthesis, structure and catalytic activities of nickel(II) complexes bearing N4 tetradentate Schiff base ligand

NASA Astrophysics Data System (ADS)

Sarkar, Saikat; Nag, Sanat Kumar; Chattopadhyay, Asoke Prasun; Dey, Kamalendu; Islam, Sk. Manirul; Sarkar, Avijit; Sarkar, Sougata

2018-05-01

Two new nickel(II) complexes [Ni(L)Cl2] (1) and [Ni(L)(NCS)2] (2) of a neutral tetradentate mono-condensed Schiff base ligand, 3-(2-(2-aminoethylamino)ethylimino)butan-2-one oxime (L) have been synthesized and characterized using different physicochemical techniques e.g. elemental analyses, spectroscopic (IR, Electronic, NMR) methods, conductivity and molecular measurements. The crystal structure of complex (2) has been determined by using single crystal X-ray diffraction method and it suggests a distorted octahedral geometry around nickel(II) having a NiN6 coordinating atmosphere. The non-coordinated Osbnd H group on the ligand L remain engaged in H-bonding interactions with the S end of the coordinated thiocyanate moiety. These H-bonding interactions lead to Osbnd S separations of 3.132 Å and play prominent role in crystal packing. It is observed that the mononuclear units are glued together with such Osbnd H…S interactions and finally results in an 1D supramolecular sheet-like arrangement. DFT/TDDFT based theoretical calculations were also performed on the ligand and the complexes aiming at the accomplishment of idea regarding their optimized geometry, electronic transitions and the molecular energy levels. Finally the catalytic behavior of the complexes for oxidation of styrene has also been carried out. A variety of reaction conditions like the effect of solvent, effect of temperature and time as well as the effect of ratio of substrate to oxidant were thoroughly studied to judge the catalytic efficiency of the Ni(II) coordination entity.

Synthesis of some transition metal complexes with new heterocyclic thiazolyl azo dye and their uses as sensitizers in photo reactions

NASA Astrophysics Data System (ADS)

AL-Adilee, Khalid J.; Abass, Ahmed K.; Taher, Ali M.

2016-03-01

A new heterocyclic thiazolylazo dye ligand, 2- [bar2-(4, 5- dimethyl thiazolyl) azo ] -4-Ethoxy Phenol (DMeTAEP), (LH) was synthesized by the diazotization of 4.5-dimethyl thiazolylazonium chloride and coupling with 4- Ethoxy phenol in alkaline alcoholic solution under suitable optimized experimental conditions to yield a new azo dye ligand. The structure of ligand and its complexes was prepared from Co(III), Ni(II), Cu(II), Zn(II), Cd(II), Hg(II), Ag (I) and Au(III) ions. They confirmed by XRD, SEM, (TG-DTG) thermal analysis, 1H-NMR,UV-visb, mass and FT-IR spectroscopic methods, elemental analysis, atomic absorption, magnetic susceptibility and molar conductance. The mole ratio [M: L], it was also studied which was 1:1 for Ag (I) and Au (III) complexes and 1:2 The rest of the metal complexes. The isolated solid complexes are found to have the general formula [M (L)2 ] Cln.mH2O, where n = 1, m = 0 when M = Co (III) and n = 0, m = 1 when M = Ni (II), and Hg(II) while n = 0 and m = 0 when M = Cu (II), Zn (II), Cd (II) and ]ML (H2O)] of Ag(I) - complex but Au(III)-complex structural formula was [Au(L)Cl] Cl conductivity measurements for prepared complexes showed 1:1 electrolyte for Co(III(and Au(III) complexes and non - electrolyte the rest of complexes. The spectral and analytical data revealed that this ligand behaves as a tridentate chelating agent and coordination number of all metal ions were found to be six except for Ag (I) and Au (III) which was four. The activities of complexes were examined as sensitizers in the photocatalytic reaction of p-nitro aniline (PNA) which is used as a model of water pollutants.

Synthesis, structural characterization, in vitro antimicrobial and anticancer activity studies of ternary metal complexes containing glycine amino acid and the anti-inflammatory drug lornoxicam

NASA Astrophysics Data System (ADS)

Mahmoud, Walaa H.; Mohamed, Gehad G.; El-Dessouky, Maher M. I.

2015-02-01

Mixed ligand complexes were synthesized using lornoxicam (LOR) as the primary ligand and glycine amino acid (HGly) as the secondary ligand. They were characterized by FT-IR, UV-Vis, mass, 1H NMR, ESR spectral studies, TG-DTG, X-ray powder diffraction and physical analytical studies. From the molar conductance, magnetic moment and electronic spectral data of the synthesized complexes, general formulae of [M(LOR)2(Gly)]·Xn·yH2O where M = Cr(III) (X = Cl, n = 2, y = 3), Mn(II) (X = Cl, n = 1, y = 1), Co(II) (X = BF4, n = 1, y = 0), Ni(II) (X = Cl, n = 1, y = 0), Cu(II) (X = BF4, n = 1, y = 2) and Zn(II) (X = BF4, n = 1, y = 2) and (M = Fe(II) (X = BF4, n = 1, y = 1) and Fe(III) (X = Cl, n = 2, y = 1) with an octahedral structure were proposed. Thermal analyses show that the complexes lose water molecules of hydration initially and subsequently expel anionic parts and organic ligands in continuous steps. The kinetic parameters namely E, ΔH∗, ΔS∗ and ΔG∗ illustrate the spontaneous association of the metal and ligands in the formation of the complexes. The antimicrobial efficiency of the LOR and HGly ligands and the ternary complexes were examined by in vitro method against various pathogenic bacterial and fungal strains. The metal complexes were found to possess efficient antimicrobial properties compared to lornoxicam and most of these complexes could turn out to be excellent models for the design of effective antibiotic drug substances. Also, the two ligands, in comparison to ternary metal complexes are screened for their anticancer activity against breastic cancer cell line. The results showed that the metal complexes be more active than the parent LOR and glycine free ligands except Cr(III) ternary complex which was found to be inactive.

Magnetic anisotropy in binuclear complexes in the weak-exchange limit: From the multispin to the giant-spin Hamiltonian

NASA Astrophysics Data System (ADS)

Maurice, Rémi; de Graaf, Coen; Guihéry, Nathalie

2010-06-01

This paper studies the physical basis of the giant-spin Hamiltonian, which is usually used to describe the anisotropy of single-molecule magnets. A rigorous extraction of the model has been performed in the weak-exchange limit of a binuclear centrosymmetric Ni(II) complex, using correlated ab initio calculations and effective Hamiltonian theory. It is shown that the giant-spin Hamiltonian is not appropriate to describe polynuclear complexes as soon as spin mixing becomes non-negligible. A relevant model is proposed involving fourth-order operators, different from the traditionally used Stevens operators. The new giant-spin Hamiltonian correctly reproduces the effects of the spin mixing in the weak-exchange limit. A procedure to switch on and off the spin mixing in the extraction has been implemented in order to separate this effect from other anisotropic effects and to numerically evaluate both contributions to the tunnel splitting. Furthermore, the new giant-spin Hamiltonian has been derived analytically from the multispin Hamiltonian at the second order of perturbation and the theoretical link between the two models is studied to gain understanding concerning the microscopic origin of the fourth-order interaction in terms of axial, rhombic, or mixed (axial-rhombic) character. Finally, an adequate method is proposed to extract the proper magnetic axes frame for polynuclear anisotropic systems.

A novel Ni(4) complex exhibiting microsecond quantum tunneling of the magnetization.

PubMed

Aromí, Guillem; Bouwman, Elisabeth; Burzurí, Enrique; Carbonera, Chiara; Krzystek, J; Luis, Fernando; Schlegel, Christoph; van Slageren, Joris; Tanase, Stefania; Teat, Simon J

2008-01-01

A highly asymmetric Ni(II) cluster [Ni(4)(OH)(OMe)(3)(Hphpz)(4)(MeOH)(3)](MeOH) (1) (H(2)phpz=3-methyl-5-(2-hydroxyphenyl)pyrazole) has been prepared and its structure determined by means of single-crystal X-ray diffraction by using synchrotron radiation. Variable-temperature bulk-magnetization measurements show that the complex exhibits intramolecular-ferromagnetic interactions leading to a spin ground state S=4 with close-lying excited states. Magnetization and high-frequency EPR measurements suggest the presence of sizable Ising-type magnetic anisotropy, with zero-field splitting parameters D=-0.263 cm(-1) and E=0.04 cm(-1) for the spin ground state, and an isotropic g value of 2.25. The presence of both axial and transverse anisotropy was confirmed through low-temperature specific heat determinations down to 300 mK, but no slow relaxation of the magnetization was observed by AC measurements down to 1.8 K. Interestingly, AC susceptibility measurements down to temperatures as low as 23 mK showed no indication of slow relaxation of the magnetization in 1. Thus, despite the presence of an anisotropy barrier (U approximately 4.21 cm(-1) for the purely axial limit), the magnetization relaxation remains extremely fast down to the lowest temperatures. The estimated quantum tunneling rate, Gamma>0.667 MHz, makes this complex a prime candidate for observation of coherent tunneling of the magnetization.

Mesoporous silica nanoparticles supported copper(II) and nickel(II) Schiff base complexes: Synthesis, characterization, antibacterial activity and enzyme immobilization

NASA Astrophysics Data System (ADS)

Tahmasbi, Leila; Sedaghat, Tahereh; Motamedi, Hossein; Kooti, Mohammad

2018-02-01

Mesoporous silica nanoparticles (MSNs) were prepared by sol-gel method and functionalized with 3-aminopropyltriethoxysilane. Schiff base grafted mesoporous silica nanoparticle was synthesized by the condensation of 2-hydroxy-3-methoxybenzaldehyde and amine-functionalized MSNs. The latter material was then treated with Cu(II) and Ni(II) salts separately to obtain copper and nickel complexes anchored mesoporous composites. The newly prepared hybrid organic-inorganic nanocomposites have been characterized by several techniques such as FT-IR, LA-XRD, FE-SEM, TEM, EDS, BET and TGA. The results showed all samples have MCM-41 type ordered mesoporous structure and functionalization occurs mainly inside the mesopore channel. The presence of all elements in synthesized nanocomposites and the coordination of Schiff base via imine nitrogen and phenolate oxygen were confirmed. MSNs and all functionalized MSNs have uniform spherical nanoparticles with a mean diameter less than 100 nm. The as-synthesized mesoporous nanocomposites were investigated for antibacterial activity against Gram-positive (B. subtilis and S. aureus) and Gram-negative (E. coli and P. aeruginosa) bacteria, as carrier for gentamicin and also for immobilization of DNase, coagulase and amylase enzymes. MSN-SB-Ni indicated bacteriocidal effect against S.aureus and all compounds were found to be good carrier for gentamicin. Results of enzyme immobilization for DNase and coagulase and α-amylase revealed that supported metal complexes efficiently immobilized enzymes.

Synthesis, characterization and anticancer studies of Ni(II), Pd(II) and Pt(II) complexes with Schiff base derived from N-methylhydrazinecarbothioamide and 2-hydroxy-5-methoxy-3-nitrobenzaldehyde

NASA Astrophysics Data System (ADS)

Arafath, Md. Azharul; Adam, Farook; Razali, Mohd. R.; Ahmed Hassan, Loiy E.; Ahamed, Mohamed B. Khadeer; Majid, Amin Malik S. A.

2017-02-01

A carbothioamide NSO tridentate Schiff base ligand (HL) and its square planar complexes Na[NiLOAc], Na[PdLOAc] and [PtLdmso] have been synthesized and characterized on the basis of melting point, elemental analysis, FT-IR, 1H NMR, 13C NMR, UV-Vis spectra. The structure of HL was elucidated with X-ray diffraction analysis. In the present study, the synthesized compounds were evaluated for their anticancer properties against three human cancer cell lines breast cancer (MCF-7), cervical (Hela), and colon (HCT-116). In addition, the cytotoxicity of the synthesized compounds was tested on a normal human cell line (human endothelial cell line EA.hy926). Among the tested compounds, the complex [NiLOAc] excelled in halting proliferation of the cervical and colon cancer cells with median inhibitory concentration (IC50) values of 28.33 and 34.4 μM, respectively. The complex, [PdLOAc] demonstrated selective cytotoxicity against breast cancer line MCF-7 with IC50 = 47.5 μM, while HL showed inhibitory effect against colon cancer cell line (HCT-116) with IC50 = 55.66 μM. The complex, [PtLdmso] showed mild activity against breast cancer (MCF-7) and cervical cancer (Hela) cells with IC50 = 64.44 and 68.3 μM, respectively, whereas, it displayed insignificant cytotoxicity against human endothelial cells (EA.hy926) with IC50 > 200 μM. Cancer cells treated with [NiLOAc] showed apoptotic features such as membrane blebbing and DNA condensation. Thus, the findings of the present study demonstrated that the series of metal complexes of HL could form the new lead for development of cancer chemotherapies to treat human cervical, breast and colon malignancies.

Cyanovanadate(III) complexes as novel additives for efficient generation of volatile cadmium species in complex samples prior to determinations by inductively coupled plasma mass spectrometry (ICP-MS)

PubMed Central

Yilmaz, Vedat; Arslan, Zikri; Rose, LaKeysha; Little, Maria D.

2013-01-01

A new method has been described for generation of volatile species of Cd using vanadium(III) cyanide complex. Aqueous solutions of 0.04 mol L−1 vanadium chloride (VCl3) and 0.12 mol L−1 potassium cyanide (KCN) were reacted on-line yielding a suspension of vanadium hydroxide, V(OH)3. This suspension was dissolved along the stream of sample solution in dilute HCl to form heptacyanovanadate(III) complex, [V(CN)7]4−. Volatile Cd species were generated by reacting the stream of sample solution and cyanovanadate(III) complex with sodium borohydride (NaBH4). Feasibility of off-line and on-online approaches was investigated for quantitative determinations. Better precision and daily stability were achieved with on-line settings. Optimum signals were obtained from sample solutions within a range of 3 to 5% v/v HCl. A concentration of 2% m/v NaBH4 was adequate to achieve an enhancement of 20-fold in the presence of cyanovanadate(III) complex. The limits of detection were 5.0 and 4.5 ng L−1 for 110Cd and 111Cd isotopes, respectively. Precision (%RSD) was better than 4.7% for six replicate measurements. The interferences of Cu(II) and Ni(II) were marginal (<10%) at 1.0 μg mL−1. Depressive effects from Bi, Se and Sn were not significant below 0.1 μg mL−1. The method was validated by determination of Cd using ICP-MS in certified reference materials of Nearshore seawater (CASS-4), Bone ash (SRM 1400), Dogfish liver (DOLT-4) and Mussel tissue (SRM 2976). PMID:24014893

Insight into the structure and mechanism of nickel-containing superoxide dismutase derived from peptide-based mimics.

