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Sample records for 1,4-diaminobutane

  1. Attempts at the production of more selective antitumourals. Part I. The antineoplastic activity of cyclophosphazenes linked to the polyamines 1,3-diaminopropane and 1,4-diaminobutane (putrescine)

    NASA Astrophysics Data System (ADS)

    Labarre, Jean-François; Guerch, Guy; Sournies, François; Spreafico, Federico; Filippeschi, Stefania

    1984-06-01

    In an attempt to design antitumour cyclophosphazenes of improved specificity by linking them to some natural tumour finders, we studied the binding of gem-N 3P 3Az 4Cl 2 to 1,3-diaminopropane and 1,4-diaminobutane (putrescine). Synthesis, mass spectrum and NMR as well as X-ray crystal structures of the two spirocyclic N 3P 3Az 4 [HN(CH 2) 3,4NH] derivatives (in which the N 3P 3Az 4 active principle is linked to the diamine in a spiro configuration) are described. Results obtained with these compounds in 3 murine tumour systems (L1210 and P388 leukaemias and P815 mastocytoma), showing their potent antineoplastic activity in vivo obtainable at well-tolerated doses, are also described.

  2. Synthesis and X-ray structure analysis of a new binuclear Schiff base Co(II) complex with the ligand N,N'-bis(3-methoxysalicylidene)-1,4-butanediamine

    SciTech Connect

    Nasr-Esfahani, M.

    2009-12-15

    The title binuclear complex, tris[N,N-bis(3-methoxysalicylidene)-1,4-diaminobutane] dicobalt(II), C{sub 60}H{sub 70}Co{sub 2}N{sub 6}O{sub 15}, was prepared by the reaction of the tetradentate Schiff base ligand bis(3-methoxysalicylidene)-1,4-diaminobutane and Co(CH{sub 3}COO){sub 2} . 4H{sub 2}O in a ethanol solution and structurally characterized by single-crystal X-ray diffraction. This complex has a dinuclear structure where two Co(II) ions are bridged by one N{sup 0},N'-bis(3-methoxysalicylidene)-1,4-diaminobutane. The two Co(II) ions, have two distorted octahedral coordination involving two O and two N atoms.

  3. Corneal epithelialisation on surface-modified hydrogel implants: artificial cornea.

    PubMed

    Ma, Aihua; Zhao, Bojun; Bentley, Adam J; Brahma, Arun; MacNeil, Sheila; Martin, Francis L; Rimmer, Stephen; Fullwood, Nigel J

    2011-03-01

    The objective was to investigate corneal re-epithelialisation of surface-modified polymethacrylate hydrogel implants in order to evaluate them as potential materials for an artificial cornea. Polymethacrylate hydrogels were modified with amines and then coated with different extracellular matrix proteins (collagen I, IV, laminin and fibronectin). The modified hydrogels were surgically implanted into bovine corneas maintained in a 3-D culture system for 5 days. The epithelial growth across the implant surface was evaluated using fluorescent, light and electron microscopy. Full epithelialisation was achieved on 1,4-diaminobutane-modified hydrogels after coating with collagen IV. Hydrogels modified with 1,4-diaminobutane but without further coating only showed partial re-epithelialisation. Hydrogels modified with other amines (1,2-diaminoethane or 1,3-diaminopropane) showed only partial re-epithelialisation; further coating with extracellular matrix proteins improved epithelialisation of these surfaces but did not result in complete re-epithelialisation. Evaluation of the corneas implanted with the 1,4-diaminobutane-modified hydrogels coated with collagen IV showed that the artificial corneas remain clear, integrate well and become covered by a healthy stratified epithelium. In conclusion the 1,4-diaminobutane surface-modified hydrogel coated with collagen IV supported the growth of a stable stratified epithelium. With further refinement this hydrogel has the potential to be used clinically for an artificial cornea. PMID:21287242

  4. Antennal and behavioral responses of Anastrepha suspensa (Diptera: Tephritidae) to a series of homologous terminal diamines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Current monitoring programs for Anastrepha fruit flies use a two-component synthetic attractant consisting of ammonium acetate (AA) and putrescine (1,4-diaminobutane). Identification of additional attractant chemicals may improve trapping efficacy. We examined response of the Caribbean fruit fly, ...

  5. Plant alkaloids of the polymethyleneamine series

    NASA Astrophysics Data System (ADS)

    Rogoza, Ludmila N.; Salakhutdinov, Nariman F.; Tolstikov, Genrikh A.

    2005-04-01

    The published data on the structures and biological activities of the plant alkaloids of the biogenic polymethyleneamine series, viz., putrescine (1,4-diaminobutane), spermidine (1,8-diamino-4 -azaoctane), and spermine (1,12-diamino-4,9-diazadodecane), are considered and systematised. The structures and biological activities of some synthetic analogues of these alkaloids are also presented.

  6. EAG and behavioral responses of the Caribbean fruit fly (Diptera:Tephritidae) to terminal diamines in a food-based lure.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Current monitoring programs for Anastrepha fruit flies utilize a food-based synthetic lure consisting of ammonium acetate and putrescine (1, 4 diaminobutane). Identification of additional attractant chemicals may lead to development of a more effective trapping system. This study, conducted with the...

  7. Antennal responses of West Indian and Caribbean fruit flies (Diptera: Tephritidae) to ammonium bicarbonate and putrescine lures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Efforts to monitor and detect tephritid fruit flies in the genus Anastrepha currently involve MultiLure traps baited with two food-based synthetic attractants; ammonium acetate and putrescine (1,4-diaminobutane). These baits are used in Central America, Florida, Texas, and the Caribbean, each region...

  8. Synthesis of biobased succinonitrile from glutamic acid and glutamine.

    PubMed

    Lammens, Tijs M; Le Nôtre, Jérôme; Franssen, Maurice C R; Scott, Elinor L; Sanders, Johan P M

    2011-06-20

    Succinonitrile is the precursor of 1,4-diaminobutane, which is used for the industrial production of polyamides. This paper describes the synthesis of biobased succinonitrile from glutamic acid and glutamine, amino acids that are abundantly present in many plant proteins. Synthesis of the intermediate 3-cyanopropanoic amide was achieved from glutamic acid 5-methyl ester in an 86 mol% yield and from glutamine in a 56 mol % yield. 3-Cyanopropanoic acid can be converted into succinonitrile, with a selectivity close to 100% and a 62% conversion, by making use of a palladium(II)-catalyzed equilibrium reaction with acetonitrile. Thus, a new route to produce biobased 1,4-diaminobutane has been discovered. PMID:21557494

