(1H-pyrazole-κN2)(2,2':6',2''-terpyridine-κ3N,N',N'')platinum(II) bis(perchlorate) nitromethane monosolvate.

PubMed

Akerman, Matthew; Akerman, Kate; Jaganyi, Deogratius; Reddy, Desigan

2011-09-01

The reaction between [PtCl(terpy)]·2H(2)O (terpy is 2,2':6',2''-terpyridine) and pyrazole in the presence of two equivalents of AgClO(4) in nitromethane yields the title compound, [Pt(C(3)H(4)N(2))(C(15)H(11)N(3))](ClO(4))(2)·CH(3)NO(2), as a yellow crystalline solid. Single-crystal X-ray diffraction shows that the dicationic platinum(II) chelate is square planar with the terpyridine ligand occupying three sites and the pyrazole ligand occupying the fourth. The torsion angle subtended by the pyrazole ring relative to the terpyridine chelate is 62.4 (6)°. Density functional theory calculations at the LANL2DZ/PBE1PBE level of theory show that in vacuo the lowest-energy conformation has the pyrazole ligand in an orientation perpendicular to the terpyridine ligand (i.e. 90°). Seemingly, the stability gained by the formation of hydrogen bonds between the pyrazole NH group and the perchlorate anion in the solid-state structure is sufficient for the chelate to adopt a higher-energy conformation.

Enhanced third-order nonlinear optical properties determined in thin films using the Z-scan technique: bis(μ-4,4'-oxydibenzoato)bis[(4'-phenyl-2,2':6',2''-terpyridine)cobalt(II)].

PubMed

Liu, Runqiang; Zhao, Ning; Liu, Ping; An, Caixia; Lian, Zhaoxun

2016-05-01

π-Conjugated organic materials exhibit high and tunable nonlinear optical (NLO) properties, and fast response times. 4'-Phenyl-2,2':6',2''-terpyridine (PTP) is an important N-heterocyclic ligand involving π-conjugated systems, however, studies concerning the third-order NLO properties of terpyridine transition metal complexes are limited. The title binuclear terpyridine Co(II) complex, bis(μ-4,4'-oxydibenzoato)-κ(3)O,O':O'';κ(3)O'':O,O'-bis[(4'-phenyl-2,2':6',2''-terpyridine-κ(3)N,N',N'')cobalt(II)], [Co2(C14H8O5)2(C21H15N3)2], (1), has been synthesized under hydrothermal conditions. In the crystal structure, each Co(II) cation is surrounded by three N atoms of a PTP ligand and three O atoms, two from a bidentate and one from a symmetry-related monodentate 4,4'-oxydibenzoate (ODA(2-)) ligand, completing a distorted octahedral coordination geometry. Neighbouring [Co(PTP)](2+) units are bridged by ODA(2-) ligands to form a ring-like structure. The third-order nonlinear optical (NLO) properties of (1) and PTP were determined in thin films using the Z-scan technique. The title compound shows a strong third-order NLO saturable absorption (SA), while PTP exhibits a third-order NLO reverse saturable absorption (RSA). The absorptive coefficient β of (1) is -37.3 × 10(-7) m W(-1), which is larger than that (8.96 × 10(-7) m W(-1)) of PTP. The third-order NLO susceptibility χ((3)) values are calculated as 6.01 × 10(-8) e.s.u. for (1) and 1.44 × 10(-8) e.s.u. for PTP.

Blue organic light-emitting diodes based on terpyridine-substituted triphenylamine chromophores

NASA Astrophysics Data System (ADS)

Fan, Congbin; Wang, Xiaomei; Luo, Jianfang

2017-02-01

Two terpyridine-substituted triphenylamine chromophores, namely 4-[4-(2,2‧:6‧,2″-terpyridinyl)]phenyltriphenylamine (chromophore I) and 4-[4-(2,2‧:6‧,2″-terpyridinyl)] styryltriphenylamine (chromophore II), have been designed and applied as emitters in organic light-emitting diodes (OLED). Chromophore I and II exhibit high thermal stability with decomposition temperatures higher than 334 °C. And these chromophores show significantly different luminescent performance due to the role of different rigid phenyl/flexible styryl unit interlinking terpyridine and triphenylamine units which have different lowest unoccupied molecular orbital (LUMO) levels. The fluorescence lifetime of chromophore I is 3-fold longer than that of chromophore II and the maximum brightness of device used chromophore I as an emitting-layer in OLED is 28-fold larger than that of chromophore II in OLED. Chromophore I as an emitter in OLED exhibits blue electroluminescence peak at 460 nm (Commission Internationale de L'Eclairage (CIE) x = 0.19, y = 0.22). By using chromophore I as an emitter in a four layers device, an efficient blue emission with the maximum brightness 3000 cd/m2 and maximum luminescence efficiency 3.6 cd/A is obtained.

Design, synthesis and photoelectrochemical properties of hexagonal metallomacrocycles based on triphenylamine: [M6(4,4'-bis(2,2':6',2''-terpyridinyl)triphenylamine)6(X)12]; [M = Fe(II), PF6- and Zn(II), BF4-].

PubMed

Hwang, Seok-Ho; Moorefield, Charles N; Wang, Pingshan; Fronczek, Frank R; Courtney, Brandy H; Newkome, George R

2006-08-07

Synthesis of a novel bis(terpyridine) ligand, 4,4'-bis(2,2':6',2''-terpyridinyl)triphenylamine, utilizing triphenylamine, as a specific angle controller, has led to the self-assembly of a unique hexagonal metallomacrocycle family, [Fe6(2)6(PF6)12] and [Zn6(2)6(BF4)12], utilizing terpyridine-metal(II)-terpyridine connectivity. The crystal structure of the novel ligand shows that the angle between the two terpyridinyl moieties is 119.69 degrees , which enabled the formation of the hexagonal-shaped macrocycles. The crystal packing architectures of this starting ligand revealed channels induced by solvent encapsulation. Following complexation of this ligand with transition metals [Fe(II) or Zn(II)] in a one-pot reaction, the resultant structures were characterized by (1)H and (13)C NMR, UV/Vis and mass spectroscopies. The expected metal-to-ligand charge transfer (MLCT; lambda(max) = 582 nm) and emission (lambda(em) = 575 nm) characteristics were exhibited by both [Fe6(2)6(PF6)12] and[Zn6(2)6(BF4)12]. The photoelectrochemical characteristics of these hexagonal metallomacrocycles demonstrate that they can be used as sensitizers in dye-sensitized solar cells.

Effects of counterions of colorful sandwich-type zinc(II) 4‧-phenyl-terpyridine compounds on photoluminescent and thermal properties

NASA Astrophysics Data System (ADS)

Zhang, Yongqiang; Zhou, Peng; Liang, Baohuan; Huang, Ling; Zhou, Yanling; Ma, Zhen

2017-10-01

Reactions between 4‧-phenyl-terpyridine (L) and several Zn(II) salts (p-toluenesulfonate, nitrate, trifluoromethane sulfonate or hexafluoroantimonate) led to the formation of the complexes [ZnL2](p-OSO2PhCH3)2 (1), [ZnL2](NO3)2 (2), [ZnL2](SO3CF3)2 (3) and [ZnL2](SbF6)2 (4), which were characterized by IR, 1H NMR, elemental analysis, UV-vis spectroscopies and single crystal X-ray diffraction, along with their TG-DTA thermal and photoluminescent properties. The four compounds show mononuclear Zn(II) structures with hexacoordinated, irregular ZnN6 octahedron geometries. Their colours and photo-luminescent properties have changed regularly depending on the counterions of the compounds.

Mono- and bis-tolyl­terpyridine iridium(III) complexes

PubMed Central

Hinkle, Lindsay M.; Young, Victor G.; Mann, Kent R.

2010-01-01

The first structure report of trichlorido[4′-(p-tolyl)-2,2′:6′,2′′-terpyridine]iridium(III) dimethyl sulfoxide solvate, [IrCl3(C22H17N3)]·C2H6OS, (I), is presented, along with a higher-symmetry setting of previously reported bis­[4′-(p-tolyl)-2,2′:6′,2′′-terpyridine]iridium(III) tris­(hexa­fluorido­phosphate) acetonitrile disolvate, [Ir(C22H17N3)2](PF6)3·2C2H3N, (II) [Yoshikawa, Yamabe, Kanehisa, Kai, Takashima & Tsukahara (2007 ▶). Eur. J. Inorg. Chem. pp. 1911–1919]. For (I), the data were collected with synchrotron radiation and the dimethyl sulfoxide solvent mol­ecule is disordered over three positions, one of which is an inversion center. The previously reported structure of (II) is presented in the more appropriate C2/c space group. The iridium complex and one PF6 − anion lie on twofold axes in this structure, making half of the mol­ecule unique. PMID:20203396

Photoexpulsion of surface-grafted ruthenium complexes and subsequent release of cytotoxic cargos to cancer cells from mesoporous silica nanoparticles.

PubMed

Frasconi, Marco; Liu, Zhichang; Lei, Juying; Wu, Yilei; Strekalova, Elena; Malin, Dmitry; Ambrogio, Michael W; Chen, Xinqi; Botros, Youssry Y; Cryns, Vincent L; Sauvage, Jean-Pierre; Stoddart, J Fraser

2013-08-07

Ruthenium(II) polypyridyl complexes have emerged both as promising probes of DNA structure and as anticancer agents because of their unique photophysical and cytotoxic properties. A key consideration in the administration of those therapeutic agents is the optimization of their chemical reactivities to allow facile attack on the target sites, yet avoid unwanted side effects. Here, we present a drug delivery platform technology, obtained by grafting the surface of mesoporous silica nanoparticles (MSNPs) with ruthenium(II) dipyridophenazine (dppz) complexes. This hybrid nanomaterial displays enhanced luminescent properties relative to that of the ruthenium(II) dppz complex in a homogeneous phase. Since the coordination between the ruthenium(II) complex and a monodentate ligand linked covalently to the nanoparticles can be cleaved under irradiation with visible light, the ruthenium complex can be released from the surface of the nanoparticles by selective substitution of this ligand with a water molecule. Indeed, the modified MSNPs undergo rapid cellular uptake, and after activation with light, the release of an aqua ruthenium(II) complex is observed. We have delivered, in combination, the ruthenium(II) complex and paclitaxel, loaded in the mesoporous structure, to breast cancer cells. This hybrid material represents a promising candidate as one of the so-called theranostic agents that possess both diagnostic and therapeutic functions.

Biological processing of dinuclear ruthenium complexes in eukaryotic cells.

PubMed

Li, Xin; Heimann, Kirsten; Dinh, Xuyen Thi; Keene, F Richard; Collins, J Grant

2016-10-20

The biological processing - mechanism of cellular uptake, effects on the cytoplasmic and mitochondrial membranes, intracellular sites of localisation and induction of reactive oxygen species - of two dinuclear polypyridylruthenium(ii) complexes has been examined in three eukaryotic cells lines. Flow cytometry was used to determine the uptake of [{Ru(phen)2}2{μ-bb12}](4+) (Rubb12) and [Ru(phen)2(μ-bb7)Ru(tpy)Cl](3+) {Rubb7-Cl, where phen = 1,10-phenanthroline, tpy = 2,2':6',2''-terpyridine and bbn = bis[4(4'-methyl-2,2'-bipyridyl)]-1,n-alkane} in baby hamster kidney (BHK), human embryonic kidney (HEK-293) and liver carcinoma (HepG2) cell lines. The results demonstrated that the major uptake mechanism for Rubb12 and Rubb7-Cl was active transport, although with a significant contribution from carrier-assisted diffusion for Rubb12 and passive diffusion for Rubb7-Cl. Flow cytometry coupled with Annexin V/TO-PRO-3 double-staining was used to compare cell death by membrane damage or apoptosis. Rubb12 induced significant direct membrane damage, particularly with HepG2 cells, while Rubb7-Cl caused considerably less membrane damage but induced greater levels of apoptosis. Confocal microscopy, coupled with JC-1 assays, demonstrated that Rubb12 depolarises the mitochondrial membrane, whereas Rubb7-Cl had a much smaller affect. Cellular localisation experiments indicated that Rubb12 did not accumulate in the mitochondria, whereas significant mitochondrial accumulation was observed for Rubb7-Cl. The effect of Rubb12 and Rubb7-Cl on intracellular superoxide dismutase activity showed that the ruthenium complexes could induce cell death via a reactive oxygen species-mediated pathway. The results of this study demonstrate that Rubb12 predominantly kills eukaryotic cells by damaging the cytoplasmic membrane. As this dinuclear ruthenium complex has been previously shown to exhibit greater toxicity towards bacteria than eukaryotic cells, the results of the present study suggest that metal-based cationic oligomers can achieve selective toxicity against bacteria, despite exhibiting a non-specific membrane damage mechanism of action.

Photoexpulsion of Surface-Grafted Ruthenium Complexes and Subsequent Release of Cytotoxic Cargos to Cancer Cells from Mesoporous Silica Nanoparticles

PubMed Central

Frasconi, Marco; Liu, Zhichang; Lei, Juying; Wu, Yilei; Strekalova, Elena; Malin, Dmitry; Ambrogio, Michael W.; Chen, Xinqi; Botros, Youssry Y.; Cryns, Vincent L.; Sauvage, Jean-Pierre; Stoddart, J. Fraser

2014-01-01

Ruthenium(II) polypyridyl complexes have emerged both as promising probes of DNA structure and as anticancer agents because of their unique photophysical and cytotoxic properties. A key consideration in the administration of those therapeutic agents is the optimization of their chemical reactivities to allow facile attack on the target sites, yet avoid unwanted side effects. Here, we present a drug delivery platform technology, obtained by grafting the surface of mesoporous silica nanoparticles (MSNPs) with ruthenium(II) dipyridophenazine (dppz) complexes. This hybrid nanomaterial displays enhanced luminescent properties relative to that of the ruthenium(II) dppz complex in a homogeneous phase. Since the coordination between the ruthenium(II) complex and a monodentate ligand linked covalently to the nanoparticles can be cleaved under irradiation with visible light, the ruthenium complex can be released from the surface of the nanoparticles by selective substitution of this ligand with a water molecule. Indeed, the modified MSNPs undergo rapid cellular uptake, and after activation with light, the release of an aqua ruthenium(II) complex is observed. We have delivered, in combination, the ruthenium(II) complex and paclitaxel, loaded in the mesoporous structure, to breast cancer cells. This hybrid material represents a promising candidate as one of the so-called theranostic agents that possess both diagnostic and therapeutic functions. PMID:23815127

Spectroscopy, electrochemistry and antiproliferative properties of Au(iii), Pt(ii) and Cu(ii) complexes bearing modified 2,2':6',2''-terpyridine ligands.

PubMed

Maroń, Anna; Czerwińska, Katarzyna; Machura, Barbara; Raposo, Luis; Roma-Rodrigues, Catarina; Fernandes, Alexandra R; Małecki, Jan G; Szlapa-Kula, Agata; Kula, Slawomir; Krompiec, Stanisław

2018-05-08

Structural, spectroscopic and electrochemical properties of six complexes [AuCl(L1)](PF6)2·CH3CN (1), [AuCl(L2)](PF6)2 (2), [PtCl(L1)](BPh4)·CH3CN (3), [PtCl(L2)](SO3CF3) (4), [CuCl2(L1)] (5) and [CuCl2(L2)]·CH3CN (6) with modified 2,2':6',2''-terpyridine ligands, 4'-(4-methoxyphenyl)-2,2':6',2''-terpyridine (L1) and 4'-(4-methoxynaphthalen-1-yl)-2,2':6',2''-terpyridine (L2) were thoroughly investigated and a significant role of the substituent (4-methoxyphenyl or 4-methoxynaphthalen-1-yl) and the metal center was demonstrated. The naphthyl-based substituent was found to increase the emission quantum yield of the luminescent Au(iii) and Pt(ii) complexes. Furthermore, the antiproliferative potential of the reported complexes was examined towards human colorectal (HCT116) and ovarian (A2780) carcinoma cell lines as well as towards normal human fibroblasts. The Au(iii) complex 2 and Cu(ii) complex 5 were found to have a higher antiproliferative effect on HCT116 colorectal and A2780 ovarian carcinoma cells when compared with the Pt(ii) complex with the same ligand (4). The order of cytotoxicity in both cell lines is 2 > 6 > 1 > 3 > 4. Complex 2 seems to be more cytotoxic towards HCT116 and A2780 cancer cell lines with IC50 values 300× and 130× higher in normal human fibroblasts compared to the respective cancer cells. The viability loss induced by the complexes agrees with Hoechst 33258 staining and the typical morphological apoptotic characteristics like chromatin condensation and nuclear fragmentation and flow cytometry assay. The induction of apoptosis correlates with the induction of reactive oxygen species (ROS). Fluorescence microscopy analysis indicates that after 3 h of incubation, complexes 1-4 are localized inside HCT116 cells and the high levels of internalization correlate with their cytotoxicity.

Effect of substituent of terpyridines on the in vitro antioxidant, antitubercular, biocidal and fluorescence studies of copper(II) complexes with clioquinol

NASA Astrophysics Data System (ADS)

Kharadi, G. J.

2014-01-01

An octahedral complexes of copper with clioquinol(CQ) and substituted terpyridine have been synthesized. The Cu(II) complexes have been characterized by elemental analyses, thermogravimetric analyses, magnetic moment measurements, FT-IR, electronic, 1H NMR and FAB mass spectra. Antimycobacterial screening of ligand and its copper compound against Mycobacterium tuberculosis shows clear enhancement in the antitubercular activity upon copper complexation. Ferric-reducing anti-oxidant power of all complexes were measured. The fluorescence spectra of complexes show red shift, which may be due to the chelation by the ligands to the metal ion. It enhances ligand ability to accept electrons and decreases the electron transition energy. The antimicrobial efficiency of the complexes were tested on five different microorganisms and showed good biological activity.

A Series of Zn(II) Terpyridine-Based Nitrate Complexes as Two-Photon Fluorescent Probe for Identifying Apoptotic and Living Cells via Subcellular Immigration.

PubMed

Liu, Dandan; Zhang, Mingzhu; Du, Wei; Hu, Lei; Li, Fei; Tian, Xiaohe; Wang, Aidong; Zhang, Qiong; Zhang, Zhongping; Wu, Jieying; Tian, Yupeng

2018-06-19

Two-photon active probe to label apoptotic cells plays a significant role in biological systems. However, discrimination of live/apoptotic cells at subcellular level under microscopy remains unachieved. Here, three novel Zn(II) terpyridine-based nitrate complexes (C1-C3) containing different pull/push units were designed. The structures of the ligands and their corresponding Zn(II) complexes were confirmed by single-crystal X-ray diffraction analysis. On the basis of the comprehensive comparison, C3 had a suitable two-photon absorption cross section in the near-infrared wavelength and good biocompatibility. Under two-photon confocal microscopy and transmission electron microscopy, it is found that C3 could target mitochondria in living cells but immigrate into the nucleolus during the apoptotic process. This dual-functional probe (C3) not only offers a valuable image tool but also acts as an indicator for cell mortality at subcellular level in a real-time manner.

Synthesis, spectral and third-order nonlinear optical properties of terpyridine Zn(II) complexes based on carbazole derivative with polyether group

NASA Astrophysics Data System (ADS)

Kong, Ming; Liu, Yanqiu; Wang, Hui; Luo, Junshan; Li, Dandan; Zhang, Shengyi; Li, Shengli; Wu, Jieying; Tian, Yupeng

2015-01-01

Four novel Zn(II) terpyridine complexes (ZnLCl2, ZnLBr2, ZnLI2, ZnL(SCN)2) based on carbazole derivative group were designed, synthesized and fully characterized. Their photophysical properties including absorption and one-photon excited fluorescence, two-photon absorption (TPA) and optical power limiting (OPL) were further investigated systematically and interpreted on the basis of theoretical calculations (TD-DFT). The influences of different solvents on the absorption and One-Photon Excited Fluorescence (OPEF) spectral behavior, quantum yields and the lifetime of the chromophores have been investigated in detail. The third-order nonlinear optical (NLO) properties were investigated by open/closed aperture Z-scan measurements using femtosecond pulse laser in the range from 680 to 1080 nm. These results revealed that ZnLCl2 and ZnLBr2 exhibited strong two-photon absorption and ZnLCl2 showed superior optical power limiting property.

Crystallographic and computational study of a network composed of [ZnCl4]2- anions and triply protonated 4'-functionalized terpyridine cations.

PubMed

Granifo, Juan; Suárez, Sebastián; Boubeta, Fernando; Baggio, Ricardo

2017-12-01

We report herein the synthesis, crystallographic analysis and a study of the noncovalent interactions observed in the new 4'-substituted terpyridine-based derivative bis[4'-(isoquinolin-2-ium-4-yl)-2,2':6',2''-terpyridine-1,1''-diium] tris[tetrachloridozincate(II)] monohydrate, (C 24 H 19 N 4 ) 2 [ZnCl 4 ] 3 ·H 2 O or (ITPH 3 ) 2 [ZnCl 4 ] 3 ·H 2 O, where (ITPH 3 ) 3+ is the triply protonated cation derived from 4'-(isoquinolin-4-yl)-2,2':6',2''-terpyridine (ITP) [Granifo et al. (2016). Acta Cryst. C72, 932-938]. The (ITPH 3 ) 3+ cation presents a number of interesting similarities and differences compared with its neutral ITP relative, mainly in the role fulfilled in the packing arrangement by the profuse set of D-H...A [D (donor) = C, N or O; A (acceptor) = O or Cl], π-π and anion...π noncovalent interactions present. We discuss these interactions in two different complementary ways, viz. using a point-to-point approach in the light of Bader's theory of Atoms In Molecules (AIM), analyzing the individual significance of each interaction, and in a more `global' analysis, making use of the Hirshfeld surfaces and the associated enrichment ratio (ER) approach, evaluating the surprisingly large co-operative effect of the superabundant weaker contacts.

Cd(II)-terpyridine-based complex as a ratiometric fluorescent probe for pyrophosphate detection in solution and as an imaging agent in living cells.

PubMed

Jiao, Shu-Yan; Li, Kun; Zhang, Wei; Liu, Yan-Hong; Huang, Zeng; Yu, Xiao-Qi

2015-01-21

The terpyridine anthracene ligand was synthesized and characterized. is a ratiometric fluorescent probe for Cd(2+) with a recognition mechanism based on intramolecular charge transfer (ICT). An complex was isolated, and its structure was established using single-crystal XRD. The complex was able to serve as a novel reversible chemosensing ensemble to allow ratiometric response to pyrophosphate (PPi) in aqueous media. Moreover, the fluorescence imaging in living cells from these two emission channels suggested that was a ratiometric probe for Cd(2+), and the in situ generated complex was also a ratiometric ensemble for PPi detection in living cells.

Structural, spectral, DFT and biological studies on macrocyclic mononuclear ruthenium (II) complexes

NASA Astrophysics Data System (ADS)

Muthukkumar, M.; Kamal, C.; Venkatesh, G.; Kaya, C.; Kaya, S.; Enoch, Israel V. M. V.; Vennila, P.; Rajavel, R.

2017-11-01

Macrocyclic mononuclear ruthenium (II) complexes have been synthesized by condensation method [Ru (L1, L2, L3) Cl2] L1 = (C36 H31 N9), L2= (C42H36N8), L3= (C32H32 N8)]. These ruthenium complexes have been established by elemental analyses and spectroscopic techniques (Fourier transform infrared spectroscopy (FT-IR), 1H- nuclear magnetic resonance (NMR), 13C- NMR and Electrospray ionization mass spectrometry (ESI-MS)). The coordination mode of the ligand has been confirmed and the octahedral geometry around the ruthenium ion has been revealed. Binding affinity and binding mode of ruthenium (II) complexes with Bovine serum Albumin (BSA) have been characterized by Emission spectra analysis. UV-Visible and fluorescence spectroscopic techniques have also been utilized to examine the interaction between ligand and its complexes L1, L2, & L3 with BSA. Chemical parameters and molecular structure of Ru (II) complexes L1H, L2H, & L3H have been determined by DFT coupled with B3LYP/6-311G** functional in both the gaseous and aqueous phases.

Ruthenium(ii)-polypyridyl zirconium(iv) metal–organic frameworks as a new class of sensitized solar cells

DOE PAGES

Maza, W. A.; Haring, A. J.; Ahrenholtz, S. R.; ...

2015-10-16

Ruthenium(ii) polypyridyl-doped metal–organic framework sensitized films on TiO 2 for photovoltaics reveal that the preparative method of dye doping/incorporation into the MOF is integral to the total solar cell efficiency.

Synthesis, structure and photoluminescence of (PLAGH){sub 2}[ZnCl{sub 4}] and comparative analysis of photoluminescence properties with tris(2,2′-bipyridine)ruthenium(II)

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

Radanović, Mirjana M.; Jelić, Miodrag G., E-mail: jelicmgm@uns.ac.rs; Romčević, Nebojša Ž.

Highlights: • New zinc(II) complex with pyridoxalaminoguanidine was synthesized. • The enhancement of the photoluminescence due to the compound formation was achieved. • Very high photoluminescence of Zn(II) compound was noticed. • Comparative analysis of photoluminescence with tris(2,2′-bipyridine) ruthenium(II) was provided. - Abstract: The first compound of zinc(II) containing pyridoxalaminoguanidine has been synthesized and characterized by elemental analysis, infrared spectra, conductometric measurements and X-ray crystallography. Single crystals of the compound were obtained in the reaction of methanolic solution of zinc(II) chloride and pyridoxalaminoguanidine hydrochloride. In this compound the coordination of chelate ligand is absent and tetrachlorido complex of zinc(II) withmore » pyridoxalaminuguanidinium cation as contraion is obtained. Photoluminescence spectra were measured. Lorentzian multipeak technique was used to determine peak wavelengths and their intensities. Photoluminescence spectroscopy upon 325, 488 and 514 nm laser excitation light was used to obtain results. This novel compound of zinc(II) was compared to the well-known organic light emitting diode material—ruthenium(II) complex with bypiridine i.e., tris(2,2′-bipyridine)ruthenium(II), under the same circumstances and the identical experimental setup. A scheme of energy levels and transitions is proposed to explain the obtained experimental results.« less

Thiophene-based terpyridine and its zinc halide complexes: third-order nonlinear optical properties in the near-infrared region.