PubMed

Shearer, Jason

2014-08-19

Nickel superoxide dismutase (NiSOD) is a nickel-containing metalloenzyme that catalyzes the disproportionation of superoxide through a ping-pong mechanism that relies on accessing reduced Ni(II) and oxidized Ni(III) oxidation states. NiSOD is the most recently discovered SOD. Unlike the other known SODs (MnSOD, FeSOD, and (CuZn)SOD), which utilize "typical" biological nitrogen and oxygen donors, NiSOD utilizes a rather unexpected ligand set. In the reduced Ni(II) oxidation state, NiSOD utilizes nitrogen ligands derived from the N-terminal amine and an amidate along with two cysteinates sulfur donors. These are unusual biological ligands, especially for an SOD: amine and amidate donors are underrepresented as biological ligands, whereas cysteinates are highly susceptible to oxidative damage. An axial histidine imidazole binds to nickel upon oxidation to Ni(III). This bond is long (2.3-2.6 Å) owing to a tight hydrogen-bonding network. All of the ligating residues to Ni(II) and Ni(III) are found within the first 6 residues from the NiSOD N-terminus. Thus, small nickel-containing metallopeptides derived from the first 6-12 residues of the NiSOD sequence can reproduce many of the properties of NiSOD itself. Using these nickel-containing metallopeptide-based NiSOD mimics, we have shown that the minimal sequence needed for nickel binding and reproduction of the structural, spectroscopic, and functional properties of NiSOD is H2N-HCXXPC. Insight into how NiSOD avoids oxidative damage has also been gained. Using small NiN2S2 complexes and metallopeptide-based mimics, it was shown that the unusual nitrogen donor atoms protect the cysteinates from oxidative damage (both one-electron oxidation and oxygen atom insertion reactions) by fine-tuning the electronic structure of the nickel center. Changing the nitrogen donor set to a bis-amidate or bis-amine nitrogen donor led to catalytically nonviable species owing to nickel-cysteinate bond oxidative damage. Only the amine/amidate nitrogen donor atoms within the NiSOD ligand set produce a catalytically viable species. These metallopeptide-based mimics have also hinted at the detailed mechanism of SOD catalysis by NiSOD. One such aspect is that the axial imidazole likely remains ligated to the Ni center under rapid catalytic conditions (i.e., high superoxide loads). This reduces the degree of structural rearrangement about the nickel center, leading to higher catalytic rates. Metallopeptide-based mimics have also shown that, although an axial ligand to Ni(III) is required for catalysis, the rates are highest when this is a weak interaction, suggesting a reason for the long axial His-Ni(III) bond found in NiSOD. These mimics have also suggested a surprising mechanistic insight: O2(-) reduction via a "H(•)" tunneling event from a R-S(H(+))-Ni(II) moiety to O2(-) is possible. The importance of this mechanism in NiSOD has not been verified.

Electron paramagnetic resonance and density-functional theory studies of Cu(II)-bis(oxamato) complexes.

PubMed

Bräuer, Björn; Weigend, Florian; Fittipaldi, Maria; Gatteschi, Dante; Reijerse, Edward J; Guerri, Annalisa; Ciattini, Samuele; Salvan, Georgeta; Rüffer, Tobias

2008-08-04

In this work we present the investigation of the influence of electronic and structural variations induced by varying the N,N'-bridge on the magnetic properties of Cu(II)- bis(oxamato) complexes. For this study the complexes [Cu(opba)] (2-) ( 1, opba = o-phenylene- bis(oxamato)), [Cu(nabo)] (2-) ( 2, nabo = 2,3-naphthalene- bis(oxamato)), [Cu(acbo)] (2-) ( 3, acbo = 2,3-anthrachinone- bis(oxamato)), [Cu(pba)] (2-) ( 4, pba = propylene- bis(oxamato)), [Cu(obbo)] (2-) ( 5, obbo = o-benzyl- bis(oxamato)), and [Cu(npbo)] (2-) ( 6, npbo = 1,8-naphthalene- bis(oxamato)), and the respective structurally isomorphic Ni(II) complexes ( 8- 13) have been prepared as ( (n)Bu 4N) (+) salts. The new complex ( (n)Bu 4N) 2[Cu(R-bnbo)].2H 2O ( 7, R-bnbo = (R)-1,1'-binaphthalene-2,2'- bis(oxamato)) was synthesized and is the first chiral complex in the series of Cu(II)-bis(oxamato) complexes. The molecular structure of 7 has been determined by single crystal X-ray analysis. The Cu(II) ions of the complexes 1- 7 are eta (4)(kappa (2) N, kappa (2) O) coordinated with a more or less distorted square planar geometry for 1- 6 and a distorted tetrahedral geometry for 7. Using pulsed Electron Nuclear Double Resonance on complex 6, detailed information about the relative orientation of the hyperfine ( A) and nuclear quadrupole tensors ( Q) of the coordinating nitrogens with respect to the g tensor were obtained. Electron Paramagnetic Resonance studies in the X, Q, and W-band at variable temperatures were carried out to extract g and A values of N ligands and Cu ion for 1- 7. The hyperfine values were interpreted in terms of spin population on the corresponding atoms. The obtained trends of the spin population for the monomeric building blocks were shown to correlate to the trends obtained in the dependence of the exchange interaction of the corresponding trinuclear complexes on their geometry.

Chemical Remediation of Nickel(II) Waste: A Laboratory Experiment for General Chemistry Students

ERIC Educational Resources Information Center

Corcoran, K. Blake; Rood, Brian E.; Trogden, Bridget G.

2011-01-01

This project involved developing a method to remediate large quantities of aqueous waste from a general chemistry laboratory experiment. Aqueous Ni(II) waste from a general chemistry laboratory experiment was converted into solid nickel hydroxide hydrate with a substantial decrease in waste volume. The remediation method was developed for a…

β-Octakis(methylthio)porphycenes: synthesis, characterisation and third order nonlinear optical studies.

PubMed

Rana, Anup; Lee, Sangsu; Kim, Dongho; Panda, Pradeepta K

2015-05-04

A novel electron deficient β-octakis(methylthio)porphycene, along with its Zn(ii) and Ni(ii) derivatives, was synthesized for the first time. The macrocyclic structure exhibits core ruffling with a largely red shifted absorption band (∼750 nm) and also a large enhancement in the third order nonlinear optical response.

Postsynthetic Improvement of the Physical Properties in a Metal-Organic Framework through a Single Crystal to Single Crystal Transmetallation.

PubMed

Grancha, Thais; Ferrando-Soria, Jesús; Zhou, Hong-Cai; Gascon, Jorge; Seoane, Beatriz; Pasán, Jorge; Fabelo, Oscar; Julve, Miguel; Pardo, Emilio

2015-05-26

A single crystal to single crystal transmetallation process takes place in the three-dimensional (3D) metal-organic framework (MOF) of formula Mg(II) 2 {Mg(II) 4 [Cu(II) 2 (Me3 mpba)2 ]3 }⋅45 H2 O (1; Me3 mpba(4-) =N,N'-2,4,6-trimethyl-1,3-phenylenebis(oxamate)). After complete replacement of the Mg(II) ions within the coordination network and those hosted in the channels by either Co(II) or Ni(II) ions, 1 is transmetallated to yield two novel MOFs of formulae Co2 (II) {Co(II) 4 [Cu(II) 2 (Me3 mpba)2 ]3 }⋅56 H2 O (2) and Ni2 (II) {Ni(II) 4 [Cu(II) 2 (Me3 mpba)2 ]3 }⋅ 54 H2 O (3). This unique postsynthetic metal substitution affords materials with higher structural stability leading to enhanced gas sorption and magnetic properties. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Octa­akis(4-amino­pyridine)-1κ4 N 1,2κ4 N 1-aqua-2κO-μ-carbonato-1:2κ3 O,O′:O′′-dinickel(II) dichloride penta­hydrate

PubMed Central

Fun, Hoong-Kun; Sinthiya, A; Jebas, Samuel Robinson; Ravindran Durai Nayagam, B.; Alfred Cecil Raj, S.

2008-01-01

In the title compound, [Ni2(CO3)(C5H6N2)8(H2O)]Cl2·5H2O, one of the the NiII ions is six-coordinated in a distorted octa­hedral geometry, with the equatorial plane defined by four pyridine N atoms from four amino­pyridine ligands, the axial positions being occupied by one water O and a carbonate O atom. The other NiII ion is also six-coordinated, by four other pyridine N atoms from four other amino­pyridine ligands and two carbonate O atoms to complete a distorted octa­hedral geometry. In the crystal structure, mol­ecules are linked into an infinite three-dimensional network by O—H⋯O, N—H⋯Cl, N—H⋯O, O—H⋯N, C—H⋯O, C—H⋯N and C/N—H⋯π inter­actions involving the pyridine rings. PMID:21580879

Pupil constriction evoked in vitro by stimulation of the oculomotor nerve in the turtle (Trachemys scripta elegans).

PubMed

Dearworth, James R; Brenner, J E; Blaum, J F; Littlefield, T E; Fink, D A; Romano, J M; Jones, M S

2009-01-01

The pond turtle (Trachemys scripta elegans) exhibits a notably sluggish pupillary light reflex (PLR), with pupil constriction developing over several minutes following light onset. In the present study, we examined the dynamics of the efferent branch of the reflex in vitro using preparations consisting of either the isolated head or the enucleated eye. Stimulation of the oculomotor nerve (nIII) using 100-Hz current trains resulted in a maximal pupil constriction of 17.4% compared to 27.1% observed in the intact animal in response to light. When current amplitude was systematically increased from 1 to 400 microA, mean response latency decreased from 64 to 45 ms, but this change was not statistically significant. Hill equations fitted to these responses indicated a current threshold of 3.8 microA. Stimulation using single pulses evoked a smaller constriction (3.8%) with response latencies and threshold similar to that obtained using train stimulation. The response evoked by postganglionic stimulation of the ciliary nerve using 100-Hz trains was largely indistinguishable from that of train stimulation of nIII. However, application of single-pulse stimulation postganglionically resulted in smaller pupil constriction at all current levels relative to that of nIII stimulation, suggesting that there is amplification of efferent drive at the ganglion. Time constants for constrictions ranged from 88 to 154 ms with relaxations occurring more slowly at 174-361 ms. These values for timing from in vitro are much faster than the time constant 1.66 min obtained for the light response in the intact animal. The rapid dynamics of pupil constriction observed here suggest that the slow PLR of the turtle observed in vivo is not due to limitations of the efferent pathway. Rather, the sluggish response probably results from photoreceptive mechanisms or central processing.

Characterization of a novel chelating resin of enhanced hydrophilicity and its analytical utility for preconcentration of trace metal ions.

PubMed

Islam, Aminul; Laskar, Mohammad Asaduddin; Ahmad, Akil

2010-06-15

A stable extractor of metal ions was synthesized through azo linking of p-hydroxybenzoic acid with Amberlite XAD-4 and was characterized by elemental analyses, infrared spectral and thermal studies. Its water regain value and hydrogen ion capacity were found to be 15.80 and 7.52mmolg(-1), respectively. Both batch and column methods were employed to study the sorption behavior for the metal ions which were subsequently determined by flame atomic absorption spectrophotometry. The optimum pH range for Co(II), Ni(II), Cu(II), Zn(II), and Pb(II) ions were 10.0, 8.0-9.0, 7.0, 7.0-8.0 and 7.0-8.0, respectively. The half-loading time, t(1/2), are 6.0, 8.0, 8.0, 8.0 and 4.0min, respectively. Comparison of breakthrough and overall capacities of the metals ascertains the high degree of column utilization (>75%). The breakthrough capacities for Co(II), Ni(II), Cu(II), Zn(II), and Pb(II) ions were found to be 0.46, 0.43, 0.42, 0.09 and 0.06mmolg(-1) with the corresponding preconcentration factor of 460, 460, 460, 360 and 260, respectively. The limit of preconcentration was in the range of 4.3-7.6microgL(-1). The detection limit for Co(II), Ni(II), Cu(II), Zn(II) and Pb(II) were found to be 0.47, 0.45, 0.50, 0.80, and 1.37microgL(-1), respectively. The Student's t (t-test) values for the analysis of standard reference materials were found to be less than the critical Student's t values at 95% confidence level. The AXAD-4-HBA has been successfully applied for the analysis of natural water, multivitamin formulation, infant milk substitute, hydrogenated oil and fish.

Ferrate(VI)-prompted removal of metals in aqueous media: mechanistic delineation of enhanced efficiency via metal entrenchment in magnetic oxides.

PubMed

Prucek, Robert; Tuček, Jiří; Kolařík, Jan; Hušková, Ivana; Filip, Jan; Varma, Rajender S; Sharma, Virender K; Zbořil, Radek

2015-02-17

The removal efficiency of heavy metal ions (cadmium(II), Cd(II); cobalt(II), Co(II); nickel(II), Ni(II); copper(II), Cu(II)) by potassium ferrate(VI) (K2FeO4, Fe(VI)) was studied as a function of added amount of Fe(VI) (or Fe) and varying pH. At pH = 6.6, the effective removal of Co(II), Ni(II), and Cu(II) from water was observed at a low Fe-to-heavy metal ion ratio (Fe/M(II) = 2:1) while a removal efficiency of 70% was seen for Cd(II) ions at a high Fe/Cd(II) weight ratio of 15:1. The role of ionic radius and metal valence state was explored by conducting similar removal experiments using Al(III) ions. The unique combination of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), in-field Mössbauer spectroscopy, and magnetization measurements enabled the delineation of several distinct mechanisms for the Fe(VI)-prompted removal of metal ions. Under a Fe/M weight ratio of 5:1, Co(II), Ni(II), and Cu(II) were removed by the formation of MFe2O4 spinel phase and partially through their structural incorporation into octahedral positions of γ-Fe2O3 (maghemite) nanoparticles. In comparison, smaller sized Al(III) ions got incorporated easily into the tetrahedral positions of γ-Fe2O3 nanoparticles. In contrast, Cd(II) ions either did not form the spinel ferrite structure or were not incorporated into the lattic of iron(III) oxide phase due to the distinct electronic structure and ionic radius. Environmentally friendly removal of heavy metal ions at a much smaller dosage of Fe than those of commonly applied iron-containing coagulants and the formation of ferrimagnetic species preventing metal ions leaching back into the environment and allowing their magnetic separation are highlighted.

Synthesis, spectroscopic and biological activities studies of acyclic and macrocyclic mono and binuclear metal complexes containing a hard-soft Schiff base

NASA Astrophysics Data System (ADS)

Abou-Hussein, Azza A. A.; Linert, Wolfgang

Mono- and bi-nuclear acyclic and macrocyclic complexes with hard-soft Schiff base, H2L, ligand derived from the reaction of 4,6-diacetylresorcinol and thiocabohydrazide, in the molar ratio 1:2 have been prepared. The H2L ligand reacts with Co(II), Ni(II), Cu(II), Zn(II), Mn(II) and UO2(VI) nitrates, VO(IV) sulfate and Ru(III) chloride to get acyclic binuclear complexes except for VO(IV) and Ru(III) which gave acyclic mono-nuclear complexes. Reaction of the acyclic mono-nuclear VO(IV) and Ru(III) complexes with 4,6-diacetylresorcinol afforded the corresponding macrocyclic mono-nuclear VO(IV) and Ru(IIII) complexes. Template reactions of the 4,6-diacetylresorcinol and thiocarbohydrazide with either VO(IV) or Ru(III) salts afforded the macrocyclic binuclear VO(IV) and Ru(III) complexes. The Schiff base, H2L, ligand acts as dibasic with two NSO-tridentate sites and can coordinate with two metal ions to form binuclear complexes after the deprotonation of the hydrogen atoms of the phenolic groups in all the complexes, except in the case of the acyclic mononuclear Ru(III) and VO(IV) complexes, where the Schiff base behaves as neutral tetradentate chelate with N2S2 donor atoms. The ligands and the metal complexes were characterized by elemental analysis, IR, UV-vis 1H-NMR, thermal gravimetric analysis (TGA) and ESR, as well as the measurements of conductivity and magnetic moments at room temperature. Electronic spectra and magnetic moments of the complexes indicate the geometries of the metal centers are either tetrahedral, square planar or octahedral. Kinetic and thermodynamic parameters were calculated using Coats-Redfern equation, for the different thermal decomposition steps of the complexes. The ligands and the metal complexes were screened for their antimicrobial activity against Staphylococcus aureus as Gram-positive bacteria, and Pseudomonas fluorescens as Gram-negative bacteria in addition to Fusarium oxysporum fungus. Most of the complexes exhibit mild antibacterial and antifungal activities against these organisms.

Synthesis, spectroscopic and biological activities studies of acyclic and macrocyclic mono and binuclear metal complexes containing a hard-soft Schiff base.