  9. Interaction of myo-inositol hexakisphosphate with biogenic and synthetic polyamines.

    PubMed

    Torres, Julia; Giorgi, Claudia; Veiga, Nicolás; Kremer, Carlos; Bianchi, Antonio

    2015-07-21

    Within all the eukaryotic cells myo-inositol phosphates (InsPs) are an important group of biomolecules that are potentially related to signaling functions. The most abundant member of this family in nature is InsP6 (phytate, L(12-) in its fully deprotonated form). The complicated chemical behavior of this molecule demands a great effort to understand its function in the cell medium. In this work we follow our earlier studies on the interaction of InsP6 with metal cations by inclusion of polyamines (both biogenic and synthetic) as potential agents to produce stable adducts. The stability constants of InsP6-amine adducts and the relevant thermodynamic parameters ΔG°, ΔH°, and ΔS° were determined at 37.0 °C and 0.15 M ionic strength by means of potentiometric titrations and isothermal titration calorimetry (ITC). The biogenic amines studied were 1,4-diaminobutane (putrescine, put), 1,5-diaminopentane (cadaverine, cad), N-(3-aminopropyl)-1,4-diaminobutane (spermidine, spd), N,N'-bis(3-aminopropyl)-1,4-diaminobutane (spermine, spm), and 1-(4-aminobutyl)guanidine (agmatine, agm), while the synthetic models of longer polyamines were 1,19-dimethyl-1,4,7,10,13,16,19-heptaazanonadecane (Me2hexaen), 1,22-dimethyl-1,4,7,10,13,16,19,22-octaazadocosane (Me2heptaen), 1,25-dimethyl-1,4,7,10,13,16,19,22,25-nonaazapentacosane (Me2octaen) and N,N'-bis(3-aminopropyl)-1,3-propanediamine (3,3,3-tet). With the aid of molecular modeling, we also studied the structural aspects of molecular recognition in operation. The final result is a balance between many parameters including charge of the species, flexibility of the amines, H-bonds in the adduct, and desolvation processes. PMID:26065509

  10. Sequestration of biogenic amines by alginic and fulvic acids.

    PubMed

    De Stefano, Concetta; Gianguzza, Antonio; Piazzese, Daniela; Porcino, Nunziatina; Sammartano, Silvio

    2006-08-01

    The interaction of natural (alginic and fulvic acids) and synthetic (polyacrylic acid 2.0 kDa) polyelectrolytes with some protonated polyamines [diamines: ethylendiamine, 1,4-diaminobutane (or putrescine), 1,5-diaminopentane (or cadaverine); triamines: N-(3-aminopropyl)-1,4-diaminobutane (or spermidine), diethylenetriamine; tetramine: N,N'-bis(3-aminopropyl)-1,4-diaminobutane (or spermine); pentamine: tetraethylene-pentamine; hexamine: pentaethylenehexamine] was studied at T=25 degrees C by potentiometry and calorimetry. Measurements were performed without supporting electrolyte, in order to avoid interference, and results were reported at I=0 mol L(-)(1). For all the systems, the formation of (am)L(2)H(i) species was found (am=amine; L=polyelectrolyte; i=1...4, depending on the amine considered). The stability of polyanion-polyammonium cation complexes is always significant, and for high-charged polycations, we observe a stability comparable to that of strong metal complexes. For example, by considering the formation reaction (am)H(i)+2L=(am)L(2)H(i) we found log K(i)=6.0, 6.5 and 10.8 for i=1, 2 and 3, respectively, in the system alginate-spermidine. Low and positive formation DeltaH(degrees) values indicate that the main contribution to the stability is entropic in nature. The sequestering ability of polyelectrolytes toward amines was modelled by a sigmoid Boltzman type equation. Some empirical relationships between stability, charges and DeltaG(degrees) and TDeltaS(degrees) are reported. Mean values per salt bridge of formation thermodynamic parameters (DeltaX(degrees) (n)) are DeltaG(degrees) (n)=-5.8+/-0.4, DeltaH degrees (n)=0.7+/-0.5 and TDeltaS(degrees) (n)=6.5+/-0.5 kJmol(-)(1) for all the systems studied in this work. PMID:16690202

  11. Characterization of Unstable Products of Flavin- and Pterin-Dependent Enzymes by Continuous-Flow Mass Spectrometry

    PubMed Central

    2015-01-01

    Continuous-flow mass spectrometry (CFMS) was used to monitor the products formed during the initial 0.25–20 s of the reactions catalyzed by the flavoprotein N-acetylpolyamine oxidase (PAO) and the pterin-dependent enzymes phenylalanine hydroxylase (PheH) and tyrosine hydroxylase (TyrH). N,N′-Dibenzyl-1,4-diaminobutane (DBDB) is a substrate for PAO for which amine oxidation is rate-limiting. CFMS of the reaction showed formation of an initial imine due to oxidation of an exo-carbon–nitrogen bond. Nonenzymatic hydrolysis of the imine formed benzaldehyde and N-benzyl-1,4-diaminobutane; the subsequent oxidation by PAO of the latter to an additional imine could also be followed. Measurement of the deuterium kinetic isotope effect on DBDB oxidation by CFMS yielded a value of 7.6 ± 0.3, in good agreement with a value of 6.7 ± 0.6 from steady-state kinetic analyses. In the PheH reaction, the transient formation of the 4a-hydroxypterin product was readily detected; tandem mass spectrometry confirmed attachment of the oxygen to C(4a). With wild-type TyrH, the 4a-hydroxypterin was also the product. In contrast, no product other than a dihydropterin could be detected in the reaction of the mutant protein E332A TyrH. PMID:24713088

  12. Thermolysis of some transition metal nitrate complexes with 1,4-diamino butane ligand.

    PubMed

    Singh, Gurdip; Singh, Chandra Prakash; Mannan, S M

    2005-06-30

    Four complexes are prepared and characterized having molecular formula [Zn(dab)(2)](NO(3))(2), [Cu(dab)(2)](NO(3))(2).H(2)O, [Ni(dab)(2)](NO(3))(2).2H(2)O and [Mn(dab)(2)](NO(3))(2), where dab: 1,4-diaminobutane. Thermolyses of these complexes were investigated by simultaneous thermogravimetry (TG), derivatives thermogravimetry (DTG), differential thermal analysis (DTA) and differential scanning calorimetry (DSC). The kinetics of the thermolysis at early stages is investigated using isothermal TG by applying model-fitting and isoconversional method. Thermolytic process is slow in inert (N(2)) and is fast in air atmosphere due to oxidative nature. To investigate the response of these complexes under the condition of rapid heating, ignition delay (D(i)) has been measured. Thermal stability of the complexes was found to increase in the order Mn < Cu < Ni < Zn. PMID:15943933