PubMed

Tan, Jingyun; Li, Rui; Li, Dandan; Zhang, Qiong; Li, Shengli; Zhou, Hongping; Yang, Jiaxiang; Wu, Jieying; Tian, Yupeng

2015-01-21

A novel 4'-(4-(diphenylamino)thienyl)-2,2':6',2''-terpyridine ligand () based on thiophene and its complexes (X = Cl, Br, I, SCN) was designed, synthesized and characterized by elemental analysis, far-IR, MALDI-TOF-MS, and single crystal X-ray diffraction analysis. Structural studies revealed that the central zinc(ii) atom adopted a distorted trigonal bipyramidal coordination model. However, there were different hydrogen bonds and stacking models with different counter anions in the crystals. The absorption properties of the compounds were investigated with the aid of TD-DFT computational methods. Furthermore, the third-order nonlinear optical (NLO) properties were systematically studied via open-aperture Z-scan methods using a tunable wavelength femtosecond laser. The results from photophysical property investigations suggested that the complexation of the thiophene-based terpyridine ligand with zinc halides resulted in strong ICT/LLCT bands of about 450 nm, and the complexes exhibited strong nonlinear optical response in the near-infrared range around 850 nm. Above all, the two-photon absorption (2PA) cross-section values (σ) were enhanced by coordination with zinc and influenced by halide ions, reaching up to 2583 GM (X = Br).

Toxicology and pharmacology of some ruthenium compounds: Vascular smooth muscle relaxation by nitrosyl derivatives of ruthenium and iridium.

PubMed

Kruszyna, H; Kruszyna, R; Hurst, J; Smith, R P

1980-07-01

A series of compounds were synthesized from ruthenium trichloride, and their ip LD50s were determined in mice: pentamminenitrosylruthenium(II) chloride, 8.9; chloronitrobis(2,2'-dipyridyl)ruthenium(II), 55;dichlorobis(2,2'-dipyridyl)ruthenium(II), 63; ruthenium trichloride, 108; and potassium pentachloronitrosylruthenate(II), 127 mg/kg. The two bis-bipyridyl complexes produced death in convulsions within minutes, whereas the remaining compounds resulted in long, debilitating courses with death occurring in 4-7d. When given in massive overdoses, however, the compounds with inorganic ligands also produced rapid convulsive death in mice, and when given iv to anesthetized cats, they produced respiratory arrest. The major toxic effects of all the complexes appeared to be due to the metal and not to its associated ligands. Only complexes having nitrosyl ligand specifically relaxed vascular smooth muscle. Potassium pentabromoiridate(III) also relaxed rabbit aortic strips that had been contracted by adrenergic agonists, but potassium pentachloroiridate(III) did not. None of the complexes was as active as nitroprusside in relaxing aortic strips or in decreasing arterial blood pressure in cats. No compound tested was as potent as cisplatin in antitumor activity. The pentamminenitrosylruthenium(II) complex also relaxed guinea pig ileum and frog rectus abdominus when these isolated muscles had been contracted by acetylcho line. It appears that these organoruthenium compounds may produce death in central respiratory arrest, as do the inorganic complexes when given iv or ip in massive overdoses. In minimally lethal doses, the complexes with inorganic ligands may affect a variety of contractile tissues, perhaps by a general mechanism involving Ca. These complexes are apt to be generally cytotoxic as well.

Highly efficient quenching of tris(2,2'-bipyridyl)ruthenium(II) electrochemiluminescence by ozone using formaldehyde, methylglyoxal, and glyoxalate as co-reactants and its application to ozone sensing.

PubMed

Gao, Ying; Liu, Xiaoyun; Qi, Wenjing; Gao, Wenyue; Li, Yunhui; Xu, Guobao

2015-06-21

Most electrochemiluminescence (ECL) systems require high concentrations of quencher to totally quench ECL. In this study, we found that ozone can quench tris(2,2'-bipyridyl)ruthenium(II) ECL using formaldehyde, methylglyoxal, or glyoxalate as co-reactants at a glassy carbon electrode with remarkable efficiencies even when the concentration of ozone is merely 0.25% of that of the co-reactant. The strongest quenching is observed with the tris(2,2'-bipyridyl)ruthenium(II)/formaldehyde ECL system. The tris(2,2'-bipyridyl)ruthenium(II)/formaldehyde ECL intensities decrease linearly with the ozone concentration over the range of 0.025-25 μM (r = 0.9947) with a limit of detection of 8 nM. The method is more sensitive and faster than most methods. It shows high selectivity in the presence of other ROS or oxidants and some metal ions, such as H2O2, ClO(-), Mg(2+), Ni(2+), etc. The method exhibits high recoveries for the detection of ozone in a ventilated photocopy room.

Heteroleptic monometallic and trimetallic ruthenium(II) complexes incorporating a π-extended dipyrrin ligand: Light-activated reactions with the A549 lung cancer cell line.

PubMed

Swavey, Shawn; Morford, Krista; Tsao, Max; Comfort, Kristen; Kilroy, Mary Kate

2017-10-01

A heteroleptic monometallic ruthenium(II) and a heteroleptic trimetallic ruthenium(II) complex have been synthesized and characterized. Both complexes have an overall 3+ charge, with the charge density greater for the monometallic complex. The electronic spectra of the monometallic ruthenium(II) complex exhibits intense π-π* transitions associated with the bipyridyl groups along with overlapping metal to ligand charge transfer (MLCT) and ligand centered π-π* transitions ranging from 520nm to approximately 600nm. The trimetallic ruthenium(II) complex, on the other hand, displays more well defined transitions with the expected π-π* transition of the bipyridyl groups at 294nm and Ru(dπ) to bpy(π*) MLCT transitions at 355nm and 502nm. In addition to these absorption bands an intense transition, 578nm, resulting from overlapping dipyrrin (π-π*) and Ru(dπ) to dipyrrin(π*) transitions is observed. Electrochemical and spectroelectrochemical experiments were used to help in assigning these transitions. Irradiation of the complexes in the presence of plasmid DNA within the photodynamic therapy window (600nm to 850nm) reveal, using electrophoresis, that both complexes are capable of causing photo-damage to the DNA backbone. The trimetallic ruthenium(II) complex; however, also shows the ability to generate photoinduced DNA damage in the absence of oxygen, suggesting a photo-oxidative process. Studies of the complexes toward lung cancer cells (A549 cell line) in the absence of light indicate little cytotoxicity up to 50μM. Upon irradiation of the cells with a low power 420nm light source the trimetallic complex showed considerably greater photo-cytotoxicity compared to the monometallic analog. A dose-dependent response curve gives an IC50 of 92μM for complex B. Copyright © 2017 Elsevier Inc. All rights reserved.

C-N bond cleavage of anilines by a (salen)ruthenium(VI) nitrido complex.

PubMed

Man, Wai-Lun; Xie, Jianhui; Pan, Yi; Lam, William W Y; Kwong, Hoi-Ki; Ip, Kwok-Wa; Yiu, Shek-Man; Lau, Kai-Chung; Lau, Tai-Chu

2013-04-17

We report experimental and computational studies of the facile oxidative C-N bond cleavage of anilines by a (salen)ruthenium(VI) nitrido complex. We provide evidence that the initial step involves nucleophilic attack of aniline at the nitrido ligand of the ruthenium complex, which is followed by proton and electron transfer to afford a (salen)ruthenium(II) diazonium intermediate. This intermediate then undergoes unimolecular decomposition to generate benzene and N2.

Catalytic water oxidation by ruthenium(II) quaterpyridine (qpy) complexes: evidence for ruthenium(III) qpy-N,N'''-dioxide as the real catalysts.

PubMed

Liu, Yingying; Ng, Siu-Mui; Yiu, Shek-Man; Lam, William W Y; Wei, Xi-Guang; Lau, Kai-Chung; Lau, Tai-Chu

2014-12-22

Polypyridyl and related ligands have been widely used for the development of water oxidation catalysts. Supposedly these ligands are oxidation-resistant and can stabilize high-oxidation-state intermediates. In this work a series of ruthenium(II) complexes [Ru(qpy)(L)2 ](2+) (qpy=2,2':6',2'':6'',2'''-quaterpyridine; L=substituted pyridine) have been synthesized and found to catalyze Ce(IV) -driven water oxidation, with turnover numbers of up to 2100. However, these ruthenium complexes are found to function only as precatalysts; first, they have to be oxidized to the qpy-N,N'''-dioxide (ONNO) complexes [Ru(ONNO)(L)2 ](3+) which are the real catalysts for water oxidation. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mono- and bis-tolylterpyridine iridium(III) complexes

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

Hinkle, Lindsay M.; Young, Jr., Victor G.; Mann, Kent R.

The first structure report of trichlorido[4'-(p-tolyl)-2,2':6',2{double_prime}-terpyridine]iridium(III) dimethyl sulfoxide solvate, [IrCl{sub 3}(C{sub 22}H{sub 17}N{sub 3})] {center_dot} C{sub 2}H{sub 6}OS, (I), is presented, along with a higher-symmetry setting of previously reported bis[4'-(p-tolyl)-2,2':6',2{double_prime}-terpyridine]iridium(III) tris(hexafluoridophosphate) acetonitrile disolvate, [Ir(C{sub 22}H{sub 17}N{sub 3})2](PF{sub 6}){sub 3} {center_dot} 2C{sub 2}H{sub 3}N, (II) [Yoshikawa, Yamabe, Kanehisa, Kai, Takashima & Tsukahara (2007). Eur. J. Inorg. Chem. pp. 1911-1919]. For (I), the data were collected with synchrotron radiation and the dimethyl sulfoxide solvent molecule is disordered over three positions, one of which is an inversion center. The previously reported structure of (II) is presented in the more appropriate C2/c space group.more » The iridium complex and one PF{sub 6}{sup -} anion lie on twofold axes in this structure, making half of the molecule unique.« less

Syntheses and Characterization of Ruthenium(II) Tetrakis(pyridine)complexes: An Advanced Coordination Chemistry Experiment or Mini-Project

ERIC Educational Resources Information Center

Coe, Benjamin J.

2004-01-01

An experiment for third-year undergraduate a student is designed which provides synthetic experience and qualitative interpretation of the spectroscopic properties of the ruthenium complexes. It involves the syntheses and characterization of several coordination complexes of ruthenium, the element found directly beneath iron in the middle of the…

A hybrid ruthenium alkynyl/zinc porphyrin "Cross Fourchée" with large cubic NLO properties.

PubMed

Merhi, Areej; Grelaud, Guillaume; Green, Katy A; Minh, Ngo Hoang; Reynolds, Michael; Ledoux, Isabelle; Barlow, Adam; Wang, Genmiao; Cifuentes, Marie P; Humphrey, Mark G; Paul, Frédéric; Paul-Roth, Christine O

2015-05-07

A new Zn(ii) porphyrin-cored ruthenium alkynyl dendrimer (2) containing twelve Ru(κ(2)-dppe)2 bis-alkynyl fragments has been prepared in two steps from 5,10,15,20-tetra(4-ethynylphenyl)porphyrinatozinc(ii) and shown to be highly active for third-harmonic generation (THG) at 1907 nm.

Molecular Models of Ruthenium(II) Organometallic Complexes

ERIC Educational Resources Information Center

Coleman, William F.

2007-01-01

This article presents the featured molecules for the month of March, which appear in the paper by Ozerov, Fafard, and Hoffman, and which are related to the study of the reactions of a number of "piano stool" complexes of ruthenium(II). The synthesis of compound 2a offers students an alternative to the preparation of ferrocene if they are only…

Molecular Engineering of Platinum(II) Terpyridine Complexes with Tetraphenylethylene-Modified Alkynyl Ligands: Supramolecular Assembly via Pt···Pt and/or π-π Stacking Interactions and the Formation of Various Superstructures.

PubMed

Cheng, Heung-Kiu; Yeung, Margaret Ching-Lam; Yam, Vivian Wing-Wah

2017-10-18

A series of platinum(II) terpyridine complexes with tetraphenylethylene-modified alkynyl ligands has been designed and synthesized. The introduction of the tetraphenylethylene motif has led to aggregation-induced emission (AIE) properties, which upon self-assembly led to the formation of metal-metal-to-ligand charge transfer (MMLCT) behavior stabilized by Pt···Pt and/or π-π interactions. Tuning the steric bulk or hydrophilicity through molecular engineering of the platinum(II) complexes has been found to alter their spectroscopic properties and result in interesting superstructures (including nanorods, nanospheres, nanowires, and nanoleaves) in the self-assembly process. The eye-catching color and emission changes upon varying the solvent compositions may have potential applications in chemosensing materials for the detection of microenvironment changes. Furthermore, the importance of the directional Pt···Pt and/or π-π interactions on the construction of distinctive superstructures has also been examined by UV-vis absorption and emission spectroscopy and transmission electron microscopy. This work represents the interplay of both inter- and intramolecular interactions as well as the energies of the two different chromophoric/luminophoric systems that may open up a new route for the development of platinum(II)-AIE hybrids as functional materials.

Half-sandwich ruthenium(II) biotin conjugates as biological vectors to cancer cells.

PubMed

Babak, Maria V; Plażuk, Damian; Meier, Samuel M; Arabshahi, Homayon John; Reynisson, Jóhannes; Rychlik, Błażej; Błauż, Andrzej; Szulc, Katarzyna; Hanif, Muhammad; Strobl, Sebastian; Roller, Alexander; Keppler, Bernhard K; Hartinger, Christian G

2015-03-23

Ruthenium(II)-arene complexes with biotin-containing ligands were prepared so that a novel drug delivery system based on tumor-specific vitamin-receptor mediated endocytosis could be developed. The complexes were characterized by spectroscopic methods and their in vitro anticancer activity in cancer cell lines with various levels of major biotin receptor (COLO205, HCT116 and SW620 cells) was tested in comparison with the ligands. In all cases, coordination of ruthenium resulted in significantly enhanced cytotoxicity. The affinity of Ru(II) -biotin complexes to avidin was investigated and was lower than that of unmodified biotin. Hill coefficients in the range 2.012-2.851 suggest strong positive cooperation between the complexes and avidin. To estimate the likelihood of binding to the biotin receptor/transporter, docking studies with avidin and streptavidin were conducted. These explain, to some extent, the in vitro anticancer activity results and support the conclusion that these novel half-sandwich ruthenium(II)-biotin conjugates may act as biological vectors to cancer cells, although no clear relationship between the cellular Ru content, the cytotoxicity, and the presence of the biotin moiety was observed. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

At the Borderline between Metal-Metal Mixed Valency and a Radical Bridge Situation: Four Charge States of a Diruthenium Complex with a Redox-Active Bis( mer-tridentate) Ligand.

PubMed

Mondal, Sudipta; Schwederski, Brigitte; Frey, Wolfgang; Fiedler, Jan; Záliš, Stanislav; Kaim, Wolfgang

2018-04-02

The complex ions [L 3 Ru(μ,η 3 :η 3 -BL)RuL 3 ] n+ (1 n+ , L 3 = 4,4',4″-tri- tert-butyl-2,6,2',6″-terpyridine and H 2 BL 2- = 1,2-bis(salicyloyl)hydrazide(2-)) were isolated with PF 6 - or ClO 4 - counterions ( n = 1) and as bis(hexafluorophosphate) ( n = 2). Structural, electrochemical, and spectroscopic characterization reveals the monocation as intermediate ( K c = 10 8.2 ) in the three-step reversible redox system 1 0/+/2+/3+ . The 1 + ion has the molecule-bridged (Ru- - -Ru 4.727 Å) ruthenium centers involved in five- and six-membered chelate rings, and it exhibits long-wavelength absorptions at λ max 2240, 1660, and 1530 nm (ε max = 1000, 3000, and 8000 M -1 cm -1 , respectively), which would be compatible with a Ru III Ru II mixed-valent situation or with a coordinated radical ion bridge. In fact, EPR and DFT analysis of 1 + reveals that the spin is equally distributed over the ligand bridge and over both metals. The oxidized paramagnetic ions 1 2+ and 1 3+ have been studied by 1 H NMR and EPR and by TD-DFT supported UV-vis-NIR and MIR (mid-IR) spectroelectrochemistry. The capacity of various kinds of bis( mer-tridentate) bridging ligands (π donors or π acceptors, cyclometalated or noncyclometalated) for mediating metal-metal interactions is discussed.

[(H2O)(terpy)Mn(μ-O)2Mn(terpy)(OH2)](NO3)3 (terpy = 2,2′:6,2″-terpyridine) and its relevance to the oxygen-evolving complex of photosystem II examined through pH dependent cyclic voltametry

PubMed Central

Cady, Clyde W.; Shinopoulos, Katherine E.; Crabtree, Robert H.; Brudvig, Gary W.

2010-01-01

Photosynthetic water oxidation occurs naturally at a tetranuclear manganese center in the photosystem II protein complex. Synthetically mimicking this tetramanganese center, known as the oxygen-evolving complex (OEC), has been an ongoing challenge of bioinorganic chemistry. Most past efforts have centered on water-oxidation catalysis using chemical oxidants. However, solar energy applications have drawn attention to electrochemical methods. In this paper, we examine the electrochemical behavior of the biomimetic water-oxidation catalyst [(H2O)(terpy)Mn(μ-O)2Mn(terpy)(H2O)](NO3)3 [terpy = 2,2′:6′,2″-terpyridine] (1) in water under a variety of pH and buffered conditions and in the presence of acetate that binds to 1 in place of one of the terminal water ligands. These experiments will show that 1 not only exhibits proton-coupled electron-transfer reactivity analogous to the OEC, but also may be capable of electrochemical oxidation of water to oxygen. PMID:20372724

Construction of New Coordination Polymers from 4’-(2,4-disulfophenyl)- 3,2’:6’3”-terpyridine: Polymorphism, pH-dependent syntheses, structures, and properties

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

Zhang, Li; Li, Chao-Jie; He, Jia-En

Nine new coordination compounds, namely, [Co(HDSPTP){sub 2}(H{sub 2}O){sub 4}]·4H{sub 2}O (H{sub 2}DSPTP=4’-(2,4-disulfophenyl)-3,2’:6’3”-terpyridine, 1 and 2), {[Ni(DSPTP)(H_2O)_4]·3H_2O}{sub n} (3), {[Cu(HDSPTP)_2(H_2O)_3]·8H_2O}{sub n} (4), {[Cu(HDSPTP)_2(H_2O)_3]·6H_2O}{sub n} (5), {[Cu(DSPTP)(H_2O)_2]·H_2O}{sub n} (6), {[Zn(DSPTP)(H_2O)_2]·2H_2O}{sub n} (7), {[Cd(DSPTP)(H_2O)_2]·2H_2O}{sub n} (8), and [Ag{sub 2}(DSPTP)(H{sub 2}O)]{sub n} (9), were constructed based on a new ligand containing both terpyridyl and sulfo groups. The reactions of H{sub 2}DSPTP with Co(NO{sub 3}){sub 2}.6H{sub 2}O resulted in two mononuclear complexes (compounds 1 and 2). They are polymorphisms that display different hydrogen bonding networks. They are selectively synthesized by altering the added alkalis. The reaction of H{sub 2}DSPTP with Ni(NO{sub 3}){sub 2}·6H{sub 2}O resultedmore » in a 1D “S-shaped” coordination chain (compound 3). The reactions of Cu(II) with H{sub 2}DSPTP at different pH value resulted in the following three compounds: two kinds of 1D chains obtained at pH 3.0 and 4.0 for compounds 4 and 5, respectively, and a 3D framework based on binuclear ring units with 4-connected sra topology (Compound 6). The reactions of H{sub 2}DSPTP with ds-block ions resulted in the following three compounds: a Zn(II) (compound 7) and a Cd(II) (compound 8) 3D frameworks with structures similar to that in compound 6, and a 3D framework based on tetranuclear Ag(I) SBUs with binodal (4,8)-connected flu type 3D framework topology. The structural diversity is mainly attributed to the rich coordination modes (from monodentate to µ{sub 7}-mode) and conformations (cis–cis and cis–trans) of HDSPTP{sup −}/DSPTP{sup 2−} ligands and the metal center and can be controllable synthesized by altering the alkalis, and pH value. Thermal stability of all compounds was performed, and the thermal behaviors of compounds 6 and 8 were further explored by PXRD. Compound 6 exhibits low thermal stability and undergo a crystalline–crystalline-amorphous phase transition as temperature increases from 25 °C to 200 °C, and show amorphous–crystalline phase transition when rehydrated. However, compound 8 exhibits high thermal stability above 500 °C. Its crystalline phase can retain above 300 °C and undergo a crystalline–crystalline phase transition as temperature increased to 400 °C, and transit back to compound 8 when rehydrated. Moreover, luminescence properties of compounds 7–9 were also investigated. - Graphical abstract: Series of coordination compounds based on a new terpyridine-based ligand, 4’-(2,4-disulfophenyl)-3,2’:6’3’’-terpyridine, were constructed. The syntheses, structural diversity, thermal stability, phase transition, and luminescent properties of selected compounds were explored. - Highlights: • Nine coordination polymers based on a new terpyridine-based ligand were obtained. • Both metal ion and coordination modes of H2DSPTP affect the structural diversity. • The Co(II) compounds are polymorphisms. • The pH-dependent syntheses of Cu(II) compounds were observed. • Compounds 6 and 8 exhibit phase transmission as temperature increased.« less

Flow-injection chemiluminescent determination of estrogen benzoate using the tris(1,10-phenanthroline) ruthenium(II)-permanganate system.

PubMed

Ma, Yan; Cao, Wei; Qiao, Shuang; Liu, Wenwen; Yang, Jinghe

2011-01-01

Chemiluminescence (CL) detection for the determination of estrogen benzoate, using the reaction of tris(1,10-phenanthroline)ruthenium(II)-Na(2)SO(3)-permanganate, is described. This method is based on the CL reaction of estrogen benzoate (EB) with acidic potassium permanganate and tris(1,10-phenanthroline)ruthenium(II). The CL intensity is greatly enhanced when Na(2)SO(3) is added. After optimization of the different experimental parameters, a calibration graph for estrogen benzoate is linear in the range 0.05-10 µg/mL. The 3 s limit of detection is 0.024 µg/mL and the relative standard deviation was 1.3% for 1.0 µg/mL estrogen benzoate (n = 11). This proposed method was successfully applied to commercial injection samples and emulsion cosmetics. The mechanism of CL reaction was also studied. Copyright © 2011 John Wiley & Sons, Ltd.

Metallomics for drug development: a further insight into intracellular activation chemistry of a ruthenium(III)-based anticancer drug gained using a multidimensional analytical approach.

PubMed

Matczuk, Magdalena; Prządka, Monika; Aleksenko, Svetlana S; Czarnocki, Zbigniew; Pawlak, Katarzyna; Timerbaev, Andrei R; Jarosz, Maciej

2014-01-01

The mechanism by which the most relevant ruthenium anticancer drugs are activated in tumors to commence their tumor-inhibiting action remains one of the challenging research tasks of present-day metallomics. This contribution aims to capture and identify eventually more reactive species of one of two bis-indazole tetrachloridoruthenate(III) compounds that are progressing in clinical trials. In view of the fact that the transport of ruthenium into cancer cells is governed by transferrin receptors, the susceptibility of the Ru drug adduct with holo-transferrin to exposure by glutathione and ascorbic acid (at their cancer cytosol concentrations) was studied by inductively coupled plasma mass spectrometry (ICP-MS), following isolation of the reaction products by ultrafiltration. Next, capillary electrophoresis coupled to ICP-MS was applied to monitor changes in the Ru speciation both under simulated cancer cytosol conditions and in real cytosol and to assign the charge state of novel metal species. The latter were identified by using tandem electrospray ionization MS in the respective ion mode. The formation of ruthenium(II) species was for the first time revealed, in which the central metal is coordinated by the reduced (GSH) or the oxidized (GSSG) form of glutathione, i.e. [Ru(II)HindCl4(GSH)](2-) and [Ru(II)HindCl4(GSSG)](2-), respectively (Hind = indazole). Ascorbic acid released the ruthenium functionality from the protein-bound form in a different way, the products of adduct cleavage containing aqua ligands. Distribution of low-molecular mass species of Ru in human cytosol was found to have very much in common with the ruthenium speciation assayed under simulated cytosol conditions.

Ruthenium(II) carbonyl complexes bearing CCC-pincer bis-(carbene) ligands: synthesis, structures and activities toward recycle transfer hydrogenation reactions.

PubMed

Naziruddin, Abbas Raja; Huang, Zhao-Jiunn; Lai, Wei-Chih; Lin, Wan-Jung; Hwang, Wen-Shu

2013-09-28

A new series of ruthenium(II) carbonyl complexes with benzene-based CCC-pincer bis-(carbene) ligands, [((R)CCC(R))Ru(CO)2(X)](0/+) and [((R)CCC(R))Ru(CO)(NN)](+) ((R)CCC(R) = 2,6-bis-(1-alkylimidazolylidene)benzene, R = Me or (n)Bu; X = I, Br, CH3CN, or 6-(aminomethyl)pyridine (ampy); NN = 2·CH3CN, or chelating ampy or bipyridine), was synthesized and fully characterized. X-Ray structure determinations revealed that these eight complexes have pseudo-octahedral configurations around the ruthenium center with the pincer ligand occupying three meridional sites. These complexes prove to be efficient precatalysts demonstrating very good activity and reusability for the transfer hydrogenation of ketones.

Chemiluminescence reactions with cationic, neutral, and anionic ruthenium(II) complexes containing 2,2'-bipyridine and bathophenanthroline disulfonate ligands.

PubMed

Francis, Paul S; Papettas, Dimitra; Zammit, Elizabeth M; Barnett, Neil W

2010-07-15

Ruthenium complexes containing 4,7-diphenyl-1,10-phenanthroline disulfonate (bathophenanthroline disulfonate; BPS) ligands, Ru(BPS)(3)(4-), Ru(BPS)(2)(bipy)(2-) and Ru(BPS)(bipy)(2), were compared to tris(2,2'-bipyridine)ruthenium(II) (Ru(bipy)(3)(2+)), including examination of the wavelengths of maximum absorption and corrected emission intensity, photoluminescence quantum yield, stability of their oxidised ruthenium(III) form, and relative chemiluminescence intensities and signal-to-blank ratios with cerium(IV) sulfate and six analytes (codeine, morphine cocaine, potassium oxalate, furosemide and hydrochlorothiazide) in acidic aqueous solution. The presence of BPS ligands in the complex increased the photoluminescence quantum yield, but decreased the stability of the oxidised form of the reagent. In contrast to previous evidence showing much greater electrochemiluminescence intensities using Ru(BPS)(2)(bipy)(2-) and Ru(BPS)(bipy)(2), these complexes did not provide superior chemiluminescence signals than their homoleptic analogues. Copyright 2010 Elsevier B.V. All rights reserved.

Ru-OSO coordination photogenerated at 100 K in tetraammineaqua(sulfur dioxide)ruthenium(II) (±)-camphorsulfonate.