PubMed

Abou-Hussein, Azza A A; Linert, Wolfgang

2012-09-01

Mono- and bi-nuclear acyclic and macrocyclic complexes with hard-soft Schiff base, H(2)L, ligand derived from the reaction of 4,6-diacetylresorcinol and thiocabohydrazide, in the molar ratio 1:2 have been prepared. The H(2)L ligand reacts with Co(II), Ni(II), Cu(II), Zn(II), Mn(II) and UO(2)(VI) nitrates, VO(IV) sulfate and Ru(III) chloride to get acyclic binuclear complexes except for VO(IV) and Ru(III) which gave acyclic mono-nuclear complexes. Reaction of the acyclic mono-nuclear VO(IV) and Ru(III) complexes with 4,6-diacetylresorcinol afforded the corresponding macrocyclic mono-nuclear VO(IV) and Ru(IIII) complexes. Template reactions of the 4,6-diacetylresorcinol and thiocarbohydrazide with either VO(IV) or Ru(III) salts afforded the macrocyclic binuclear VO(IV) and Ru(III) complexes. The Schiff base, H(2)L, ligand acts as dibasic with two NSO-tridentate sites and can coordinate with two metal ions to form binuclear complexes after the deprotonation of the hydrogen atoms of the phenolic groups in all the complexes, except in the case of the acyclic mononuclear Ru(III) and VO(IV) complexes, where the Schiff base behaves as neutral tetradentate chelate with N(2)S(2) donor atoms. The ligands and the metal complexes were characterized by elemental analysis, IR, UV-vis (1)H-NMR, thermal gravimetric analysis (TGA) and ESR, as well as the measurements of conductivity and magnetic moments at room temperature. Electronic spectra and magnetic moments of the complexes indicate the geometries of the metal centers are either tetrahedral, square planar or octahedral. Kinetic and thermodynamic parameters were calculated using Coats-Redfern equation, for the different thermal decomposition steps of the complexes. The ligands and the metal complexes were screened for their antimicrobial activity against Staphylococcus aureus as Gram-positive bacteria, and Pseudomonas fluorescens as Gram-negative bacteria in addition to Fusarium oxysporum fungus. Most of the complexes exhibit mild antibacterial and antifungal activities against these organisms. Copyright © 2012 Elsevier B.V. All rights reserved.

Effect of IDA and TREN chelating agents and buffer systems on the purification of human IgG with immobilized nickel affinity membranes.

PubMed

Ribeiro, Mariana Borsoi; Vijayalakshmi, Mookambesvaran; Todorova-Balvay, Daniele; Bueno, Sonia Maria Alves

2008-01-01

The purification of IgG from human plasma was studied by comparing two affinity membranes complexed with Ni(II), prepared by coupling iminodiacetic acid (IDA) and Tris(2-aminoethyl)amine (TREN) to poly(ethylenevinyl alcohol), PEVA, hollow fiber membranes. The Ni(II)-TREN-PEVA hollow fiber membrane had lower capacity for human IgG than the complex Ni(II)-IDA-PEVA, but with similar selectivity. The IgG in peak fractions eluted from the Ni(II)-IDA-PEVA with a stepwise concentration gradient of Tris-HCl pH 7.0 (100-700 mM) reached a purity of 98% (based on IgG, IgM, IgA, albumin, and transferrin nephelometric analysis). Adsorption IgG data at different temperatures (4-37 degrees C) were analyzed using Langmuir model resulting in a calculated maximum capacity at 25 degrees C of 204.6 mg of IgG/g of dry membrane. Decrease in Kd with increasing temperature (1.7x10(-5) to 5.3x10(-6) M) indicated an increase in affinity with increased temperature. The positive value of enthalpy change (26.2 kJ/mol) indicated that the adsorption of IgG in affinity membrane is endothermic. Therefore, lower temperature induces adsorption as verified experimentally.

Potentiometric and spectroscopic study of the interaction of 3d transition metal ions with inositol hexakisphosphate

NASA Astrophysics Data System (ADS)

Veiga, Nicolás; Macho, Israel; Gómez, Kerman; González, Gabriel; Kremer, Carlos; Torres, Julia

2015-10-01

Among myo-inositol phosphates, the most abundant in nature is the myo-inositol hexakisphosphate, InsP6. Although it is known to be vital to cell functioning, the biochemical research into its metabolism needs chemical and structural analysis of all the protonation, complexation and precipitation processes that it undergoes in the biological media. In view of its high negative charge at physiological level, our group has been leading a thorough research into the InsP6 chemical and structural behavior in the presence of the alkali and alkaline earth metal ions essential for life. The aim of this article is to extend these studies, dealing with the chemical and structural features of the InsP6 interaction with biologically relevant 3d transition metal ions (Fe(II), Fe(III), Mn(II), Co(II), Ni(II), Cu(II) and Zn(II)), in a non-interacting medium and under simulated physiological conditions. The metal-complex stability constants were determined by potentiometry, showing under ligand-excess conditions the formation of mononuclear species in different protonation states. Under metal ion excess, polymetallic species were detected for Fe(II), Fe(III), Zn(II) and Cu(II). Additionally, the 31P NMR and UV-vis spectroscopic studies provided interesting structural aspects of the strong metal ion-InsP6 interaction.

Syntheses, structural characterization and spectroscopic studies of cadmium(II)-metal(II) cyanide complexes with 4-(2-aminoethyl)pyridine

NASA Astrophysics Data System (ADS)

Karaağaç, Dursun; Kürkçüoğlu, Güneş Süheyla; Şenyel, Mustafa; Hökelek, Tuncer

2017-02-01

Three new cadmium(II)-metal(II) cyanide complexes, [Cd(4aepy)2(H2O)2][Ni(CN)4] (1), [Cd(4aepy)2(H2O)2][Pd(CN)4] (2) and [Cd(4aepy)2(H2O)2][Pt(CN)4] (3) [4aepy = 4-(2-aminoethyl)pyridine], have been synthesized and characterized by elemental, thermal, FT-IR and Raman spectral analyses. The crystal structures of 1 and 2 have been determined by single crystal X-ray diffraction technique, in which they crystallize in the monoclinic system and C2/c space group. The M(II) [M(II) = Ni(II), Pd(II) and Pt(II)] ions are coordinated with the carbon atoms of the four cyanide groups in the square planar geometries and the [M(CN)4]2- ions act as counter ions. The Cd(II) ions display an N4O2 coordination sphere with a distorted octahedral geometry, the nitrogen donors belonging to four molecules of the organic 4aepy that act as unidentate ligands and two oxygen atoms from aqua ligands. 3D supramolecular structures of 1 and 2 were occurred by M⋯π and hydrogen bonding (Nsbnd H⋯N and Osbnd H⋯N) interactions. Vibrational assignments of all the observed bands were given and the spectral properties were also supported the crystal structures of the complexes. A possible decompositions of the complexes were investigated in the temperature range 30-800 °C in the static atmosphere.

Speciation study in the sulfamethoxazole-copper-pH-soil system: implications for retention prediction.

PubMed

Morel, Marie-Christine; Spadini, Lorenzo; Brimo, Khaled; Martins, Jean M F

2014-05-15

Sulfamethoxazole (SMX) is a persistent sulfonamide antibiotic drug used in the veterinary and human medical sectors and is widely detected in natural waters. To better understand the reactive transport of this antibiotic in soil, the speciation of the SMX-Cu(II)-H(+) system in solution and the combined sorption of these components in a natural vineyard soil were investigated by acid-base titrimetry and infrared spectroscopy. Cu(II) is considered to represent a strongly complexing trace element cation (such as Cd(2+), Zn(2+), Pb(2+), Ni(2+), etc.) in comparison to more prevalent but more weakly binding cations (such as Ca(2+) and Mg(2+)). Titrimetric studies showed that, relative to other antibiotics, such as tetracycline, SMX is a weak copper chelating agent and a weak soil sorbent at the soil pH (pH6). However, the sorption of SMX in soil increases strongly (by a factor of 6) in the presence of copper. This finding strongly supports the hypothetical formation of ternary SMX-Cu-soil complexes, especially considering that copper is dominantly sorbed in a state at pH6. The data were successfully modelled with PhreeqC assuming the existence of binary and ternary surface complexes in equilibrium with aqueous Cu, SMX and Cu-SMX complexes. It is thought that other strongly complexing cations present on the surface of reactive organic and mineral soil phases, such as Cd(II), Ni(II), Zn(II), Pb(II), Fe(II/III), Mn(II/IV) and Al(III), affect the solid/solution partitioning of SMX. This study thus suggests that surface-adsorbed cations significantly increase the sorption of SMX. Copyright © 2014 Elsevier B.V. All rights reserved.

A Ni(II) Bis(diphosphine)-Hydride Complex Containing Proton Relays - Structural Characterization and Electrocatalytic Studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Das, Partha Pratim; Stolley, Ryan M.; Van Der Eide, Edwin F.

The syntheses of the new 1,5-diphenyl-3,7-di(isopropyl)-1,5-diaza-3,7-diphosphacyclooctane ligand, PiPr2NPh2, is reported. The two equivalents of the ligand react with [Ni(CH3CN)6](BF4)2 to form the bis-diphosphine Ni(II)-complex [Ni(PiPr2NPh2)2](BF4)2, which acts as a proton reduction electrocatalyst. In addition to [Ni(PiPr2NPh2)2]2+, we report the syntheses and structural characterization of the Ni(0)-complex Ni(PiPr2NPh2)2, and the Ni(II)-hydride complex [HNi(PiPr2NPh2)2]BF4. The [HNi(PiPr2NPh2)2]BF4 complex represents the first Ni(II)-hydride in the [Ni(PR2NR'2)2]2+ family of compounds to be isolated and structurally characterized. In addition to the experimental data, the mechanism of electrocatalysis facilitated by [Ni(PiPr2NPh2)2]2+ is analyzed using linear free energy relationships recently established for the [Ni(PR2NR'2)2]2+ family. We thank Dr.more » Aaron Appel, Dr. Simone Raugei and Dr. Eric Wiedner for helpful discussions. This research was supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences. Mass spectrometry was provided at W. R. Wiley Environmental Molecular Sciences Laboratory (EMSL), a national scientific user facility sponsored by the Department of Energy’s office of Biological and Environmental Research located at Pacific Northwest National Laboratory. Pacific Northwest National Laboratory is operated by Battelle for the U.S. Department of Energy.« less

Mononuclear late first row transition metal complexes of ONO donor hydrazone ligand: Synthesis, characterization, crystallographic insight, in vivo and in vitro anti-inflammatory activity

NASA Astrophysics Data System (ADS)

Kendur, Umashri; Chimmalagi, Geeta H.; Patil, Sunil M.; Gudasi, Kalagouda B.; Frampton, Christopher S.; Mangannavar, Chandrashekhar V.; Muchchandi, Iranna S.

2018-02-01

Air and moisture stable coordination compounds of late first row transition metal ions, viz., Co(II), Ni(II), Cu(II) and Zn(II) with a newly designed ligand, (E)-2-amino-N'-(1-(2-hydroxy-6-methyl-4-oxo-4H-pyran-3-yl)ethylidene)benzohydrazide (H2L) were prepared and extensively characterized using various spectro-analytical techniques. The ligand acts both in mono as well as doubly deprotonated manner. The ligand to metal stoichiometry was found to be 1:2 in case of complexes using chloride salts, whereas 1:1 in case of copper (II) complex using its acetate salt. The molecular structures of H2L, nickel and copper complexes were unambiguously determined by single-crystal X-ray diffraction studies reveal that H2L exists in a zwitterionic form while copper complex has copper centre in a distorted square planar environment. On the other hand, cobalt, nickel and zinc complexes display distorted octahedral coordination around the metal ion. In case of [Ni(HL)2].H2O, intramolecular Csbnd H⋯π stacking interaction were observed between the centroid of five membered chelate ring and phenyl proton C5sbnd H5 and intermolecular Csbnd H⋯π stacking interaction between the centroid of phenyl ring, dehydroacetic acid (DHA) ring and phenyl protons. The [Cu(L)DMF] complex is stabilized by intramolecular hydrogen bonding N1H⋯N2 and by intermolecular hydrogen bonding N1H⋯O4. Intermolecular interactions were investigated by Hirshfeld surfaces. Further, H2L and its metal complexes were screened for their in vivo and in vitro anti-inflammatory activities. The activity of the ligand has enhanced on coordination with transition metals. The tested compounds have shown excellent activity, which is almost equipotent to the standard used in the study.

Spectroscopic studies and biological evaluation of some transition metal complexes of azo Schiff-base ligand derived from (1-phenyl-2,3-dimethyl-4-aminopyrazol-5-one) and 5-((4-chlorophenyl)diazenyl)-2-hydroxybenzaldehyde

NASA Astrophysics Data System (ADS)

Anitha, C.; Sheela, C. D.; Tharmaraj, P.; Sumathi, S.

2012-10-01

A series of metal(II) complexes of VO(II), Co(II), Ni(II), Cu(II) and Zn(II) have been synthesized from the azo Schiff base ligand 4-((E)-4-((E)-(4-chlorophenyl)diazenyl)-2-hydroxybenzylideneamino)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one (CDHBAP) and characterized by elemental analysis, spectral (IR, UV-Vis, 1H NMR, ESR and EI-mass), magnetic moment measurements, molar conductance, DNA, SEM, X-ray crystallography and fluorescence studies. The electronic absorption spectra and magnetic susceptibility measurements of the complexes indicate square pyramidal geometry for VO(II) and octahedral geometry for all the other complexes. The important infrared (IR) spectral bands corresponding to the active groups in the ligand and the solid complexes under investigation were studied and implies that CDHBAP is coordinated to the metal ions in a neutral tridentate manner. The redox behavior of copper(II) and vanadyl(II) complexes have been studied by cyclic voltammetry. The nuclease activity of the above metal(II) complexes shows that the complexes cleave DNA. All the synthesized complexes can serve as potential photoactive materials as indicated from their characteristic fluorescence properties. The antibacterial and antifungal activities of the synthesized ligand and its metal complexes were screened against bacterial species (Staphylococcus aureus, Salmonella typhi, Escherichia coli, Bacillus subtilis, Shigella sonnie) and fungi (Candida albicans, Aspergillus niger, Rhizoctonia bataicola). Amikacin and Ketoconozole were used as references for antibacterial and antifungal studies. The activity data show that the metal complexes have a promising biological activity comparable with the parent Schiff base ligand against bacterial and fungal species. The second harmonic generation (SHG) efficiency of the ligand was measured and the NLO (non-linear optical) properties of the ligand are expected to result in the realization of advanced optical devices in optical fiber communication (OFC) and optical computing. The SEM image of the copper(II) complex implies that the size of the particles is 1 μm.

The role of metals and dithiolate ligands on structural, electronic and optical properties of [M(bipyridine)(dithiolate)] complexes: A theoretical study

NASA Astrophysics Data System (ADS)

Samiee, Sepideh; Taghvaeian, Samira

2018-06-01

A series of [M(diimine)(dithiolate)] complexes of general formula [M(bpy)(dithiolate)] {bpy = 2,2‧-bipyridine;dithiolate = 1,2-benzenedithiolate (bdt2-), 3,4-toluenedithiolate (tdt2-) and 4-cyanobenzene-1,2-dithiolate (cbdt2-); M = Ni(II), Pd(II) and Pt(II)} have been studied by density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations. The geometries, stabilities, electronic structures, optical absorption spectra in different phases as well as thermodynamic parameters are explored. The changes of metal ion center and dithiolate ligands on some molecular properties are also discussed. These calculated results are in good agreement with the experimental data. The bonding analyses show that the Msbnd S bond is covalent so that always polarized towards sulfur atom, whereas the Msbnd N bond exhibits a considerable amount of electrostatic interaction. Detailed NBO analysis indicates that these complexes can be easily oxidized than reduced, and acts as the reducing agent. The HOMO-LUMO energy gaps of all complexes under study are founded about 2 eV and the strong absorption from 400 to 700 nm which match with the solar spectra very well. Besides, the simulated absorption spectra are in accordance with the trends of energy gaps. Comparison of the absorption spectra in dichloromethane solution with those in gas phase show that the solvatochromic effect. The order of magnitude for light harvesting efficiencies (LHE) of all complexes is Pt > Pd > Ni and cbdt2- > bdt2- > tdt2-. Our results confirm the effect and role of metals and dithiolate ligands on enhancing the optical properties of these complexes. Thus, the result of this work can serve as a rational tool for the design and synthesis of diimine-dithiolate complexes and broadens the scope for further investigations into potential dyes for use in the field of dye-sensitized solar cells (DSSC).