  13. Synthesis of water-soluble, nonimmunogenic polyamide cross-linking agents.

    PubMed

    Hai, T T; Pereira, D E; Nelson, D J

    1998-01-01

    Novel polyamides were developed that can be used as cross-linking agents for proteins such as hemoglobin. Water-soluble, nonimmunogenic polyamides containing oxygen and sulfur atoms in the backbone were prepared by the polycondensation of the diacids bis(carboxymethyloxyacetyl)-1,4-diaminobutane (1a) or 3, 3'-thiodipropionic acid (1b) with diethylene glycol bis(3-aminopropyl) ether (2). The resulting alpha,omega-diacids were converted to the corresponding activated esters using any of a variety of carboxylic acid activating reagents including the novel reagent diphenyl(1-methylimidazol-2-thiyl)phosphonate (9). The resulting polyamides could be activated with a broad spectrum of groups that allow for the cross-linking and surface modification of proteins. PMID:9815156

  14. Attempts at the production of more selective antitumourals. Part II. The antineoplastic activity of cyclophosphazenes linked to spermine

    NASA Astrophysics Data System (ADS)

    Sournies, François; Labarre, Jean-François; Spreafico, Federico; Filippeschi, Stefania; Quan Jin, Xing

    1986-09-01

    In an attempt to design antitumour cyclophosphazenes of improved specificity by linking them to some natural tumour finders, we studied the binding of gem-N 3P 3Az 4Cl 2 to spermine. Synthesis, NMR and mass spectra of the vectorized drug (in which two N 3P 3Az 4 active principles are linked to spermine in a DISPIROBINO configuration) are described. Results obtained with this compound in 6 murine tumour systems (L1210 and P388 leukaemias, 3LL carcinoma, M5076 reticulum cell sarcoma, B16 melanoma and line 16 mammary carcinoma), are also described and compared with results previously obtained about the targeting of gem-N 3P 3Az 4Cl 2 through 1,3-diaminopropane and 1,4-diaminobutane (putrescine).

  15. The immobilization of lipase on PVDF-co-HFP membrane

    NASA Astrophysics Data System (ADS)

    Kayhan, Naciye; Eyüpoǧlu, Volkan; Adem, Şevki

    2016-04-01

    Lipase is an enzyme having a lot of different industrial applications such as biodiesel production, biopolymer synthesis, enantiopure pharmaceutical productions, agrochemicals, etc. Its immobilized form on different substances is more conventional and useful than its free form. Supporting material was prepared using PVDF-co-HFP in laboratory conditions and attached 1,4-diaminobutane (DA) and epichlorohydrin (EPI) ligands to the membrane to immobilize lipase enzyme. The immobilization conditions such as enzyme amount, pH, the concentration of salt, thermal stability and activity were stabilized for our experimental setup. Then, biochemical characterizations were performed on immobilized lipase PVDF-co-HFP regarding optimal pH activity, temperature and thermal stability. Also, the desorption ratios of immobilized enzyme in two different pathway were investigated to confirm immobilization stability for 24 hours.

  16. Olfaction in dragonflies: electrophysiological evidence.

    PubMed

    Rebora, Manuela; Salerno, Gianandrea; Piersanti, Silvana; Dell'otto, Alessandro; Gaino, Elda

    2012-02-01

    The problem of olfaction in Paleoptera (Odonata, Ephemeroptera) cannot be considered fully elucidated until now. These insects have been traditionally considered anosmic, because their brain lacks glomerular antennal lobes, typically involved in Neoptera odor perception. In order to understand if the presumed coeloconic olfactory receptors described on the antennal flagellum of adult Odonata are really functioning, we performed an electrophysiological investigation with electroantennogram (EAG) and single cell recordings (SCR), using Libellula depressa L. (Odonata, Libellulidae) as a model species. Odors representing different chemical classes such as (Z)-3-hexenyl acetate (acetate ester), (E)-2-hexenal, octanal (aldehydes), (Z)-3-hexen-1-ol (alcohol), propionic acid, butyric acid (carboxylic acids), and 1,4-diaminobutane (amine) were tested. Most of the tested chemicals elicited depolarizing EAG responses in both male and female antennae; SCR show unambiguously for the first time the presence of olfactory neurons in the antennae of L. depressa and strongly support the olfactory function of the coeloconic sensilla located on the antennal flagellum of this species. Electrophysiological activity may not necessarily indicate behavioral activity, and the biological role of olfactory responses in Odonata must be determined in behavioral bioassays. This study represents a starting point for further behavioral, electrophysiological, neuroanatomical and molecular investigation on Odonata olfaction, a research field particularly interesting owing to the basal position of Paleoptera, also for tracing evolutionary trends in insect olfaction. PMID:22154954

  17. Systems strategies for developing industrial microbial strains.

    PubMed

    Lee, Sang Yup; Kim, Hyun Uk

    2015-10-01

    Industrial strain development requires system-wide engineering and optimization of cellular metabolism while considering industrially relevant fermentation and recovery processes. It can be conceptualized as several strategies, which may be implemented in an iterative fashion and in different orders. The key challenges have been the time-, cost- and labor-intensive processes of strain development owing to the difficulties in understanding complex interactions among the metabolic, gene regulatory and signaling networks at the cell level, which are collectively represented as overall system performance under industrial fermentation conditions. These challenges can be overcome by taking systems approaches through the use of state-of-the-art tools of systems biology, synthetic biology and evolutionary engineering in the context of industrial bioprocess. Major systems metabolic engineering achievements in recent years include microbial production of amino acids (L-valine, L-threonine, L-lysine and L-arginine), bulk chemicals (1,4-butanediol, 1,4-diaminobutane, 1,5-diaminopentane, 1,3-propanediol, butanol, isobutanol and succinic acid) and drugs (artemisinin). PMID:26448090

  18. Capillary gas chromatographic determination of putrescine and cadaverine in serum of cancer patients using trifluoroacetylacetone as derivatizing reagent.