PubMed

Phillips, Anthony E; Cole, Jacqueline M; d'Almeida, Thierry; Low, Kian Sing

2012-02-06

The photoinduced O-bound coordination mode in RuSO(2) complexes, previously observed only at 13 K, has been generated at 100 K in tetraammineaqua(sulfur dioxide)ruthenium(II) (±)-camphorsulfonate. This coordination state, often denoted MS1, decays to the η(2)-bound MS2 state, with an estimated half-life of 3.4(8) h and a long-lived population of 2.9(4)% at 120 K.

Studies on the synthesis, spectra, catalytic and antibacterial activities of binuclear ruthenium(II) complexes.

PubMed

Krishnamoorthy, P; Sathyadevi, P; Deepa, K; Dharmaraj, N

2010-09-15

A new series of stable binuclear ruthenium(II) carbonyl complexes of the general formula [{RuX(CO)(EPh(3))(2)}(2)L] (where X=H or Cl; E=P or As and L=dibasic tetradentate diacetyl resorcinol (H(2)-DAR)) have been synthesised by reacting ruthenium(II) starting complexes [RuHX(CO)(EPh(3))(3)] (where X=H or Cl; E=P or As) and 4,6-diacetylresorcinol (H(2)-DAR) ligand in benzene medium. The structure of the new binuclear ruthenium(II) carbonyl complexes was established using elemental analysis, spectra (FT-IR, UV-vis and (1)H NMR), electrochemical and thermal studies. In these reactions, the 4,6-diacetylresorcinol (H(2)-DAR) ligand behaves as a binegative tetradentate chelating ligand coordinating through O,O atoms of both the carbonyl and phenolic C-O groups by replacing a molecule of PPh(3)/AsPh(3) and a hydride ion from the starting complexes. Further, all these complexes were also employed as new catalysts for the oxidation of primary and secondary alcohols in the presence of N-methylmorpholine-N-oxide (NMO) as a more viable co-oxidant. The free ligand and their metal complexes have also been screened for their antibacterial activity against the growth of gram +ve and gram -ve bacterial cultures. Copyright 2010 Elsevier B.V. All rights reserved.

A Sulfhydryl-Reactive Ruthenium (II) Complex and Its Conjugation to Protein G as a Universal Reagent for Fluorescent Immunoassays

PubMed Central

Goud, Thirumani Venkatshwar; Huang, Bor-Rong; Lin, Tzu-Chau; Biellmann, Jean-François; Chen, Chien-Sheng

2012-01-01

To develop a fluorescent ruthenium complex for biosensing, we synthesized a novel sulfhydryl-reactive compound, 4-bromophenanthroline bis-2,2′-dipyridine Ruthenium bis (hexafluorophosphate). The synthesized Ru(II) complex was crosslinked with thiol-modified protein G to form a universal reagent for fluorescent immunoassays. The resulting Ru(II)-protein G conjugates were identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The emission peak wavelength of the Ru(II)-protein G conjugate was 602 nm at the excitation of 452 nm which is similar to the spectra of the Ru(II) complex, indicating that Ru(II)-protein G conjugates still remain the same fluorescence after conjugation. To test the usefulness of the conjugate for biosensing, immunoglobulin G (IgG) binding assay was conducted. The result showed that Ru(II)-protein G conjugates were capable of binding IgG and the more cross-linkers to modify protein G, the higher conjugation efficiency. To demonstrate the feasibility of Ru(II)-protein G conjugates for fluorescent immunoassays, the detection of recombinant histidine-tagged protein using the conjugates and anti-histidine antibody was developed. The results showed that the histidine-tagged protein was successfully detected with dose-response, indicating that Ru(II)-protein G conjugate is a useful universal fluorescent reagent for quantitative immunoassays. PMID:22563441

Ruthenium-catalyzed insertion of adjacent diol carbon atoms into C-C bonds: Entry to type II polyketides.

PubMed

Bender, Matthias; Turnbull, Ben W H; Ambler, Brett R; Krische, Michael J

2017-08-25

Current catalytic processes involving carbon-carbon bond activation rely on π-unsaturated coupling partners. Exploiting the concept of transfer hydrogenative coupling, we report a ruthenium(0)-catalyzed cycloaddition of benzocyclobutenones that functionalizes two adjacent saturated diol carbon-hydrogen bonds. These regio- and diastereoselective processes enable convergent construction of type II polyketide substructures. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

An unusual stable mononuclear Mn(III) bis-terpyridine complex exhibiting Jahn-Teller compression: electrochemical synthesis, physical characterisation and theoretical study.

PubMed

Romain, Sophie; Duboc, Carole; Neese, Frank; Rivière, Eric; Hanton, Lyall R; Blackman, Allan G; Philouze, Christian; Leprêtre, Jean-Claude; Deronzier, Alain; Collomb, Marie-Noëlle

2009-01-01

The mononuclear manganese bis-terpyridine complex [Mn(tolyl-terpy)(2)](X)(3) (1(X)(3); X=BF(4), ClO(4), PF(6); tolyl-terpy=4'-(4-methylphenyl)-2,2':6',2"-terpyridine), containing Mn in the unusual +III oxidation state, has been isolated and characterised. The 1(3+) ion is a rare example of a mononuclear Mn(III) complex stabilised solely by neutral N ligands. Complex 1(3+) is obtained by electrochemical oxidation of the corresponding Mn(II) compound 1(2+) in anhydrous acetonitrile. Under these conditions the cyclic voltammogram of 1(2+) exhibits not only the well-known Mn(II)/Mn(III) oxidation at E(1/2)=+0.91 V versus Ag/Ag(+) (+1.21 V vs. SCE) but also a second metal-based oxidation process corresponding to Mn(III)/Mn(IV) at E(1/2)=+1.63 V (+1.93 V vs. SCE). Single crystals of 1(PF(6))(3)2 CH(3)CN were obtained by an electrocrystallisation procedure. X-ray analysis unambiguously revealed its tetragonally compressed octahedral geometry and high-spin character. The electronic properties of 1(3+) were investigated in detail by magnetic measurements and theoretical calculations, from which a D value of +4.82 cm(-1) was precisely determined. Density functional and complete active space self consistent field ab initio calculations both correctly predict a positive sign of D, in agreement with the compressed tetragonal distortion observed in the X-ray structure of 1(PF(6))(3)2 CH(3)CN. The different contributions to D were calculated, and the results show that 1) the spin-orbit coupling part (+2.593 cm(-1)) is predominant compared to the spin-spin interaction (+1.075 cm(-1)) and 2) the excited triplet states make the dominant contribution to the total D value.

Ruthenium(II)-catalysed remote C-H alkylations as a versatile platform to meta-decorated arenes

NASA Astrophysics Data System (ADS)

Li, Jie; Korvorapun, Korkit; de Sarkar, Suman; Rogge, Torben; Burns, David J.; Warratz, Svenja; Ackermann, Lutz

2017-06-01

The full control of positional selectivity is of prime importance in C-H activation technology. Chelation assistance served as the stimulus for the development of a plethora of ortho-selective arene functionalizations. In sharp contrast, meta-selective C-H functionalizations continue to be scarce, with all ruthenium-catalysed transformations currently requiring difficult to remove or modify nitrogen-containing heterocycles. Herein, we describe a unifying concept to access a wealth of meta-decorated arenes by a unique arene ligand effect in proximity-induced ruthenium(II) C-H activation catalysis. The transformative nature of our strategy is mirrored by providing a step-economical entry to a range of meta-substituted arenes, including ketones, acids, amines and phenols--key structural motifs in crop protection, material sciences, medicinal chemistry and pharmaceutical industries.

Fabricating Electrochromic Thin Films Based on Metallo-Polymers Using Layer-by-Layer Self-Assembly: An Attractive Laboratory Experiment

ERIC Educational Resources Information Center

Schott, Marco; Beck, Matthias; Winkler, Franziska; Lorrmann, Henning; Kurth, Dirk G.

2015-01-01

Metallo-supramolecular polyelectrolytes (MEPE) based on iron(II)-acetate and 1,4-bis(2,2':6',2?-terpyridin-4'-yl)benzene are assembled by layer-by-layer deposition on transparent electrode surfaces. When a potential is applied, the color of the film can be switched from blue to transparent. Due to the strong absorption and the fast switching…

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

Kruszyna, H.; Kruszyna, R.; Hurst, J.

A series of compounds were synthesized from ruthenium trichloride, and their ip LD50s were determined in mice: pentamminenitrosylruthenium(II) chloride, 8.9; chloronitrobis(2,2'-dipyridyl)ruthenium(II), 55; dichlorobis(2,2'-dipyridyl)ruthenium(II) 63; ruthenium trichloride, 108; and potassium pentachloronitrosylruthenate(II), 127 mg/kg. The two bis-bipyridyl complexes produced death in convulsions within minutes, whereas the remaining compounds resulted in long, debilitating courses with death occuring in 4 to 7 d. When given in massive overdoses, however, the compounds with inorganic ligands also produced rapid convulsive death in mice, and when given iv to anesthetized cats, they produced respiratory arrest. The major toxic effects of all the complexes appeared to be duemore » to the metal and not to its associated ligands. Only complexes having a nitrosyl ligand specifically relaxed vascular smooth muscle. Potassium pentabromoiridate(III) also relaxed rabbit aortic strips that had been contracted by adrenergic argonists, but potassium pentachloroiridate(III) did not. None of the complexes was as active as nitroprusside in relaxing aortic strips or in decreasing arterial blood pressure in cats. No compound tested was as potent as cisplatin in antitumor activity. The pentamminenitrosylruthenium(II) complex also relaxed guinea pig ileum and frog rectus abdominum when these isolated muscles had been contracted by acetylcholine. It appears that these organoruthenium compounds may produce death in central respiratory arrest, as do the inorganic complexes when given iv or ip in massive overdoses. In minimllylethal doses, the complexes with inorganic ligands may affect a variety of contractile tissues, perhaps by a general mechanism involving Ca. These complexes are apt to be generally cytotoxic as well.« less

Electrochemical DNA biosensor for detection of porcine oligonucleotides using ruthenium(II) complex as intercalator label redox

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

Halid, Nurul Izni Abdullah; Hasbullah, Siti Aishah; Heng, Lee Yook

2014-09-03

A DNA biosensor detection of oligonucleotides via the interactions of porcine DNA with redox active complex based on the electrochemical transduction is described. A ruthenium(II) complex, [Ru(bpy){sub 2}(PIP)]{sup 2+}, (bpy = 2,2′bipyridine, PIP = 2-phenylimidazo[4,5-f[[1,10-phenanthroline]) as DNA label has been synthesized and characterized by 1H NMR and mass spectra. The study was carried out by covalent bonding immobilization of porcine aminated DNA probes sequences on screen printed electrode (SPE) modified with succinimide-acrylic microspheres and [Ru(bpy){sub 2}(PIP)]{sup 2+} was used as electrochemical redox intercalator label to detect DNA hybridization event. Electrochemical detection was performed by cyclic voltammetry (CV) and differential pulsemore » voltammetry (DPV) over the potential range where the ruthenium (II) complex was active. The results indicate that the interaction of [Ru(bpy){sub 2}(PIP)]{sup 2+} with hybridization complementary DNA has higher response compared to single-stranded and mismatch complementary DNA.« less

Flow injection chemiluminescent determination of tetracycline using a tris(2,2'-bipyridine)ruthenium(II)-cerium(IV) sulphate system.

PubMed

Guo, Liangqia; Xie, Zenghong; Lin, Xucong; Liu, Xiaohua; Zhang, Weilin; Chen, Guonan

2004-01-01

A flow-injection chemiluminescence method for the determination of tetracycline was developed. The method is based on an enhancement by tetracycline of the chemiluminescence light emission of tris(2,2'-bipyridine)ruthenium(II). In sulphuric acid medium, the chemiluminescence is generated by the continuous oxidation of tris(2,2'-bipyridine)ruthenium(II) by cerium (IV) sulphate. The light-emission intensity is greatly enhanced in the presence of tetracycline. Under the optimum conditions, the calibration curve is linear over the range 3.75 x 10(-8) g/mL-1.5 x 10(-5) g/mL for tetracycline with the linear equation: deltaINT = 205.898 x C - 20.442 (R2 = 0.9974). The detection limit is 3.27 x 10(-8) g/mL. The proposed method was also successfully used to determine tetracycline in pharmaceutical formulation (mean recovery of tetracycline, 100.7%). Copyright 2004 John Wiley & Sons, Ltd.

Ruthenium(II) polypyridyl complexes as dual inhibitors of telomerase and topoisomerase.

PubMed

Liao, Guoliang; Chen, Xiang; Wu, Jingheng; Qian, Chen; Wang, Yi; Ji, Liangnian; Chao, Hui

2015-09-14

One novel ruthenium polypyridyl complex, [Ru(bpy)2(icip)](2+) (1), and two previously reported ruthenium polypyridyl complexes, [Ru(bpy)2(pdppz)](2+) ()2 and [Ru(bpy)2(tactp)](2+) (3) (bpy = 2,2'-bipyridine, icip = 2-(indeno[2,1-b]chromen-6-yl)-1H-imidazo[4,5-f][1,10]phenanthroline, pdppz = phenanthro[4,5-abc]dipyrido[3,2-h:2',3'-j]phenazine, tactp = 4,5,9,18-tetraazachryseno[9,10-b]-triphenylene), have been synthesised. As expected, these complexes show inhibition towards telomerase by inducing and stabilising the G-quadruplex structure, and behave as topoisomerase I/II poisons at the same time. Additionally, the acute and chronic cytotoxicities of the complexes are considered. Furthermore, cell apoptosis experiments are used to briefly study the mechanism. Because studies involving multi-target inhibition towards topoisomerase and telomerase of Ru(II) complexes have not been reported previously, the present research may help to develop innovative chemical strategies and therapies.

Förster resonance energy transfer studies of luminescent gold nanoparticles functionalized with ruthenium(II) and rhenium(I) complexes: modulation via esterase hydrolysis.

PubMed

Leung, Frankie Chi-Ming; Tam, Anthony Yiu-Yan; Au, Vonika Ka-Man; Li, Mei-Jin; Yam, Vivian Wing-Wah

2014-05-14

A number of ruthenium(II) and rhenium(I) bipyridine complexes functionalized with lipoic acid moieties have been synthesized and characterized. Functionalization of gold nanoparticles with these chromophoric ruthenium(II) and rhenium(I) complexes has resulted in interesting supramolecular assemblies with Förster resonance energy transfer (FRET) properties that could be modulated via esterase hydrolysis. The luminescence of the metal complex chromophores was turned on upon cleavage of the ester bond linkage by esterase to reduce the efficiency of FRET quenching. The prepared nanoassembly conjugates have been characterized by transmission electron microscopy (TEM), energy-dispersive X-ray analysis (EDX), Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), UV-visible spectroscopy, and emission spectroscopy. The quenching mechanism has also been studied by transient absorption and time-resolved emission decay measurements. The FRET efficiencies were found to vary with the nature of the chromophores and the length of the spacer between the donor (transition metal complexes) and the acceptor (gold nanoparticles).

Separation and characterization of metallosupramolecular libraries by ion mobility mass spectrometry.

PubMed

Li, Xiaopeng; Chan, Yi-Tsu; Casiano-Maldonado, Madalis; Yu, Jing; Carri, Gustavo A; Newkome, George R; Wesdemiotis, Chrys

2011-09-01

The self-assembly of Zn(II) ions and bis(terpyridine) (tpy) ligands carrying 120° or 180° angles between their metal binding sites was utilized to prepare metallosupramolecular libraries with the connectivity. These combinatorial libraries were separated and characterized by ion mobility mass spectrometry (IM MS) and tandem mass spectrometry (MS(2)). The 180°-angle building blocks generate exclusively linear complexes, which were used as standards to determine the architectures of the assemblies resulting from the 120°-angle ligands. The latter ligand geometry promotes the formation of macrocyclic hexamers, but other n-mers with smaller (n = 5) or larger ring sizes (n = 7-9) were identified as minor products, indicating that the angles in the bis(terpyridine) ligand and within the coordinative tpy-Zn(II)-tpy bonds are not as rigid, as previously believed. Macrocyclic and linear isomers were detected in penta- and heptameric assemblies; in the larger octa- and nonameric assemblies, ring-opened conformers with compact and folded geometries were observed in addition to linear extended and cyclic architectures. IM MS(2) experiments provided strong evidence that the macrocycles present in the libraries were already formed in solution, during the self-assembly process, not by dissociation of larger complexes in the gas phase. The IM MS/MS(2) methods provide a means to analyze, based on size and shape (architecture), supramolecular libraries that are not amenable to liquid chromatography, LC-MS, NMR, and/or X-ray techniques.

Concomitant and conformational polymorphism in 4‧-(isoquinolyl-2,2‧:6‧,2″-terpyridine and 4‧-(4-quinolyl)-2,2‧:6‧,2″-terpyridine

NASA Astrophysics Data System (ADS)

Njogu, Eric M.; Nyamori, Vincent O.; Omondi, Bernard

2018-02-01

The occurrence of concomitant polymorphism in 4‧-(isoquinolyl)-2,2‧:6‧,2″-terpyridine, 1a and 1b (2-quinterpy) and conformational polymorphism in 4‧-(4-quinolyl)-2,2‧:6‧,2″-terpyridine (4-quinterpy) has been identified to due to crystallization process and solvent, respectively. Crystallization of 2-quinterpy in acetone yielded the concomitant polymorphs 1a and 1b which crystallize in the monoclinic P21/c and the orthorhombic Pna21 space groups, respectively. The polymorph 2a was grown from bulk 4-quinterpy in dimethyl sulfoxide, crystallizes in the monoclinic P21/c space group, while 2b grown from acetonitrile or even acetone crystallizes in the monoclinic system but in P21/n space group.

Masking of Lewis acidity trends in the solid-state structures of trichlorido- and tribromido(2,2':6',2''-terpyridine-κ(3)N,N',N'')gallium(III).

PubMed

Kazakov, Igor V; Bodensteiner, Michael; Timoshkin, Alexey Y

2014-03-01

The molecular structures of trichlorido(2,2':6',2''-terpyridine-κ(3)N,N',N'')gallium(III), [GaCl3(C15H11N3)], and tribromido(2,2':6',2''-terpyridine-κ(3)N,N',N'')gallium(III), [GaBr3(C15H11N3)], are isostructural, with the Ga(III) atom displaying an octahedral geometry. It is shown that the Ga-N distances in the two complexes are the same within experimental error, in contrast to expected bond lengthening in the bromide complex due to the lower Lewis acidity of GaBr3. Thus, masking of the Lewis acidity trends in the solid state is observed not only for complexes of group 13 metal halides with monodentate ligands but for complexes with the polydentate 2,2':6',2''-terpyridine donor as well.

Synthesis, characterization, redox behavior, DNA and protein binding and antibacterial activity studies of ruthenium(II) complexes of bidentate schiff bases.

PubMed

Paul, Hena; Sen, Buddhadeb; Mondal, Tapan Kumar; Chattopadhyay, Pabitra

2017-08-03

Two new ruthenium(II) complexes of Schiff base ligands (L) derived from cinnamaldehyde and ethylenediamine formulated as [Ru(L)(bpy) 2 ](ClO 4 ) 2 , where L 1 = N,N'-bis(4-nitrocinnamald-ehyde)ethylenediamine and L 2 = N,N'-bis(2-nitrocinnamaldehyde)-ethylenediamine for complex 1 and 2, respectively, were isolated in pure form. The complexes were characterized by physicochemical and spectroscopic methods. The electrochemical behavior of the complexes showed the Ru(III)/Ru(II) couple at different potentials with quasi-reversible voltammograms. The interaction of the complexes with calf thymus DNA (CT-DNA) using absorption, emission spectral studies and electrochemical techniques have been used to determine the binding constant, K b and the linear Stern-Volmer quenching constant, K SV . The results indicate that the ruthenium(II) complexes interact with CT-DNA strongly in a groove binding mode. The interactions of bovine serum albumin (BSA) with the complexes were also investigated with the help of absorption and fluorescence spectroscopy tools. Absorption spectroscopy proved the formation of a ground state BSA-[Ru(L)(bpy) 2 ](ClO 4 ) 2 complex. The antibacterial study showed that the Ru(II) complexes (1 and 2) have better activity than the standard antibiotics but weak activity than the ligands.

Mitochondria are the primary target in the induction of apoptosis by chiral ruthenium(II) polypyridyl complexes in cancer cells.

PubMed

Wang, Jin-Quan; Zhang, Ping-Yu; Qian, Chen; Hou, Xiao-Juan; Ji, Liang-Nian; Chao, Hui

2014-03-01

A series of novel chiral ruthenium(II) polypyridyl complexes (Δ-Ru1, Λ-Ru1, Δ-Ru2, Λ-Ru2, Δ-Ru3, Λ-Ru3) were synthesized and evaluated to determine their antiproliferative activities. Colocalization, inductively coupled plasma mass spectrometry, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay studies showed that these ruthenium(II) complexes accumulated preferentially in the mitochondria and exhibited cytotoxicity against various cancer cells in vitro. The complex Δ-Ru1 is of particular interest because it was found to have half-maximal inhibitory concentrations comparable to those of cisplatin and better activity than cisplatin against a cisplatin-resistant cell line, A549-CP/R. Δ-Ru1 induced alterations in the mitochondrial membrane potential and triggered intrinsic mitochondria-mediated apoptosis in HeLa cells, which involved the regulation of Bcl-2 family members and the activation of caspases. Taken together, these data suggest that Δ-Ru1 may be a novel mitochondria-targeting anticancer agent.

Strategic design of a ruthenium catalyst for both CO2 reduction and H2O oxidation: the electronic influence of the co-ligands.

PubMed

Das, Biswanath; Ezzedinloo, Lida; Bhadbhade, Mohan; Bucknall, Martin P; Colbran, Stephen B

2017-09-05

A new ruthenium(ii) complex capable of catalysing both CO 2 reduction and water oxidation was designed and synthesised. The electro-catalytic efficiency and robustness of the complex together with the electronic effect of its co-ligands were investigated to develop next generation dual activity electrocatalysts.

Ru-bis(pyridine)pyrazolate (bpp)-Based Water-Oxidation Catalysts Anchored on TiO2: The Importance of the Nature and Position of the Anchoring Group.

PubMed

Francàs, Laia; Richmond, Craig; Garrido-Barros, Pablo; Planas, Nora; Roeser, Stephan; Benet-Buchholz, Jordi; Escriche, Lluís; Sala, Xavier; Llobet, Antoni

2016-04-04

Three distinct functionalisation strategies have been applied to the in,in-[{Ru(II)(trpy)}2(μ-bpp)(H2O)2](3+) (trpy=2,2':6',2''-terpyridine, bpp=bis(pyridine)pyrazolate) water-oxidation catalyst framework to form new derivatives that can adsorb onto titania substrates. Modifications included the addition of sulfonate, carboxylate, and phosphonate anchoring groups to the terpyridine and bis(pyridyl)pyrazolate ligands. The complexes were characterised in solution by using 1D NMR, 2D NMR, and UV/Vis spectroscopic analysis and electrochemical techniques. The complexes were then anchored on TiO2-coated fluorinated tin oxide (FTO) films, and the reactivity of these new materials as water-oxidation catalysts was tested electrochemically through controlled-potential electrolysis (CPE) with oxygen evolution detected by headspace analysis with a Clark electrode. The results obtained highlight the importance of the catalyst orientation with respect to the titania surface in regard to its capacity to catalytically oxidize water to dioxygen. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

Duan, Lele; Manbeck, Gerald F.; Kowalczyk, Marta

Ruthenium complexes with proton-responsive ligands [Ru(tpy)(nDHBP)(NCCH 3)](CF 3SO 3) 2 (tpy = 2,2':6',2"-terpyridine; nDHBP = n,n'-dihydroxy-2,2'-bipyridine, n = 4 or 6) were examined in this study for reductive chemistry and as catalysts for CO 2 reduction. Electrochemical reduction of [Ru(tpy)(nDHBP)(NCCH 3)] 2+ generates deprotonated species through interligand electron transfer in which the initially formed tpy radical anion reacts with a proton source to produce singly and doubly deprotonated complexes that are identical to those obtained by base titration. A third reduction (i.e., reduction of [Ru(tpy)(nDHBP–2H +)] 0) triggers catalysis of CO 2 reduction; however, the catalytic efficiency is strikingly lowermore » than that of unsubstituted [Ru(tpy)(bpy)(NCCH 3)] 2+ (bpy = 2,2'-bipyridine). Cyclic voltammetry, bulk electrolysis, and spectroelectrochemical infrared experiments suggest the reactivity of CO 2 at both the Ru center and the deprotonated quinone-type ligand. Lastly, the Ru carbonyl formed by the intermediacy of a metallocarboxylic acid is stable against reduction, and mass spectrometry analysis of this product indicates the presence of two carbonates formed by the reaction of DHBP–2H + with CO 2.« less

γ-Sultam-cored N,N-ligands in the ruthenium(ii)-catalyzed asymmetric transfer hydrogenation of aryl ketones.

PubMed

Rast, Slavko; Modec, Barbara; Stephan, Michel; Mohar, Barbara

2016-02-14

The synthesis of new enantiopure syn- and anti-3-(α-aminobenzyl)-benzo-γ-sultam ligands 6 and their application in the ruthenium(ii)-catalyzed asymmetric transfer hydrogenation (ATH) of ketones using formic acid/triethylamine is described. In particular, benzo-fused cyclic ketones afforded excellent enantioselectivities in reasonable time employing a low loading of the syn ligand-containing catalyst. A never-before-seen dynamic kinetic resolution (DKR) during reduction of a γ-keto carboxylic ester (S7) derivative of 1-indanone is realized leading as well to excellent induction.

Spectroelectrochemical studies of hole percolation on functionalised nanocrystalline TiO2 films: a comparison of two different ruthenium complexes.