Theoretical study of the magnetic exchange coupling behavior substituting Cr(III) with Mo(III) in cyano-bridged transition metal complexes

NASA Astrophysics Data System (ADS)

Zhang, Yi-Quan; Luo, Cheng-Lin

Molecular magnetism in a series of cyano-bridged first and second transition metal complexes has been investigated using density functional theory (DFT) combined with the broken-symmetry (BS) approach. Several exchange-correlation (XC) functionals in the ADF package were used to investigate complexes I [-(Me3tacn)2(cyclam)NiMo2(CN)6]2+, II [-(Me3tacn)2(cyclam)Ni-Cr2(CN)6]2+, III [(Me3tacn)6MnMo6(CN)18]2+, and IV [(Me3tacn)6MnCr6(CN)18]2+ (Me3tacn = N,N?,N‴-trimethyl-1,4,7-triazacyclononane). For models A (the molded structure of complex I) and B (the modeled structure of complex II), all the XCs given qualitatively reasonable results and predict ferromagnetic coupling character between M (M = MoIII for A or CrIII for B) and NiII in coincidence with the experimental results (see Tables and ). The calculated using Operdew, OPBE, O3LYP, and B3LYP functionals and experimental J values show that substituting CrIII with MoIII will enhance the ferromagnetic exchange coupling interactions. But VWN, PW91, PBE, VSXC, and tau-HCTH functionals have no way to differentiate the relative strength of the intramolecular magnetic exchange coupling interactions of A and B correctly. For models C (the modeled structure of complex III) and D (the modeled structure of complex IV), all the XCs in ADF and B3LYP in Gaussian 03 with several basis sets show that substituting CrIII with MoIII will enhance the antiferromagnetic exchange coupling interactions. From the above calculations, the substitution of CrIII by MoIII will enhance the magnetic coupling interactions, whether the magnetic coupling interactions are ferro- or antiferromagnetic. Moreover, Kahn's model was applied to investigate the above facts.

Whole-genome sequence of Cupriavidus sp. strain BIS7, a heavy-metal-resistant bacterium.

PubMed

Hong, Kar Wai; Thinagaran, Dinaiz al; Gan, Han Ming; Yin, Wai-Fong; Chan, Kok-Gan

2012-11-01

Cupriavidus sp. strain BIS7 is a Malaysian tropical soil bacterium that exhibits broad heavy-metal resistance [Co(II), Zn(II), Ni(II), Se(IV), Cu(II), chromate, Co(III), Fe(II), and Fe(III)]. It is particularly resistant to Fe(II), Fe(III), and Zn(II). Here we present the assembly and annotation of its genome.

Genetic characterization, nickel tolerance, biosorption, kinetics, and uptake mechanism of a bacterium isolated from electroplating industrial effluent.

PubMed

Nagarajan, N; Gunasekaran, P; Rajendran, P

2015-04-01

Electroplating industries in Madurai city produce approximately 49,000 L of wastewater and 1200 L of sludge every day revealing 687-5569 ppm of nickel (Ni) with other contaminants. Seventeen Ni-tolerant bacterial strains were isolated from nutrient-enriched effluents. Among them one hyper Ni accumulating strain was scored and identified as Bacillus cereus VP17 on the basis of morphology, biochemical tests, 16S rDNA gene sequencing, and phylogenetic analysis. Equilibrium data of Ni(II) ions using the bacterium as sorbent at isothermal conditions (37 °C) and pH 6 were best adjusted by Langmuir (R(2) = 0.6268) and Freundlich models (R(2) = 0.9505). Experimental validation reveals Ni sorption takes place on a heterogeneous surface of the biosorbent, and predicted metal sorption capacity is 434 ppm. The pseudo-second-order kinetic model fitted the biosorption kinetic data better than the pseudo-first-order kinetic model (R(2) = 0.9963 and 0.3625). Scanning electron microscopy, energy dispersive X-ray, and Fourier transform infrared spectroscopy studies of the bacterial strain with and without Ni(II) ion reveals the biosorption mechanism. The results conclude possibilities of using B. cereus VP17 for Ni bioremediation.

Concerted ligand exchange and the roles of counter anions in the reversible structural switching of crystalline peptide metallo-macrocycles.

PubMed

Miyake, Ryosuke; Shionoya, Mitsuhiko

2014-06-02

To understand reversible structural switching in crystalline materials, we studied the mechanism of reversible crystal-to-crystal transformation of a tetranuclear Ni(II) macrocycle consisting of artificial β-dipeptides. On the basis of detailed structural analyses and thermodynamic measurements made in a comparison of pseudo-isostructural crystals (NO3 and BF4 salts), we herein discuss how ligand-exchange reactions take place in the crystal due to changes in water content and temperature. Observations of the structural transformation of NO3 salt indicated that a pseudo crystalline phase transformation takes place through concerted ligand-exchange reactions at the four Ni(II) centers of the macrocycle with hydrogen bond switching. A mechanism for this ligand exchange was supported by IR spectroscopy. Thermodynamic measurements suggested that the favorable compensation relationship of the enthalpy changes due to water uptake and structural changes are keys to the reversible structural transformation. On the basis of a comparison with the pseudo-isostructural crystals, it is apparent that the crystal packing structure and the types of counter anions are important factors for facilitating reversible ligand exchange with single crystallinity.

Mixed ligand complexation of some transition metal ions in solution and solid state: Spectral characterization, antimicrobial, antioxidant, DNA cleavage activities and molecular modeling

NASA Astrophysics Data System (ADS)

Shobana, Sutha; Dharmaraja, Jeyaprakash; Selvaraj, Shanmugaperumal

2013-04-01

Equilibrium studies of Ni(II), Cu(II) and Zn(II) mixed ligand complexes involving a primary ligand 5-fluorouracil (5-FU; A) and imidazoles viz., imidazole (him), benzimidazole (bim), histamine (hist) and L-histidine (his) as co-ligands(B) were carried out pH-metrically in aqueous medium at 310 ± 0.1 K with I = 0.15 M (NaClO4). In solution state, the stoichiometry of MABH, MAB and MAB2 species have been detected. The primary ligand(A) binds the central M(II) ions in a monodentate manner whereas him, bim, hist and his co-ligands(B) bind in mono, mono, bi and tridentate modes respectively. The calculated Δ log K, log X and log X' values indicate higher stability of the mixed ligand complexes in comparison to binary species. Stability of the mixed ligand complex equilibria follows the Irving-Williams order of stability. In vitro biological evaluations of the free ligand(A) and their metal complexes by well diffusion technique show moderate activities against common bacterial and fungal strains. Oxidative cleavage interaction of ligand(A) and their copper complexes with CT DNA is also studied by gel electrophoresis method in the presence of oxidant. In vitro antioxidant evaluations of the primary ligand(A), CuA and CuAB complexes by DPPH free radical scavenging model were carried out. In solid, the MAB type of M(II)sbnd 5-FU(A)sbnd his(B) complexes were isolated and characterized by various physico-chemical and spectral techniques. Both the magnetic susceptibility and electronic spectral analysis suggest distorted octahedral geometry. Thermal studies on the synthesized mixed ligand complexes show loss of coordinated water molecule in the first step followed by decomposition of the organic residues subsequently. XRD and SEM analysis suggest that the microcrystalline nature and homogeneous morphology of MAB complexes. Further, the 3D molecular modeling and analysis for the mixed ligand MAB complexes have also been carried out.

Defining the electronic and geometric structure of one-electron oxidized copper-bis-phenoxide complexes.

PubMed

Storr, Tim; Verma, Pratik; Pratt, Russell C; Wasinger, Erik C; Shimazaki, Yuichi; Stack, T Daniel P

2008-11-19

The geometric and electronic structure of an oxidized Cu complex ([CuSal](+); Sal = N,N'-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexane-(1R,2R)-diamine) with a non-innocent salen ligand has been investigated both in the solid state and in solution. Integration of information from UV-vis-NIR spectroscopy, magnetic susceptibility, electrochemistry, resonance Raman spectroscopy, X-ray crystallography, X-ray absorption spectroscopy, and density functional theory calculations provides critical insights into the nature of the localization/delocalization of the oxidation locus. In contrast to the analogous Ni derivative [NiSal](+) (Storr, T.; et al. Angew. Chem., Int. Ed. 2007, 46, 5198), which exists solely in the Ni(II) ligand-radical form, the locus of oxidation is metal-based for [CuSal](+), affording exclusively a Cu(III) species in the solid state (4-300 K). Variable-temperature solution studies suggest that [CuSal](+) exists in a reversible spin-equilibrium between a ligand-radical species [Cu(II)Sal(*)](+) (S = 1) and the high-valent metal form [Cu(III)Sal](+) (S = 0), indicative of nearly isoenergetic species. It is surprising that a bis-imine-bis-phenolate ligation stabilizes the Cu(III) oxidation state, and even more surprising that in solution a spin equilibrium occurs without a change in coordination number. The oxidized tetrahydrosalen analogue [CuSal(red)](+) (Sal(red) = N,N'-bis(3,5-di- tert-butylhydroxybenzyl)-1,2-cyclohexane-(1R,2R)-diamine) exists as a temperature-invariant Cu(II)-ligand-radical complex in solution, demonstrating that ostensibly simple variations of the ligand structure affect the locus of oxidation in Cu-bis-phenoxide complexes.

Defining the Electronic and Geometric Structure of One-Electron Oxidized Copper–Bis-phenoxide Complexes

PubMed Central

Storr, Tim; Verma, Pratik; Pratt, Russell C.; Wasinger, Erik C.; Shimazaki, Yuichi; Stack, T. Daniel P.

2009-01-01

The geometric and electronic structure of an oxidized Cu complex ([CuSal]+; Sal = N, N′-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexane-(1R,2R)-diamine) with a non-innocent salen ligand has been investigated both in the solid state and in solution. Integration of information from UV–vis–NIR spectroscopy, magnetic susceptibility, electrochemistry, resonance Raman spectroscopy, X-ray crystallography, X-ray absorption spectroscopy, and density functional theory calculations provides critical insights into the nature of the localization/delocalization of the oxidation locus. In contrast to the analogous Ni derivative [NiSal]+ (Storr, T.; et al. Angew. Chem., Int. Ed. 2007, 46, 5198), which exists solely in the Ni(II) ligand-radical form, the locus of oxidation is metal-based for [CuSal]+, affording exclusively a Cu(III) species in the solid state (4–300 K). Variable-temperature solution studies suggest that [CuSal]+ exists in a reversible spin-equilibrium between a ligand-radical species [Cu(II)Sal•]+ (S = 1) and the high-valent metal form [Cu(III)Sal]+ (S = 0), indicative of nearly isoenergetic species. It is surprising that a bis-imine–bis-phenolate ligation stabilizes the Cu(III) oxidation state, and even more surprising that in solution a spin equilibrium occurs without a change in coordination number. The oxidized tetrahydrosalen analogue [CuSalred]+ (Salred = N, N′-bis(3,5-di-tert-butylhydroxybenzyl)-1,2-cyclohexane-(1R,2R)-diamine) exists as a temperature-invariant Cu(II)–ligand-radical complex in solution, demonstrating that ostensibly simple variations of the ligand structure affect the locus of oxidation in Cu–bis-phenoxide complexes. PMID:18939830

Two pathways for electrocatalytic oxidation of hydrogen by a nickel bis(diphosphine) complex with pendant amines in the second coordination sphere.

PubMed

Yang, Jenny Y; Smith, Stuart E; Liu, Tianbiao; Dougherty, William G; Hoffert, Wesley A; Kassel, W Scott; Rakowski DuBois, M; DuBois, Daniel L; Bullock, R Morris

2013-07-03

A nickel bis(diphosphine) complex containing pendant amines in the second coordination sphere, [Ni(P(Cy)2N(t-Bu)2)2](BF4)2 (P(Cy)2N(t-Bu)2 = 1,5-di(tert-butyl)-3,7-dicyclohexyl-1,5-diaza-3,7-diphosphacyclooctane), is an electrocatalyst for hydrogen oxidation. The addition of hydrogen to the Ni(II) complex gives three isomers of the doubly protonated Ni(0) complex [Ni(P(Cy)2N(t-Bu)2H)2](BF4)2. Using the pKa values and Ni(II/I) and Ni(I/0) redox potentials in a thermochemical cycle, the free energy of hydrogen addition to [Ni(P(Cy)2N(t-Bu)2)2](2+) was determined to be -7.9 kcal mol(-1). The catalytic rate observed in dry acetonitrile for the oxidation of H2 depends on base size, with larger bases (NEt3, t-BuNH2) resulting in much slower catalysis than n-BuNH2. The addition of water accelerates the rate of catalysis by facilitating deprotonation of the hydrogen addition product before oxidation, especially for the larger bases NEt3 and t-BuNH2. This catalytic pathway, where deprotonation occurs prior to oxidation, leads to an overpotential that is 0.38 V lower compared to the pathway where oxidation precedes proton movement. Under the optimal conditions of 1.0 atm H2 using n-BuNH2 as a base and with added water, a turnover frequency of 58 s(-1) is observed at 23 °C.

A Readily Accessible Chiral NNN Pincer Ligand with a Pyrrole Backbone and Its Ni(II) Chemistry: Syntheses, Structural Chemistry, and Bond Activations.

PubMed

Wenz, Jan; Kochan, Alexander; Wadepohl, Hubert; Gade, Lutz H

2017-03-20

A new class of chiral C 2 -symmetric N-donor pincer ligands, 2,5-bis(2-oxazolinyldimethylmethyl)pyrroles (PdmBox)H, was synthesized starting from the readily available ethyl 2,2-dimethyl-3-oxobutanoate (1). The synthesis of the ligand backbone was achieved by oxidative enole coupling with CuC1 2 followed by Paal-Knorr-type pyrrole synthesis. The corresponding protioligands ( R PdmBox)H (R = iPr: 5a; Ph: 5b) were obtained by condensation with amino alcohols and subsequent zinc-catalyzed cyclization. Reaction of the lithiated ligands with [NiCl 2 (dme)] yielded the corresponding square-planar nickel(II) complexes [( R PdmBox)NiCl] (6a/b). Salt metathesis of 6a with the corresponding alkali or cesium salts in acetone led to the formation of air- and moisture-stable [( iPr PdmBox)NiX] (X = F (7), X = Br (8), X = I (9), X = N 3 (10), X = OAc (11). Furthermore, the conversion of [( iPr PdmBox)NiF] (7) with hydride transfer reagents such as PhSiH 3 led to the stable hydrido species [( iPr PdmBox)NiH] (27), the stoichiometric transformations of which were studied. Treatment of 6a with organometallic reagents such as ZnEt 2 , PhLi, PhC≡CLi, NsLi, or ( 4F Bn) 2 Mg(THF) 2 gave the corresponding alkyl, alkynyl, or aryl complexes. The availability of the new nonisomerizable PdmBox pincer ligands allowed the comparative study of their ligation to square-planar complexes as helically twisted spectator ligands as opposed to the enforced planar rigidity of their iso-PmBox analogues and the way this influences the reactivity of the Ni complexes.

Whole-Genome Sequence of Cupriavidus sp. Strain BIS7, a Heavy-Metal-Resistant Bacterium

PubMed Central

Hong, Kar Wai; Thinagaran, Dinaiz a/l; Gan, Han Ming; Yin, Wai-Fong

2012-01-01

Cupriavidus sp. strain BIS7 is a Malaysian tropical soil bacterium that exhibits broad heavy-metal resistance [Co(II), Zn(II), Ni(II), Se(IV), Cu(II), chromate, Co(III), Fe(II), and Fe(III)]. It is particularly resistant to Fe(II), Fe(III), and Zn(II). Here we present the assembly and annotation of its genome. PMID:23115161

Redox chemistry of nickel(II) complexes supported by a series of noninnocent β-diketiminate ligands.