    PubMed

    Khuhawar, M Y; Memon, A A; Jaipal, P D; Bhanger, M I

    1999-02-19

    Trifluoroacetylacetone (FAA) derivatives of 1,4-diaminobutane (putrescine) (Pu) and 1,5-diaminopentane (cadaverine) (CA) were prepared and characterized by elemental microanalysis, IR, and mass spectrometry. Diamine derivatives were eluted from capillary gas chromatographic (CGC) column BP1 (12 m x 0.22 mm I.D.) or BP5 (50 m x 0.22 mm) with layer thickness 0.25 microm, using nitrogen as a carrier gas and flame ionization detection (FID). A solvent extraction procedure was developed for the extraction of Pu and CA from aqueous solution with a linear calibration range 0-20 microg/0.2 ml of extract with a detection limit of 0.5-0.6 ng/injection. The method was applied for the determination of Pu and CA in the serum of five cancer patients before and after radiotherapy. The serum of two healthy persons was also analyzed for Pu and CA contents. Pu and CA concentrations were found within the range 1.16-3.96 microg/ml and 0.88-1.46 microg/ml in cancer patients as compared to 0.11-0.16 microg/ml and 0.06-0.075 microg/ml respectively in healthy persons with a coefficient of variation (CV) within 0.62-5.47%. Pu and CA concentrations decreased on radiotherapy in cancer patients, but were much higher than in healthy persons. PMID:10080628

  19. Biotechnological production of polyamines by bacteria: recent achievements and future perspectives.

    PubMed

    Schneider, Jens; Wendisch, Volker F

    2011-07-01

    In Bacteria, the pathways of polyamine biosynthesis start with the amino acids L-lysine, L-ornithine, L-arginine, or L-aspartic acid. Some of these polyamines are of special interest due to their use in the production of engineering plastics (e.g., polyamides) or as curing agents in polymer applications. At present, the polyamines for industrial use are mainly synthesized on chemical routes. However, since a commercial market for polyamines as well as an industry for the fermentative production of amino acid exist, and since bacterial strains overproducing the polyamine precursors L-lysine, L-ornithine, and L-arginine are known, it was envisioned to engineer these amino acid-producing strains for polyamine production. Only recently, researchers have investigated the potential of amino acid-producing strains of Corynebacterium glutamicum and Escherichia coli for polyamine production. This mini-review illustrates the current knowledge of polyamine metabolism in Bacteria, including anabolism, catabolism, uptake, and excretion. The recent advances in engineering the industrial model bacteria C. glutamicum and E. coli for efficient production of the most promising polyamines, putrescine (1,4-diaminobutane), and cadaverine (1,5-diaminopentane), are discussed in more detail. PMID:21552989

  20. New macrocyclic schiff base complexes incorporating a homopiperazine unit: Synthesis of some Co(II), Ni(II),Cu(II) and Zn(II) complexes and crystal structure and theoretical studies

    NASA Astrophysics Data System (ADS)

    Keypour, Hassan; Rezaeivala, Majid; Ramezani-Aktij, Ameneh; Bayat, Mehdi; Dilek, Nefise; Ünver, Hüseyin

    2016-07-01

    A new macrocyclic Schiff base ligand, L, was synthesized by condensation reaction of 1,4-bis(2-formylphenyl)homopiperazine and 1,4-diaminobutane in acetonitrile. The Schiff base ligand was characterized by using elemental analyses, FT-IR, 1H, 13C NMR and mass spectroscopic techniques. The metal (II) complexes [ML], were synthesized from the reaction of MCl2.nH2O (M: Co, Ni, Cu and Zn) with Schiff base ligand, L and characterized by elemental analyses and FT-IR. X-ray crystal structure of [CoLCl]+ distorted square pyramidal geometry with an N4Cl core, arising from coordination by the four donor nitrogen atoms from the macrocyclic framework and one Cl atom. It crystallizes triclinic space group, P-1 with a = 7.1777(1) Å, b = 11.0357 (2) Å, c = 15.1520(2) Å, V = 1183.14(3), Z = 2, Dc = 1.556 g cm-3, μ (MoKα) = 0.156 mm-1. Also, the bonding situation between the [MCl]+ and Ligand (L) fragments in [MLCl]ClO4 (M = Co(II), Ni(II), Cu(II), Zn(II)) complexes were carried out by energy-decomposition analysis (EDA). The results showed that there is an increasing trend in the case of ΔEelstat of the complexes by changing the M from Co(II) to Zn(II).

  1. Some new [(thione)2Au(diamine)]Cl3 complexes: Synthesis, spectroscopic characterization, computational and in vitro cytotoxic studies

    NASA Astrophysics Data System (ADS)

    Al-Maythalony, Bassem A.; Monim-ul-Mehboob, M.; Altaf, Muhammad; Wazeer, Mohammed I. M.; Isab, Anvarhusein A.; Altuwaijri, Saleh; Ahmed, Ayesha; Dhuna, Vikram; Bhatia, Gaurav; Dhuna, Kshitija; Kamboj, Sukhdev Singh

    2013-11-01

    Recent advances in oncology are focused on developing new complexes of gold(III) with various ligands that show augmented anti-proliferative potential and reduced toxicity as compared to cis-platin. In this study, new Au(III) complexes of the type [(thione)2Au(diamine)]Cl3 are reported, where thione = 1,3-imidazolidine-2-thione (Imt), 1,3-Diazinane-2-thione (Diaz) and diamine = 1,2-diaminoethane (en), 1,3-diaminopropane (pn) or 1,4-diaminobutane (bn). The solid state IR as well as 13C and 15N NMR data indicate that Au(III) center is bonded via sulfur of thiocarbonyl Sdbnd Crbond2 site of the thiones and also chelated by the diamines from the trans side of coordinated thiones. Spectroscopic data are evaluated by comparisons with calculated data from the built and optimized structure by GAUSSIAN 09 at the RB3LYP level with LanL2DZ bases set. These new Au(III) complexes based on mixed thione and diamine ligands are very similar to the square planar structure of tetracoordinate [Au(en)2]Cl3complex. In this study, cytotoxicity data for these gold(III) complexes against C6 glioma cell lines are also reported, and the results indicate some complexes have cytotoxicity comparable to cis-platin.

  2. Transition metal ion directed supramolecular assembly of one- and two-dimensional polyrotaxanes incorporating cucurbituril.

    PubMed

    Park, Ki-Min; Whang, Dongmok; Lee, Eunsung; Heo, Jungseok; Kim, Kimoon

    2002-01-18

    This paper reports a synthetic strategy to construct one- and two-dimensional (1D and 2D) polyrotaxanes, in which a number of rings are threaded onto a coordination polymer, by the combination of self-assembly and coordination chemistry. Our approach to construct polyrotaxanes with high structural regularity involves threading a cucurbituril (CB) "bead" with a short "string" to form a stable pseudorotaxane, followed by linking the pseudorotaxanes with metal ions as "linkers" to organize into a 1D or 2D polyrotaxane. A 4- or 3-pyridylmethyl group is attached to each end of 1,4-diaminobutane or 1,5-diaminopentane to produce the short "strings", which then react with the cucurbituril "bead" to form stable pseudorotaxanes. The reaction of the pseudorotaxanes with various transition metal ions including CuII, CoII, NiII, AgI, and CdII produces 1D or 2D polyrotaxanes, in which many molecular "beads" are threaded onto 1D or 2D coordination polymers as confirmed by X-ray crystallography. The overall structure of a polyrotaxane is the result of interplay among various factors that include the coordination preferences of the metal ion, spatial disposition of the donor atoms with respect to the CB beads in the pseudorotaxane, and the size and coordination ability of the counteranion. PMID:11843162