PubMed

Li, Xiaoe; Nazeeruddin, Mohammad K; Thelakkat, Mukundan; Barnes, Piers R F; Vilar, Ramón; Durrant, James R

2011-01-28

We report the application of spectroelectrochemical techniques to compare the hole percolation dynamics of molecular networks of two ruthenium bipyridyl complexes adsorbed onto mesoporous, nanocrystalline TiO(2) films. The percolation dynamics of the ruthenium complex cis-di(thiocyanato)(2,2'-bipyridyl-4,4'-dicarboxylic acid)-(2,2'-bipyridyl-4,4'-tridecyl) ruthenium(II), N621, is compared with those observed for an analogous dye with an additional tri-phenyl amine (TPA) donor moiety, cis-di(thiocyanato)(2,2'-bipyridyl-4,4'-dicarboxylic acid)-(2,2'-bipyridyl-4,4'-bis(vinyltriphenylamine)) ruthenium(II), HW456. The in situ oxidation of these ruthenium complexes adsorbed to the TiO(2) films is monitored by cyclic voltammetry and voltabsorptometry, whilst the dynamics of hole (cation) percolation between adsorbed ruthenium complexes is monitored by potentiometric spectroelectrochemistry and chronoabsorptometry. The hole diffusion coefficient, D(eff), is shown to be dependent on the dye loading on the nanocrystalline TiO(2) film, with a threshold observed at ∼60% monolayer surface coverage for both dyes. The hole diffusion coefficient of HW456 is estimated to be 2.6 × 10(-8) cm(2)/s, 20-fold higher than that obtained for the control N621, attributed to stronger electronic coupling between the TPA moieties of HW456 accelerating the hole percolation dynamics. The presence of mercuric ions, previously shown to bind to the thiocyanates of analogous ruthenium complexes, resulted in a quenching of the hole percolation for N621/TiO(2) films and an enhancement for HW456/TiO(2) films. These results strongly suggest that the hole percolation pathway is along the overlapped neighbouring -NCS groups for the N621 molecules, whereas in HW456 molecules cation percolation proceeds between intermolecular TPA ligands. These results are discussed in the context of their relevance to the process of dye regeneration in dye sensitised solar cells, and to the molecular wiring of wide bandgap inorganic materials for battery and sensing applications.

Multicolor Luminescence from Conjugates of Genetically Encoded Elastin-like Polymers and Terpyridine-Lanthanides

DOE PAGES

Ghosh, Koushik; Balog, Eva Rose M.; Kahn, Jennifer L.; ...

2015-08-20

Functional hybrid materials with optically active metal-ligand moieties embedded within a polymer matrix have a great potential in (bio)materials science, including applications in light-emitting diode devices. Here, we report a simple strategy to incorporate terpyridine derivatives into the side chains of elastin-like polymers (ELPs). The further binding of trivalent lanthanide ions with the terpyridine ligands generated an array of photoluminescence ranging from the visible to the near-infrared regions. Lastly, as thin films, these ELP-based optical materials also exhibited distinct morphologies that depend upon the temperature of the aqueous solutions from which the hybrid polymers were spin coated or drop cast.

The thermodynamic effects of ligand structure on the molecular recognition of mononuclear ruthenium polypyridyl complexes with B-DNA

USDA-ARS?s Scientific Manuscript database

The ruthenium(II) polypyridyl complexes (RPCs), [(phen)2Ru(tatpp)]Cl2 (3Cl2) and [(phen)2Ru (tatpp)Ru(phen)2]Cl4 (4Cl4), containing the large planar and redox-active tetraazatetrapyrido- pentacene (tatpp) ligand, cleave DNA in the presence of reducing agents in cell-free assays and show significant...

Carboxylate-assisted ruthenium-catalyzed alkyne annulations by C-H/Het-H bond functionalizations.

PubMed

Ackermann, Lutz

2014-02-18

To improve the atom- and step-economy of organic syntheses, researchers would like to capitalize upon the chemistry of otherwise inert carbon-hydrogen (C-H) bonds. During the past decade, remarkable progress in organometallic chemistry has set the stage for the development of increasingly viable metal catalysts for C-H bond activation reactions. Among these methods, oxidative C-H bond functionalizations are particularly attractive because they avoid the use of prefunctionalized starting materials. For example, oxidative annulations that involve sequential C-H and heteroatom-H bond cleavages allow for the modular assembly of regioselectively decorated heterocycles. These structures serve as key scaffolds for natural products, functional materials, crop protecting agents, and drugs. While other researchers have devised rhodium or palladium complexes for oxidative alkyne annulations, my laboratory has focused on the application of significantly less expensive, yet highly selective ruthenium complexes. This Account summarizes the evolution of versatile ruthenium(II) complexes for annulations of alkynes via C-H/N-H, C-H/O-H, or C-H/N-O bond cleavages. To achieve selective C-H bond functionalizations, we needed to understand the detailed mechanism of the crucial C-H bond metalation with ruthenium(II) complexes and particularly the importance of carboxylate assistance in this process. As a consequence, our recent efforts have resulted in widely applicable methods for the versatile preparation of differently decorated arenes and heteroarenes, providing access to among others isoquinolones, 2-pyridones, isoquinolines, indoles, pyrroles, or α-pyrones. Most of these reactions used Cu(OAc)2·H2O, which not only acted as the oxidant but also served as the essential source of acetate for the carboxylate-assisted ruthenation manifold. Notably, the ruthenium(II)-catalyzed oxidative annulations also occurred under an ambient atmosphere of air with cocatalytic amounts of Cu(OAc)2·H2O. Moreover, substrates displaying N-O bonds served as "internal oxidants" for the syntheses of isoquinolones and isoquinolines. Detailed experimental mechanistic studies have provided strong support for a catalytic cycle that relies on initial carboxylate-assisted C-H bond ruthenation, followed by coordinative insertion of the alkyne, reductive elimination, and reoxidation of the thus formed ruthenium(0) complex.

Intervalence transfer of ferrocene moieties adsorbed on electrode surfaces by a conjugated linkage

NASA Astrophysics Data System (ADS)

Chen, Wei; Brown, Lauren E.; Konopelski, Joseph P.; Chen, Shaowei

2009-03-01

Effective intervalence transfer occurred between the metal centers of ferrocene moieties that were adsorbed onto a ruthenium thin film surface by ruthenium-carbene π bonds, a direct verification of Hush's four-decade-old prediction. Electrochemical measurements showed two pairs of voltammetric peaks where the separation of the formal potentials suggested a Class II behavior. Additionally, the potential spacing increased with increasing ferrocene surface coverage, most probably as a consequence of the enhanced contribution from through-space electronic interactions between the metal centers. In contrast, the incorporation of a sp 3 carbon spacer into the ferrocene-ruthenium linkage led to the diminishment of interfacial electronic communication.

Electrooxidative Ruthenium-Catalyzed C-H/O-H Annulation by Weak O-Coordination.

PubMed

Qiu, Youai; Tian, Cong; Massignan, Leonardo; Rogge, Torben; Ackermann, Lutz

2018-05-14

Electrocatalysis has been identified as a powerful strategy for organometallic catalysis, and yet electrocatalytic C-H activation is restricted to strongly N-coordinating directing groups. The first example of electrocatalytic C-H activation by weak O-coordination is presented, in which a versatile ruthenium(II) carboxylate catalyst enables electrooxidative C-H/O-H functionalization for alkyne annulations in the absence of metal oxidants; thereby exploiting sustainable electricity as the sole oxidant. Mechanistic insights provide strong support for a facile organometallic C-H ruthenation and an effective electrochemical reoxidation of the key ruthenium(0) intermediate. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Pentamethylcyclopentadienyl-ruthenium catalysts for regio- and enantioselective allylation of nucleophiles.

PubMed

Bruneau, Christian; Renaud, Jean-Luc; Demerseman, Bernard

2006-07-05

Ruthenium(II) complexes containing the pentamethylcyclopentadienyl ligand efficiently perform the activation of allylic carbonates and halides to generate cationic and dicationic ruthenium(IV) complexes. This activation has been transferred as a key step to the catalytic allylation of nucleophiles. The structural and electronic properties of the allylic moieties lead to the regioselective formation of chiral products resulting from nucleophilic addition to their most substituted terminus. The catalytic activity of various Ru(Cp*) precatalysts in several allylic substitutions by C and O nucleophiles will be presented. The enantioselective version that has been demonstrated by using optically pure bisoxazoline ligands will also be discussed.

Reactivity of nitrido complexes of ruthenium(VI), osmium(VI), and manganese(V) bearing Schiff base and simple anionic ligands.

PubMed

Man, Wai-Lun; Lam, William W Y; Lau, Tai-Chu

2014-02-18

Nitrido complexes (M≡N) may be key intermediates in chemical and biological nitrogen fixation and serve as useful reagents for nitrogenation of organic compounds. Osmium(VI) nitrido complexes bearing 2,2':6',2″-terpyridine (terpy), 2,2'-bipyridine (bpy), or hydrotris(1-pyrazolyl)borate anion (Tp) ligands are highly electrophilic: they can react with a variety of nucleophiles to generate novel osmium(IV)/(V) complexes. This Account describes our recent results studying the reactivity of nitridocomplexes of ruthenium(VI), osmium(VI), and manganese(V) that bear Schiff bases and other simple anionic ligands. We demonstrate that these nitrido complexes exhibit rich chemical reactivity. They react with various nucleophiles, activate C-H bonds, undergo N···N coupling, catalyze the oxidation of organic compounds, and show anticancer activities. Ruthenium(VI) nitrido complexes bearing Schiff base ligands, such as [Ru(VI)(N)(salchda)(CH3OH)](+) (salchda = N,N'-bis(salicylidene)o-cyclohexyldiamine dianion), are highly electrophilic. This complex reacts readily at ambient conditions with a variety of nucleophiles at rates that are much faster than similar reactions using Os(VI)≡N. This complex also carries out unique reactions, including the direct aziridination of alkenes, C-H bond activation of alkanes and C-N bond cleavage of anilines. The addition of ligands such as pyridine can enhance the reactivity of [Ru(VI)(N)(salchda)(CH3OH)](+). Therefore researchers can tune the reactivity of Ru≡N by adding a ligand L trans to nitride: L-Ru≡N. Moreover, the addition of various nucleophiles (Nu) to Ru(VI)≡N initially generate the ruthenium(IV) imido species Ru(IV)-N(Nu), a new class of hydrogen-atom transfer (HAT) reagents. Nucleophiles also readily add to coordinated Schiff base ligands in Os(VI)≡N and Ru(VI)≡N complexes. These additions are often stereospecific, suggesting that the nitrido ligand has a directing effect on the incoming nucleophile. M≡N is also a potential platform for the design of new oxidation catalysts. For example, [Os(VI)(N)Cl4](-) catalyzes the oxidation of alkanes by a variety of oxidants, and the addition of Lewis acids greatly accelerates these reactions. [Mn(V)(N)(CN)4]2(-) is another highly efficient oxidation catalyst, which facilitates the epoxidation of alkenes and the oxidation of alcohols to carbonyl compounds using H2O2. Finally, M≡N can potentially bind to and exert various effects on biomolecules. For example, a number of Os(VI)≡N complexes exhibit novel anticancer properties, which may be related to their ability to bind to DNA or other biomolecules.

Structure-reactivity relationships in the hydrogenation of carbon dioxide with ruthenium complexes bearing pyridinylazolato ligands.

PubMed

Muller, Keven; Sun, Yu; Heimermann, Andreas; Menges, Fabian; Niedner-Schatteburg, Gereon; van Wüllen, Christoph; Thiel, Werner R

2013-06-10

Pyridinylazolato (N-N') ruthenium(II) complexes of the type [(N-N')RuCl(PMe3)3] have been obtained in high yields by treating the corresponding functionalised azolylpyridines with [RuCl2 (PMe3)4] in the presence of a base. (15)N NMR spectroscopy was used to elucidate the electronic influence of the substituents attached to the azolyl ring. The findings are in agreement with slight differences in the bond lengths of the ruthenium complexes. Furthermore, the electronic nature of the azolate moiety modulates the catalytic activity of the ruthenium complexes in the hydrogenation of carbon dioxide under supercritical conditions and in the transfer hydrogenation of acetophenone. DFT calculations were performed to shed light on the mechanism of the hydrogenation of carbon dioxide and to clarify the impact of the electronic nature of the pyridinylazolate ligands. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A ruthenium(II) complex as turn-on Cu(II) luminescent sensor based on oxidative cyclization mechanism and its application in vivo

NASA Astrophysics Data System (ADS)

Zhang, Yunfei; Liu, Zonglun; Yang, Kui; Zhang, Yi; Xu, Yongqian; Li, Hongjuan; Wang, Chaoxia; Lu, Aiping; Sun, Shiguo

2015-02-01

Copper ions play a vital role in a variety of fundamental physiological processes not only in human beings and plants, but also for extensive insects and microorganisms. In this paper, a novel water-soluble ruthenium(II) complex as a turn-on copper(II) ions luminescent sensor based on o-(phenylazo)aniline was designed and synthesized. The azo group would undergo a specific oxidative cyclization reaction with copper(II) ions and turn into high luminescent benzotriazole, triggering significant luminescent increasements which were linear to the concentrations of copper(II) ions. The sensor distinguished by its high sensitivity (over 80-fold luminescent switch-on response), good selectivity (the changes of the emission intensity in the presence of other metal ions or amino acids were negligible) and low detection limit (4.42 nM) in water. Moreover, the copper(II) luminescent sensor exhibited good photostability under light irradiation. Furthermore, the applicability of the proposed sensor in biological samples assay was also studied and imaged copper(II) ions in living pea aphids successfully.

A DFT-D study on the electronic and photophysical properties of ruthenium (II) complex with a chelating sulfoxide group

NASA Astrophysics Data System (ADS)

Li, Huifang; Zhang, Lisheng; Lin, Hui; Fan, Xiaolin

2014-06-01

Electronic and photophysical properties of [Ru(bpy)2(OSO)]+ (bpy = 2,2‧-bipyridine; OSO = methylsulfinylbenzoate) were examined theoretically to better understand the differences between S- and O-linked ruthenium sulfoxide complexes. It is found that the strength of Ru-O1 linkage is significantly larger than that of Ru-S linkage, which makes the charge transfer amount from surrounding ligands to central Ru decreased. The energy gap is closed due to the highest occupied molecular orbital energy increases to a larger extent than the lowest unoccupied molecular orbital energy. Thereby, red shifted absorption and emission maxima in such photochromic ruthenium sulfoxide complexes can be explained.

Ruthenium(II)-Catalyzed C-H Activation of Imidamides and Divergent Couplings with Diazo Compounds: Substrate-Controlled Synthesis of Indoles and 3H-Indoles.

PubMed

Li, Yunyun; Qi, Zisong; Wang, He; Yang, Xifa; Li, Xingwei

2016-09-19

Indoles are an important structural motif that is commonly found in biologically active molecules. In this work, conditions for divergent couplings between imidamides and acceptor-acceptor diazo compounds were developed that afforded NH indoles and 3H-indoles under ruthenium catalysis. The coupling of α-diazoketoesters afforded NH indoles by cleavage of the C(N2 )-C(acyl) bond whereas α-diazomalonates gave 3H-indoles by C-N bond cleavage. This reaction constitutes the first intermolecular coupling of diazo substrates with arenes by ruthenium-catalyzed C-H activation. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Formic acid acting as an efficient oxygen scavenger in four-electron reduction of oxygen catalyzed by a heterodinuclear iridium-ruthenium complex in water.

PubMed

Fukuzumi, Shunichi; Kobayashi, Takeshi; Suenobu, Tomoyoshi

2010-09-01

A heterodinuclear iridium-ruthenium complex [Ir(III)(Cp*)(H(2)O)(bpm)Ru(II)(bpy)(2)](SO(4))(2) (Cp* = eta(5)-pentamethyl-cyclopentadienyl, bpm = 2,2'-bipyrimidine, bpy = 2,2'-bipyridine) acts as an effective catalyst for removal of dissolved O(2) by the four-electron reduction of O(2) with formic acid in water at an ambient temperature.

Steric and Electronic Effects of Bidentate Phosphine Ligands on Ruthenium(II)-Catalyzed Hydrogenation of Carbon Dioxide.

PubMed

Zhang, Pan; Ni, Shao-Fei; Dang, Li

2016-09-20

The reactivity difference between the hydrogenation of CO2 catalyzed by various ruthenium bidentate phosphine complexes was explored by DFT. In addition to the ligand dmpe (Me2 PCH2 CH2 PMe2 ), which was studied experimentally previously, a more bulky diphosphine ligand, dmpp (Me2 PCH2 CH2 CH2 PMe2 ), together with a more electron-withdrawing diphosphine ligand, PN(Me) P (Me2 PCH2 N(Me) CH2 PMe2 ), have been studied theoretically to analyze the steric and electronic effects on these catalyzed reactions. Results show that all of the most favorable pathways for the hydrogenation of CO2 catalyzed by bidentate phosphine ruthenium dihydride complexes undergo three major steps: cis-trans isomerization of ruthenium dihydride complex, CO2 insertion into the Ru-H bond, and H2 insertion into the ruthenium formate ion. Of these steps, CO2 insertion into the Ru-H bond has the lowest barrier compared with the other two steps in each preferred pathway. For the hydrogenation of CO2 catalyzed by ruthenium complexes of dmpe and dmpp, cis-trans isomerization of ruthenium dihydride complex has a similar barrier to that of H2 insertion into the ruthenium formate ion. However, in the reaction catalyzed by the PN(Me) PRu complex, cis-trans isomerization of the ruthenium dihydride complex has a lower barrier than H2 insertion into the ruthenium formate ion. These results suggest that the steric effect caused by the change of the outer sphere of the diphosphine ligand on the reaction is not clear, although the electronic effect is significant to cis-trans isomerization and H2 insertion. This finding refreshes understanding of the mechanism and provides necessary insights for ligand design in transition-metal-catalyzed CO2 transformation. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Reaction of tris(bipyridine)ruthenium(III) with hydroxide and its application in a solar energy storage system

PubMed Central

Creutz, Carol; Sutin, Norman

1975-01-01

Irradiation of Ru(bipy)32+ (bipy = 2,2′-bipyridine) with light below 560 nm results in the formation of a charge-transfer excited state potentially capable of reducing water to dihydrogen with concomitant production of Ru(bipy)33+. The latter may be reduced by hydroxide [Formula: see text] to form dioxygen and regenerate the starting complex. The use of these reactions in a cell designed to bring about the photochemical decomposition of water is proposed. The stoichiometry, kinetics, and mechanism of the Ru(bipy)33+-hydroxide reaction have been investigated by conventional and stopped-flow spectrophotometry. The dioxygen yield is a sharp function of pH, attaining its maximum value (about 80%) at pH 9. At low pH (3 and 4.8) the production of ruthenium(II) is first order with kobsd = (1.41 ± 0.04) × 10-4 sec-1 (25°, ionic strength μ = 1.00 M with sodium sulfate). In the intermediate pH range (7.9-10.0) complex kinetics are observed. In the hydroxide range 0.01-0.50 M, ruthenium(II) production is predominantly first order with kobsd = ka[OH-] + kb[OH-]2 sec-1; ka = 148 M-1 sec-1 and kb = 138 M-2 sec-1 (25°, μ = 1.00 M, sodium sulfate). For the ka term, the activation parameters are ΔH‡ = 15.3 ± 1.0 kcal mol-1 and ΔS‡ = 7 ± 3 cal deg-1 mol-1 (1 cal = 4.184 J). An intermediate species (λmax 800 nm) forms at the same rate as ruthenium(II) in this hydroxide range. It disappears with kobsd = 1.2 + 1.1 × 102 [OH-] sec-1 at 25°. Similarly absorbing (λmax 750 to 800 nm) species are generated by the addition of hydroxyl radical to M(bipy)32+/3+ [M = Fe(II), Os(II), Ru(II), Cr(III), Ru(III)] in pulse radiolysis experiments. The kinetics above pH 7 are described in terms of rate-determining nucleophilic attack by hydroxide on the bound bipyridine ring. The hydroxide adduct so generated is tentatively identified with that observed in the pulse radiolysis experiments with Ru(bipy)32+. For reduction of Ru(bipy)33+ by hydrogen peroxide ruthenium(II) production is first order with kobsd = kc[HO2-] + kd[H2O2] where kc = 5.4 × 107 M-1 sec-1 and kd = 8.3 M-1 sec-1 (25°, μ = 1.00 M, pH 3.5 to 9.7). This reaction produces dioxygen in 83 ± 15% yield at pH 6.8 and in 1.0 N sulfuric acid. PMID:16592265

Half a grid is better than no grid: competition between 2,2':6',2''-terpyridine and 3,6-di(pyrid-2-yl)pyridazine for copper(II).

PubMed

Constable, Edwin C; Decurtins, Silvio; Housecroft, Catherine E; Keene, Tony D; Palivan, Cornelia G; Price, Jason R; Zampese, Jennifer A

2010-03-07

The reaction between Cu(NO(3))(2).3H(2)O, 2,2':6',2''-terpyridine (tpy) and 3,6-di(pyrid-2-yl)pyridazine (1) in a 2 : 2 : 1 molar equivalent ratio in aqueous MeCN in the presence of excess NH(4)PF(6) leads to competition between the assembly of the dinuclear half-grid [Cu(2)(1)(tpy)(2)][PF(6)](4).2H(2)O and the mononuclear complex [Cu(1)(2)(OH(2))][PF(6)](2). The yield of [Cu(2)(1)(tpy)(2)][PF(6)](4).2H(2)O has been optimized using microwave conditions. [Cu(1)(2)(OH(2))][PF(6)](2) can be selectively produced by treating Cu(NO(3))(2).3H(2)O with 1 (1 : 2 molar equivalents) in aqueous MeCN in the presence of NH(4)PF(6). The single crystal structures of [Cu(2)(1)(tpy)(2)][PF(6)](4).4MeNO(2) and [Cu(1)(2)(OH(2))][PF(6)](2) are presented. In the [Cu(2)(1)(tpy)(2)](4+) cation, ligand 1 bridges the two copper(II) centres, each of which is further coordinated by a tpy ligand. The copper(II) coordination geometry is closely associated with the arrangement of the two tpy ligands which engage in efficient face-to-face pi-stacking. Magnetic data for crystalline [Cu(2)(1)(tpy)(2)][PF(6)](4).4MeNO(2) are consistent with a weak antiferromagnetic interaction between the two copper(II) centres. EPR spectroscopic data for a powder sample of [Cu(2)(1)(tpy)(2)][PF(6)](4).2H(2)O are consistent with the dinuclear structure, but in frozen DMF and DMSO solutions, the data indicate that the dinuclear structure of [Cu(2)(1)(tpy)(2)](4+) is not preserved.

Cytotoxic hydrogen bridged ruthenium quinaldamide complexes showing induced cancer cell death by apoptosis.

PubMed

Lord, Rianne M; Allison, Simon J; Rafferty, Karen; Ghandhi, Laura; Pask, Christopher M; McGowan, Patrick C

2016-08-16

This report presents the first known p-cymene ruthenium quinaldamide complexes which are stabilised by a hydrogen-bridging atom, [{(p-cym)Ru(II)X(N,N)}{H(+)}{(N,N)XRu(II)(p-cym)}][PF6] (N,N = functionalised quinaldamide and X = Cl or Br). These complexes are formed by a reaction of [p-cymRu(μ-X)2]2 with a functionalised quinaldamide ligand. When filtered over NH4PF6, and under aerobic conditions the equilibrium of NH4PF6 ⇔ NH3 + HPF6 enables incorporation of HPF6 and the stabilisation of two monomeric ruthenium complexes by a bridging H(+), which are counter-balanced by a PF6 counterion. X-ray crystallographic analysis is presented for six new structures with OO distances of 2.420(4)-2.448(15) Å, which is significant for strong hydrogen bonds. Chemosensitivity studies against HCT116, A2780 and cisplatin-resistant A2780cis human cancer cells showed the ruthenium complexes with a bromide ancillary ligand to be more potent than those with a chloride ligand. The 4'-fluoro compounds show a reduction in potency for both chloride and bromide complexes against all cell lines, but an increase in selectivity towards cancer cells compared to non-cancer ARPE-19 cells, with a selectivity index >1. Mechanistic studies showed a clear correlation between IC50 values and induction of cell death by apoptosis.

Pharmacophore Modelling and 4D-QSAR Study of Ruthenium(II) Arene Complexes as Anticancer Agents (Inhibitors) by Electron Conformational- Genetic Algorithm Method.

PubMed

Yavuz, Sevtap Caglar; Sabanci, Nazmiye; Saripinar, Emin

2018-01-01

The EC-GA method was employed in this study as a 4D-QSAR method, for the identification of the pharmacophore (Pha) of ruthenium(II) arene complex derivatives and quantitative prediction of activity. The arrangement of the computed geometric and electronic parameters for atoms and bonds of each compound occurring in a matrix is known as the electron-conformational matrix of congruity (ECMC). It contains the data from HF/3-21G level calculations. Compounds were represented by a group of conformers for each compound rather than a single conformation, known as fourth dimension to generate the model. ECMCs were compared within a certain range of tolerance values by using the EMRE program and the responsible pharmacophore group for ruthenium(II) arene complex derivatives was found. For selecting the sub-parameter which had the most effect on activity in the series and the calculation of theoretical activity values, the non-linear least square method and genetic algorithm which are included in the EMRE program were used. In addition, compounds were classified as the training and test set and the accuracy of the models was tested by cross-validation statistically. The model for training and test sets attained by the optimum 10 parameters gave highly satisfactory results with R2 training= 0.817, q 2=0.718 and SEtraining=0.066, q2 ext1 = 0.867, q2 ext2 = 0.849, q2 ext3 =0.895, ccctr = 0.895, ccctest = 0.930 and cccall = 0.905. Since there is no 4D-QSAR research on metal based organic complexes in the literature, this study is original and gives a powerful tool to the design of novel and selective ruthenium(II) arene complexes. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

New ruthenium carboxylate complexes having a 1-5-. eta. sup 5 -cyclooctadienyl ligand

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

Osakada, Kohtaro; Grohmann, A.; Yamamoto, Akio

1990-07-01

Reaction of 3-butenoic acid with Ru(cod)(cot) (cod) = 1-2-{eta}{sup 2}:5-6-{eta}{sup 2}-cyclooctadiene; cot = 1-6-{eta}{sup 6}-cyclooctatriene in the presence of PMe{sub 3} gives a new ruthenium(II) complex formulated as Ru(1-5-{eta}{sup 5}-C{sub 8}H{sub 11}){eta}{sup 1}(O),{eta}{sup 2}(C,C{prime}-OCOCH{sub 2}CH{double bond}CH{sub 2})(PMe{sub 3}) (1). X-ray crystallography revealed its structure as having a piano-stool coordination around the ruthenium center. Crystals of 1 are tetragonal, space group P4{sub 3}2{sub 1}2, with a = 12.559 (3) {angstrom}, c = 20.455 (4) {angstrom}, and Z = 8. {sup 1}H and {sup 13}C({sup 1}H) NMR spectra of 1 agree well for the structure with the allyl entity of the carboxylatemore » {pi}-bonded through the C{double bond}C double bond to ruthenium.« less

4,2':6',4"- and 3,2':6',3"-Terpyridines: The Conflict between Well-Defined Vectorial Properties and Serendipity in the Assembly of 1D-, 2D- and 3D-Architectures.