PubMed

Takaichi, June; Morimoto, Yuma; Ohkubo, Kei; Shimokawa, Chizu; Hojo, Takayuki; Mori, Seiji; Asahara, Haruyasu; Sugimoto, Hideki; Fujieda, Nobutaka; Nishiwaki, Nagatoshi; Fukuzumi, Shunichi; Itoh, Shinobu

2014-06-16

Nickel complexes of a series of β-diketiminate ligands ((R)L(-), deprotonated form of 2-substituted N-[3-(phenylamino)allylidene]aniline derivatives (R)LH, R = Me, H, Br, CN, and NO2) have been synthesized and structurally characterized. One-electron oxidation of the neutral complexes [Ni(II)((R)L(-))2] by AgSbF6 or [Ru(III)(bpy)3](PF6)3 (bpy = 2,2'-bipyridine) gave the corresponding metastable cationic complexes, which exhibit an EPR spectrum due to a doublet species (S = 1/2) and a characteristic absorption band in near IR region ascribable to a ligand-to-ligand intervalence charge-transfer (LLIVCT) transition. DFT calculations have indicated that the divalent oxidation state of nickel ion (Ni(II)) is retained, whereas one of the β-diketiminate ligands is oxidized to give formally a mixed-valence complex, [Ni(II)((R)L(-))((R)L(•))](+). Thus, the doublet spin state of the oxidized cationic complex can be explained by taking account of the antiferromagnetic interaction between the high-spin nickel(II) ion (S = 1) and the organic radical (S = 1/2) of supporting ligand. A single-crystal structure of one of the cationic complexes (R = H) has been successfully determined to show that both ligands in the cationic complex are structurally equivalent. On the basis of theoretical analysis of the LLIVCT band and DFT calculations as well as the crystal structure, the mixed-valence complexes have been assigned to Robin-Day class III species, where the radical spin is equally delocalized between the two ligands to give the cationic complex, which is best described as [Ni(II)((R)L(0.5•-))2](+). One-electron reduction of the neutral complexes with decamethylcobaltocene gave the anionic complexes when the ligand has the electron-withdrawing substituent (R = CN, NO2, Br). The generated anionic complexes exhibited EPR spectra due to a doublet species (S = 1/2) but showed no LLIVCT band in the near-IR region. Thus, the reduced complexes are best described as the d(9) nickel(I) complexes supported by two anionic β-diketiminate ligands, [Ni(I)((R)L(-))2](-). This conclusion was also supported by DFT calculations. Substituent effects on the electronic structures of the three oxidation states (neutral, cationic, and anionic) of the complexes are systematically evaluated on the basis of DFT calculations.

More Constraints on the Physical Conditions of the Kinematically Complex, Multiphase Absorption Line System at z=0.93 toward PG1206+459

NASA Astrophysics Data System (ADS)

Rosenwasser, Ben; Muzahid, Sowgat; Norris, Jackson; Charlton, Jane C.

2015-01-01

We present the results of photo- and collisional ionization modeling of the strong MgII absorption system at redshift z~0.93 towards the quasar PG1206+459. This system has been extensively studied over the last two decades (Churchill & Charlton 1999; Ding et al. 2003; Tripp et al. 2011) using a combination of spectra from Keck/HIRES, HST/FOS, HST/STIS, and HST/COS. Here we present newconstraints using the most complete spectral coverage including more recent observations of OVI and the Lyman series from HST/COS. Numerous absorption components are seen over a large velocity spread (~1500km/s), and multiple ionization phases are required to account for the detected transitions, which include MgI, MgII, FeII, SiII, SiIII, SiIV, CII, CIII, CIV, SIII, SIV, SV, SVI, NIII, NIV, NV, OIII, OIV, OV, OVI, and NeVIII. Considering the new constraints, we revisit the question of the physical nature of the structures that produce this absorber.

Further Investigation of a Nickel-Based Homogeneous Water Oxidation Catalyst with Two cis Labile Sites.

PubMed

Luo, Gang-Yi; Huang, Hai-Hua; Wang, Jia-Wei; Lu, Tong-Bu

2016-03-08

The reaction of N,N'-dimethyl-N,N'-bis(pyridin-2-ylmethyl)-1,2-diaminoethane ligand (L) with Ni(ClO4)2 ⋅6 H2O generated a complex of [NiL(H2O)2](ClO4)2 (1) with two cis labile sites occupied by two coordinated H2O molecules, which can homogeneously electrocatalyze water oxidation in pH 6.5 acetate (OAc(-)) buffer at room temperature. The catalytic mechanism was studied by electrochemical experiments and density functional theory calculations to elucidate the following steps: (a) one of two water molecules in 1 is exchanged by OAc(-) to generate [NiL(H2O)(OAc)](+) when dissolved in OAc(-) buffer, (b) Ni(II) is directly oxidized to Ni(IV) and OAc(-) is replaced with OH(-) to form [Ni(IV) L(OH)2 ](2+), and (c) a peroxide intermediate is formed through the intramolecular O-O coupling in the presence of OAc(-), which undergoes further oxidation to release O2. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis, spectroscopic, thermal, voltammetric studies and biological activity of crystalline complexes of pyridine-2,6-dicarboxylic acid and 8-hydroxyquinoline

NASA Astrophysics Data System (ADS)

Çolak, Alper Tolga; Çolak, Ferdağ; Yeşilel, Okan Zafer; Büyükgüngör, Orhan

2009-11-01

Two new compounds (8-H 2Q) 2[M(dipic) 2]·6H 2O (M = Co ( 1) and Ni ( 2), 8-HQ = 8-hydroxyquinoline, dipic = dipicolinate) have been prepared and characterized by elemental analysis, spectral (IR and UV-vis), thermal analyses, magnetic measurements and single-crystal X-ray diffraction techniques. Both 1 and 2 consist two 8-hydroxyquinolinium cations, one bis(dipicolinate)M(II) anion [M = Co(II), Ni(II)] and six uncoordinated water molecules. Both 1 and 2 crystallize in the monoclinic space group C2/c. In the compounds anion, each dipic ligand simultaneously exhibits tridentate coordination modes through N atom of pyridine ring and oxygen atoms of the carboxylate groups. The crystal packing of 1 and 2 is a composite of intermolecular hydrogen bonding and C-O⋯π interactions. The in vitro antibacterial and antifungal activities of 1 and 2 were evaluated by the agar well diffusion method by MIC tests. Both new compounds showed the same antimicrobial activity against Gram-positive bacteria and yeast and fungi expect Gram-negative bacteria.

Surface rejuvenation for multilayer metal deposition on polymer microspheres via self-seeded electroless plating

NASA Astrophysics Data System (ADS)

Karagoz, Bunyamin; Sirkecioglu, Okan; Bicak, Niyazi

2013-11-01

A surface rejuvenation process was developed for generation variable thickness of metal deposits on polymer microspheres via electroless plating. Thus, Ni(II), Cu(II) and Ag(I) complexes formed on triethylenetetramine (TETA) functional crosslinked poly(glycidyl methacrylate) (PGMA) microspheres were reduced to zero-valent metals. The resulting metals (1.1-1.5 mmol g-1) were employed as seed points for electroless metal plating (self-seeding) without using Pd or tin pre-activating species. Treatment of the metalized surfaces with hydrazine or hydrazinium formate was demonstrated to reactivate (rejuvenate) the surface and allows further metal deposition from electroless plating solutions. Followed repeating of the surface rejuvenation-metalization steps resulted in step wise increasing of the metal deposits (90-290 mg per g in each cycle), as inferred from metal analyses, ESEM and XPS analysis. Experiments showed that, after 6 times of cycling the metal deposits exceed 1 g per g of the microspheres on average. The process seemed to be promising for tuning up of the metal thickness by stepwise electroless plating.

High-affinity gold nanoparticle pin to label and localize histidine-tagged protein in macromolecular assemblies

PubMed Central

Anthony, Kelsey C.; You, Changjiang; Piehler, Jacob; Pomeranz Krummel, Daniel A.

2014-01-01

SUMMARY There is significant demand for experimental approaches to aid protein localization in electron microscopy micrographs and ultimately in three-dimensional reconstructions of macromolecular assemblies. We report preparation and use of a reagent consisting of tris-nitrilotriacetic acid (tris-NTA) conjugated with a monofunctional gold nanoparticle (AuNPtris-NTA) for site-specific, non-covalent labeling of protein termini fused to a histidine-tag (His-tag). Multivalent binding of tris-NTA to a His-tag via complexed Ni(II) ions results in subnanomolar affinity and a defined 1:1 stoichiometry. Precise localization of AuNPtris-NTA labeled proteins by electron microscopy is further ensured by the reagent’s short conformationally restricted linker. We have employed AuNPtris-NTA to localize His-tagged proteins in an oligomeric ATPase and in the bacterial 50S ribosomal subunit. AuNPtris-NTA can specifically bind to the target proteins in these assemblies and is clearly discernible. Our new labeling reagent should find broad application in non-covalent site-specific labeling of protein termini to pinpoint their location in macromolecular assemblies. PMID:24560806

Speciation, photosensitivity, and reactions of transition metal ions in atmospheric droplets

NASA Astrophysics Data System (ADS)

Weschler, C. J.; Mandich, M. L.; Graedel, T. E.

1986-04-01

Dissolved transition metal ions (TMI) are common constituents of atmospheric droplets. They are known to catalyze sulfur oxidation in droplets and are suspected of being involved in other chemical processes as well. We have reviewed the relevant equilibrium constants and chemical reactions of the major TMI (iron, manganese, copper, and nickel), their ability to form complexes in aqueous solution, and their potential involvement in photochemical processes in atmospheric droplets. Among the results are the following: (1) The major Fe(III) species in atmospheric water droplets are [Fe(OH)(H2O)5]2+, [Fe(OH)2(H2O)4]+, and [Fe(SO3)(H2O)5]+; the partitioning among these complexes is a function of pH. In contrast, Cu(II), Mn(II), and Ni(II) exist almost entirely in the droplets as hexaquo complexes. (2) Within the tropospheric solar spectrum, some of the complexes of Fe(III) have large absorption cross-sections. In this work we report cross-section data for several of the complexes. Absorption of solar photons by such complexes is generally followed by cleavage, which in the same process reduces the iron (III) atom and produces a reactive free radical. This mechanism has the potential to be a significant and heretofore unappreciated source of free radicals in atmospheric droplets. (3) TMI participate in redox reactions with H2O2 and its associated species HO2· and O2-. These reactions furnish the potential for catalytic cycles involving TMI in atmospheric droplets under a variety of illumination and acidity conditions. (4) A number of organic processes in atmospheric droplets may involve TMI. Among these processes are the production and destruction of alkylhydroperoxides, the chemical chains linking RO2· radicals to stable alcohols and acids, and the oxidation of aliphatic aldehydes to organic acids.

Nickel L-edge and K-edge X-ray absorption spectroscopy of non-innocent Ni[S₂C₂(CF₃)₂]₂(n) series (n = -2, -1, 0): direct probe of nickel fractional oxidation state changes.

PubMed

Gu, Weiwei; Wang, Hongxin; Wang, Kun

2014-05-07

A series of nickel dithiolene complexes Ni[S2C2(CF3)2]2(n) (n = -2, -1, 0) has been investigated using Ni L- and K-edge X-ray absorption spectroscopy (XAS). The L3 centroid shifts about 0.3 eV for a change of one unit in the formal oxidation state (or 0.3 eV per oxi), corresponding to ~33% of the shift for Ni oxides or fluorides (about 0.9 eV per oxi). The K-edge XAS edge position shifts about 0.7 eV per oxi, corresponding to ~38% of that for Ni oxides (1.85 eV per oxi). In addition, Ni L sum rule analysis found the Ni(3d) ionicity in the frontier orbitals being 50.5%, 44.0% and 38.5% respectively (for n = -2, -1, 0), in comparison with their formal oxidation states (of Ni(II), Ni(III), and Ni(IV)). For the first time, direct and quantitative measurement of the Ni fractional oxidation state changes becomes possible for Ni dithiolene complexes, illustrating the power of L-edge XAS and L sum rule analysis in such a study. The Ni L-edge and K-edge XAS can be used in a complementary manner to better assess the oxidation states for Ni.

Synthesis, spectral characterization and computed optical analysis of potent triazole based compounds

NASA Astrophysics Data System (ADS)

Sumrra, Sajjad H.; Mushtaq, Fazila; Khalid, Muhammad; Raza, Muhammad Asam; Nazar, Muhammad Faizan; Ali, Bakhat; Braga, Ataualpa A. C.

2018-02-01

Biologically active triazole Schiff base ligand (L) and metal complexes [Fe(II), Co(II), Ni(II), Cu(II) and Zn(II)] are reported herein. The ligand acted as tridentate and coordinated towards metallic ions via azomethine-N, triazolic-N moiety and deprotonated-O of phenyl substituents in an octahedral manner. These compounds were characterized by physical, spectral and analytical analysis. The synthesized ligand and metal complexes were screened for antibacterial pathogens against Chromohalobacter salexigens, Chromohalobacter israelensi, Halomonas halofila and Halomonas salina, antifungal bioassay against Aspergillus niger and Aspergellus flavin, antioxidant (DPPH, phosphomolybdate) and also for enzyme inhibition [butyrylcholinesterase (BChE) and acetylcholinesterase (AChE)] studies. The results of these activities indicated the ligand to possess potential activity which significantly increased upon chelation. Moreover, vibrational bands, frontier molecular orbitals (FMOs) and natural bond analysis (NBO) of ligand (1) were carried out through density functional theory (DFT) with B3lYP/6-311 ++G (d,p) approach. While, UV-Vis analysis was performed by time dependent TD-DFT with B3lYP/6-311 ++G (d,p) method. NBO analysis revealed that investigated compound (L) contains enormous molecular stability owing to hyper conjugative interactions. Theoretical spectroscopic findings showed good agreement to experimental spectroscopic data. Global reactivity descriptors were calculated using the energies of FMOs which indicated compound (L) might be bioactive. These parameters confirmed the charge transfer phenomenon and reasonable correspondence with experimental bioactivity results.

Mg(II) and Ni(II) induce aggregation of poly(rA)poly(rU) to either tetra-aggregate or triplex depending on the metal ion concentration.

PubMed

Biver, Tarita; Busto, Natalia; García, Begoña; Leal, José M; Menichetti, Luisa; Secco, Fernando; Venturini, Marcella

2015-10-01

The ability of magnesium(II) and nickel(II) to induce dramatic conformational changes in the synthetic RNA poly(rA)poly(rU) has been investigated. Kinetic experiments, spectrofluorometric titrations, melting experiments and DSC measurements contribute in shedding light on a complex behaviour where the action of metal ions (Na(+), Mg(2+), Ni(2+)), in synergism with other operators as the intercalating dye coralyne and temperature, all concur in stabilising a peculiar RNA form. Mg(2+) and Ni(2+) (M) bind rapidly and almost quantitatively to the duplex (AU) to give a RNA/metal ion complex (AUM). Then, by the union of two AUM units, an unstable tetra-aggregate (UAUA(M2)*) is formed which, in the presence of a relatively modest excess of metal, evolves to the UAUM triplex by releasing a single AM strand. On the other hand, under conditions of high metal content, the UAUA(M2)* intermediate rearranges to give a more stable tetra-aggregate (UAUA(M2)). As concerns the role of coralyne (D), it is found that D strongly interacts with UAUA(M2). Also, in the presence of coralyne, the ability of divalent ions to promote the transition of AUD into UAUD is enhanced, according to the efficiency sequence [Ni(2+)]≫[Mg(2+)]≫[Na(+)]. Copyright © 2015 Elsevier Inc. All rights reserved.