  3. Amine modification of digested peptide at C-terminal end during protein digestion by protease.

    PubMed

    Ito, Toshiyuki; Sugita, Yoshiaki; Takao, Koichi; Ikeguchi, Yoshihiko; Shirahata, Akira

    2007-10-01

    We recently reported that C-terminal polyamine modification occurs when proteins are digested with trypsin in the presence of polyamine [Biochem. Biophys. Res. Commun., 356, 159-162 (2007)]. In the present study, the characteristics of this C-terminal modification in the presence of protease and amine were investigated. When hemoglobin (HB) was digested with trypsin in the presence of N-(2-pyridyl)-1,4-diaminobutane (Py4), formation of the modified peptide was dependent on time and on HB or Py4 concentration. When synthetic peptide was treated with trypsin in the presence of Py4, ca. 0.1% of the peptide was modified with Py4. When HB or cytochrome C was treated with a range of serine proteases in the presence of various amines (Py4, N-(2-pyridyl)-1,3-diaminopropane, tranexamic acid, isonicotinic acid hydrazide and ampicillin), the modified peptide was detected in all cases tested, thus suggesting that amine modification widely accompanies digestion by proteases. PMID:17917247

  4. Studies on DNA binding behaviour of biologically active transition metal complexes of new tetradentate N2O2 donor Schiff bases: Inhibitory activity against bacteria

    NASA Astrophysics Data System (ADS)

    Sobha, S.; Mahalakshmi, R.; Raman, N.

    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 N2O2 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 H2O2. 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.

  5. Genetic and Functional Analysis of the Biosynthesis of a Non-Ribosomal Peptide Siderophore in Burkholderia xenovorans LB400.

    PubMed

    Vargas-Straube, María José; Cámara, Beatriz; Tello, Mario; Montero-Silva, Francisco; Cárdenas, Franco; Seeger, Michael

    2016-01-01

    B. xenovorans LB400 is a model bacterium for the study of the metabolism of aromatic compounds. The aim of this study was the genomic and functional characterization of a non-ribosomal peptide synthetase containing gene cluster that encodes a siderophore in B. xenovorans LB400. The mba gene cluster from strain LB400 encodes proteins involved in the biosynthesis and transport of a hydroxamate-type siderophore. Strain LB400 has a unique mba gene organization, although mba gene clusters have been observed in diverse Burkholderiales. Bioinformatic analysis revealed the presence of promoters in the mba gene cluster that strongly suggest regulation by the ferric uptake regulator protein (Fur) and by the alternative RNA polymerase extracytoplasmic function sigma factor MbaF. Reverse transcriptase PCR analyses showed the expression of iron-regulated transcriptional units mbaFGHIJKL, mbaN, mbaABCE, mbaO, mbaP and mbaD genes under iron limitation. Chrome azurol S (CAS) assay strongly suggests that strain LB400 synthesized a siderophore under iron limitation. Mass spectrometry ESI-MS and MALDI-TOF-MS analyses revealed that the siderophore is a non-ribosomal peptide, and forms an iron complex with a molecular mass of 676 Da. Based on bioinformatic prediction, CAS assay and MS analyses, we propose that the siderophore is L-Nδ-hydroxy-Nδ-formylOrn-D-β-hydroxyAsp-L-Ser-L-Nδ-hydroxy-Nδ-formylOrn-1,4-diaminobutane that is closely related to malleobactin-type siderophores reported in B. thailandensis. PMID:26963250

  6. Genetic and Functional Analysis of the Biosynthesis of a Non-Ribosomal Peptide Siderophore in Burkholderia xenovorans LB400

    PubMed Central

    Vargas-Straube, María José; Cámara, Beatriz; Tello, Mario; Montero-Silva, Francisco; Cárdenas, Franco; Seeger, Michael

    2016-01-01

    B. xenovorans LB400 is a model bacterium for the study of the metabolism of aromatic compounds. The aim of this study was the genomic and functional characterization of a non-ribosomal peptide synthetase containing gene cluster that encodes a siderophore in B. xenovorans LB400. The mba gene cluster from strain LB400 encodes proteins involved in the biosynthesis and transport of a hydroxamate-type siderophore. Strain LB400 has a unique mba gene organization, although mba gene clusters have been observed in diverse Burkholderiales. Bioinformatic analysis revealed the presence of promoters in the mba gene cluster that strongly suggest regulation by the ferric uptake regulator protein (Fur) and by the alternative RNA polymerase extracytoplasmic function sigma factor MbaF. Reverse transcriptase PCR analyses showed the expression of iron-regulated transcriptional units mbaFGHIJKL, mbaN, mbaABCE, mbaO, mbaP and mbaD genes under iron limitation. Chrome azurol S (CAS) assay strongly suggests that strain LB400 synthesized a siderophore under iron limitation. Mass spectrometry ESI-MS and MALDI-TOF-MS analyses revealed that the siderophore is a non-ribosomal peptide, and forms an iron complex with a molecular mass of 676 Da. Based on bioinformatic prediction, CAS assay and MS analyses, we propose that the siderophore is L-Nδ-hydroxy-Nδ-formylOrn-D-β-hydroxyAsp-L-Ser-L-Nδ-hydroxy-Nδ-formylOrn-1,4-diaminobutane that is closely related to malleobactin-type siderophores reported in B. thailandensis. PMID:26963250

  7. Structural Investigations of N-carbamoylputrescine Amidohydrolase from Medicago truncatula: Insights into the Ultimate Step of Putrescine Biosynthesis in Plants.

    PubMed

    Sekula, Bartosz; Ruszkowski, Milosz; Malinska, Maura; Dauter, Zbigniew

    2016-01-01

    Putrescine, 1,4-diaminobutane, is an intermediate in the biosynthesis of more complexed polyamines, spermidine and spermine. Unlike other eukaryotes, plants have evolved a multistep pathway for putrescine biosynthesis that utilizes arginine. In the final reaction, N-carbamoylputrescine is hydrolyzed to putrescine by N-carbamoylputrescine amidohydrolase (CPA, EC 3.5.1.53). During the hydrolysis, consecutive nucleophilic attacks on the substrate by Cys158 and water lead to formation of putrescine and two by-products, ammonia and carbon dioxide. CPA from the model legume plant, Medicago truncatula (MtCPA), was investigated in this work. Four crystal structures were determined: the wild-type MtCPA in complex with the reaction intermediate, N-(dihydroxymethyl)putrescine as well as with cadaverine, which is a longer analog of putrescine; and also structures of MtCPA-C158S mutant unliganded and with putrescine. MtCPA assembles into octamers, which resemble an incomplete left-handed helical twist. The active site of MtCPA is funnel-like shaped, and its entrance is walled with a contribution of the neighboring protein subunits. Deep inside the catalytic cavity, Glu48, Lys121, and Cys158 form the catalytic triad. In this studies, we have highlighted the key residues, highly conserved among the plant kingdom, responsible for the activity and selectivity of MtCPA toward N-carbamoylputrescine. Moreover, since, according to previous reports, a close MtCPA relative from Arabidopsis thaliana, along with several other nitrilase-like proteins, are subjected to allosteric regulation by substrates, we have used the structural information to indicate a putative secondary binding site. Based on the docking experiment, we postulate that this site is adjacent to the entrance to the catalytic pocket. PMID:27066023

  8. Development and evaluation of a highly sensitive rapid response enzymatic nanointerfaced biosensor for detection of putrescine.