PubMed

Klein, Y Maximilian; Prescimone, Alessandro; Constable, Edwin C; Housecroft, Catherine E

2017-06-30

A comparative investigation of the coordination assemblies formed between Co(NCS)₂ and two monotopic 4,2':6',4''-terpyridine (4,2':6',4"-tpy) ligands or two related ditopic ligands is reported. Crystals were grown by layering MeOH solutions of Co(NCS)₂ over a CHCl₃ or 1,2-C₆H₄Cl₂ solution of the respective ligand at room temperature. With 4'-(2-methylpyrimidin-5-yl)-4,2':6',4"-terpyridine ( 6 ), the 1D-coordination polymer {[Co₂(NCS)₄(MeOH)₄( 6 )₂]∙2MeOH∙8H₂O} n assembles with 6 coordinating only through the outer N-donors of the 4,2':6',4"-tpy unit; coordination by the MeOH solvent blocks two cobalt coordination sites preventing propagation in a higher-dimensional network. A combination of Co(NCS)₂ and 1-(4,2':6',4"-terpyridin-4'-yl)ferrocene ( 7 ) leads to {[Co(NCS)₂( 7 )₂]∙4CHCl₃} n which contains a (4,4) net; the 2D-sheets associate through π-stacking interactions between ferrocenyl and pyridyl units. A 3D-framework is achieved through use of the ditopic ligand 1,4-bis( n propoxy)-2,5-bis(4,2':6',4"-terpyridin-4'-yl)benzene ( 8 ) which acts as a 4-connecting node in {[Co(NCS)₂( 8 )₂] . 2C₆H₄Cl₂} n ; the combination of metal and ligand planar 4-connecting nodes results in a {6⁵.8} cds net. For a comparison with the coordinating abilities of the previously reported 1,4-bis( n octoxy)-2,5-bis(4,2':6',4"-terpyridin-4'-yl)benzene ( 3 ), a more flexible analogue 9 was prepared. {[Co(NCS)₂( 9 )]∙2CHCl₃} n contains a (4,4) net defined by both metal and ligand planar 4-connecting nodes. The n octoxy tails of 9 protrude from each side of the (4,4) net and thread through adjacent sheets; the arene-attached n octoxy chains associate through a combination of van der Waals and C-H...π interactions.

Hydrothermal syntheses, crystal structures and luminescence properties of zinc(II) and cadmium(II) coordination polymers based on bifunctional 3,2 Prime :6 Prime ,3 Prime Prime -terpyridine-4 Prime -carboxylic acid

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

Li, Na; Guo, Hui-Lin; Hu, Huai-Ming, E-mail: ChemHu1@NWU.EDU.CN

2013-02-15

Five new coordination polymers, [Zn{sub 2}(ctpy){sub 2}Cl{sub 2}]{sub n} (1), [Zn{sub 2}(ctpy){sub 2}(ox)(H{sub 2}O){sub 2}]{sub n} (2), [Zn{sub 2}(ctpy)(3-btc)(H{sub 2}O)]{sub n}{center_dot}0.5nH{sub 2}O (3), [Cd(ctpy){sub 2}(H{sub 2}O)]{sub n} (4), [Cd{sub 4}(ctpy){sub 2}(2-btc){sub 2}(H{sub 2}O){sub 2}]{sub n}{center_dot}2nH{sub 2}O (5), (Hctpy=3,2 Prime :6 Prime ,3 Prime Prime -terpyridine-4 Prime -carboxylic acid, H{sub 2}ox=oxalic acid, H{sub 3}(3-btc)=1,3,5-benzenetricarboxylic acid, H{sub 3}(2-btc)=1,2,4-benzenetricarboxylic acid) have been synthesized under hydrothermal conditions and characterized by elemental analysis, IR spectroscopy, and single-crystal X-ray diffraction. Compounds 1-2 are a one-dimensional chain with weak interactions to form 3D supramolecular structures. Compound 3 is a 4-nodal 3D topology framework comprised of binuclear zincmore » units and (ctpy){sup -} anions. Compound 4 shows two dimensional net. Compound 5 is a (4,5,6)-connected framework with {l_brace}4{sup 4}{center_dot}6{sup 2}{r_brace}{l_brace}4{sup 6}{center_dot}6{sup 4}{r_brace}{sub 2}{l_brace}4{sup 9}{center_dot}6{sup 6}{r_brace} topology. In addition, the thermal stabilities and photoluminescence properties of 1-5 were also studied in the solid state. - Graphical abstract: Five new Zn/Cd compounds with 3,2 Prime :6 Prime ,3 Prime Prime -terpyridine-4 Prime -carboxylic acid were prepared. The photoluminescence and thermal stabilities properties of 1-5 were investigated in the solid state. Highlights: Black-Right-Pointing-Pointer Five new zinc/cadmium metal-organic frameworks have been hydrothermal synthesized. Black-Right-Pointing-Pointer The structural variation is attributed to the diverse metal ions and auxiliary ligand. Black-Right-Pointing-Pointer Compounds 1-5 exhibit 1D ring chain, 2D layer and 3D open-framework, respectively. Black-Right-Pointing-Pointer These compounds exhibit strong solid state luminescence emission at room temperature.« less

Luminescence Quenching of the Tris(2,2’-bipyrazine) Ruthenium(II) Cation, and Its Monoprotonated Complex.

DTIC Science & Technology

1984-01-01

10 ROA ENT. POCT ASK B.E REPMNGORNTIDOCUMEANDTDR RATIO PAGE UNI UES Yorkhniverity Chemistr Deparment . CNT OL IN OFaIC NAMEtle AND TYPE 2. REPORT &TE0...Alternatively, in view of the high negative charge on the quencher and high positive charge on the excited ruthenium species, some kind of exciplex may be...Southampton S09 5NH White Oak Laboratory United Kingdom Silver Spring, Maryland 20910 Dr. T. Katan Dr. Sam Perone Lockheed Missiles and Chemistry

Unusual mode of protein binding by a cytotoxic π-arene ruthenium(ii) piano-stool compound containing an O,S-chelating ligand.

PubMed

Hildebrandt, Jana; Görls, Helmar; Häfner, Norman; Ferraro, Giarita; Dürst, Matthias; Runnebaum, Ingo B; Weigand, Wolfgang; Merlino, Antonello

2016-08-02

A new pseudo-octahedral π-arene ruthenium(ii) piano-stool compound, containing an O,S-bidentate ligand (compound 1) and showing significant cytotoxic activity in vitro, was synthesized and characterized. In solution stability and interaction with the model protein bovine pancreatic ribonuclease (RNase A) were investigated by using UV-Vis absorption spectroscopy. Its crystal structure and that of the adduct formed upon reaction with RNase A were obtained by X-ray crystallography. The comparison between the structure of purified compound 1 and that of the fragment bound to RNase A reveals an unusual mode of protein binding that includes ligand exchange and alteration of coordination sphere geometry.

A multi-target caffeine derived rhodium(i) N-heterocyclic carbene complex: evaluation of the mechanism of action.

PubMed

Zhang, Jing-Jing; Muenzner, Julienne K; Abu El Maaty, Mohamed A; Karge, Bianka; Schobert, Rainer; Wölfl, Stefan; Ott, Ingo

2016-08-16

A rhodium(i) and a ruthenium(ii) complex with a caffeine derived N-heterocyclic carbene (NHC) ligand were biologically investigated as organometallic conjugates consisting of a metal center and a naturally occurring moiety. While the ruthenium(ii) complex was largely inactive, the rhodium(i) NHC complex displayed selective cytotoxicity and significant anti-metastatic and in vivo anti-vascular activities and acted as both a mammalian and an E. coli thioredoxin reductase inhibitor. In HCT-116 cells it increased the reactive oxygen species level, leading to DNA damage, and it induced cell cycle arrest, decreased the mitochondrial membrane potential, and triggered apoptosis. This rhodium(i) NHC derivative thus represents a multi-target compound with promising anti-cancer potential.

Photophysical investigaions and the bioimaings of α-, β-, γ-pyridine-based terpyridine derivatives

NASA Astrophysics Data System (ADS)

Zhang, Jun; Wang, Hui

2018-04-01

Three unprecedented triphenylamine-based D-A type terpyridine derivatives (TriphenL1-TriphenL3) with different positions of nitrogen atom in the terpyridine moiety were carefully designed and fully characterized, which was further confirmed via single-crystal X-ray diffraction determination. The photophysical properties of all the three compounds were comprehensively studied by both theoretical calculations and experimental techniques, which revealed that TriphenL3 with γ-pyridine in the NIR region possessed large two-photon absorption cross-section. Experiments including photophysical tests and cytotoxicity demonstrated these dyes were characterized with larger Stokes shifts, longer fluorescence lifetime, low toxicity and good cell penetrability, thus TriphenL1-TriphenL3 were succeed to be devoted as cell stains, suggesting a prospect for applications of in vitro and vivo cellular imaging.

Hydrogenation of imines catalysed by ruthenium(II) complexes based on lutidine-derived CNC pincer ligands.

PubMed

Hernández-Juárez, Martín; Vaquero, Mónica; Álvarez, Eleuterio; Salazar, Verónica; Suárez, Andrés

2013-01-14

The preparation of new Ru(II) complexes incorporating fac-coordinated lutidine-derived CNC ligands is reported. These derivatives are selectively deprotonated by (t)BuOK at one of the methylene arms of the pincer, leading to catalytically active species in the hydrogenation of imines.

Electrogenerated chemiluminescence of tris(2,2' bipyridine)ruthenium(II) using common biological buffers as co-reactant, pH buffer and supporting electrolyte.

PubMed

Kebede, Noah; Francis, Paul S; Barbante, Gregory J; Hogan, Conor F

2015-11-07

A series of aliphatic tertiary amines (HEPES, POPSO, EPPS and BIS-TRIS) commonly used to buffer the pH in biological experiments, were examined as alternative, non-toxic co-reactants for the electrogenerated chemiluminescence (ECL) of tris(2,2'-bipyridine)ruthenium(ii) ([Ru(bpy)3](2+)). These were found to be very attractive as "multi-tasking" reagents, serving not only as co-reactants, but also fulfiling the roles of pH buffer and supporting electrolyte within an aqueous environment; thus significantly simplifying the overall ECL analysis. Sub-nanomolar detection limits were obtained for [Ru(bpy)3](2+) in the presence of BIS-TRIS, making this species an valuable option for co-reactant ECL-based bioanalytical applications.

Precise ruthenium fission product isotopic analysis using dynamic reaction cell inductively coupled plasma mass spectrometry (DRC-ICP-MS)

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

Brown, Christopher F.; Dresel, P. Evan; Geiszler, Keith N.

2006-05-09

99Tc is a subsurface contaminant of interest at numerous federal, industrial, and international facilities. However, as a mono-isotopic fission product, 99Tc lacks the ability to be used as a signature to differentiate between the different waste disposal pathways that could have contributed to subsurface contamination at these facilities. Ruthenium fission-product isotopes are attractive analogues for the characterization of 99Tc sources because of their direct similarity to technetium with regard to subsurface mobility, and their large fission yields and low natural background concentrations. We developed an inductively coupled plasma mass spectrometry (ICP-MS) method capable of measuring ruthenium isotopes in groundwater samplesmore » and extracts of vadose zone sediments. Samples were analyzed directly on a Perkin Elmer ELAN DRC II ICP-MS after a single pass through a 1-ml bed volume of Dowex AG 50W-X8 100-200 mesh cation exchange resin. Precise ruthenium isotopic ratio measurements were achieved using a low-flow Meinhard-type nebulizer and long sample acquisition times (150,000 ms). Relative standard deviations of triplicate replicates were maintained at less than 0.5% when the total ruthenium solution concentration was 0.1 ng/ml or higher. Further work was performed to minimize the impact caused by mass interferences using the dynamic reaction cell (DRC) with O2 as the reaction gas. The aqueous concentrations of 96Mo and 96Zr were reduced by more than 99.7% in the reaction cell prior to injection of the sample into the mass analyzer quadrupole. The DRC was used in combination with stable-mass correction to quantitatively analyze samples containing up to 2-orders of magnitude more zirconium and molybdenum than ruthenium. The analytical approach documented herein provides an efficient and cost-effective way to precisely measure ruthenium isotopes and quantitate total ruthenium (natural vs. fission-product) in aqueous matrixes.« less

A Smart Europium-Ruthenium Complex as Anticancer Prodrug: Controllable Drug Release and Real-Time Monitoring under Different Light Excitations.

PubMed

Li, Hongguang; Xie, Chen; Lan, Rongfeng; Zha, Shuai; Chan, Chi-Fai; Wong, Wing-Yan; Ho, Ka-Lok; Chan, Brandon Dow; Luo, Yuxia; Zhang, Jing-Xiang; Law, Ga-Lai; Tai, William C S; Bünzli, Jean-Claude G; Wong, Ka-Leung

2017-11-09

A unique, dual-function, photoactivatable anticancer prodrug, RuEuL, has been tailored that features a ruthenium(II) complex linked to a cyclen-europium chelate via a π-conjugated bridge. Under irradiation at 488 nm, the dark-inactive prodrug undergoes photodissociation, releasing the DNA-damaging ruthenium species. Under evaluation-window irradiation (λ irr = one-photon 350 nm or two-photon 700 nm), the drug delivery process can be quantitatively monitored in real-time because of the long-lived red europium emission. Linear relationships between released drug concentration and ESI-MS or luminescence responses are established. Finally, the efficiency of the new prodrug is demonstrated both in vitro RuEuL anticancer prodrug over some existing ones and open the way for decisive improvements in multipurpose prodrugs.

Probing the interaction of bisintercalating (2,2':6',2″-terpyridine)platinum(II) complexes with glutathione and rabbit plasma.

PubMed

Harper, Benjamin W J; Morris, Thomas T; Gailer, Jürgen; Aldrich-Wright, Janice R

2016-10-01

Platinum(II) complexes have demonstrated considerable success in the treatment of cancer, but severe toxic side effects drive the search for new complexes with increased tumour selectivity and better efficacy. A critical concept that has to be considered in the context of designing novel Pt complexes is their interactions with biomolecules other than DNA. To this end, here the interactions of 16 previously reported bisintercalating (2,2':6',2″-terpyridine)platinum(II) complexes, [{Pt(terpy)} 2 μ-(X)] n+ (where X is a linker) with glutathione (GSH) by means of 1 H and 195 Pt NMR spectroscopy were investigated. The GSH half-life (GSH t 1/2 ) was determined following the incubation of each [{Pt(terpy)} 2 μ-(X)] n+ complex with GSH (8mM). It was observed that complexes 1-7, 11, 12 and 14-16 reacted more rapidly than cisplatin, whereas complexes 8-10, 13 and 17 reacted more slowly (≥200min). There was no apparent correlation between linker length and the GSH t 1/2 . In order to understand these interactions, two complexes: 1 (t 1/2 <1min) and a previously studied 17 [Pt(5,6-dimethyl-1,10-phenanthroline)(1S,2S-diaminocyclohexane)] (56MESS) (GSH t 1/2 =4080min) were incubated with rabbit plasma. A "metallomics" approach was used to analyse plasma for all platinum species at the 5 and the 60min time point and provided results that were congruent with the reaction of the selected Pt complexes with GSH. Our studies demonstrate that the combined application of NMR spectroscopy, cytotoxicity studies and a metallomics approach can contribute to better understand the interaction of [{Pt(terpy)} 2 μ-(X)] n+ complexes with biomolecules to better assess which compounds may be advanced to in vivo studies. Copyright © 2016 Elsevier Inc. All rights reserved.

Binding of Pentaammineruthenium(II) Residues to the Tris(bipyrazine)ruthenium(II) Cation.

DTIC Science & Technology

1987-08-01

de Quimica , Universidade de Sao Paulo, CP 20780, Sao Paulo, SP, Brazil and Department of Chemistry, York University, North York, Ontario, Canada M3J...absorption spectra in the near-infrared region were obtained with a Cary 1 7 spectrophotometer, with the samples dissolved in D20. Nuclear magnetic

Reduced Graphene Oxide-Immobilized Tris(bipyridine)ruthenium(II) Complex for Efficient Visible-Light-Driven Reductive Dehalogenation Reaction.

PubMed

Li, Xiaoyan; Hao, Zhongkai; Zhang, Fang; Li, Hexing

2016-05-18

A sodium benzenesulfonate (PhSO3Na)-functionalized reduced graphene oxide was synthesized via a two-step aryl diazonium coupling and subsequent NaCl ion-exchange procedure, which was used as a support to immobilize tris(bipyridine)ruthenium(II) complex (Ru(bpy)3Cl2) by coordination reaction. This elaborated Ru(bpy)3-rGO catalyst exhibited excellent catalytic efficiency in visible-light-driven reductive dehalogenation reactions under mild conditions, even for ary chloride. Meanwhile, it showed the comparable reactivity with the corresponding homogeneous Ru(bpy)3Cl2 catalyst. This high catalytic performance could be attributed to the unique two-dimensional sheet-like structure of Ru(bpy)3-rGO, which efficiently diminished diffusion resistance of the reactants. Meanwhile, the nonconjugated PhSO3Na-linkage between Ru(II) complex and the support and the very low electrical conductivity of the catalyst inhibited energy/electron transfer from Ru(II) complex to rGO support, resulting in the decreased support-induced quenching effect. Furthermore, it could be easily recycled at least five times without significant loss of catalytic reactivity.

Formation of vinyl halides via a ruthenium-catalyzed three-component coupling.

PubMed

Trost, Barry M; Pinkerton, Anthony B

2002-06-26

The ruthenium-catalyzed three-component coupling of an alkyne, an enone, and halide ion to form E- or Z-vinyl halides has been investigated. Through systematic optimization experiments, the conditions effecting the olefin selectivity were examined. In general, more polar solvents such as DMF favored the formation of the E-isomer, and less polar solvents such as acetone favored formation of the Z-isomer. The optimized conditions for the formation of E-vinyl chlorides were found to be the use of cyclopentadienyl ruthenium (II) cyclooctadiene chloride, stannic chloride pentahydrate as a cocatalyst, and for a chloride source, either ammonium chloride in DMF/water mixtures or tetramethylammonium chloride in DMF. A range of several other ruthenium (II) catalysts was also shown to be effective. A wide variety of vinyl chlorides could be formed under these conditions. Substrates with tethered alcohols or ketones either five or six carbons from the alkyne portion gave instead diketone or cyclohexenone products. For formation of vinyl bromides, a catalyst system involving the use of cyclopentadienylruthenium (II) tris(acetonitrile) hexafluorophosphate with stannic bromide as a cocatalyst was found to be most effective. The use of ammonium bromide in DMF/acetone mixtures was optimal for the synthesis of E-vinyl bromides, and the use of lithium bromide in acetone was optimal for formation of the corresponding Z-isomer. Under either set of conditions, a wide range of vinyl bromides could be formed. When alkynes with propargylic substituents are used, enhanced selectivity for formation of the Z-isomer is observed. When aryl acetylenes are used as the coupling partners, complete selectivity for the Z-isomer is obtained. A mechanism involving a cis or trans halometalation is invoked to explain formation of the observed products. The vinyl halides have been shown to be precursors to alpha-hydroxy ketones and cyclopentenones, and as coupling partners in Suzuki-type reactions.

Terpyridine complexes of first row transition metals and electrochemical reduction of CO₂ to CO.

PubMed

Elgrishi, Noémie; Chambers, Matthew B; Artero, Vincent; Fontecave, Marc

2014-07-21

Homoleptic terpyridine complexes of first row transition metals are evaluated as catalysts for the electrocatalytic reduction of CO2. Ni and Co-based catalytic systems are shown to reduce CO2 to CO under the conditions tested. The Ni complex was found to exhibit selectivity for CO2 over proton reduction while the Co-based system generates mixtures of CO and H2 with CO : H2 ratios being tuneable through variation of the applied potential.

Noninnocent Proton-Responsive Ligand Facilitates Reductive Deprotonation and Hinders CO 2 Reduction Catalysis in [Ru(tpy)(6DHBP)(NCCH 3 )] 2+ (6DHBP = 6,6'-(OH) 2 bpy)

DOE PAGES

Duan, Lele; Manbeck, Gerald F.; Kowalczyk, Marta; ...

2016-04-14

Ruthenium complexes with proton-responsive ligands [Ru(tpy)(nDHBP)(NCCH 3)](CF 3SO 3) 2 (tpy = 2,2':6',2"-terpyridine; nDHBP = n,n'-dihydroxy-2,2'-bipyridine, n = 4 or 6) were examined in this study for reductive chemistry and as catalysts for CO 2 reduction. Electrochemical reduction of [Ru(tpy)(nDHBP)(NCCH 3)] 2+ generates deprotonated species through interligand electron transfer in which the initially formed tpy radical anion reacts with a proton source to produce singly and doubly deprotonated complexes that are identical to those obtained by base titration. A third reduction (i.e., reduction of [Ru(tpy)(nDHBP–2H +)] 0) triggers catalysis of CO 2 reduction; however, the catalytic efficiency is strikingly lowermore » than that of unsubstituted [Ru(tpy)(bpy)(NCCH 3)] 2+ (bpy = 2,2'-bipyridine). Cyclic voltammetry, bulk electrolysis, and spectroelectrochemical infrared experiments suggest the reactivity of CO 2 at both the Ru center and the deprotonated quinone-type ligand. Lastly, the Ru carbonyl formed by the intermediacy of a metallocarboxylic acid is stable against reduction, and mass spectrometry analysis of this product indicates the presence of two carbonates formed by the reaction of DHBP–2H + with CO 2.« less

Peroxydisulfate activation by [RuII(tpy)(pic)(H2O)]+. Kinetic, mechanistic and anti-microbial activity studies.

PubMed

Chatterjee, Debabrata; Banerjee, Priyabrata; Bose, Jagadeesh C K; Mukhopadhyay, Sudit

2012-03-07

The oxidation of [Ru(II)(tpy)(pic)H(2)O](+) (tpy = 2,2',6',2''-terpyridine; pic(-) = picolinate) by peroxidisulfate (S(2)O(8)(2-)) as precursor oxidant has been investigated kinetically by UV-VIS, IR and EPR spectroscopy. The overall oxidation of Ru(II)- to Ru(IV)-species takes place in a consecutive manner involving oxidation of [Ru(II)(tpy)(pic)H(2)O](+) to [Ru(III)(tpy)(pic)(OH)](+), and its further oxidation of to the ultimate product [Ru(IV)(tpy)(pic)(O)](+) complex. The time course of the reaction was followed as a function of [S(2)O(8)(2-)], ionic strength (I) and temperature. Kinetic data and activation parameters are interpreted in terms of an outer-sphere electron transfer mechanism. Anti-microbial activity of Ru(II)(tpy)(pic)H(2)O](+) complex by inhibiting the growth of Escherichia coli DH5α in presence of peroxydisulfate has been explored, and the results of the biological studies have been discussed in terms of the [Ru(IV)(tpy)(pic)(O)](+) mediated cleavage of chromosomal DNA of the bacteria.

Anti-Leishmania activity of new ruthenium(II) complexes: Effect on parasite-host interaction.

PubMed

Costa, Mônica S; Gonçalves, Yasmim G; Nunes, Débora C O; Napolitano, Danielle R; Maia, Pedro I S; Rodrigues, Renata S; Rodrigues, Veridiana M; Von Poelhsitz, Gustavo; Yoneyama, Kelly A G

2017-10-01

Leishmaniasis is a parasitic disease caused by protozoa of the genus Leishmania. The many complications presented by the current treatment - including high toxicity, high cost and parasite resistance - make the development of new therapeutic agents indispensable. The present study aims to evaluate the anti-Leishmania potential of new ruthenium(II) complexes, cis‑[Ru II (η 2 -O 2 CR)(dppm) 2 ]PF 6 , with dppm=bis(diphenylphosphino)methane and R=4-butylbenzoate (bbato) 1, 4-(methylthio)benzoate (mtbato) 2 and 3-hydroxy-4-methoxybenzoate (hmxbato) 3, in promastigote cytotoxicity and their effect on parasite-host interaction. The cytotoxicity of complexes was analyzed by MTT assay against Leishmania (Leishmania) amazonensis, Leishmania (Viannia) braziliensis, Leishmania (Leishmania) infantum promastigotes and the murine macrophage (RAW 264.7). The effect of complexes on parasite-host interaction was evaluated by in vitro infectivity assay performed in the presence of two different concentrations of each complex: the promastigote IC 50 value and the concentration nontoxic to 90% of RAW 264.7 macrophages. Complexes 1-3 exhibited potent cytotoxic activity against all Leishmania species assayed. The IC 50 values ranged from 7.52-12.59μM (complex 1); 0.70-3.28μM (complex 2) and 0.52-1.75μM (complex 3). All complexes significantly inhibited the infectivity index at both tested concentrations. The infectivity inhibitions ranged from 37 to 85%. Interestingly, the infectivity inhibitions due to complex action did not differ significantly at either of the tested concentrations, except for the complex 1 against Leishmania (Leishmania) infantum. The infectivity inhibitions resulted from reductions in both percentage of infected macrophages and number of parasites per macrophage. Taken together the results suggest remarkable leishmanicidal activity in vitro by these new ruthenium(II) complexes. Copyright © 2017 Elsevier Inc. All rights reserved.

Remote fluorescence imaging of dynamic concentration profiles with micrometer resolution using a coherent optical fiber bundle.

PubMed

Amatore, Christian; Chovin, Arnaud; Garrigue, Patrick; Servant, Laurent; Sojic, Neso; Szunerits, Sabine; Thouin, Laurent

2004-12-15

Dynamic concentration profiles within the diffusion layer of an electrode were imaged in situ using fluorescence detection through a multichannel imaging fiber. In this work, a coherent optical fiber bundle is positioned orthogonal to the surface of an electrode and is used to report spatial and temporal micrometric changes in the fluorescence intensity of an initial fluorescent species. The fluorescence signal is directly related to the local concentration of a redox fluorescent reagent, which is electrochemically modulated by the electrode. Fluorescence images are collected through the optical fiber bundle during the oxidation of tris(2,2'-bipyridine)ruthenium(II) to ruthenium(III) at a diffusion-limited rate and allow the concentration profiles of Ru(II) reagent to be monitored in situ as a function of time. Tris(2,2'-bipyridine)ruthenium(II) is excited at 485 nm and emits fluorescence at 605 nm, whereas the Ru(III) oxidation state is not fluorescent. Our experiments emphasize the influence of two parameters on the micrometer spatial resolution: the numerical aperture of optical fibers within the bundle and the Ru(II) bulk concentration. The extent of the volume probed by each individual fiber of the bundle is discussed qualitatively in terms of a primary inner-filter effect and refractive index gradient. Experimentally measured fluorescence intensity profiles were found to be in very good agreement with concentration profiles predicted upon considering planar diffusion and thus validate the concept of this new application of imaging fibers. The originality of this remote approach is to provide a global view of the entire diffusion layer at a given time through one single image and to allow the time expansion of the diffusion layer to be followed quantitatively in real time.