Crystal structure, complexation, spectroscopic characterization and antimicrobial evaluation of 3,4-dihydroxybenzylidene isonicotinyl-hydrazone

NASA Astrophysics Data System (ADS)

Jeragh, Bakir; Ali, Mayada S.; El-Asmy, Ahmed A.

2015-06-01

A single crystal of 3,4-dihydroxybenzylidene isonicotinylhydrazone, HBINH, has been grown and solved by X-ray crystallography. The VO2+, Zr4+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Hg2+ and Pd2+ complexes of HBINH have been prepared and spectroscopically characterized. The data confirmed the formulae [Co(HBINH)(H2O)Cl]Cl·H2O, [Pd(HBINH)Cl2], [Zn(HBINH)2Cl2], [Cd(HBINH)(H2O)2Cl2]·1½H2O, [(VO)2(HBINH-3H)(OH)(H2O)], [Ni2(HBINH)(H2O)6Cl2]Cl2, [Cu2(HBINH-3H)(H2O)2(OAc)]·3H2O, [Zr2(HBINH-3H)Cl4]Cl, [Hg2(HBINH)Cl4] and the dimer {[Cu(HBINH)Cl]Cl}2. Most of the complexes have intense colors and high melting points and some are electrolytes in DMSO solution. The ligand behaves as a neutral bidentate in the Co(II), Cu(II), Pd(II), Zn(II) and Cd(II) complexes; dibasic tetradentate in [Ni2(HBINH)(H2O)6Cl2]Cl2 and tribasic tetradentate in [Cu2(HBINH-3H)(OAc)]·5H2O, [(VO)2(HBINH-3H)(OH)(H2O)] and [Zr2(HBINH-3H)Cl4]Cl by the loss of 3H+ due to the deprotonation of the two hydroxyl groups and the enolization of the amide (Odbnd CNH) group. A tetrahedral geometry was proposed for the Co(II), Cu(II), Zn(II) and Hg(II) complexes; square-planar for the Pd(II) complex; square-pyramid for the VO2+ complex and octahedral for the Ni(II) and Cd(II) complexes. The complexes [Cd(HBINH)(H2O)2Cl2]·1½H2O, [(VO)2(HBINH-3H)(OH)(H2O)] and [Cu2(HBINH-3H)-(H2O)2(OAc)]·3H2O have activities against Bacillus sp. M3010, Candida albicans, Escherichia coli, Staphylococcus aureus and Slamonella sp. PA393.

Design and synthesis of binucleating macrocyclic clefts derived from Schiff-base calixpyrroles.

PubMed

Givaja, Gonzalo; Volpe, Manuel; Leeland, James W; Edwards, Michael A; Young, Thomas K; Darby, S Barnie; Reid, Stuart D; Blake, Alexander J; Wilson, Claire; Wolowska, Joanna; McInnes, Eric J L; Schröder, Martin; Love, Jason B

2007-01-01

The syntheses, characterisation and complexation reactions of a series of binucleating Schiff-base calixpyrrole macrocycles are described. The acid-templated [2+2] condensations between meso-disubstituted diformyldipyrromethanes and o-phenylenediamines generate the Schiff-base pyrrolic macrocycles H(4)L(1) to H(4)L(6) upon basic workup. The single-crystal X-ray structures of both H(4)L(3).2 EtOH and H(4)L(6).H2O confirm that [2+2] cyclisation has occurred, with either EtOH or H2O hydrogen-bonded within the macrocyclic cleft. A series of complexation reactions generate the dipalladium [Pd2(L)] (L=L(1) to L(5)), dinickel [Ni2(L(1))] and dicopper [Cu2(L)] (L=L(1) to L(3)) complexes. All of these complexes have been structurally characterised in the solid state and are found to adopt wedged structures that are enforced by the rigidity of the aryl backbone to give a cleft reminiscent of the structures of Pacman porphyrins. The binuclear nickel complexes [Ni2(mu-OMe)2Cl2(HOMe)2(H(4)L(1))] and [Ni2(mu-OH)2Cl2(HOMe)(H(4)L(5))] have also been prepared, although in these cases the solid-state structures show that the macrocyclic ligand remains protonated at the pyrrolic nitrogen atoms, and the Ni(II) cations are therefore co-ordinated by the imine nitrogen atoms only to give an open conformation for the complex. The dicopper complex [Cu2(L(3))] was crystallised in the presence of pyridine to form the adduct [Cu2(py)(L(3))], in which, in the solid state, the pyridine ligand is bound within the binuclear molecular cleft. Reaction between H(4)L(1) and [Mn(thf){N(SiMe(3))2}2] results in clean formation of the dimanganese complex [Mn2(L(1))], which, upon crystallisation, formed the mixed-valent complex [Mn2(mu-OH)(L(1))] in which the hydroxo ligand bridges the metal centres within the molecular cleft.

Synthesis, characterization, molecular modeling and biological activity of metal complexes derived from (E)-N'-(furan-2-ylmethylene)morpholine-4-carbothiohydrazide

NASA Astrophysics Data System (ADS)

El-Samanody, El-Sayed A.; Emam, Sanaa M.; Emara, Esam M.

2017-10-01

A new series of some biologically active Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) complexes was synthesized from the novel thiosemicarbazone ligand; (E)-N'-(furan-2-ylmethylene)morpholine-4-carbothiohydrazide (HL). Elemental, spectral, thermal analyses, magnetic susceptibility and molar conductivity measurements were used to elucidate the structure of separated compounds. The data prove that the ligand reacts with all metal ions in a neutral thione form. The electrolytic tetra-coordinate Cu(II); Zn(II) complexes (5, 6; 10) bind through the thione sulfur, furfural oxygen and azomethine nitrogen atoms of the ligand (NSO type) to construct fused five membered rings. However, the rest non-electrolyte octahedral complexes chelate via the furfural oxygen and azomethine nitrogen atoms of the ligand (NO type). Molecular modeling was conducted for the ligand and two representative complexes (1, 5) in order to substantiate their chemical structures. Thermal analyses are compatible with molecular modeling studies to support the proposed thermal decomposition pathways of metal complexes which start with the rupture of the long and weak N-NH bond. The thermal stability of metal complexes varies according to the number of solvents of crystallization, ionic radii and steric effect of anions. The ESR spectra of Cu(II) complexes are compatible with a primarily (dx2-y2)1 ground state with axial symmetry. The ligand and its Co(II); Cu(II); Cd(II) complexes (1; 5, 8; 11) along with their mixtures with metaldehyde were screened in vitro for their molluscicidal activity against Eobania vermiculata. Combination with metaldehyde enhances the toxicity effect of the tested compounds through reducing the period required for mortality and increasing the percentage of mortality after 24 h of treatments. The tested compounds gathered with metaldehyde are strongly affecting on the activity of ACP and ALP enzymes and TP content which are very important factors in the mucous secretion of Eobania vermiculata. These effects lead to excess mucous secretion, causing dryness and death for the snails.

Substitutional impact on biological activity of new water soluble Ni(II) complexes: Preparation, spectral characterization, X-ray crystallography, DNA/protein binding, antibacterial activity and in vitro cytotoxicity.

PubMed

Umadevi, C; Kalaivani, P; Puschmann, H; Murugan, S; Mohan, P S; Prabhakaran, R

2017-02-01

A series of new water soluble nickel(II) complexes containing triphenylphosphine and 4-methoxysalicylaldehyde-4(N)-substituted thiosemicarbazones were synthesized and characterized. Crystallographic investigations confirmed the structure of the complexes (1-4) having the general structure [Ni(4-Msal-Rtsc)(PPh 3 )] (Where R=H (1); CH 3 (2); C 2 H 5 (3); C 6 H 5 (4)) which showed that thiosemicarbazone ligands coordinated to nickel(II) ion as ONS tridentate bibasic donor. DNA/BSA protein binding ability of the ligands and their new complexes were studied by taking calf-thymus DNA (CT-DNA) and Bovine serum albumin (BSA) through absorption and emission titrations. Ethidium bromide (EB) displacement study showed the intercalative binding trend of the complexes to DNA. From the albumin binding studies, the mechanism of quenching was found as static and the alterations in the secondary structure of BSA by the compounds were confirmed with synchronous spectral studies. The binding affinity of the complexes to CT-DNA and BSA has the order of [Ni(4-Msal-etsc)(PPh 3 )] (3) >[Ni(4-Msal-mtsc)(PPh 3 )] (2) >[Ni(4-Msal-tsc)(PPh 3 )] (1) >[Ni(4-Msal-ptsc)(PPh 3 )] (4). In vitro cytotoxicity of the complexes was tested on human lung cancer cells (A549), human cervical cancer cells (HeLa), human liver carcinoma cells (Hep G2). All the complexes exhibited significant activity against three cancer cells. Among them, complex 4 exhibited almost 2.5 fold activity than cisplatin in A549 and HepG2 cell lines. In HeLa cell line, the complexes exhibited significant activity which is less than cisplatin. While comparing the activity of the complexes in A549 and HepG2 cell lines it falls in the order 4>1>2>3>cisplatin. The results obtained from DNA, protein binding and cytotoxicity studies, it is concluded that the cytotoxicity of the complexes as determined by MTT assay were not unduly influenced by the complexes having different binding efficiency with DNA and protein. The complexes exhibited good spectrum of antibacterial activity against four pathogenic bacteria such as E. faecalis (gram +ve), S. aureus (gram +ve), E. coli (gram -ve) and P. aeruginosa (gram -ve). Copyright © 2016 Elsevier B.V. All rights reserved.

Crystal structures, DFT calculations, and Hirshfeld surface analyses of two new copper(II) and nickel(II) Schiff base complexes derived from meso-1,2-diphenyl-1,2-ethylenediamine

NASA Astrophysics Data System (ADS)

Seifikar Ghomi, Leila; Behzad, Mahdi; Tarahhomi, Atekeh; Arab, Ali

2017-12-01

Two new Ni(II) and Cu(II) complexes of a tetradentate Schiff base ligand (1 and 2, respectively), derived from the condensation of meso-1,2-diphenyl-1,2-ethylenediamine with 2-hydroxy-6-methoxy benzaldehyde, were synthesized and characterized by IR, UV-Vis, 1H NMR spectroscopy, and X-Ray crystallography. The central metal ions in both complexes are coordinated via the N2O2 coordination sphere of the ligand with square-planar geometry. DFT results revealed that the Msbnd N and Msbnd O interactions (M = Ni, Cu) are weaker than the typical covalent single bond indicating that ionic and electrostatic interactions are dominated in Msbnd N and Msbnd O bonds. Hirshfeld surface (HS) analyses of the studied structures 1 and 2 have been performed. The study using 3D HSs and 2D fingerprint plots (FPs) highlighted the dominant contacts H⋯H, C⋯H/H⋯C and O⋯H/H⋯O in both structures, and H⋯Cl in 2. The molecular assemblies held by C⋯O/O⋯C (in 1) and C⋯C (in 1 and 2) type dipole-dipole interactions are also found in the crystal packing contributing towards stability. The significant contributions arising from the mentioned interactions in crystal packing are also revealed from the Hirshfeld surface FPs showing a major contribution to total HS area for the H⋯H contacts for both structures.

Synthesis of non-toxic As and Cr nanoparticles through redox activity of highly flexible layered coordination polymer of Ni(II).

PubMed

Agarwal, Rashmi A

2018-03-09

A simple method for the sequestration of As(III) and Cr(VI) from water has been demonstrated by utilizing a highly flexible porous coordination polymer (PCP) of Ni(II) in its as synthesized form or without solvent removal. This PCP reduces the high toxicity of As(III) and Cr(VI) ions into non-toxic As(0) and Cr/Cr 2 O 3 /CrO 2 (zero, tri and tetravalent) nanoparticles (NPs) within its pores, and this is characterized by powder x-ray diffraction, x-ray photoelectron spectroscopy and high-resolution transmission electron microscopy analysis. The high functionality of this polymer is due to the presence of monodentate carboxylate groups of a benzenetricarboxylate linker, which provide anchoring sites to the metal ions of the metal precursors. Due to the highly oxidising nature of these toxic ions, a redox reaction takes place between the framework metal ions and toxic metal ions, which is explained by an electron paramagnetic resonance study. This is the first report to synthesize non-toxic, as well as useful, NPs of As and Cr from their highly toxic ions within the cavities of a PCP for remediation of the toxic waste stream and contaminated waste water.

Determination of kinetic and equilibrium parameters of the batch adsorption of Mn(II), Co(II), Ni(II) and Cu(II) from aqueous solution by black carrot (Daucus carota L.) residues.

PubMed

Güzel, Fuat; Yakut, Hakan; Topal, Giray

2008-05-30

In this study, the effect of temperature on the adsorption of Mn(II), Ni(II), Co(II) and Cu(II) from aqueous solution by modified carrot residues (MCR) was investigated. The equilibrium contact times of adsorption process for each heavy metals-MCR systems were determined. Kinetic data obtained for each heavy metal by MCR at different temperatures were applied to the Lagergren equation, and adsorption rate constants (kads) at these temperatures were determined. These rate constants related to the adsorption of heavy metal by MCR were applied to the Arrhenius equation, and activation energies (Ea) were determined. In addition, the isotherms for adsorption of each heavy metal by MCR at different temperatures were also determined. These isothermal data were applied to linear forms of isotherm equations that they fit the Langmuir adsorption isotherm, and the Langmuir constants (qm and b) were calculated. b constants determined at different temperatures were applied to thermodynamic equations, and thermodynamic parameters such as enthalpy (Delta H), free energy (Delta G), and entropy (Delta S) were calculated and these values show that adsorption of heavy metal on MCR was an endothermic process and process of adsorption was favoured at high temperatures.

Chitosan film loaded with silver nanoparticles-sorbent for solid phase extraction of Al(III), Cd(II), Cu(II), Co(II), Fe(III), Ni(II), Pb(II) and Zn(II).

PubMed

Djerahov, Lubomir; Vasileva, Penka; Karadjova, Irina; Kurakalva, Rama Mohan; Aradhi, Keshav Krishna

2016-08-20

The present study describes the ecofriendly method for the preparation of chitosan film loaded with silver nanoparticles (CS-AgNPs) and application of this film as efficient sorbent for separation and enrichment of Al(III), Cd(II), Cu(II), Co(II), Fe(III), Ni(II), Pb(II) and Zn(II). The stable CS-AgNPs colloid was prepared by dispersing the AgNPs sol in chitosan solution at appropriate ratio and further used to obtain a cast film with very good stability under storage and good mechanical strength for easy handling in aqueous medium. The incorporation of AgNPs in the structure of CS film and interaction between the polymer matrix and nanoparticles were confirmed by UV-vis and FTIR spectroscopy. The homogeneously embedded AgNPs (average diameter 29nm, TEM analysis) were clearly observed throughout the film by SEM. The CS-AgNPs nanocomposite film shows high sorption activity toward trace metals under optimized chemical conditions. The results suggest that the CS-AgNPs nanocomposite film can be feasibly used as a novel sorbent material for solid-phase extraction of metal pollutants from surface waters. Copyright © 2016 Elsevier Ltd. All rights reserved.

Simultaneous removal of heavy-metal ions in wastewater samples using nano-alumina modified with 2,4-dinitrophenylhydrazine.

PubMed

Afkhami, Abbas; Saber-Tehrani, Mohammad; Bagheri, Hasan

2010-09-15

2,4-Dinitrophenylhydrazine (DNPH) immobilized on sodium dodecyl sulfate coated nano-alumina was developed for the removal of metal cations Pb(II), Cd(II), Cr(III), Co(II), Ni(II) and Mn(II) from water samples. The research results displayed that adsorbent has the highest adsorption capacity for Pb(II), Cr(III) and Cd(II) in ions mixture system. Optimal experimental conditions including pH, adsorbent dosage and contact time have been established. Langmuir and Freundlich isotherm models were applied to analyze the experimental data. The best interpretation for the experimental data was given by the Freundlich adsorption isotherm equation for Mn(II), Pb(II), Cr(III) and Cd(II) ions and by Langmuir isotherm equation for Ni(II) and Co(II) ions. Desorption experiments by elution of the adsorbent with a mixture of nitric acid and methanol show that the modified alumina nanoparticles could be reused without significant losses of its initial properties even after three adsorption-desorption cycles. Thus, modified nano-alumina with DNPH is favorable and useful for the removal of these metal ions, and the high adsorption capacity makes it a good promising candidate material for Pb(II),Cr(III) and Cd(II) removal. Copyright 2010 Elsevier B.V. All rights reserved.