    PubMed

    Shanmugam, Saranya; Thandavan, Kavitha; Gandhi, Sakthivel; Sethuraman, Swaminathan; Rayappan, John Bosco Balaguru; Krishnan, Uma Maheswari

    2011-12-21

    Putrescine (1,4-diaminobutane) a biologically active diamine has been found to be a valuable analyte for several clinical and analytical purposes. The present work deals with diamine oxidase immobilized on iron oxide nanoparticles for quantifying the amount of putrescine produced, by the decarboxylation of ornithine, which is converted into hydrogen peroxide by the enzyme diamine oxidase (DAO). This reaction can be quantified using electrochemical techniques, which forms the basis of this work. Iron oxide (Fe(3)O(4)) nanoparticles, synthesized using thermal co-precipitation, were chosen for immobilization of DAO due to its simple preparation procedure, high surface area and cost-effectiveness. The size of the particles was in the range of 25-35 nm and the enzyme was linked covalently by carbodiimide activation and confirmed using FT-IR. For detecting the hydrogen peroxide released in the reaction, a glassy carbon-working electrode coated with enzyme linked iron oxide nanoparticles was poised at +0.4 V versus an Ag/AgCl reference electrode and a platinum wire was used as the counter electrode. A step-wise increase in current was observed and linearity was obtained in the range of 2-8 nM, with 0.65 nM as the minimum detection limit and the response time was found to be 0.3 seconds. Ascorbic acid, a common interfering molecule in biological samples, did not interfere with the measurements indicating the high degree of specificity of the diamine oxidase-based nano-interfaced biosensor. PMID:22022700

  9. Nucleophilic substitution in preparation and surface modification of hypercrosslinked stationary phases.

    PubMed

    Janků, Simona; Škeříková, Veronika; Urban, Jiří

    2015-04-01

    Four linear diaminoalkanes (1,2-diaminoethane, 1,4-diaminobutane, 1,6-diaminohexane, and 1,8-diaminooctane) have been used to hypercrosslink poly(styrene-co-vinylbenzyl chloride-co-divinylbenzene) monolithic stationary phases by nucleophilic substitution reaction. The column efficiency of polymer monoliths improved with longer diaminoalkane with 1,8-diaminoctane providing the highest efficiency. The concentration of 1,8-diaminoctane, together with hypercrosslinking time and temperature has been optimized. To improve the permeability of prepared columns, the hypercrosslinking modification has been combined with an early termination of polymerization reaction and decrease in polymerization temperature. The optimal column has been prepared by a polymerization reaction for 2h at 65°C and hypercrosslinked in the presence of 3% 1,8-diaminooctane for 2h at 95°C. The repeatability study of the presented protocol provided relative standard deviation for nine columns prepared independently out of three individual polymerization mixtures in between 2.0-12.0% for retention factors and 1.5-6.5% for plate heights, respectively. Further, we have modified residual chloromethyl groups with 2-aminoethanesulfonic acid (taurine) to prepare monolithic columns suitable for separation of small polar molecules in hydrophilic interaction chromatography. The highest retention of polar thiourea showed the column modified at 70°C for 20 h. Taurine-modified hypercrosslinked column showed the minimum of van Deemter curve of 20 μm. The prepared column provided dual-retention mechanism, including hydrophilic interaction and reversed-phase liquid chromatography that can be controlled by the composition of the mobile phase. The prepared column has been successfully used for an isocratic separation of low-molecular phenolic acids. PMID:25728663

  10. Comparison of kinetic properties of amine oxidases from sainfoin and lentil and immunochemical characterization of copper/quinoprotein amine oxidases.

    PubMed

    Zajoncová, L; Frébort, I; Luhová, L; Sebela, M; Galuszka, P; Pec, P

    1999-01-01

    Kinetic properties of novel amine oxidase isolated from sainfoin (Onobrychis viciifolia) were compared to those of typical plant amine oxidase (EC 1.4.3.6) from lentil (Lens culinaris). The amine oxidase from sainfoin was active toward substrates, such as 1,5-diaminopentane (cadaverine) with K(m) of 0.09 mM and 1,4-diaminobutane (putrescine) with K(m) of 0.24 mM. The maximum rate of oxidation for cadaverine at saturating concentration was 2.7 fold higher than that of putrescine. The amine oxidase from lentil had the maximum rate for putrescine comparable to the rate of sainfoin amine oxidase with the same substrate. Both amine oxidases, like other plant Cu-amine oxidases, were inhibited by substrate analogs (1,5-diamino-3-pentanone, 1,4-diamino-2-butanone and aminoguanidine), Cu2+ chelating agents (diethyltriamine, 1,10-phenanthroline, 8-hydroxyquinoline, 2,2'-bipyridyl, imidazole, sodium cyanide and sodium azide), some alkaloids (L-lobeline and cinchonine), some lathyrogens (beta-aminopropionitrile and aminoacetonitrile) and other inhibitors (benzamide oxime, acetone oxime, hydroxylamine and pargyline). Tested by Ouchterlony's double diffusion in agarose gel, polyclonal antibodies against the amine oxidase from sainfoin, pea and grass pea cross-reacted with amine oxidases from several other Fabaceae and from barley (Hordeum vulgare) of Poaceae, while amine oxidase from the filamentous fungus Aspergillus niger did not cross-react at all. However, using Western blotting after SDS-PAGE with rabbit polyclonal antibodies against the amine oxidase from Aspergillus niger, some degree of similarity of plant amine oxidases from sainfoin, pea, field pea, grass pea, fenugreek, common melilot, white sweetclover and Vicia panonica with the A. niger amine oxidase was confirmed. PMID:10092944

  11. Structural Investigations of N-carbamoylputrescine Amidohydrolase from Medicago truncatula: Insights into the Ultimate Step of Putrescine Biosynthesis in Plants