Versatile synthesis of cationic N-heterocyclic carbene-gold(i) complexes containing a second ancillary ligand. Design of heterobimetallic ruthenium-gold anticancer agents.

PubMed

Fernández-Gallardo, Jacob; Elie, Benelita T; Sanaú, Mercedes; Contel, María

2016-02-21

We describe a versatile and quick route to cationic gold(i) complexes containing N-heterocyclic carbenes and a second ancillary ligand (such as phosphanes, phosphites, arsines and amines) of interest for the synthesis of compounds with potential catalytic and medicinal applications. The general synthetic strategy has been applied in the preparation of novel cationic heterobimetallic ruthenium(ii)-gold(i) complexes that are highly cytotoxic to renal cancer Caki-1 and colon cancer HCT 116 cell lines while showing a synergistic effect and being more selective than their monometallic counterparts.

Reaction mechanism of Ru(II) piano-stool complexes: umbrella sampling QM/MM MD study.

PubMed

Futera, Zdeněk; Burda, Jaroslav V

2014-07-15

Biologically relevant interactions of piano-stool ruthenium(II) complexes with ds-DNA are studied in this article by hybrid quantum mechanics-molecular mechanics (QM/MM) computational technique. The whole reaction mechanism is divided into three phases: (i) hydration of the [Ru(II) (η(6) -benzene)(en)Cl](+) complex, (ii) monoadduct formation between the resulting aqua-Ru(II) complex and N7 position of one of the guanines in the ds-DNA oligomer, and (iii) formation of the intrastrand Ru(II) bridge (cross-link) between two adjacent guanines. Free energy profiles of all the reactions are explored by QM/MM MD umbrella sampling approach where the Ru(II) complex and two guanines represent a quantum core, which is described by density functional theory methods. The combined QM/MM scheme is realized by our own software, which was developed to couple several quantum chemical programs (in this study Gaussian 09) and Amber 11 package. Calculated free energy barriers of the both ruthenium hydration and Ru(II)-N7(G) DNA binding process are in good agreement with experimentally measured rate constants. Then, this method was used to study the possibility of cross-link formation. One feasible pathway leading to Ru(II) guanine-guanine cross-link with synchronous releasing of the benzene ligand is predicted. The cross-linking is an exergonic process with the energy barrier lower than for the monoadduct reaction of Ru(II) complex with ds-DNA. Copyright © 2014 Wiley Periodicals, Inc.

New ruthenium(II) carbonyl complexes bearing disulfide Schiff base ligands and their applications as catalyst for some organic transformations

NASA Astrophysics Data System (ADS)

Prakash, Govindan; Viswanathamurthi, Periasamy

2014-08-01

Schiff base disulfide ligands (H2L1-6) were synthesized from the condensation of cystamine with salicylaldehyde(H2L1), 5-chlorosalicylaldehyde(H2L2), o-vanillin(H2L3), 2-hydroxyacetophenone(H2L4), 3-methyl-2-hydroxyacetophenone(H2L5), and 2-hydroxy-1-naphthaldehyde(H2L6). H2L1-6 reacts with the ruthenium precursor complex [RuHCl(CO)(PPh3)3] in benzene giving rise to six new ruthenium(II) complexes of general formula [Ru(CO)L1-6]. Characterization of the new complexes was carried out by using elemental and spectral (IR, UV-Vis, NMR (1H and 13C) and Mass) techniques. An octahedral geometry was assigned for all the complexes based on the spectral data obtained. The catalytic efficiency of the new complexes in aldehyde to amide conversion in the presence of NaHCO3, N-alkylation of aniline in the presence of t-BuOK, and transfer hydrogenation of ketones in the presence of iPrOH/KOH reactions were studied. Furthermore, the effect of solvents and catalyst/substrate ratio on the catalytic aldehyde to amide conversion were also discussed.

New ruthenium(II) carbonyl complexes bearing disulfide Schiff base ligands and their applications as catalyst for some organic transformations.

PubMed

Prakash, Govindan; Viswanathamurthi, Periasamy

2014-08-14

Schiff base disulfide ligands (H2L(1-6)) were synthesized from the condensation of cystamine with salicylaldehyde(H2L(1)), 5-chlorosalicylaldehyde(H2L(2)), o-vanillin(H2L(3)), 2-hydroxyacetophenone(H2L(4)), 3-methyl-2-hydroxyacetophenone(H2L(5)), and 2-hydroxy-1-naphthaldehyde(H2L(6)). H2L(1-6) reacts with the ruthenium precursor complex [RuHCl(CO)(PPh3)3] in benzene giving rise to six new ruthenium(II) complexes of general formula [Ru(CO)L(1-6)]. Characterization of the new complexes was carried out by using elemental and spectral (IR, UV-Vis, NMR ((1)H and (13)C) and Mass) techniques. An octahedral geometry was assigned for all the complexes based on the spectral data obtained. The catalytic efficiency of the new complexes in aldehyde to amide conversion in the presence of NaHCO3, N-alkylation of aniline in the presence of t-BuOK, and transfer hydrogenation of ketones in the presence of iPrOH/KOH reactions were studied. Furthermore, the effect of solvents and catalyst/substrate ratio on the catalytic aldehyde to amide conversion were also discussed. Copyright © 2014 Elsevier B.V. All rights reserved.

4,2’:6’,4”- and 3,2’:6’,3”-Terpyridines: The Conflict between Well-Defined Vectorial Properties and Serendipity in the Assembly of 1D-, 2D- and 3D-Architectures

PubMed Central

Klein, Y. Maximilian; Prescimone, Alessandro; Constable, Edwin C.

2017-01-01

A comparative investigation of the coordination assemblies formed between Co(NCS)2 and two monotopic 4,2’:6’,4’’-terpyridine (4,2’:6’,4”-tpy) ligands or two related ditopic ligands is reported. Crystals were grown by layering MeOH solutions of Co(NCS)2 over a CHCl3 or 1,2-C6H4Cl2 solution of the respective ligand at room temperature. With 4’-(2-methylpyrimidin-5-yl)-4,2’:6’,4”-terpyridine (6), the 1D-coordination polymer {[Co2(NCS)4(MeOH)4(6)2]∙2MeOH∙8H2O}n assembles with 6 coordinating only through the outer N-donors of the 4,2’:6’,4”-tpy unit; coordination by the MeOH solvent blocks two cobalt coordination sites preventing propagation in a higher-dimensional network. A combination of Co(NCS)2 and 1-(4,2‘:6’,4”-terpyridin-4’-yl)ferrocene (7) leads to {[Co(NCS)2(7)2]∙4CHCl3}n which contains a (4,4) net; the 2D-sheets associate through π-stacking interactions between ferrocenyl and pyridyl units. A 3D-framework is achieved through use of the ditopic ligand 1,4-bis(npropoxy)-2,5-bis(4,2’:6’,4”-terpyridin-4’-yl)benzene (8) which acts as a 4-connecting node in {[Co(NCS)2(8)2]∙2C6H4Cl2}n; the combination of metal and ligand planar 4-connecting nodes results in a {65.8} cds net. For a comparison with the coordinating abilities of the previously reported 1,4-bis(noctoxy)-2,5-bis(4,2’:6’,4”-terpyridin-4’-yl)benzene (3), a more flexible analogue 9 was prepared. {[Co(NCS)2(9)]∙2CHCl3}n contains a (4,4) net defined by both metal and ligand planar 4-connecting nodes. The noctoxy tails of 9 protrude from each side of the (4,4) net and thread through adjacent sheets; the arene-attached noctoxy chains associate through a combination of van der Waals and C–H...π interactions. PMID:28773088

Bis(dipyridophenazine)(2-(2'-pyridyl)pyrimidine-4-carboxylic acid)ruthenium(II) hexafluorophosphate: a lesson in stubbornness.

PubMed

Joshi, Tanmaya; Pierroz, Vanessa; Ferrari, Stefano; Gasser, Gilles

2014-07-01

Ruthenium complexes are currently considered to be among the most promising alternatives to platinum anticancer drugs. In this work, thirteen structural analogues and organelle/receptor-targeting peptide bioconjugates of a cytotoxic bis(dppz)-Ru(II) complex [Ru(dppz)2 (CppH)](PF6 )2 (1) were prepared, characterized, and assessed for their cytotoxicity and cellular localization (CppH=2-(2'-pyridyl)pyrimidine-4-carboxylic acid; dppz=dipyrido[3,2-a:2',3'-c]phenazine). It was observed that structural modifications (lipophilicity, charge, and size-based) result in the cytotoxic potency of 1 being compromised. Confocal microscopy studies revealed that unlike 1, the screened complexes/bioconjugates do not have a preferential accumulation in mitochondria. The results of this important structure-activity relationship strongly support our initial hypothesis that accumulation in mitochondria is crucial for 1 to exert its cytotoxic action. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ultrafast relaxation dynamics of amine-substituted bipyridyl ruthenium(II) complexes

NASA Astrophysics Data System (ADS)

Song, Hongwei; Wang, Xian; Yang, WenWen; He, Guiying; Kuang, Zhuoran; Li, Yang; Xia, Andong; Zhong, Yu-Wu; Kong, Fan'ao

2017-09-01

The excited state properties of a series of ruthenium(II) amine-substituted bipyridyl complexes, [Ru(bpy)n(NNbpy)3-n]2+, were investigated by steady-state and transient absorption spectroscopy, as well as quantum chemical calculations. The steady-state absorption spectra of these complexes in CH3CN show a distinct red-shift of the 1MLCT absorption with increasing numbers of amine substituent, whereas the emission spectra indicate an energy gap order of [Ru(bpy)3]2+ > [Ru(bpy)2(NNbpy)]2+ > [Ru(NNbpy)3]2+ > [Ru(bpy)(NNbpy)2]2+. Nanosecond, femtosecond transient absorption and electrochemical measurements suggest that NNbpy ligand has a strong influence on the electronic and emission properties of these complexes, due to electron-rich amine substituent. We illustrate how the numbers of amine substituent modulate the spectroscopic properties of transition metal complexes, which is related to the design of new electro-active systems with novel photoelectrochemical properties.

The synthesis, lipophilicity and cytotoxic effects of new ruthenium(II) arene complexes with chromone derivatives.

PubMed

Pastuszko, Adam; Majchrzak, Kinga; Czyz, Malgorzata; Kupcewicz, Bogumiła; Budzisz, Elzbieta

2016-06-01

A series of arene ruthenium(II) complexes with the general formula [(η(6)-arene)Ru(L)X2] (where arene=p-cymene, benzene, hexamethylbenzene or mesitylene, L=aminoflavone or aminochromone derivatives and X=Cl, I) were synthesized and characterized by elemental analysis, MS, IR and (1)H NMR spectroscopy. The stability of the selected complexes was assessed by UV-Vis spectroscopy in 24-hour period. The lipophilicity of the synthesized complexes was determined by the shake-flask method, and their cytotoxicity evaluated in vitro on patient-derived melanoma populations. The most active complexes against melanoma cells contain 7-aminoflavone and 6-aminoflavone as a ligand. The relationship between the cytotoxicity of all the obtained compounds and their logP values was determined and briefly analyzed with two different patterns observed. Copyright © 2016 Elsevier Inc. All rights reserved.

Lipophilicity Assessment of Ruthenium(II)-Arene Complexes by the Means of Reversed-Phase Thin-Layer Chromatography and DFT Calculations

PubMed Central

Shweshein, Khalil Salem A. M.; Andrić, Filip; Radoičić, Aleksandra; Gruden-Pavlović, Maja; Tešić, Živoslav; Milojković-Opsenica, Dušanka

2014-01-01

The lipophilicity of ten ruthenium(II)-arene complexes was assessed by reversed-phase thin-layer chromatography (RP-TLC) on octadecyl silica stationary phase. The binary solvent systems composed of water and acetonitrile were used as mobile phase in order to determine chromatographic descriptors for lipophilicity estimation. Octanol-water partition coefficient, logK OW, of tested complexes was experimentally determined using twenty-eight standard solutes which were analyzed under the same chromatographic conditions as target substances. In addition, ab initio density functional theory (DFT) computational approach was employed to calculate logK OW values from the differences in Gibbs' free solvation energies of the solute transfer from n-octanol to water. A good overall agreement between DFT calculated and experimentally determined logK OW values was established (R 2 = 0.8024–0.9658). PMID:24587761

Mono and binuclear ruthenium(II) complexes containing 5-chlorothiophene-2-carboxylic acid ligands: Spectroscopic analysis and computational studies

NASA Astrophysics Data System (ADS)

Swarnalatha, Kalaiyar; Kamalesu, Subramaniam; Subramanian, Ramasamy

2016-11-01

New Ruthenium complexes I, II and III were synthesized using 5-chlorothiophene-2-carboxylic acid (5TPC), as ligand and the complexes were characterized by elemental analysis, FT-IR, 1H, 13C NMR, and mass spectroscopic techniques. Photophysical and electrochemical studies were carried out and the structures of the synthesized complex were optimized using density functional theory (DFT). The molecular geometry, the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO) energies and Mulliken atomic charges of the molecules are determined at the B3LYP method and standard 6-311++G (d,p) basis set starting from optimized geometry. They possess excellent stabilities and their thermal decomposition temperatures are 185 °C, 180 °C and 200 °C respectively, indicating that the metal complexes are suitable for the fabrication processes of optoelectronic devices.

Aquation Is a Crucial Activation Step for Anticancer Action of Ruthenium(II) Polypyridyl Complexes to Trigger Cancer Cell Apoptosis.

PubMed

Li, Meng; Lai, Lanhai; Zhao, Zhennan; Chen, Tianfeng

2016-01-01

Aquation has been proposed as crucial chemical action step for ruthenium (Ru) complexes, but its effects on the action mechanisms remain elusive. Herein, we have demonstrated the aquation process of a potent Ru polypyridyl complex (RuBmp=[Ru(II) (bmbp)(phen)Cl]ClO4 , bmbp=2,6-bis(6-methylbenzimidazol-2-yl) pyridine, phen=phenanthroline) with a chloride ligand, and revealed that aquation of RuBmp effectively enhanced its hydrophilicity and cellular uptake, thus significantly increasing its anticancer efficacy. The aquation products (H-RuBmp=[Ru(II) (bmbp)(phen)Cl]ClO4 , [Ru(II) (bmbp)(phen)(H2 O)]ClO4 , bmbp) exhibited a much higher apoptosis-inducing ability than the intact complex, with involvement of caspase activation, mitochondria dysfunction, and interaction with cell membrane death receptors. H-RuBmp demonstrated a higher interaction potency with the cell membrane and induced higher levels of ROS overproduction in cancer cells to regulate the AKT, MAPK, and p53 signaling pathways. Taken together, this study could provide useful information for fine-tuning the rational design of next-generation metal medicines. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Photo-degradation of CT-DNA with a series of carbothioamide ruthenium (II) complexes - Synthesis and structural analysis

NASA Astrophysics Data System (ADS)

Muthuraj, V.; Umadevi, M.

2018-04-01

The present research article is related with the method of preparation, structure and spectroscopic properties of a series of carbothioamide ruthenium (II) complexes with N and S donor ligands namely, 2-((6-chloro-4-oxo-4H-chromen-3-yl)methylene) hydrazine carbothioamide (ClChrTs)/2-((6-methoxy-4-oxo-4H-chromen-3-yl)methylene)hydrazine carbothioamide (MeOChrTS). The synthesized complexes were characterized by several techniques using analytical methods as well as by spectral techniques such as FT-IR, 1HNMR, 13CNMR, ESI mass and thermogravimetry/differential thermal analysis (TG-DTA). The IR spectra shows that the ligand acts as a neutral bidentate with N and S donor atoms. The biological activity of the prepared compounds and metal complexes were tested against cell line of calf-thymus DNA via an intercalation mechanism (MCF-7). In addition, the interaction of Ru(II) complexes and its free ligands with CT-DNA were also investigated by titration with UV-Vis spectra, fluorescence spectra, and Circular dichroism studies. Results suggest that both of the two Ru(II) complexes can bind with calf-thymus DNA via an intercalation mechanism.

Preliminary evaluation of monolithic column high-performance liquid chromatography with tris(2,2'-bipyridyl)ruthenium(II) chemiluminescence detection for the determination of quetiapine in human body fluids.

PubMed

Bellomarino, Sara A; Brown, Allyson J; Conlan, Xavier A; Barnett, Neil W

2009-03-15

High-performance liquid chromatography (HPLC) with tris(2,2'-bipyridyl)ruthenium(II) chemiluminescence detection methodology is reported for the determination of the atypical antipsychotic drug quetiapine and the observation of its major active and inactive metabolites in human urine and serum. The method uses a monolithic chromatographic column allowing high flow rates of 3 mLmin(-1) enabling rapid quantification. Flow injection analysis (FIA) with tris(2,2'-bipyridyl)ruthenium(II) chemiluminescence detection and HPLC time of flight mass spectrometry (TOF-MS) were used for the determination of quetiapine in a pharmaceutical preparation to establish its suitability as a calibration standard. The limit of detection achieved with FIA was 2 x 10(-11) molL(-1) in simple aqueous solution. The limits of detection achieved with HPLC were 7 x 10(-8) and 2 x 10(-10) molL(-1) in urine and serum, respectively. The calibration range for FIA was between 5 x 10(-9) and 1 x 10(-6) molL(-1). The calibration ranges for HPLC were between 1 x 10(-7)-1 x 10(-4) and 1 x 10(-8)-1 x 10(-4) molL(-1) in urine and serum, respectively. The quetiapine concentrations in patient samples were found to be 3 x 10(-6) molL(-1) in urine and 7 x 10(-7) molL(-1) in serum. Without the need for preconcentration, the HPLC detection limits compared favourably with those in previously published methodologies. The metabolites were identified using HPLC-TOF-MS.

Fe N-Heterocyclic Carbene Complexes as Promising Photosensitizers.

PubMed

Liu, Yizhu; Persson, Petter; Sundström, Villy; Wärnmark, Kenneth

2016-08-16

The photophysics and photochemistry of transition metal complexes (TMCs) has long been a hot field of interdisciplinary research. Rich metal-based redox processes, together with a high variety in electronic configurations and excited-state dynamics, have rendered TMCs excellent candidates for interconversion between light, chemical, and electrical energies in intramolecular, supramolecular, and interfacial arrangements. In specific applications such as photocatalytic organic synthesis, photoelectrochemical cells, and light-driven supramolecular motors, light absorption by a TMC-based photosensitizer and subsequent excited-state energy or electron transfer constitute essential steps. In this context, TMCs based on rare and expensive metals, such as ruthenium and iridium, are frequently employed as photosensitizers, which is obviously not ideal for large-scale implementation. In the search for abundant and environmentally benign solutions, six-coordinate Fe(II) complexes (Fe(II)L6) have been widely considered as highly desirable alternatives. However, not much success has been achieved due to the extremely short-lived triplet metal-to-ligand charge transfer ((3)MLCT) excited state that is deactivated by low-lying metal-centered (MC) states on a 100 fs time scale. A fundamental strategy to design useful Fe-based photosensitizers is thus to destabilize the MC states relative to the (3)MLCT state by increasing the ligand field strength, with special focus on making eg σ* orbitals on the Fe center energetically less accessible. Previous efforts to directly transplant successful strategies from Ru(II)L6 complexes unfortunately met with limited success in this regard, despite their close chemical kinship. In this Account, we summarize recent promising results from our and other groups in utilizing strongly σ-donating N-heterocyclic carbene (NHC) ligands to make strong-field Fe(II)L6 complexes with significantly extended (3)MLCT lifetimes. Already some of the first homoleptic bis(tridentate) complexes incorporating (CNHC^Npyridine^CNHC)-type ligands gratifyingly resulted in extension of the (3)MLCT lifetime by more than 2 orders of magnitude compared to the parental [Fe(tpy)2](2+) (tpy = 2,2':6',2″-terpyridine) complex. Quantum chemical (QC) studies also revealed that the (3)MC instead of the (5)MC state likely dictates the deactivation of the (3)MLCT state, a behavior distinct from traditional Fe(II)L6 complexes but rather resembling Ru analogues. A heteroleptic Fe(II) NHC complex featuring mesoionic bis(1,2,3-triazol-5-ylidene) (btz) ligands also delivered a 100-fold elongation of the (3)MLCT lifetime relative to its parental [Fe(bpy)3](2+) (bpy = 2,2'-bipyridine) complex. Again, a Ru-like deactivation mechanism of the (3)MLCT state was indicated by QC studies. With a COOH-functionalized homoleptic complex, a record (3)MLCT lifetime of 37 ps was recently observed on an Al2O3 nanofilm. As a proof of concept, it was further demonstrated that the significant improvement in the (3)MLCT lifetime indeed benefits efficient light harvesting with Fe(II) NHC complexes. For the first time, close-to-unity electron injection from the lowest-energy (3)MLCT state to a TiO2 nanofilm was achieved by a stable Fe(II) complex. This is in complete contrast to conventional Fe(II)L6-derived photosensitizers that could only make use of high-energy photons. These exciting results significantly broaden the understanding of the fundamental photophysics and photochemistry of d(6) Fe(II) complexes. They also open up new possibilities to develop solar energy-converting materials based on this abundant, inexpensive, and intrinsically nontoxic element.

Reversible mechanochromic luminescence at room temperature in cationic platinum(II) terpyridyl complexes.

PubMed

Han, Ali; Du, Pingwu; Sun, Zijun; Wu, Haotian; Jia, Hongxing; Zhang, Rui; Liang, Zhenning; Cao, Rui; Eisenberg, Richard

2014-04-07

Reversible mechanochromic luminescence in cationic platinum(II) terpyridyl complexes is described. The complexes [Pt(Nttpy)Cl]X2 (Nttpy = 4'-(p-nicotinamide-N-methylphenyl)-2,2':6',2″-terpyridine, X = PF6 (1), SbF6 (2), Cl (3), ClO4 (4), OTf (5), BF4 (6)) exhibit different colors under ambient light in the solid state, going from red to orange to yellow. All of these complexes are brightly luminescent at both room temperature and 77 K. Upon gentle grinding, the yellow complexes (4-6) turn orange and exhibit bright red luminescence. The red luminescence can be changed back to yellow by the addition of a few drops of acetonitrile to the sample. Crystallographic studies of the yellow and red forms of complex 5 suggest that the mechanochromic response is likely the result of a change in intermolecular Pt···Pt distances upon grinding.

Reversible interconversion between a nitrido complex of Os(VI) and an ammino complex of osmium(II)

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

Pipes, D.W.; Bakir, M.; Vitols, S.E.

1990-07-04

The reaction between (N(n-Bu){sub 4})(Os(N)(X){sub 4}) (X = Cl, Br) and 2,2{prime}:6{prime},2{double prime}-terpyridine (tpy) in acetone under reflux gave the salts (Os(N)(typ)(X){sub 2})X. The X-ray crystal structure of (Os(N)(tpy)(Cl){sub 2})Cl showed that the chloride ligands occupy mutually trans axial positions relative to the nitrido ligand. Reduction potentials were measured or estimated at pH = 3 for the intermediate Os(VI/V), Os(V/IV), Os(IV/III), and Os(III/II) couples. From those measurements, it was shown that the Os(V) intermediate, (Os{sup V}(N)(tpy)(Cl){sub 2}), is both a powerful oxidant and a strong reductant, highly unstable with respect to disproportionation into Os(VI) and Os(IV).

Photoinduced water oxidation sensitized by a tetranuclear Ru(II) dendrimer.

PubMed

La Ganga, Giuseppina; Nastasi, Francesco; Campagna, Sebastiano; Puntoriero, Fausto

2009-12-07

A multimetallic ruthenium(II) dendrimer is used for the first time to photosensitize dioxygen production from water by IrO2 nanoparticles; the system is more efficient than an analogous system based on the more commonly used [Ru(bpy)3]2+-type photosensitizers, in particular for the ability of the dendrimer to take advantage of the red portion of the solar spectrum.

Functional microporous materials of metal carboxylate: Gas-occlusion properties and catalytic activities

NASA Astrophysics Data System (ADS)

Mori, Wasuke; Sato, Tomohiko; Ohmura, Tesushi; Nozaki Kato, Chika; Takei, Tohru

2005-08-01

Copper(II) terephthalate is the first transition metal complex found capable of adsorbing gases. This complex has opened the new field of adsorbent complex chemistry. It is recognized as the lead complex in the construction of microporous complexes. This specific system has been expanded to a systematic series of derivatives of other isomorphous transition metals, molybdenum(II), ruthenium(II, III), and rhodium(II). These complexes with open frameworks are widely recognized as very useful materials for applications to catalysis, separation at molecular level, and gas storage.

Electrochemistry of mixed-metal bimetallic complexes containing the pentacyanoferrate(II) or pentaammineruthenium(II) metal center

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

Moore, K.J.; Lee, L.; Mabbott, G.A.

1983-03-30

The electrochemistry of a series of mixed-metal bimetallic complexes of the type B/sub 5/MLM'B'/sub 5/, where B/sub 5/M = (CNN)/sub 5/Fe/sup II/ or (NH/sub 3/)/sub 5/Ru/sup II/, L = pyrazine, 4,4'-bipyridine, or 4-cyanopyridine, M'B'/sub 5/ = Rh/sup III/(NH/sub 3/)/sub 5/ or Co/sup III/(CN)/sub 5/, is reported. The bimetallic complexes all have metal-to-ligand charge-transfer (MLCT) bands associated with the M-B unit (d/sub ..pi../M ..-->.. p/sub ..pi../*L). The effect of the remote metal center, M'B'/sub 5/, is to function as a Lewis acid, shifting the MLCT maximum to lower energy and shifting the M/sup III///sup II/ reduction potential more positive with respectmore » to free B/sub 5/ML. The remote metal influence is attenuated by longer bridging ligands and by reduced ..pi..-overlap. A comparison of the electrochemical data of the mixed-valence Fe(II)/Fe(III) and Ru(II)/Ru(III) complexes to the mixed-metal Fe(II)/Co(III) and Ru(II)/Rh(III) complexes has enabled a quantitative measure of the stabilization due to electron delocalization in the mixed-valence complexes. The results show that electron delocalization is greater for the ruthenium complexes than for the iron complexes, is a small contributor to the total stabilization of the mixed-valence state, and even in ruthenium drops off rapidly as the length of the bridge increases.« less

Oxidative demetalation of cyclohexadienyl ruthenium(II) complexes: a net Ru-mediated dearomatization.

PubMed

Pigge, F Christopher; Coniglio, John J; Rath, Nigam P

2003-05-29

[reaction: see text] An experimentally simple method for the demetalation of spirocyclic cyclohexadienylruthenium(II) complexes has been developed. Treatment of an alkoxy-substituted cyclohexadienyl complex with CuCl(2) affords either azaspiro[4.5]decane derivatives or heavily functionalized tetrahydroisoquinolines. The former reaction manifold completes a net Ru-mediated dearomatization as the organometallic starting materials are prepared from (eta(6)-arene)Ru(II) precursors. Both of these heterocyclic products are well suited for further synthetic elaboration.