Flexible porous coordination polymer of Ni(II) for developing nanoparticles through acid formation and redox activity of the framework

NASA Astrophysics Data System (ADS)

Agarwal, Rashmi A.

2017-10-01

Immobilization of the nanoparticles (NPs) in a two dimensional porous coordination polymer (PCP) is currently an emerging field for a number of applications. But still it is a great challenge to fabricate any specified metal NPs in a single network. Herein the synthesis of Au, Pd, Mn, Fe, Cu, Zn, Mg, Li, Fe/Cu, Zn/Mg etc, NPs in a highly flexible PCP of Ni(II); {[Ni3(TBIB)2(BTC)2(H2O)6]·5C2H5OH·9H2O}n [TBIB = 1,3,5-tri(1H-benzo[d]imidazol-1-yl)benzene, H3BTC = 1,3,5-benzenetricarboxylic acid] have been reported. This universal host is able to grow mixed metal NPs from mixed metal precursors. Monodentate carboxylate groups of BTC linker act as anchoring sites for the metal ions of the metal precursors. This is the main driving force to grow NPs within the cavities along with the high flexibility of this polymer at room temperature. Mechanism involves acid formation followed by redox reaction to synthesize metal NPs explained by EPR and FTIR. Paramagnetic properties have been shown by as-synthesized Fe NPs integrated framework at room temperature under applied magnetic field up to 17,500 Oe.

Synthesis of non-toxic As and Cr nanoparticles through redox activity of highly flexible layered coordination polymer of Ni(II)

NASA Astrophysics Data System (ADS)

Agarwal, Rashmi A.

2018-03-01

A simple method for the sequestration of As(III) and Cr(VI) from water has been demonstrated by utilizing a highly flexible porous coordination polymer (PCP) of Ni(II) in its as synthesized form or without solvent removal. This PCP reduces the high toxicity of As(III) and Cr(VI) ions into non-toxic As(0) and Cr/Cr2O3/CrO2 (zero, tri and tetravalent) nanoparticles (NPs) within its pores, and this is characterized by powder x-ray diffraction, x-ray photoelectron spectroscopy and high-resolution transmission electron microscopy analysis. The high functionality of this polymer is due to the presence of monodentate carboxylate groups of a benzenetricarboxylate linker, which provide anchoring sites to the metal ions of the metal precursors. Due to the highly oxidising nature of these toxic ions, a redox reaction takes place between the framework metal ions and toxic metal ions, which is explained by an electron paramagnetic resonance study. This is the first report to synthesize non-toxic, as well as useful, NPs of As and Cr from their highly toxic ions within the cavities of a PCP for remediation of the toxic waste stream and contaminated waste water.

Synthesis, characterization and extraction studies of some metal (II) complexes containing (hydrazoneoxime and bis-acylhydrazone) moieties

NASA Astrophysics Data System (ADS)

Al-Ne'aimi, Mohammed Mahmmod; Al-Khuder, Mohammed Moudar

2013-03-01

In this study, diacetylmonoximebenzoylhydrazone (L1H2) and 1,4-diacetylbenzene bis(benzoyl hydrazone) (L2H2) were synthesized by the condensation of benzohydrazide with diacetyl monoxime and 1,4-diacetylbenzene, respectively. Complexes of these ligands with Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) inos were prepared with a metal:ligand ratio of 1:2 for L1H2 ligand, and 1:1 for L2H2 ligand. The ligands and their complexes were elucidated on the basis of elemental analyses CHN, AAS, FT-IR, 1H- and 13C NMR spectra, UV-vis spectra and magnetic susceptibility measurements. Results show the L1H2 ligand act as monoanionic O,N,N-tridentate and coordination takes place in the enol form through the oxime nitrogen, the imine nitrogen and the enolate oxygen atoms with a N4O2 donor environment, while the L2H2 ligand act as a dianionic O,N,N,O-tetradentate and coordination takes place in the enol form through the enolate oxygen and the azomethine nitrogen atoms with a N2O2 donor environment. These results are consistent with the formation of mononuclear metal (II) complexes [M(L1H)2], and binuclear polymeric metal (II) complexes [{M2(L2)}n]. The extraction ability of both ligands were examined in chloroform by the liquid-liquid extraction of selected transition metal [Co2+, Ni2+, Cu2+, Zn2+ and Pb2+] cations. The effects of pH and contact time on the percentage extraction of metal (II) ions were studied under the optimum extraction conditions. The (L1H2) ligand shows strong binding ability toward copper(II) and lead(II) ions, while the (L2H2) ligand shows strong binding ability toward nickel(II) and zinc(II) ions.

Synthesis, characterization and extraction studies of some metal (II) complexes containing (hydrazoneoxime and bis-acylhydrazone) moieties.

PubMed

Al-Ne'aimi, Mohammed Mahmmod; Al-Khuder, Mohammed Moudar

2013-03-15

In this study, diacetylmonoximebenzoylhydrazone (L(1)H(2)) and 1,4-diacetylbenzene bis(benzoyl hydrazone) (L(2)H(2)) were synthesized by the condensation of benzohydrazide with diacetyl monoxime and 1,4-diacetylbenzene, respectively. Complexes of these ligands with Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) inos were prepared with a metal:ligand ratio of 1:2 for L(1)H(2) ligand, and 1:1 for L(2)H(2) ligand. The ligands and their complexes were elucidated on the basis of elemental analyses CHN, AAS, FT-IR, (1)H- and (13)C NMR spectra, UV-vis spectra and magnetic susceptibility measurements. Results show the L(1)H(2) ligand act as monoanionic O,N,N-tridentate and coordination takes place in the enol form through the oxime nitrogen, the imine nitrogen and the enolate oxygen atoms with a N(4)O(2) donor environment, while the L(2)H(2) ligand act as a dianionic O,N,N,O-tetradentate and coordination takes place in the enol form through the enolate oxygen and the azomethine nitrogen atoms with a N(2)O(2) donor environment. These results are consistent with the formation of mononuclear metal (II) complexes [M(L(1)H)(2)], and binuclear polymeric metal (II) complexes [{M(2)(L(2))}(n)]. The extraction ability of both ligands were examined in chloroform by the liquid-liquid extraction of selected transition metal [Co(2+), Ni(2+), Cu(2+), Zn(2+) and Pb(2+)] cations. The effects of pH and contact time on the percentage extraction of metal (II) ions were studied under the optimum extraction conditions. The (L(1)H(2)) ligand shows strong binding ability toward copper(II) and lead(II) ions, while the (L(2)H(2)) ligand shows strong binding ability toward nickel(II) and zinc(II) ions. Copyright © 2012 Elsevier B.V. All rights reserved.

Mechanisms for Reduction of Natural Waters Technogenic Pollution by Metals due to Complexions with Humus Substances (Zoning: Western Siberia and the European Territory of Russia)

NASA Astrophysics Data System (ADS)

Dinu, M. I.

2017-11-01

The article described the complexation of metal ions with humus substances in natural waters (small lakes). Humus substances as the major biochemical components of natural water have a significant impact on the forms and migration of metals and the toxicity of natural objects. This article presents the results of large-scale chemical experiments: the study of the structural features (zonal aspects) of humus substances extracted from soil and water natural climatic zones (more than 300 objects) in Russia (European Russia and West Siberia); the influence of structural features on the physic-chemical parameters of humus acids and, in particular, on their complexing ability. The functional specifics of humus matter extracted from soils is estimated using spectrometric techniques. The conditional stability constants for Fe(III), Cu(II), Pb(II), Cd(II), Zn(II), Ni(II), Co(II), Mn(II), Cr(III), Ca(II), Mg(II), Sr(II), and Al(III) are experimentally determined with the electrochemical, spectroscopic analysis methods. The activities of metals are classified according to their affinity to humus compounds in soils and water. The determined conditional stability constants of the complexes are tested by model experiments, and it is demonstrated that Fe and Al ions have higher conditional stability constants than the ions of alkali earth metals, Pb, Cu, and Zn. Furthermore, the influence of aluminium ions and iron on the complexation of copper and lead as well as the influence of lead and copper on complexation of cobalt and nickel have been identified. The metal forms in a large number of lakes are calculated basing on the experiments’ results. The main chemical mechanisms of the distribution of metals by forms in the water of the lakes in European Russia and West Siberia are described.

Inorganic and organic structures as interleavers among [bis(1-methyl-3-(p-carboxylatephenyl)triazenide 1-oxide)Ni(II)] complexes to form supramolecular arrangements

NASA Astrophysics Data System (ADS)

Santos, Aline Joana Rolina Wohlmuth Alves; dos Santos Hackbart, Helen Cristina; Giacomini, Gabriela Xavier; Bersch, Patrícia; Paraginski, Gustavo Luiz; Hörner, Manfredo

2016-12-01

Alternative compounds to capture metal ions are triazenes 1-oxide since they are basic compounds O(N) with negative charge in the deprotonated form. The proximity of both coordination sites (O and N) enables these compounds to have good chelating ability and a tendency to stabilize in the formation of rings with soft and hard transition metal ions. The structure analysis by single crystal X-ray diffraction of compounds (1) and (2) demonstrate the formation of 3D supramolecular arrangements through ion-ion, ion-dipolo and dipolo-dipolo interactions. In one of them, there are [(H2O)2(CH3CH3SO)K2]2+ as linkers of polymerization and, in another complex, there are [(H2O)(CH3CH3SO)Ni(H2O)6]2+ as a linker of polymerization. These linkers act in the polymerization of the novel mononuclear complex [bis(1-methyl (p-carboxylatephenyl) triazenide 1-oxide) NiII] (3). The crystallography analysis of (1) and (2) showed distorted quadratic geometry for Ni (II), thus, there are two axial positions available in Ni (II) to be used in catalysis studies and as sensor or biosensor. In addition, this study shows the support of this novel mononuclear complex of Ni (II) (3) on protonated chitosan chains (4). The compounds (3) and (4) were characterized by spectroscopic analysis, infrared (IR) and energy dispersive X-ray detector (EDS), and by differential scanning calorimetry analysis (DSC). The specificity of ligand 1-methyl (p-carboxyphenyl) triazene 1-oxide to capture potassium and nickel ions will be tested at different pH values, as well as the capacity of the triazenide 1-oxide of Ni (II) complex, supported on chitosan polymer, or not, to act as a catalyst for organic reactions and biomimetic organic reactions.

USSR Report, Chemistry

DTIC Science & Technology

1985-03-14

USSR Academy of Sciences lAbstract] A study is made of the mechanism of attachment of Ni(II) by covalent bonding to a polyethylene-graft- polyacrylic ...and 12.5 percent of its plastics and synthetic resins.. The republic’s share in national production of potassium fertilizers, which is 53.6 percent...our republic, the return from 1 kg of active ingredient in nitrogen-phosphorus- potassium fertilizer averages 6 kg of grain, which is the reason why

Albumin Redhill, a human albumin variant.

PubMed

Brand, S; Hutchinson, D W; Donaldson, D

1984-01-31

Albumin Redhill, a variant human albumin with the same C-terminal amino acid as albumin A but with arginine at the N-terminus has been isolated by chromatofocusing from the sera of an English family. Albumin Redhill appears to contain two sites of mutation in its protein chain and is probably a proalbumin. The ability of albumin Redhill to bind Ni(II) or Cu(II) ions is considerably less than that of albumin A.

Disulfiram and Copper Ions Kill Mycobacterium tuberculosis in a Synergistic Manner

PubMed Central

Dalecki, Alex G.; Haeili, Mehri; Shah, Santosh; Speer, Alexander; Niederweis, Michael; Kutsch, Olaf

2015-01-01

Tuberculosis is a severe disease affecting millions worldwide. Unfortunately, treatment strategies are hampered both by the prohibitively long treatment regimen and the rise of drug-resistant strains. Significant effort has been expended in the search for new treatments, but few options have successfully emerged, and new treatment modalities are desperately needed. Recently, there has been growing interest in the synergistic antibacterial effects of copper ions (CuII/I) in combination with certain small molecular compounds, and we have previously reported development of a drug screening strategy to harness the intrinsic bactericidal properties of CuII/I. Here, we describe the copper-dependent antimycobacterial properties of disulfiram, an FDA-approved and well-tolerated sobriety aid. Disulfiram was inhibitory to mycobacteria only in the presence of CuII/I and exerted its bactericidal activity well below the active concentration of CuII/I or disulfiram alone. No other physiologically relevant bivalent transition metals (e.g., FeII, NiII, MnII, and CoII) exhibited this effect. We demonstrate that the movement of the disulfiram-copper complex across the cell envelope is porin independent and can inhibit intracellular protein functions. Additionally, the complex is able to synergistically induce intracellular copper stress responses significantly more than CuII/I alone. Our data suggest that by complexing with disulfiram, CuII/I is likely allowed unfettered access to vulnerable intracellular components, bypassing the normally sufficient copper homeostatic machinery. Overall, the synergistic antibacterial activity of CuII/I and disulfiram reveals the susceptibility of the copper homeostasis system of Mycobacterium tuberculosis to chemical attacks and establishes compounds that act in concert with copper as a new class of bacterial inhibitors. PMID:26033731

Immobilization of heavy metals in electroplating sludge by biochar and iron sulfide.

PubMed

Lyu, Honghong; Gong, Yanyan; Tang, Jingcshun; Huang, Yao; Wang, Qilin

2016-07-01

Electroplating sludge (ES) containing large quantities of heavy metals is regarded as a hazardous waste in China. This paper introduced a simple method of treating ES using environmentally friendly fixatives biochar (BC) and iron sulfide (FeS), respectively. After 3 days of treatment with FeS at a FeS-to-ES mass ratio of 1:5, the toxicity characteristic leaching procedure (TCLP)-based leachability of total Cr (TCr), Cu(II), Ni(II), Pb(II), and Zn(II) was decreased by 59.6, 100, 63.8, 73.5, and 90.5 %, respectively. After 5 days of treatment with BC at a BC-to-ES mass ratio of 1:2, the TCLP-based leachability was declined by 35.1, 30.6, 22.3, 23.1, and 22.4 %, respectively. Pseudo first-order kinetic model adequately simulated the sorption kinetic data. Structure and morphology analysis showed that adsorption, electrostatic attraction, surface complexation, and chemical precipitation were dominant mechanisms for heavy metals immobilization by BC, and that chemical precipitation (formation of metal sulfide and hydroxide precipitates), iron exchange (formation of CuFeS2), and surface complexation were mainly responsible for heavy metals removal by FeS. Economic costs of BC and FeS were 500 and 768 CNY/t, lower than that of Na2S (940 CNY/t). The results suggest that BC and FeS are effective, economic, and environmentally friendly fixatives for immobilization of heavy metals in ES before landfill disposal.

Alkali metal and ammonium fluoro(trifluoroacetato)metallates M'[ M''3(μ3-F)(CF3COO)6(CF3COOH)3], where M' = Li, Na, K, NH4, Rb, or Cs and M'' = Ni or Co. Synthesis and crystal structures

NASA Astrophysics Data System (ADS)

Tereshchenko, D. S.; Morozov, I. V.; Boltalin, A. I.; Karpova, E. V.; Glazunova, T. Yu.; Troyanov, S. I.