    PubMed Central

    Sekula, Bartosz; Ruszkowski, Milosz; Malinska, Maura; Dauter, Zbigniew

    2016-01-01

    Putrescine, 1,4-diaminobutane, is an intermediate in the biosynthesis of more complexed polyamines, spermidine and spermine. Unlike other eukaryotes, plants have evolved a multistep pathway for putrescine biosynthesis that utilizes arginine. In the final reaction, N-carbamoylputrescine is hydrolyzed to putrescine by N-carbamoylputrescine amidohydrolase (CPA, EC 3.5.1.53). During the hydrolysis, consecutive nucleophilic attacks on the substrate by Cys158 and water lead to formation of putrescine and two by-products, ammonia and carbon dioxide. CPA from the model legume plant, Medicago truncatula (MtCPA), was investigated in this work. Four crystal structures were determined: the wild-type MtCPA in complex with the reaction intermediate, N-(dihydroxymethyl)putrescine as well as with cadaverine, which is a longer analog of putrescine; and also structures of MtCPA-C158S mutant unliganded and with putrescine. MtCPA assembles into octamers, which resemble an incomplete left-handed helical twist. The active site of MtCPA is funnel-like shaped, and its entrance is walled with a contribution of the neighboring protein subunits. Deep inside the catalytic cavity, Glu48, Lys121, and Cys158 form the catalytic triad. In this studies, we have highlighted the key residues, highly conserved among the plant kingdom, responsible for the activity and selectivity of MtCPA toward N-carbamoylputrescine. Moreover, since, according to previous reports, a close MtCPA relative from Arabidopsis thaliana, along with several other nitrilase-like proteins, are subjected to allosteric regulation by substrates, we have used the structural information to indicate a putative secondary binding site. Based on the docking experiment, we postulate that this site is adjacent to the entrance to the catalytic pocket. PMID:27066023

  12. [H{sub 3}N(CH{sub 2}){sub 4}NH{sub 3}]{sub 2}[Al{sub 4}(C{sub 2}O{sub 4})(H{sub 2}PO{sub 4}){sub 2}(PO{sub 4}){sub 4}].4[H{sub 2}O]: A new layered aluminum phosphate-oxalate

    SciTech Connect

    Peng Li; Li Jiyang; Yu Jihong . E-mail: jihong@mail.jlu.edu.cn; Li Guanghua; Fang Qianrong; Xu Ruren . E-mail: rrxu@mail.jlu.edu.cn

    2005-09-15

    A new layered inorganic-organic hybrid aluminum phosphate-oxalate [H{sub 3}N(CH{sub 2}){sub 4}NH{sub 3}]{sub 2}[Al{sub 4}(C{sub 2}O{sub 4})(H{sub 2}PO{sub 4}){sub 2}(PO{sub 4}){sub 4}].4[H{sub 2}O](AlPO-CJ25) has been synthesized hydrothermally, by using 1,4-diaminobutane (DAB) as structure-directing agent. The structure has been solved by single-crystal X-ray diffraction analysis and further characterized by IR, {sup 31}P MAS NMR, TG-DTA as well as compositional analyses. Crystal data: the triclinic space group P-1, a=8.0484(7) A, b=8.8608(8) A, c=13.2224(11) A, {alpha}=80.830(6) deg. , {beta}=74.965(5) deg. , {gamma}=78.782(6) deg. , Z=2, R {sub 1[} {sub I} {sub >2} {sub {sigma}} {sub (} {sub I} {sub )]}=0.0511 and wR {sub 2(alldata)}=0.1423. The alternation of AlO{sub 4} tetrahedra and PO{sub 4} tetrahedra gives rise to the four-membered corner-sharing chains, which are interconnected through AlO{sub 6} octahedra to form the layered structure with 4,6-net sheet. Interestingly, oxalate ions are bis-bidentately bonded by participating in the coordination of AlO{sub 6}, and bridging the adjacent AlO{sub 6} octahedra. The layers are held with each other through strong H-bondings between the terminal oxygens. The organic ammonium cations and water molecules are located in the large cavities between the interlayer regions. -- Graphical abstract: The alternation of AlO{sub 4} tetrahedra and PO{sub 4} tetrahedra gives rise to the four-membered corner-sharing chains, which are interconnected through AlO{sub 6} octahedra to form the layered structure with 4,6-net sheet. Oxalate ions are bis-bidentately boned by participating in the coordination of AlO{sub 6}, and bridging the adjacent AlO{sub 6} octahedra.

  13. A new series of pillared uranyl-vanadates based on uranophane-type sheets in the uranium-vanadium-linear alkyl diamine systems

    SciTech Connect

    Jouffret, Laurent; Rivenet, Murielle; Abraham, Francis

    2010-01-15

    A new family of three-dimensional (3D) uranyl vanadates (C{sub 3}N{sub 2}H{sub 12}){l_brace}[(UO{sub 2})(H{sub 2}O)][(UO{sub 2})(VO{sub 4})]{sub 4}{r_brace}.1H{sub 2}O (C3UV), (C{sub 4}N{sub 2}H{sub 14}){l_brace}[(UO{sub 2})(H{sub 2}O)][(UO{sub 2})(VO{sub 4})]{sub 4}{r_brace}.2H{sub 2}O (C4UV), (C{sub 5}N{sub 2}H{sub 16}) {l_brace}[(UO{sub 2})(H{sub 2}O)][(UO{sub 2})(VO{sub 4})]{sub 4}{r_brace} (C5UV), (C{sub 6}N{sub 2}H{sub 20}) {l_brace}[(UO{sub 2})(H{sub 2}O)][(UO{sub 2})(VO{sub 4})]{sub 4}{r_brace} (C6UV) and (C{sub 7}N{sub 2}H{sub 22}) {l_brace}[(UO{sub 2})(H{sub 2}O)][(UO{sub 2})(VO{sub 4})]{sub 4}{r_brace} (C7UV) was prepared from mild-hydrothermal reactions using 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane and 1,7-diaminoheptane as structure directing agents. The five compounds are orthorhombic, space group Cmc2{sub 1}, with a{approx}15.6, b{approx}14.1, c{approx}13.6 A. The structures were solved using single-crystal X-ray diffraction data. The compounds contain the same three-dimensional inorganic framework built from uranyl-vanadate layers of uranophane-type anion topology pillared by [UO{sub 6}(H{sub 2}O)] pentagonal bipyramids. The doubly protonated diamines reside in the cavities created by the inorganic framework and are linked to the inorganic framework through hydrogen bonds involving one nitrogen atom. The structure is compared with that of uranyl-phosphates and uranyl-arsenates containing alkaline metals. The use of alkaline metals for the synthesis of uranyl-vanadates leads to carnotite-type compounds. - Graphical abstract: The (C{sub 6}N{sub 2}H{sub 20}){l_brace}[(UO{sub 2})(H{sub 2}O)][(UO{sub 2})(VO{sub 4})]{sub 4}{r_brace} compound: projection in the (1 0 0) and in the (0 0 1) planes showing the amine position.