Fundamental Factors Impacting the Stability of Phosphonate-Derivatized Ruthenium Polypyridyl Sensitizers Adsorbed on Metal Oxide Surfaces.

PubMed

Raber, McKenzie; Brady, Matthew David; Troian-Gautier, Ludovic; Dickenson, John; Marquard, Seth L; Hyde, Jacob; Lopez, Santiago; Meyer, Gerald J; Meyer, Thomas J; Harrison, Daniel P

2018-06-08

A series of 18 ruthenium(II) polypyridyl complexes were synthesized and evaluated under electrochemically oxidative conditions, which generates the Ru(III) oxidation state and mimics the harsh conditions experienced during the kinetically-limited regime that can occur in dye-sensitized solar cells (DSSCs) and dye-sensitized photoelectrosynthesis cells (DSPECs), to further develop fundamental insights into the factors governing molecular sensitizer surface stability in aqueous 0.1 M HClO4 (aq). Both desorption and oxidatively induced ligand substitution were observed on planar fluorine doped tin oxide, FTO, electrodes, with a dependence on the E1/2 Ru(III/II) redox potential dictating the comparative ratios of the processes. Complexes such as RuP4OMe (E1/2 = 0.91 vs Ag/AgCl) displayed virtually only desorption, while complexes such as RuPbpz (E1/2 > 1.62 V vs Ag/AgCl) displayed only chemical decomposition. Comparing isomers of 4,4'- and 5,5-disubstituted-2,2'-bipyridine ancillary polypyridyl ligands, a dramatic increase in the rate of desorption of the Ru(III) complexes was observed for the 5,5'-ligands. Nanoscopic indium doped tin oxide thin films, nanoITO, were also sensitized and analyzed with cyclic voltammetry, UV-Vis absorption spectroscopy, and XPS, allowing for further distinction of desorption versus ligand substitution processes. Desorption loss to bulk solution associated with the planar surface of FTO is essentially non-existent on nanoITO, where both desorption and ligand substitution are shut down with RuP4OMe. These results revealed that minimizing time spent in the oxidized form, incorporating electron donating groups, maximizing hydrophobicity, and minimizing molecular bulk near the adsorbed ligand are critical to optimizing the performance of ruthenium(II) polypyridyl complexes in dye-sensitized solar cell devices.

Determination of heavy metals in mussel and oyster samples with tris (2,2‧-bipyridyl) ruthenium (II)/graphene/Nafion® modified glassy carbon electrodes

NASA Astrophysics Data System (ADS)

Palisoc, Shirley T.; Uy, Donald Jans S.; Natividad, Michelle T.; Lopez, Toni Beth G.

2017-11-01

Tris (2,2‧-bipyridyl)ruthenium(II)/graphene/Nafion® modified glassy carbon electrodes (GCEs) were fabricated using the drop coating method. The modified electrode was used as the working electrode in differential pulse voltammetry (DPV) for the determination of lead, cadmium, and copper in mussel and oyster samples. The concentration of Tris (2,2‧-bipyridyl) ruthenium (II) and graphene were varied while those of Nafion®, methanol, and ethanol were held constant in the coating solution. The morphology and elemental composition of the fabricated electrodes were analyzed by scanning electron microscopy and energy-dispersive x-ray spectroscopy. Cyclic voltammetry (CV) was done to investigate the reversibility and stability of the modified electrodes. The modified electrode with the best figures of merit was utilized for the detection of copper (Cu2+), lead (Pb2+) and cadmium (Cd2+) via DPV. This was the electrode modified with 4 mg [Ru (bpy)3]2+ and 3 mg graphene. The anodic current and metal concentration showed linear relationship in the range of 48 ppb-745 ppb for Pb2+, 49 ppb-613 ppb for Cd2+, and 28 ppb-472 ppb for Cu2+. The limits of detection for lead, cadmium, and copper were 48 ppb, 49 ppb, and 28 ppb, respectively. Results from atomic absorption spectrometry (AAS) were compared with those measured with DPV. Lead, cadmium, and copper were in mussels, oysters, and sea water. In addition, DPV was able to detect other metals such as zinc, iron, tin and mercury in sea water samples and some samples of oysters.

Preparation of Different Substitued Polypyridine Ligands, Ruthenium(II)-Bridged Complexes and Spectoscopıc Studies.

PubMed

Obali, Aslihan Yilmaz; Ucan, Halil Ismet

2016-09-01

Novel different substitued polypyridine ligands 4-((4-(1H-imidazo[4,5-f][1,10]phenanthroline-2-yl)phenoxy)methyl)benzaldehyde (BA-PPY), (E)-N-(4-((4-(1H-imidazo[4,5-f][1,10]phenanthroline-2-yl)phenoxy)methyl)benzylidene)-pyrene-4-amine (PR-PPY), (E)-N-(4-((4-(1H-imidazo[4,5-f][1,10] phenanthroline-2-yl)phenoxy)methyl)benzylidene)-1,10-phenanthroline-5amine (FN-PPY), 2-(4-(bromomethyl)phenyl)-1H-imidazo[4,5-f][1,10] phenanthroline (BR-PPY), 2-(4-(azidomethyl)phenyl)-1H-imidazo[4,5-f][1,10]phenanthroline (N3-PPY) and triazole containing polypyridine ligand 3,4-bis[(4-(metoxy)-1,2,3-triazole)1-methylphenyl)-1H-imidazo[4,5-f][1,10]phenanthroline)] benzaldehyde (BA-DIPPY) and Ruthenium(II) complexes were synthesized and characterized. Their photopysical properties were investigated. The complexes RuP(PR-PPY), RuB(PR-PPY, RuP(FN-PPY) and RuB(FN-PPY) exhibited a broad absorption bands at 485, 475, 476, and 453 nm, respectively, assignable to the spin-allowed MLCT (dπ-π*) transition. The emission maxima of the pyrene-appended polypyridine ligand PR-PPY was observed at λems = 616 nm and the phenanthroline-appended polypyridine ligand FN-PPY was observed at λems = 668 nm. And the emission maxima of the complexes RuP(PR-PPY), RuB(PR-PPY), RuP(FN-PPY) and RuB(FN-PPY) were observed at λems = 646, 646, 685 and 685 nm, respectively. As seen in fluorescence spectra, the fluorescence intensities of the ligands are higher than their metal complexes. This is because of quenching effect of Ruthenium(II) metal on chromophore groups.

Characterization of a trinuclear ruthenium species in catalytic water oxidation by Ru(bda)(pic)2 in neutral media.

PubMed

Zhang, Biaobiao; Li, Fei; Zhang, Rong; Ma, Chengbing; Chen, Lin; Sun, Licheng

2016-06-30

A Ru(III)-O-Ru(IV)-O-Ru(III) type trinuclear species was crystallographically characterized in water oxidation by Ru(bda)(pic)2 (H2bda = 2,2'-bipyridine-6,6'-dicarboxylic acid; pic = 4-picoline) under neutral conditions. The formation of a ruthenium trimer due to the reaction of Ru(IV)[double bond, length as m-dash]O with Ru(II)-OH2 was fully confirmed by chemical, electrochemical and photochemical methods. Since the oxidation of the trimer was proposed to lead to catalyst decomposition, the photocatalytic water oxidation activity was rationally improved by the suppression of the formation of the trimer.

A ruthenium(II) complex inhibits tumor growth in vivo with fewer side-effects compared with cisplatin.

PubMed

Wang, Jin-Quan; Zhang, Ping-Yu; Ji, Liang-Nian; Chao, Hui

2015-05-01

The antitumor activity of a ruthenium(II) polypyridyl complex, Δ-[Ru(bpy)2(HPIP)](ClO4)2 (Δ-Ru1, where bpy=2,2'-bipyridine, HPIP=2-(2-hydroxyphenyl)imidazo[4,5-f][1,10]phenanthroline), was evaluated. The in vivo experiments showed that Δ-Ru1 inhibited the growth of a human cervical carcinoma cell line (HeLa) xenotransplanted into nude mice with efficiency similar to that of cisplatin. Histopathology examination of the tumors from treated xenograft models was consistent with apoptosis in tumor cells. Importantly, in striking contrast with cisplatin, Δ-Ru1 did not cause any detectable side effects on the kidney, liver, peripheral neuronal system, or the hematological system at the pharmacologically effective dose. The preclinical studies reported here provide support for the clinical use of Δ-Ru1 as an exciting new drug candidate with lower toxicity than cisplatin, endowed with proapoptotic properties. Copyright © 2015 Elsevier Inc. All rights reserved.

Electrogenerated chemiluminescence of tris(2,2'-bipyridine)ruthenium(II) using N-(3-aminopropyl)diethanolamine as coreactant.

PubMed

Kitte, Shimeles Addisu; Wang, Chao; Li, Suping; Zholudov, Yuriy; Qi, Liming; Li, Jianping; Xu, Guobao

2016-10-01

Coreactant plays a critical role for the application of electrochemiluminescence (ECL). Herein, N-(3-aminopropyl)diethanolamine (APDEA) has been explored as a potential coreactant for enhancing tris(2,2'-bipyridyl)ruthenium(II) ECL. It is much more effective than tripropylamine at gold and platinum electrodes although it has one primary amine group besides a tertiary amine group. The presence of primary amine group and hydroxyl groups in APDEA promotes the oxidation rates of amine and thus remarkably increases ECL intensity. The ECL intensities of the Ru(bpy)3 (2+)/APDEA system are approximately 10 and 36 times stronger than that of Ru(bpy)3 (2+)/tripropylamine system and about 1.6 and 1.14 times stronger than that of Ru(bpy)3 (2+)/N-butyldiethanolamine system at Au and Pt electrodes, respectively. The ECL intensity of the Ru(bpy)3 (2+)/APDEA system is 2.42 times stronger than that of Ru(bpy)3 (2+)/N-butyldiethanolamine at glassy carbon electrodes.

Dynamics of the His79-heme alkaline transition of yeast iso-1-cytochrome c probed by conformationally gated electron transfer with Co(II)bis(terpyridine).

PubMed

Cherney, Melisa M; Junior, Carolyn C; Bergquist, Bryan B; Bowler, Bruce E

2013-08-28

Alkaline conformers of cytochrome c may be involved in both its electron transport and apoptotic functions. We use cobalt(II)bis(terpyridine), Co(terpy)2(2+), as a reagent for conformationally gated electron-transfer (gated ET) experiments to study the alkaline conformational transition of K79H variants of yeast iso-1-cytochrome c expressed in Escherichia coli , WT*K79H, with alanine at position 72 and Saccharomyces cerevisiae , yK79H, with trimethyllysine (Tml) at position 72. Co(terpy)2(2+) is well-suited to the 100 ms to 1 s time scale of the His79-mediated alkaline conformational transition of these variants. Reduction of the His79-heme alkaline conformer by Co(terpy)2(2+) occurs primarily by gated ET, which involves conversion to the native state followed by reduction, with a small fraction of the His79-heme alkaline conformer directly reduced by Co(terpy)2(2+). The gated ET experiments show that the mechanism of formation of the His79-heme alkaline conformer involves only two ionizable groups. In previous work, we showed that the mechanism of the His73-mediated alkaline conformational transition requires three ionizable groups. Thus, the mechanism of heme crevice opening depends upon the position of the ligand mediating the process. The microscopic rate constants provided by gated ET studies show that mutation of Tml72 (yK79H variant) in the heme crevice loop to Ala72 (WT*K79H variant) affects the dynamics of heme crevice opening through a small destabilization of both the native conformer and the transition state relative to the His79-heme alkaline conformer. Previous pH jump data had indicated that the Tml72→Ala mutation primarily stabilized the transition state for the His79-mediated alkaline conformational transition.

Dynamics of the His79-heme Alkaline Transition of Yeast Iso-1-cytochrome c Probed by Conformationally-gated Electron Transfer with Co(II)bis(terpyridine)†

PubMed Central

Cherney, Melisa M.; Junior, Carolyn C.; Bergquist, Bryan B.; Bowler, Bruce E.

2013-01-01

Alkaline conformers of cytochrome c may be involved in both its electron transport and apoptotic functions. We use cobalt(II)bis(terpyridine), Co(terpy)22+, as a reagent for conformationally-gated electron transfer (gated ET) experiments to study the alkaline conformational transition of K79H variants of yeast iso-1-cytochrome c expressed in Escherichia coli, WT*K79H, with alanine at position 72, and Saccharomyces cerevisiae, yK79H, with trimethyllysine (Tml) at position 72. Co(terpy)22+ is well-suited to the 100 ms to 1 s time scale of the His79-mediated alkaline conformational transition of these variants. Reduction of the His79-heme alkaline conformer by Co(terpy)22+ occurs primarily by gated ET, which involves conversion to the native state followed by reduction, with a small fraction of the His79- heme alkaline conformer directly reduced by Co(terpy)22+. The gated ET experiments show that the mechanism of formation of the His79-heme alkaline conformer involves only two ionizable groups. In previous work, we showed that the mechanism of the His73-mediated alkaline conformational transition requires three ionizable groups. Thus, the mechanism of heme crevice opening depends upon the position of the ligand mediating the process. The microscopic rate constants provided by gated ET studies show that mutation of Tml72 (yK79H variant) in the heme crevice loop to Ala72 (WT*K79H variant) affects the dynamics of heme crevice opening through a small destabilization of both the native conformer and the transition state relative to the His79-heme alkaline conformer. Previous pH jump data had indicated that the Tml72→Ala mutation primarily stabilized the transition state for the His79-mediated alkaline conformational transition. PMID:23899348

Carboxylate-assisted C–H activation of phenylpyridines with copper, palladium and ruthenium: a mass spectrometry and DFT study† †Electronic supplementary information (ESI) available: Details on the mass-spectrometry experiments and theoretical calculations, Hammett studies, potential energy surfaces, energies, optimized Gaussian geometries and laser-power dependence during the IRMPD spectra measurements. See DOI: 10.1039/c5sc01729g

PubMed Central

Gray, A.; Tsybizova, A.

2015-01-01

The C–H activation of 2-phenylpyridine, catalyzed by copper(ii), palladium(ii) and ruthenium(ii) carboxylates, was studied in the gas phase. ESI-MS, infrared multiphoton dissociation spectroscopy and quantum chemical calculations were combined to investigate the intermediate species in the reaction. Collision induced dissociation (CID) experiments and DFT calculations allowed estimation of the energy required for this C–H activation step and the subsequent acetic acid loss. Hammett plots constructed from the CID experiments using different copper carboxylates as catalysts revealed that the use of stronger acids accelerates the C–H activation step. The reasoning can be traced from the associated transition structures that suggest a concerted mechanism and the key effect of the carbon–metal bond pre-formation. Carboxylates derived from stronger acids make the metal atom more electrophilic and therefore shift the reaction towards the formation of C–H activated products. PMID:29861892

Photophysical studies of chromium sensitizers designed for excited state hole transfer to semiconductors and sequential hole/electron transfers from photoexcited cadmium sulfide nanorods to mononuclear ruthenium water-oxidation catalysts

NASA Astrophysics Data System (ADS)

Tseng, Huan-Wei

This dissertation describes three research projects related to solar cells and solar water splitting with a goal of utilizing solar energy, a renewable energy source. The first project is focused on photophysical studies of four newly-synthesized Cr(III) tris-bipyridyl complexes featuring the 4-dmcbpy (dimethyl 2,2'-bipyridine-4,4'-dicarboxylate) ligand. Static and time-resolved emission results suggest that the complexes store ˜1.7 eV of energy for multiple microseconds. Using cyclic voltammetry, it is found that the inclusion of 4-dmcbpy shifts the E1/2 of CrIII/II by +0.2 V from the homoleptic parent complexes without 4-dmcbpy. All four complexes have excited state potentials of CrIII*/II between +1.8 and +2.0 V vs. NHE, placing them among the most powerful photooxidants reported and making them candidates for hole-injection sensitizers. The second project continues with Cr(III) complexes, but using iminopyridine Schiff base ligands. Two complexes feature hexadentate ligands and the other two are their tris-bidentate analogues. One of each pair contains methyl ester groups for attachment to semiconductors. Cyclic voltammograms show that the hexadentate and tris-bidentate analogues have almost identical reduction potentials, but the addition of ester substituents shifts the reduction potentials by +0.2 V. The absorption spectra of the hexadentate complexes show improved absorption of visible light compared to the tris-bidentate analogues. For freshly prepared sample solutions in CH3CN, time-resolved emission and transient absorption measurements for the Cr(III) tris-bidentate ester complex show a doublet excited state with a 17-19 microsecond lifetime at room temperature, while no emission or transient absorption signals from the doublet states are observed for the hexadentate analogue under the same conditions. The dramatic difference is due to the presence of a nonligated bridgehead nitrogen atom. The third project features charge transfer interactions between a photoexcited cadmium sulfide nanorod and [Ru(diethyl 2,2'-bipyridine-4,4'-dicarboxylate)(2,2':6',2"-terpyridine)Cl] +, a mononuclear water-oxidation catalyst. Upon photoexcitation, hole transfer from the cadmium sulfide nanorod oxidizes the catalyst (Ru 2+ → Ru3+) on a 100 ps to 1 ns timescale. This is followed by electron transfer (10-100 ns) from the nanorod to reduce the Ru3+ center. The relatively slow electron transfer dynamics may provide opportunities for the accumulation of multiple holes at the catalyst, which is required for water oxidation.

DFT-INDO/S modeling of new high molar extinction coefficient charge-transfer sensitizers for solar cell applications.

PubMed

Nazeeruddin, Mohammad K; Wang, Qing; Cevey, Le; Aranyos, Viviane; Liska, Paul; Figgemeier, Egbert; Klein, Cedric; Hirata, Narukuni; Koops, Sara; Haque, Saif A; Durrant, James R; Hagfeldt, Anders; Lever, A B P; Grätzel, Michael

2006-01-23

A new ruthenium(II) complex, tetrabutylammonium [ruthenium (4-carboxylic acid-4'-carboxylate-2,2'-bipyridine)(4,4'-di(2-(3,6-dimethoxyphenyl)ethenyl)-2,2'-bipyridine)(NCS)(2)] (N945H), was synthesized and characterized by analytical, spectroscopic, and electrochemical techniques. The absorption spectrum of the N945H sensitizer is dominated by metal-to-ligand charge-transfer (MLCT) transitions in the visible region, with the lowest allowed MLCT bands appearing at 25 380 and 18 180 cm(-1). The molar extinction coefficients of these bands are 34 500 and 18 900 M(-1) cm(-1), respectively, and are significantly higher when compared to than those of the standard sensitizer cis-dithiocyanatobis(4,4'-dicarboxylic acid-2,2'-bipyridine)ruthenium(II). An INDO/S and density functional theory study of the electronic and optical properties of N945H and of N945 adsorbed on TiO(2) was performed. The calculations point out that the top three frontier-filled orbitals have essentially ruthenium 4d (t(2g) in the octahedral group) character with sizable contribution coming from the NCS ligand orbitals. Most critically the calculations reveal that, in the TiO(2)-bound N945 sensitizer, excitation directs charge into the carboxylbipyridine ligand bound to the TiO(2) surface. The photovoltaic data of the N945 sensitizer using an electrolyte containing 0.60 M butylmethylimidazolium iodide, 0.03 M I(2), 0.10 M guanidinium thiocyanate, and 0.50 M tert-butylpyridine in a mixture of acetonitrile and valeronitrile (volume ratio = 85:15) exhibited a short-circuit photocurrent density of 16.50 +/- 0.2 mA cm(-2), an open-circuit voltage of 790 +/- 30 mV, and a fill factor of 0.72 +/- 0.03, corresponding to an overall conversion efficiency of 9.6% under standard AM (air mass) 1.5 sunlight, and demonstrated a stable performance under light and heat soaking at 80 degrees C.

Synthesis, structure, DNA binding and anticancer activity of mixed ligand ruthenium(II) complex

NASA Astrophysics Data System (ADS)

Gilewska, Agnieszka; Masternak, Joanna; Kazimierczuk, Katarzyna; Trynda, Justyna; Wietrzyk, Joanna; Barszcz, Barbara

2018-03-01

In order to obtain a potential chemotherapeutic which is not affected on the normal BALB/3T3 cell line, a new arene ruthenium(II) complex {[RuCl(L1)(η6-p-cymene)]PF6}2 · H2O has been synthesized by a direct reaction of precursor, [{(η6-p-cymene)Ru(μ-Cl)}2Cl2], with N,N-chelating ligand (L1 - 2,2‧-bis(4,5-dimethylimidazole). The compound has been fully characterized by elemental analysis, X-ray diffraction, IR, UV-Vis and 1H, 13C NMR spectroscopies. X-ray analysis have confirmed that the compound crystallized in the monoclinic group Cc as an inversion twin. The asymmetric unit contains two symmetrically independent cationic complexes [RuCl(L1)(η6-p-cymene)]+ whose charge is balanced by two PF6- counterions. The shape of each cationic coordination polyhedral can be described as a distorted dodecahedron and shows a typical piano-stool geometry. In addition, an analysis of the crystal structure and the Hirshfeld surface analysis were used to detect and visualize important hydrogen bonds and intermolecular interaction. Moreover, the antiproliferative behavior of the obtained complex was assayed against three human cells: MV-4-11, LoVo, MCF-7 and BALB/3T3 - normal mice fibroblast cells. To predict a binding mode, a potential interaction of ruthenium complex with calf thymus DNA (CT-DNA) has been explored using UV absorption and circular dichroism (CD).

Bending nanofibers into nanospirals: coordination chemistry as a tool for shaping hydrophobic assemblies.

PubMed

Kossoy, Elizaveta; Weissman, Haim; Rybtchinski, Boris

2015-01-02

In the current work, we demonstrate how coordination chemistry can be employed to direct self-assembly based on strong hydrophobic interactions. To investigate the influence of coordination sphere geometry on aqueous self-assembly, we synthesized complexes of the amphiphilic perylene diimide terpyridine ligand with the first-row transition-metal centers (zinc, cobalt, and nickel). In aqueous medium, aggregation of these complexes is induced by hydrophobic interactions between the ligands. However, the final shapes of the resulting assemblies depend on the preferred geometry of the coordination spheres typical for the particular metal center. The self-assembly process was characterized by UV/Vis spectroscopy, zeta potential measurements, and cryogenic transmission electron microscopy (cryo-TEM). Coordination of zinc(II) and cobalt(II) leads to the formation of unique nanospiral assemblies, whereas complexation of nickel(II) leads to the formation of straight nanofibers. Notably, coordination bonds are utilized not as connectors between elementary building blocks, but as directing interactions, enabling control over supramolecular geometry. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Dinuclear polypyridylruthenium(II) complexes: flow cytometry studies of their accumulation in bacteria and the effect on the bacterial membrane.

PubMed

Li, Fangfei; Feterl, Marshall; Warner, Jeffrey M; Keene, F Richard; Collins, J Grant

2013-12-01

To determine the energy dependency of and the contribution of the membrane potential to the cellular accumulation of the dinuclear complexes [{Ru(phen)2}2{μ-bbn}](4+) (Rubbn) and the mononuclear complexes [Ru(Me4phen)3](2+) and [Ru(phen)2(bb7)](2+) in Staphylococcus aureus and Escherichia coli, and to examine their effect on the bacterial membrane. The accumulation of the ruthenium complexes in bacteria was determined using flow cytometry at a range of temperatures. The cellular accumulation of the ruthenium complexes was also determined in cells that had been incubated with the metal complexes in the presence or absence of metabolic stimulators or inhibitors and/or commercial dyes to determine the membrane potential or membrane permeability. The accumulation of ruthenium complexes in the two bacterial strains was shown to increase with increasing incubation temperature, with the relative increase in accumulation greater with E. coli, particularly for Rubb12 and Rubb16. No decrease in accumulation was observed for Rubb12 in ATP-inhibited cells. While carbonyl cyanide m-chlorophenyl hydrazone (CCCP) did depolarize the cell membrane, no reduction in the accumulation of Rubb12 was observed; however, all ruthenium complexes, when incubated with S. aureus at concentrations twice their MIC, depolarized the membrane to a similar extent to CCCP. Except for the mononuclear complex [Ru(Me4phen)3](2+), incubation of any of the other ruthenium complexes allowed a greater quantity of the membrane-impermeable dye TO-PRO-3 to be taken up by S. aureus. The results indicate that the potential new antimicrobial Rubbn complexes enter the cell in an energy-independent manner, depolarize the cell membrane and significantly permeabilize the cellular membrane.

Protic NNN and NCN Pincer-Type Ruthenium Complexes Featuring (Trifluoromethyl)pyrazole Arms: Synthesis and Application to Catalytic Hydrogen Evolution from Formic Acid.

PubMed

Nakahara, Yoshiko; Toda, Tatsuro; Matsunami, Asuka; Kayaki, Yoshihito; Kuwata, Shigeki

2018-01-04

NNN and NCN pincer-type ruthenium(II) complexes featuring two protic pyrazol-3-yl arms with a trifluoromethyl (CF 3 ) group at the 5-position were synthesized and structurally characterized to evaluate the impact of the substitution on the properties and catalysis. The increased Brønsted acidity by the highly electron-withdrawing CF 3 pendants was demonstrated by protonation-deprotonation experiments. By contrast, the IR spectra of the carbonyl derivatives as well as the cyclic voltammogram indicated that the electron density of the ruthenium atom is negligibly influenced by the CF 3 group. Catalysis of these complexes in the decomposition of formic acid to dihydrogen and carbon dioxide was also examined. The NNN pincer-type complex 1 a with the CF 3 group exhibited a higher catalytic activity than the tBu-substituted analogue 1 b. In addition, the bis(CF 3 -pyrazolato) ammine derivative 4 catalyzed the reaction even in the absence of base additives. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

μ(3)-Carbonato-κO:O':O''-tris-{(η-ben-zene)[(R)-1-(1-amino-ethyl)naphthyl-κC,N]ruthenium(II)} hexa-fluorido-phosphate dichloro-methane solvate.

PubMed

Sortais, Jean-Baptiste; Brelot, Lydia; Pfeffer, Michel; Barloy, Laurent

2008-02-15

The title compound, [Ru(3)(C(12)H(12)N)(3)(CO(3))(C(6)H(6))(3)]PF(6)·CH(2)Cl(2), was obtained unintentionally as the product of an attempted deprotonation of the monomeric parent ruthenium complex [Ru(C(12)H(12)N)(C(6)H(6))(C(2)H(3)N)]PF(6). The carbonate ligand bridges three half-sandwich cyclo-ruthenated fragments, each of them exhibiting a pseudo-tetra-hedral geometry. The configuration of the Ru atoms is S. The naphthyl groups of the enanti-opure cyclo-ruthenated benzylic amine ligands point in the same direction, adopting a propeller shape.