2013-01-01

A series of fluoro(trifluoroacetato)metallates were synthesized by crystallization from solutions in trifluoroacetic acid containing nickel(II) or cobalt(II) nitrate hydrates and alkali metal or ammonium fluorides: Li[Ni3(μ3-F)(CF3COO)6(CF3COOH)3](CF3COOH)3 ( I), M'[Ni3(μ3-F)(CF3COO)6(CF3COOH)3] ( M' = Na ( II), NH4 ( IV), Rb ( V), and Cs ( VI)), NH4[Co3(μ3-F) (CF3COO)6(CF3COOH)3] ( III), and Cs[Ni3(μ3-F)(CF3COO)6(CF3COOH)3](CF3COOH)0.5 ( VII). The crystal structures of these compounds were determined by single-crystal X-ray diffraction. All structures contain triangular trinuclear complex anions [ M 3″(μ3-F)(CF3COO)6(CF3COOH)3]- ( M″ = Ni, Co) structurally similar to trinuclear 3d metal oxo carboxylate complexes. The three-coordinated F atom is located at the center of the triangle formed by Ni(II) or Co(II) atoms. The metal atoms are linked in pairs by six bridging trifluoroacetate groups located above and below the plane of the [ M″3 F] triangle. The oxygen atoms of the axial CF3COOH molecules complete the coordination environment of M″ atoms to an octahedron.

Ferrate(VI)-Prompted Removal of Metals in Aqueous Media: Mechanistic Delineation of Enhanced Efficiency via Metal Entrenchment in Magnetic Oxides

EPA Science Inventory

The removal efficiency of heavy metal ions (cadmium(II) – Cd(II), cobalt(II) – Co(II), nickel(II) – Ni(II), and copper(II) – Cu(II)) by potassium ferrate(VI) (K2FeO4, Fe(VI)), was studied as a function of added amount of Fe(VI) (or Fe) and varying pH. At pH = 6.6, the effective r...

trans-Bis(azido-kappaN)bis(pyridine-2-carboxamide-kappa2N1,O2)nickel(II).

PubMed

Daković, Marijana; Popović, Zora

2007-11-01

In the title compound, [Ni(N(3))(2)(C(6)H(6)N(2)O)(2)], the Ni(II) atom lies on an inversion centre. The distorted octahedral nickel(II) coordination environment contains two planar trans-related N,O-chelating picolinamide ligands in one plane and two monodentate azide ligands perpendicular to this plane. Molecules are linked into a three-dimensional framework by N-H...N hydrogen bonds.

Impregnated multiwalled carbon nanotubes as efficient sorbent for the solid phase extraction of trace amounts of heavy metal ions in food and water samples.

PubMed

Gouda, Ayman A; Al Ghannam, Sheikha M

2016-07-01

A new, sensitive and simple solid phase extraction (SPE), separation and preconcentration method of some heavy metal ions, Cd(II), Cu(II), Ni(II), Pb(II) and Zn(II) at trace levels using multiwalled carbon nanotubes (MWCNTs) impregnated with 2-(2-benzothiazolylazo)orcinol (BTAO) from food and water samples were investigated. The effect of analytical parameters was examined. The metals retained on the nanotubes at pH 7.0 were eluted by 5.0mL HNO3 (2.0molL(-1)). The influence of matrix ions on the proposed method was evaluated. The preconcentration factor was calculated and found to be 100. The detection limits (LODs) for Cd(II), Cu(II), Ni(II), Pb(II) and Zn(II) were found at 0.70, 1.2, 0.80, 2.6 and 2.2μgL(-1), respectively. The relative standard deviation (RSD) and the recoveries of the standard addition method were lower than 5.0% and 95-102%, respectively. The new procedure was successfully applied to the determination of trace amounts of the studied metal ions in various food and water samples and validated using certified reference materials SRM 1570A (spinach leaves) with satisfactory and compatible results. Copyright © 2016 Elsevier Ltd. All rights reserved.

Removal of Cr6 + and Ni2+ from aqueous solution using bagasse and fly ash.

PubMed

Rao, M; Parwate, A V; Bhole, A G

2002-01-01

Raw bagasse and fly ash, the waste generated in sugar mills and boilers respectively have been used as low-cost potential adsorbents. Raw bagasse was pretreated with 0.1N NaOH followed by 0.1N CH3COOH before its application. These low-cost adsorbents were used for the removal of chromium and nickel from an aqueous solution. The kinetics of adsorption and extent of adsorption at equilibrium are dependent on the physical and chemical characteristics of the adsorbent, adsorbate and experimental system. The effect of hydrogen ion concentration, contact time, sorbent dose, initial concentrations of adsorbate and adsorbent and particle size on the uptake of chromium and nickel were studied in batch experiments. The Sorption data has been correlated with Langmuir, Freundlich and Bhattacharya and Venkobachar adsorption models. The efficiencies of adsorbent materials for the removal of Cr(VI) and Ni(II) were found to be between 56.2 and 96.2% and 83.6 and 100%, respectively. These results were obtained at the optimized conditions of pH, contact time, sorbent dose, sorbate concentration of 100 mg/l and with the variation of adsorbent particles size between 0.075 and 4.75 mm. The order of selectivity is powdered activated carbon > bagasse > fly ash for Cr(VI) removal and powdered activated carbon > fly ash > bagasse for Ni(II) removal.

Bright metal coatings from sustainable electrolytes: the effect of molecular additives on electrodeposition of nickel from a deep eutectic solvent.

PubMed

Abbott, Andrew P; Ballantyne, Andrew; Harris, Robert C; Juma, Jamil A; Ryder, Karl S

2017-01-25

Organic and inorganic additives are often added to nickel electroplating solutions to improve surface finish, reduce roughness and promote uniform surface morphology of the coatings. Such additives are usually small molecules and often referred to as brighteners or levellers. However, there have been limited investigations into the effect of such additives on electrodeposition from ionic liquids (ILs) and deep eutectic solvents (DESs). Here we study the effect of four additives on electrolytic nickel plating from an ethyleneglycol based DES; these are nicotinic acid (NA), methylnicotinate (MN), 5,5-dimethylhydantoin (DMH) and boric acid (BA). The additives show limited influence on the bulk Ni(ii) speciation but have significant influence on the electrochemical behaviour of Ni deposition. Small concentrations (ca. 15 mM) of NA and MN show inhibition of Ni(ii) reduction whereas high concentrations of DMH and BA are required for a modest difference in behaviour from the additive free system. NA and MN also show that they significantly alter the nucleation and growth mechanism when compared to the additive free system and those with DMH and BA. Each of the additive systems had the effect of producing brighter and flatter bulk electrodeposits with increased coating hardness but XRD shows that NA and MN direct crystal growth to the [111] orientation whereas DMH and BA direct crystal growth to the [220] orientation.

Functionalized polyethylene fibers for the selective capture of palladium ions from aqueous solution

NASA Astrophysics Data System (ADS)

Pang, Li-juan; Li, Rong; Hu, Jiang-tao; Zhang, Lin-juan; Zhang, Ming-xing; Yang, Chen-guang; Wu, Guo-zhong

2018-03-01

An innovative ultrahigh molecular weight polyethylene (UHMWPE) fibrous adsorbent was successfully synthesized via radiation grafting and applied to the selective capture of palladium ions from dilute aqueous solutions. The influence of the pH, initial Pd(II) concentration, and temperature on the adsorption performance was examined in a batch adsorption experiment. Pd K-edge extended X-ray absorption fine structure (EXAFS) spectra indicated that Pd(II) was immobilized on the adsorbent surface via a ligand exchange reaction that formed a stable UHMWPE-PMDA-Pd complex. Although the concentrations of coexisting ions (Cu(II), Zn(II), Cr(VI), Fe(III), and Ni(II)) in the solution were much higher than that of Pd(II), the adsorption capacity for Pd(II) of the as-prepared absorbent was significantly greater than that for other metal ions. Kinetic studies showed good correlation with the pseudo-second-order model. The maximum capacity for Pd(II) adsorption was approximately 221.8 mg·g-1 at 298 K. The adsorption behavior conformed to the Langmuir isotherm model. Thermodynamic studies revealed that the adsorption of Pd(II) was a feasible, spontaneous, and endothermic process.

Nanomolar Copper Enhances Mercury Methylation by Desulfovibrio desulfuricans ND132

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lu, Xia; Johs, Alexander; Zhao, Linduo

Methylmercury (MeHg) is produced by certain anaerobic microorganisms, such as the sulfate-reducing bacterium Desulfovibrio desulfuricans ND132, but environmental factors affecting inorganic mercury [Hg(II)] uptake and methylation remain unclear. We report that the presence of a small amount of copper ions [Cu(II), <100 nM] enhances Hg(II) uptake and methylation by washed cells of ND132, while Hg(II) methylation is inhibited at higher Cu(II) concentrations because of the toxicity of copper to the microorganism. The enhancement or inhibitory effect of Cu(II) is dependent on both time and concentration. The presence of nanomolar concentrations of Cu(II) facilitates rapid uptake of Hg(II) (within minutes) andmore » doubles MeHg production within a 24 h period, but micromolar concentrations of Cu(II) completely inhibit Hg(II) methylation. Metal ions such as zinc [Zn(II)] and nickel [Ni(II)] also inhibit but do not enhance Hg(II) methylation under the same experimental conditions. Furthermore, these observations suggest a synergistic effect of Cu(II) on Hg(II) uptake and methylation, possibly facilitated by copper transporters or metallochaperones in this organism, and highlight the fact that complex environmental factors affect MeHg production in the environment.« less

Functionalisation of mesoporous silica gel with 2-[(phosphonomethyl)-amino]acetic acid functional groups. Characterisation and application

NASA Astrophysics Data System (ADS)

Caldarola, Dario; Mitev, Dimitar P.; Marlin, Lucile; Nesterenko, Ekaterina P.; Paull, Brett; Onida, Barbara; Bruzzoniti, Maria Concetta; Carlo, Rosa Maria De; Sarzanini, Corrado; Nesterenko, Pavel N.

2014-01-01

A new complexing adsorbent was prepared by chemical modification of mesoporous silica Kieselgel 60 (dp = 37-63 μm, average pore size 6 nm, specific surface area 425 m2 g-1) with 3-glycidoxypropyltrimethoxysilane and 2-[(phosphonomethyl)amino]acetic acid (PMA), commonly known as glyphosate. The prepared adsorbent was fully characterised using elemental analysis, thermal gravimetric analysis (TGA), acid-base potentiometric titration, Fourier Transform Infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), nitrogen adsorption isotherms at 77 K (BET), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS). The concentration of bonded PMA groups calculated from the nitrogen content was 0.38 mmol per gram. The adsorption of transition metal ions on PMA functionalised silica (HEPMAS) was studied from aqueous solutions having different pH and the following selectivity was established, Zn(II) < Co(II) < Cd(II) < Mn(II) < Ni(II) < Cu(II). The calculated values of distribution coefficients D for the adsorption of ecotoxic metal ions on HEPMAS are 5.0 × 104, 4.9 × 105 and 2.6 × 104 for Zn(II), Pb(II) and Cd(II), respectively.

Spin crossover behaviour in Hofmann-like coordination polymer Fe(py)2[Pd(CN)4] with 57Fe Mössbauer spectra

NASA Astrophysics Data System (ADS)

Kitazawa, Takafumi; Kishida, Takanori; Kawasaki, Takeshi; Takahashi, Masashi

2017-11-01

We have prepared the 2D spin crossover complexes Fe(L)2Pd(CN)4 (L = py : 1a; py-D5 : 1b and py-15N : 1c). 1a has been characterised by 57Fe Mossbauer spectroscopic measurements, single crystal X-ray determination and SQUID measurements. The Mössbauer spectra for 1a indicate that the iron(II) spin states are in high spin states at 298 K and are in low spin states at 77 K. The crystal structures of 1a at 298 K and 90 K also show the high spin state and the low spin state respectively, associated with the Fe(II)-N distances. The spin transition temperature range of 1a is higher than that of Fe(py)2Ni(CN)4 since Pd(II) ions are larger and heavier than Ni(II) ions. SQUID data indicate isotope effects among 1a, 1b and 1c are observed in very small shifts of the transition temperatures probably due to larger and heavier Pd(II) ions. The delicate shifts would be associated with subtle balances between different vibrations around Fe(II) atoms and electronic factors.

Nanomolar Copper Enhances Mercury Methylation by Desulfovibrio desulfuricans ND132

DOE PAGES

Lu, Xia; Johs, Alexander; Zhao, Linduo; ...

2018-05-29

Methylmercury (MeHg) is produced by certain anaerobic microorganisms, such as the sulfate-reducing bacterium Desulfovibrio desulfuricans ND132, but environmental factors affecting inorganic mercury [Hg(II)] uptake and methylation remain unclear. We report that the presence of a small amount of copper ions [Cu(II), <100 nM] enhances Hg(II) uptake and methylation by washed cells of ND132, while Hg(II) methylation is inhibited at higher Cu(II) concentrations because of the toxicity of copper to the microorganism. The enhancement or inhibitory effect of Cu(II) is dependent on both time and concentration. The presence of nanomolar concentrations of Cu(II) facilitates rapid uptake of Hg(II) (within minutes) andmore » doubles MeHg production within a 24 h period, but micromolar concentrations of Cu(II) completely inhibit Hg(II) methylation. Metal ions such as zinc [Zn(II)] and nickel [Ni(II)] also inhibit but do not enhance Hg(II) methylation under the same experimental conditions. Furthermore, these observations suggest a synergistic effect of Cu(II) on Hg(II) uptake and methylation, possibly facilitated by copper transporters or metallochaperones in this organism, and highlight the fact that complex environmental factors affect MeHg production in the environment.« less

Synthesis, characterization, crystal structure, superoxide dismutase and biological activities of nickel (II) complexes with bidentate ligands possessing N and O donor atoms

NASA Astrophysics Data System (ADS)

Sangeeta, S.; Ahmad, K.; Noorussabah, N.; Bharti, S.; Mishra, M. K.; Sharma, S. R.; Choudhary, M.

2017-12-01

Two new Schiff bases 2-((E)-(4-bromo-2-chlorophenylimino)methyl)-4-bromophenol(HL1) and1-((E)-(4-bromo-2-chlorophenylimino)methyl)naphthalene-2-ol (HL2) and their new nickel (II) complexes [Ni(L1)2]·DMF(1) and [Ni(L2)2] (2) have been synthesized and characterized by various physico- chemical and spectroscopic methods. The solid-state structures of synthesized compounds were determined by single crystal X-ray crystallography, which revealed square planar geometry around Ni (II) ion. Infrared spectra, UV-Vis, thermal analysis and magnetic susceptibility measurements agreed with the observed crystal structures. The ligand (HL1) crystallized in the Orthorhombic system of the space group Pbca,a = 7.5485(4)Å, b = 11.5514(5) Å, c = 30.1370(14)Å, α = 90°, β = 90°, γ = 90°and Z = 8. Complex[Ni(L1)2]·DMF(1) crystallized in the Triclinic system of the space group P-1, a = 8.9954(3) Å, b = 9.4593(4) Å, c = 13.2657(5) Å, α = 101.478°, β = 99.595°, γ = 117.651°and Z = 2, whereas complex [Ni(L2)2]·(2) crystallized in the Monoclinic system of the space group P21/c, a = 9.301(9)Å, b = 12.149(8)Å, c = 13.792(10)Å, α = 90°, β = 106.35(4).°, γ = 90°and Z = 2. The Schiff bases (HL1and HL2) behaved as monobasic bidentate ligands possessing N and O donor atoms. The SOD activities of HL1 and its Ni (II) complex[Ni(L1)2]·DMF(1) have been measured using xanthine-xanthine oxidase as a source of superoxide radical and NBT assay as O2- scavenger. In vitro antimicrobial activities of the Ni(II) complexes (1) and (2)against Bacillus cereus and Staphylococcus aureus as Gram + ve and Salmonella typhi, Klebsiella pneumonia and Escherichia coli as Gram-ve species have been investigated comparing with the Schiff base ligands (HL1and HL2).