  14. Improving putrescine production by Corynebacterium glutamicum by fine-tuning ornithine transcarbamoylase activity using a plasmid addiction system.

    PubMed

    Schneider, Jens; Eberhardt, Dorit; Wendisch, Volker F

    2012-07-01

    Corynebacterium glutamicum shows a great potential for the production of the polyamide monomer putrescine (1,4-diaminobutane). Previously, we constructed the putrescine-producing strain PUT1 by deletion of argF, the gene for ornithine transcarbamoylase (OTC), and argR, encoding the L-arginine repressor, combined with heterologous expression of the Escherichia coli gene for L-ornithine decarboxylase SpeC. As a consequence of argF deletion, this strain requires supplementation of L-arginine and shows growth-decoupled putrescine production. To avoid costly supplementation with L-arginine and the strong feedback inhibition of the key enzyme N-acetylglutamate kinase (ArgB) by L-arginine, a plasmid addiction system for low-level argF expression was developed. By fine-tuning argF expression through modifications of the promoter, the translational start codon and/or the ribosome binding site, high productivity and titer could be obtained. OTC activity varied almost thousandfold between 960 and 1 mU mg⁻¹ resulting in putrescine yields on glucose from less than 0.001 up to 0.26 g g⁻¹, the highest yield in bacteria reported to date. The most promising strain, designated PUT21, was characterized comprehensively. PUT21 strain grew with a rate of 0.19 h⁻¹ in mineral salt medium without the need for L-arginine supplementation and produced putrescine with a yield of 0.16 g g⁻¹ glucose at a volumetric productivity of 0.57 g L⁻¹ h⁻¹ and a specific productivity of 0.042 g g⁻¹ h⁻¹. The carbon balance suggested that no major unidentified by-product was produced. Compared to the first-generation strain PUT1, the putrescine yield observed with PUT21 was increased by 60%. In fed-batch cultivation with C. glutamicum PUT21, a putrescine titer of 19 g L⁻¹ at a volumetric productivity of 0.55 g L⁻¹ h⁻¹ and a yield of 0.16 g g⁻¹ glucose could be achieved. Moreover, while plasmid segregation of the initial strain required antibiotic selection

  15. Designed self-assembly of molecular necklaces.

    PubMed

    Park, Ki-Min; Kim, Soo-Young; Heo, Jungseok; Whang, Dongmok; Sakamoto, Shigeru; Yamaguchi, Kentaro; Kim, Kimoon

    2002-03-13

    This paper reports an efficient strategy to synthesize molecular necklaces, in which a number of small rings are threaded onto a large ring, utilizing the principles of self-assembly and coordination chemistry. Our strategy involves (1) threading a molecular "bead" with a short "string" to make a pseudorotaxane and then (2) linking the pseudorotaxanes with a metal complex with two cis labile ligands acting as an "angle connector" to form a cyclic product (molecular necklace). A 4- or 3-pyridylmethyl group is attached to each end of 1,4-diaminobutane or 1,5-diaminopentane to produce the short "strings" (C4N4(2+), C4N3(2+), C5N4(2+), and C5N3(2+)), which then react with a cucurbituril (CB) "bead" to form stable pseudorotaxanes (PR44(2+), PR43(2+), PR54(2+), and PR53(2+), respectively). The reaction of the pseudorotaxanes with Pt(en)(NO(3))(2) (en = ethylenediamine) produces a molecular necklace [4]MN, in which three molecular "beads" are threaded on a triangular framework, and/or a molecular necklace [5]MN, in which four molecular "beads" are threaded on a square framework. Under refluxing conditions, the reaction with PR44(2+) or PR54(2+) yields exclusively [4]MN (MN44T or MN54T, respectively), whereas that with PR43(2+) or PR53(2+) produces exclusively [5]MN (MN43S or MN53S, respectively). The products have been characterized by various methods including X-ray crystallography. At lower temperatures, on the other hand, the reaction with PR44(2+) or PR54(2+) affords both [4]MN and [5]MN. The supermolecules reported here are the first series of molecular necklaces obtained as thermodynamic products. The overall structures of the molecular necklaces are strongly influenced by the structures of pseudorotaxane building blocks, which is discussed in detail on the basis of the X-ray crystal structures. The temperature dependence of the product distribution observed in this self-assembly process is also discussed. PMID:11878967

  16. A series of M(II)Cu(II)3 stars (M = Mn, Ni, Cu, Zn) exhibiting unusual magnetic properties.

    PubMed

    Mondal, Suraj; Mandal, Shuvankar; Carrella, Luca; Jana, Arpita; Fleck, Michel; Köhn, Andreas; Rentschler, Eva; Mohanta, Sasankasekhar

    2015-01-01

    The work in this report describes the syntheses, electrospray ionization mass spectromtery, structures, and experimental and density functional theoretical (DFT) magnetic properties of four tetrametallic stars of composition [M(II)(Cu(II)L)3](ClO4)2 (1, M = Mn; 2, M = Ni; 3, M = Cu; 4, M = Zn) derived from a single-compartment Schiff base ligand, N,N'-bis(salicylidene)-1,4-butanediamine (H2L), which is the [2 + 1] condensation product of salicylaldehyde and 1,4-diaminobutane. The central metal ion (Mn(II), Ni(II), Cu(II), or Zn(II)) is linked with two μ2-phenoxo bridges of each of the three [Cu(II)L] moieties, and thus the central metal ion is encapsulated in between three [Cu(II)L] units. The title compounds are rare or sole examples of stars having these metal-ion combinations. In the cases of 1, 3, and 4, the four metal ions form a centered isosceles triangle, while the four metal ions in 2 form a centered equilateral triangle. Both the variable-temperature magnetic susceptibility and variable-field magnetization (at 2-10 K) of 1-3 have been measured and simulated contemporaneously. While the Mn(II)Cu(II)3 compound 1 exhibits ferromagnetic interaction with J = 1.02 cm(-1), the Ni(II)Cu(II)3 compound 2 and Cu(II)Cu(II)3 compound 3 exhibit antiferromagnetic interaction with J = -3.53 and -35.5 cm(-1), respectively. Variable-temperature magnetic susceptibility data of the Zn(II)Cu(II)3 compound 4 indicate very weak antiferromagnetic interaction of -1.4 cm(-1), as expected. On the basis of known correlations, the magnetic properties of 1-3 are unusual; it seems that ferromagnetic interaction in 1 and weak/moderate antiferromagnetic interaction in 2 and 3 are possibly related to the distorted coordination environment of the peripheral copper(II) centers (intermediate between square-planar and tetrahedral). DFT calculations have been done to elucidate the magnetic properties. The DFT-computed J values are quantitatively (for 1) or qualitatively (for 2 and 3) matched