Transfer Hydro-dehalogenation of Organic Halides Catalyzed by Ruthenium(II) Complex.

PubMed

You, Tingjie; Wang, Zhenrong; Chen, Jiajia; Xia, Yuanzhi

2017-02-03

A simple and efficient Ru(II)-catalyzed transfer hydro-dehalogenation of organic halides using 2-propanol solvent as the hydride source was reported. This methodology is applicable for hydro-dehalogenation of a variety of aromatic halides and α-haloesters and amides without additional ligand, and quantitative yields were achieved in many cases. The potential synthetic application of this method was demonstrated by efficient gram-scale transformation with catalyst loading as low as 0.5 mol %.

Synthesis, Photochemical, and Redox Properties of Gold(I) and Gold(III) Pincer Complexes Incorporating a 2,2′:6′,2″-Terpyridine Ligand Framework

PubMed Central

2015-01-01

Reaction of [Au(C6F5)(tht)] (tht = tetrahydrothiophene) with 2,2′:6′,2″-terpyridine (terpy) leads to complex [Au(C6F5)(η1-terpy)] (1). The chemical oxidation of complex (1) with 2 equiv of [N(C6H4Br-4)3](PF6) or using electrosynthetic techniques affords the Au(III) complex [Au(C6F5)(η3-terpy)](PF6)2 (2). The X-ray diffraction study of complex 2 reveals that the terpyridine acts as tridentate chelate ligand, which leads to a slightly distorted square-planar geometry. Complex 1 displays fluorescence in the solid state at 77 K due to a metal (gold) to ligand (terpy) charge transfer transition, whereas complex 2 displays fluorescence in acetonitrile due to excimer or exciplex formation. Time-dependent density functional theory calculations match the experimental absorption spectra of the synthesized complexes. In order to further probe the frontier orbitals of both complexes and study their redox behavior, each compound was separately characterized using cyclic voltammetry. The bulk electrolysis of a solution of complex 1 was analyzed by spectroscopic methods confirming the electrochemical synthesis of complex 2. PMID:26496068

Phosphorescent binuclear iridium complexes based on terpyridine-carboxylate: an experimental and theoretical study.

PubMed

Andreiadis, Eugen S; Imbert, Daniel; Pécaut, Jacques; Calborean, Adrian; Ciofini, Ilaria; Adamo, Carlo; Demadrille, Renaud; Mazzanti, Marinella

2011-09-05

The phosphorescent binuclear iridium(III) complexes tetrakis(2-phenylpyridine)μ-(2,2':6',2''-terpyridine-6,6''-dicarboxylic acid)diiridium (Ir1) and tetrakis(2-(2,4-difluorophenyl) pyridine))μ-(2,2':6',2''-terpyridine-6,6''-dicarboxylic acid)diiridium (Ir2) were synthesized in a straightforward manner and characterized using X-ray diffraction, NMR, UV-vis absorption, and emission spectroscopy. The complexes have similar solution structures in which the two iridium centers are equivalent. This is further confirmed by the solid state structure of Ir2. The newly reported complexes display intense luminescence in dichloromethane solutions with maxima at 538 (Ir1) and 477 nm (Ir2) at 298 K (496 and 468 nm at 77 K, respectively) and emission quantum yields reaching ~18% for Ir1. The emission quantum yield for Ir1 is among the highest values reported for dinuclear iridium complexes. It shows only a 11% decrease with respect to the emission quantum yield reported for its mononuclear analogue, while the molar extinction coefficient is roughly doubled. This suggests that such architectures are of potential interest for the development of polymetallic assemblies showing improved optical properties. DFT and time-dependent-DFT calculations were performed on the ground and excited states of the complexes to provide insights into their structural, electronic, and photophysical properties.

Size-controllable APTS stabilized ruthenium(0) nanoparticles catalyst for the dehydrogenation of dimethylamine-borane at room temperature.

PubMed

Zahmakıran, Mehmet; Philippot, Karine; Özkar, Saim; Chaudret, Bruno

2012-01-14

Dimethylamine-borane, (CH(3))(2)NHBH(3), has been considered as one of the attractive materials for the efficient storage of hydrogen, which is still one of the key issues in the "Hydrogen Economy". In a recent communication we have reported the synthesis and characterization of 3-aminopropyltriethoxysilane stabilized ruthenium(0) nanoparticles with the preliminary results for their catalytic performance in the dehydrogenation of dimethylamine-borane at room temperature. Herein, we report a complete work including (i) effect of initial [APTS]/[Ru] molar ratio on both the size and the catalytic activity of ruthenium(0) nanoparticles, (ii) collection of extensive kinetic data under non-MTL conditions depending on the substrate and catalyst concentrations to define the rate law of Ru(0)/APTS-catalyzed dehydrogenation of dimethylamine-borane at room temperature, (iii) determination of activation parameters (E(a), ΔH(#) and ΔS(#)) for Ru(0)/APTS-catalyzed dehydrogenation of dimethylamine-borane; (iv) demonstration of the catalytic lifetime of Ru(0)/APTS nanoparticles in the dehydrogenation of dimethylamine-borane at room temperature, (v) testing the bottlability and reusability of Ru(0)/APTS nanocatalyst in the room-temperature dehydrogenation of dimethylamine-borane, (vi) quantitative carbon disulfide (CS(2)) poisoning experiments to find a corrected TTO and TOF values on a per-active-ruthenium-atom basis, (vii) a summary of extensive literature review for the catalysts tested in the catalytic dehydrogenation of dimethylamine-borane as part of the results and discussions.

A ruthenium polypyridyl intercalator stalls DNA replication forks, radiosensitizes human cancer cells and is enhanced by Chk1 inhibition

NASA Astrophysics Data System (ADS)

Gill, Martin R.; Harun, Siti Norain; Halder, Swagata; Boghozian, Ramon A.; Ramadan, Kristijan; Ahmad, Haslina; Vallis, Katherine A.

2016-08-01

Ruthenium(II) polypyridyl complexes can intercalate DNA with high affinity and prevent cell proliferation; however, the direct impact of ruthenium-based intercalation on cellular DNA replication remains unknown. Here we show the multi-intercalator [Ru(dppz)2(PIP)]2+ (dppz = dipyridophenazine, PIP = 2-(phenyl)imidazo[4,5-f][1,10]phenanthroline) immediately stalls replication fork progression in HeLa human cervical cancer cells. In response to this replication blockade, the DNA damage response (DDR) cell signalling network is activated, with checkpoint kinase 1 (Chk1) activation indicating prolonged replication-associated DNA damage, and cell proliferation is inhibited by G1-S cell-cycle arrest. Co-incubation with a Chk1 inhibitor achieves synergistic apoptosis in cancer cells, with a significant increase in phospho(Ser139) histone H2AX (γ-H2AX) levels and foci indicating increased conversion of stalled replication forks to double-strand breaks (DSBs). Normal human epithelial cells remain unaffected by this concurrent treatment. Furthermore, pre-treatment of HeLa cells with [Ru(dppz)2(PIP)]2+ before external beam ionising radiation results in a supra-additive decrease in cell survival accompanied by increased γ-H2AX expression, indicating the compound functions as a radiosensitizer. Together, these results indicate ruthenium-based intercalation can block replication fork progression and demonstrate how these DNA-binding agents may be combined with DDR inhibitors or ionising radiation to achieve more efficient cancer cell killing.

A ruthenium polypyridyl intercalator stalls DNA replication forks, radiosensitizes human cancer cells and is enhanced by Chk1 inhibition.

PubMed

Gill, Martin R; Harun, Siti Norain; Halder, Swagata; Boghozian, Ramon A; Ramadan, Kristijan; Ahmad, Haslina; Vallis, Katherine A

2016-08-25

Ruthenium(II) polypyridyl complexes can intercalate DNA with high affinity and prevent cell proliferation; however, the direct impact of ruthenium-based intercalation on cellular DNA replication remains unknown. Here we show the multi-intercalator [Ru(dppz)2(PIP)](2+) (dppz = dipyridophenazine, PIP = 2-(phenyl)imidazo[4,5-f][1,10]phenanthroline) immediately stalls replication fork progression in HeLa human cervical cancer cells. In response to this replication blockade, the DNA damage response (DDR) cell signalling network is activated, with checkpoint kinase 1 (Chk1) activation indicating prolonged replication-associated DNA damage, and cell proliferation is inhibited by G1-S cell-cycle arrest. Co-incubation with a Chk1 inhibitor achieves synergistic apoptosis in cancer cells, with a significant increase in phospho(Ser139) histone H2AX (γ-H2AX) levels and foci indicating increased conversion of stalled replication forks to double-strand breaks (DSBs). Normal human epithelial cells remain unaffected by this concurrent treatment. Furthermore, pre-treatment of HeLa cells with [Ru(dppz)2(PIP)](2+) before external beam ionising radiation results in a supra-additive decrease in cell survival accompanied by increased γ-H2AX expression, indicating the compound functions as a radiosensitizer. Together, these results indicate ruthenium-based intercalation can block replication fork progression and demonstrate how these DNA-binding agents may be combined with DDR inhibitors or ionising radiation to achieve more efficient cancer cell killing.

Teaching Inorganic Photophysics and Photochemistry with Three Ruthenium(II) Polypyridyl Complexes: A Computer-Based Exercise

ERIC Educational Resources Information Center

Garino, Claudio; Terenzi, Alessio; Barone, Giampaolo; Salassa, Luca

2016-01-01

Among computational methods, DFT (density functional theory) and TD-DFT (time-dependent DFT) are widely used in research to describe, "inter alia," the optical properties of transition metal complexes. Inorganic/physical chemistry courses for undergraduate students treat such methods, but quite often only from the theoretical point of…

Mechanistic information from the first volume profile analysis for a reversible intermolecular electron-transfer reaction involving pentaammine(isonicotinamide)ruthenium and cytochrome c

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

Baensch, B.; Meier, M.; Martinez, P.

1994-10-12

The reversible intermolecular electron-transfer reaction between pentaammine(isonicotinamide)ruthenium(II/III) and horse-heart cytochrome c iron(III/II) was subjected to a detailed kinetic and thermodynamic study as a function of temperature and pressure. Theoretical calculations based on the Marcus-Hush theory were employed to predict all rate and equilibrium constants as well as activation parameters. There is an excellent agreement between the kinetically and thermodynamically determined equilibrium constants and associated pressure parameters. These data are used to construct a volume profile for the overall process, from which it follows that the transition state lies halfway between the reactant and product states on a volume basis. Themore » reorganization in the transition state has reached a similar degree in both directions of the electron-transfer process and corresponds to a {lambda}{sup {double_dagger}} value of 0.44 for this reversible reaction. This is the first complete volume profile analysis for a reversible intermolecular electron-transfer reaction.« less

Bioorthogonal Diversification of Peptides through Selective Ruthenium(II)-Catalyzed C-H Activation.

PubMed

Schischko, Alexandra; Ren, Hongjun; Kaplaneris, Nikolaos; Ackermann, Lutz

2017-02-01

Methods for the chemoselective modification of amino acids and peptides are powerful techniques in biomolecular chemistry. Among other applications, they enable the total synthesis of artificial peptides. In recent years, significant momentum has been gained by exploiting palladium-catalyzed cross-coupling for peptide modification. Despite major advances, the prefunctionalization elements on the coupling partners translate into undesired byproduct formation and lengthy synthetic operations. In sharp contrast, we herein illustrate the unprecedented use of versatile ruthenium(II)carboxylate catalysis for the step-economical late-stage diversification of α- and β-amino acids, as well as peptides, through chemo-selective C-H arylation under racemization-free reaction conditions. The ligand-accelerated C-H activation strategy proved water-tolerant and set the stage for direct fluorescence labelling as well as various modes of peptide ligation with excellent levels of positional selectivity in a bioorthogonal fashion. The synthetic utility of our approach is further demonstrated by twofold C-H arylations for the complexity-increasing assembly of artificial peptides within a multicatalytic C-H activation manifold. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Structure and Magnetic Properties in Ruthenium-Based Full-Heusler Alloys: AB INITIO Calculations

NASA Astrophysics Data System (ADS)

Bahlouli, S.; Aarizou, Z.; Elchikh, M.

2013-12-01

In this paper, we present ab initio calculations within density functional theory (DFT) to investigate structure, electronic and magnetic properties of Ru2CrZ (Z = Si, Ge and Sn) full-Heusler alloys. We have used the developed full-potential linearized muffin tin orbitals (FP-LMTO) based on the local spin density approximation (LSDA) with the PLane Wave expansion (PLW). In particular, we found that these Ruthenium-based Heusler alloys have the antiferromagnetic (AFM) type II as ground state. Then, we studied and discussed the magnetic properties belonging to our different magnetic structures: AFM type II, AFM type I and ferromagnetic (FM) phase. We also found that Ru2CrSi and Ru2CrGe exhibit a semiconducting behavior whereas Ru2CrSn has a semimetallic-like behavior as it is experimentally found. We made an estimation of Néel temperatures (TN) in the framework of the mean-field theory and used the energy differences approach to deduce the relevant short-range nearest-neighbor (J1) and next-nearest-neighbor (J2) interactions. The calculated TN are somewhat overestimated to the available experimental ones.

Binuclear ruthenium(III) bis(thiosemicarbazone) complexes: Synthesis, spectral, electrochemical studies and catalytic oxidation of alcohol

NASA Astrophysics Data System (ADS)

Mohamed Subarkhan, M.; Ramesh, R.

2015-03-01

A new series of binuclear ruthenium(III) thiosemicarbazone complexes of general formula [(EPh3)2(X)2Ru-L-Ru(X)2(EPh3)2] (where E = P or As; X = Cl or Br; L = NS chelating bis(thiosemicarbazone ligands) has been synthesized and characterized by analytical and spectral (FT-IR, UV-Vis and EPR). IR spectra show that the thiosemicarbazones behave as monoanionic bidentate ligands coordinating through the azomethine nitrogen and thiolate sulphur. The electronic spectra of the complexes indicate that the presence of d-d and intense LMCT transitions in the visible region. The complexes are paramagnetic (low spin d5) in nature and all the complexes show rhombic distortion around the ruthenium ion with three different 'g' values (gx ≠ gy ≠ gz) at 77 K. All the complexes are redox active and exhibit an irreversible metal centered redox processes (RuIII-RuIII/RuIV-RuIV; RuIII-RuIII/RuII-RuII) within the potential range of 0.38-0.86 V and -0.39 to -0.66 V respectively, versus Ag/AgCl. Further, the catalytic efficiency of one of the complexes [Ru2Cl2(AsPh3)4(L1)] (4) has been investigated in the case of oxidation of primary and secondary alcohols into their corresponding aldehydes and ketones in the presence of N-methylmorpholine-N-oxide(NMO) as co-oxidant. The formation of high valent RuVdbnd O species is proposed as catalytic intermediate for the catalytic cycle.

SEPARATION OF RUTHENIUM FROM AQUEOUS SOLUTIONS

DOEpatents

Callis, C.F.; Moore, R.L.

1959-09-01

>The separation of ruthenium from aqueous solutions containing uranium plutonium, ruthenium, and fission products is described. The separation is accomplished by providing a nitric acid solution of plutonium, uranium, ruthenium, and fission products, oxidizing plutonium to the hexavalent state with sodium dichromate, contacting the solution with a water-immiscible organic solvent, such as hexone, to extract plutonyl, uranyl, ruthenium, and fission products, reducing with sodium ferrite the plutonyl in the solvent phase to trivalent plutonium, reextracting from the solvent phase the trivalent plutonium, ruthenium, and some fission products with an aqueous solution containing a salting out agent, introducing ozone into the aqueous acid solution to oxidize plutonium to the hexavalent state and ruthenium to ruthenium tetraoxide, and volatizing off the ruthenium tetraoxide.

cis-Bis(O-methyl-dithio-carbonato-κ(2) S,S')bis-(tri-phenyl-phosphane-κP)ruthenium(II).

PubMed

Valerio-Cárdenas, Cintya; Hernández-Ortega, Simón; Reyes-Martínez, Reyna; Morales-Morales, David

2013-01-01

In the title compound, [Ru(CH3OCS2)2(C18H15P)2], the Ru(II) atom is in a distorted octa-hedral coordination by two xanthate anions (CH3OCS2) and two tri-phenyl-phosphane (PPh3) ligands. Both bidentate xanthate ligands coordinate the Ru(II) atom with two slightly different Ru-S bond lengths but with virtually equal bite angles [71.57 (4) and 71.58 (3)°]. The packing of the complexes is assured by C-H⋯O and C-H⋯π inter-actions.

Synthesis, Characterization and Cytotoxicity Studies of Palladium(II)-Proflavine Complexes

PubMed Central

Polyanskaya, Tatyana V.; Kazhdan, Irene; Motley, D. Michelle; Walmsley, Judith A.

2010-01-01

An investigation of the reaction of Pd(II) complexes with proflavine (3,6-diaminoacridine) resulted in the isolation of the compounds [Pd(terpy)(proflavine)](NO3)(HSO4)·3H2O, 1, (terpy = 2,2’:6’,2”-terpyridine), [Pd(en)(proflavineH))](NO3)(SO4), 2, (en = ethylenediamine), and [Pd(proflavineH)Cl2](SO4)0.5 ·H2O, 3. They have been isolated and characterized by NMR, IR, and electrospray ionization mass spectrometry techniques and by elemental analyses. The proflavine was bonded to the Pd(II) through the endocyclic nitrogen in 1, but through the proflavine NH2 in 2. Compound 3 appeared to be polymeric in the solid state with a 1:1 mole ratio of Pd(II):proflavine. Upon solution of 3 in DMSO, two unique species were formed. In one species the Pd(II) was bonded to Two proflavines through the endocyclic nitrogen (1:2 mole ratio) and in the other species, a Pd(II) was bonded to each NH2 group of a single proflavine (2:1 mole ratio). Molecular modeling of the equilibrium geometry by Spartan 8 produced structures which were consistent with the experimental data on the solutions of the three compounds. In vitro cytotoxicity testing against two breast cancer cell lines and one ovarian cancer cell line showed that compounds 1 and 3 had significant activity. PMID:20709409

Binding properties of chiral ruthenium(II) complexes Λ- and Δ-[Ru(bpy)2dppz-11-CO2Me]2+ toward the triplex RNA poly(U)•poly(A)*poly(U).

PubMed

Ni, Wen; Liu, Xiaohua; Tan, Lifeng

2018-05-24

Two chiral ruthenium(II) complexes containing ligand dppz-CO 2 Me (dppz-11-CO 2 Me = dipyrido[3,2-a,2',3'-c]phenazine-11-carboxylic acid methyl ester), Δ-[Ru(bpy) 2 dppz-11-CO 2 Me] 2+ (bpy = 2,2'-bipyridine; Δ-1) and Λ-[Ru(bpy) 2 dppz-11-CO 2 Me] 2+ (Λ-1), were synthesized and characterized. The binding of the two enantiomers with the triplex RNA poly(U)•poly(A)*poly(U) was carried out by various biophysical techniques. Analysis of the absorption and fluorescence features indicates that the binding strengths of the two enantiomers toward the triplex RNA differ only slightly from each other. The total increase in viscosity and shape of the curves for the triplex RNA with Λ-1 is similar to that with Δ-1, suggesting the binding modes of two enantiomers with the triplex RNA are intercalation. Thermal melting measurements indicate that the stabilization effects clearly depended on the concentrations of Λ-1 and Δ-1. However, the third-strand stabilizing effect of Δ-1 dramatically differs from that of Λ-1 when they interact with the chiral environment of the RNA triple at pH = 7.0 and [Na + ] = 35 mM. Combined with the CD (CD = circular dichroism) variations of the triplex RNA with either Λ-1 or Δ-1, the reason for their different triplex stabilization effects may originate from the two enantiomers through different orientations intercalating into nucleobases of the triplex. In addition, effects of higher ionic strengths on the triplex stabilization in the absence and presence of the two enantiomers have also been studied. The results presented here may be useful for understanding the binding properties of the triplex RNA with small molecule, particularly chiral ruthenium(II) complexes. Copyright © 2018 Elsevier Inc. All rights reserved.

Aggregation-Induced Emission-Active Ruthenium(II) Complex of 4,7-Dichloro Phenanthroline for Selective Luminescent Detection and Ribosomal RNA Imaging.

PubMed

Sheet, Sanjoy Kumar; Sen, Bhaskar; Patra, Sumit Kumar; Rabha, Monosh; Aguan, Kripamoy; Khatua, Snehadrinarayan

2018-05-02

The development of red emissive aggregation-induced emission (AIE) active probes for organelle-specific imaging is of great importance. Construction of metal complex-based AIE-active materials with metal-to-ligand charge transfer (MLCT), ligand-to-metal charge transfer (LMCT) emission together with the ligand-centered and intraligand (LC/ILCT) emission is a challenging task. We developed a red emissive ruthenium(II) complex, 1[PF 6 ] 2 , and its perchlorate analogues of the 4,7-dichloro phenanthroline ligand. 1[PF 6 ] 2 has been characterized by spectroscopic and single-crystal X-ray diffraction. Complex 1 showed AIE enhancement in water, highly dense polyethylene glycol media, and also in the solid state. The possible reason behind the AIE property may be the weak supramolecular π···π, C-H···π, and C-Cl···H interactions between neighboring phen ligands as well as C-Cl···O halogen bonding (XB). The crystal structures of the two perchlorate analogues revealed C-Cl···O distances shorter than the sum of the van der Waals radii, which confirmed the XB interaction. The AIE property was supported by scanning electron microscopy, transmission electron microscopy, dynamic light scattering, and atomic force microscopy studies. Most importantly, the probe was found to be low cytotoxicity and to efficiently permeate the cell membrane. The cell-imaging experiments revealed rapid staining of the nucleolus in HeLa cells via the interaction with nucleolar ribosomal ribonucleic acid (rRNA). It is expected that the supramolecular interactions as well as C-Cl···O XB interaction with rRNA is the origin of aggregation and possible photoluminescence enhancement. To the best of our knowledge, this is the first report of red emissive ruthenium(II) complex-based probes with AIE characteristics for selective rRNA detection and nucleolar imaging.

Impact of various lipophilic substituents on ruthenium(II), rhodium(III) and iridium(III) salicylaldimine-based complexes: synthesis, in vitro cytotoxicity studies and DNA interactions.

PubMed

Cassells, Irwin; Stringer, Tameryn; Hutton, Alan T; Prince, Sharon; Smith, Gregory S

2018-05-30

A series of bidentate salicylaldimine ligands was prepared and reacted with either [RuCl(µ-Cl)(p-cymene)] 2 , [RhCl(µ-Cl)(Cp*)] 2 or [IrCl(µ-Cl)(Cp*)] 2 . All of the compounds were characterised using an array of spectroscopic and analytical techniques, namely, nuclear magnetic resonance (NMR) spectroscopy, infrared (IR) spectroscopy and mass spectrometry. Single crystal X-ray diffraction (XRD) was used to confirm the bidentate coordination mode of the salicylaldimine ligand to the metal centre. The platinum group metal (PGM) complexes were screened against the MCF7 breast cancer cell line. The ruthenium and iridium salicylaldimine complexes showed comparable or greater cytotoxicity than cisplatin against the MCF7 cancer cells, as well as greater cytotoxicity than their rhodium counterparts. Three of the salicylaldimine complexes showed potent activity in the range 18-21 µM. Two of these complexes had a greater affinity for cancerous cells than for CHO non-cancerous cells (SI > 4). Preliminary mechanistic studies suggest that the ruthenium complexes undergo solvation prior to 5'-GMP binding, whereas the iridium complexes were inert to the solvation process.

Insights into the Binding Sites of Organometallic Ruthenium Anticancer Compounds on Peptides Using Ultra-High Resolution Mass Spectrometry

NASA Astrophysics Data System (ADS)

Wills, Rebecca H.; Habtemariam, Abraha; Lopez-Clavijo, Andrea F.; Barrow, Mark P.; Sadler, Peter J.; O'Connor, Peter B.

2014-04-01

The binding sites of two ruthenium(II) organometallic complexes of the form [(η6-arene)Ru( N, N)Cl]+, where arene/ N, N = biphenyl (bip)/bipyridine (bipy) for complex AH076, and biphenyl (bip)/ o-phenylenediamine ( o-pda) for complex AH078, on the peptides angiotensin and bombesin have been investigated using Fourier transform ion cyclotron resonance (FTICR) mass spectrometry. Fragmentation was performed using collisionally activated dissociation (CAD), with, in some cases, additional data being provided by electron capture dissociation (ECD). The primary binding sites were identified as methionine and histidine, with further coordination to phenylalanine, potentially through a π-stacking interaction, which has been observed here for the first time. This initial peptide study was expanded to investigate protein binding through reaction with insulin, on which the binding sites proposed are histidine, glutamic acid, and tyrosine. Further reaction of the ruthenium complexes with the oxidized B chain of insulin, in which two cysteine residues are oxidized to cysteine sulfonic acid (Cys-SO3H), and glutathione, which had been oxidized with hydrogen peroxide to convert the cysteine to cysteine sulfonic acid, provided further support for histidine and glutamic acid binding, respectively.

[Ru(dpp)(3)][(4-Clph)(4)B](2) nanoislands directly assembled on an ITO electrode surface and its electrogenerated chemiluminescence.

PubMed

Chen, Ying; Mao, Jianfei; Liu, Chunhua; Yuan, Hongyan; Xiao, Dan; Choi, Martin M F

2009-01-20

In this work, solid-state tris(4,7-diphenyl-1,10-phenanthroline) ruthenium(II) ditetrakis(4-chlorophenyl)borate ([Ru(dpp)(3)][(4-Clph)(4)B](2)) nanoislands are assembled spontaneously and simultaneously on an indium-doped tin oxide (ITO) glass electrode surface via a facile dewetting procedure. The fabrication process is very simple and also amenable to mass production. The as-prepared ruthenium complex nanoislands exhibit useful properties. The electrode is more electrochemically active and can produce strong, stable, reproducible solid-state electrochemiluminescence (ECL) signals using oxalate as the coreactant. The self-assembled nanoislands exhibit semiconductor-like broad, red-shift ECL spectrum. More importantly, they extend the application of the ruthenium complex ECL system from the usual alkaline to acidic conditions. The pH turn-off behavior of the ECL is observed for the first time and can serve as an ultrasensitive pH sensor around physiological pH 7.0. The solid-state [Ru(dpp)(3)][(4-Clph)(4)B](2) ECL signal is efficiently inhibited by phenol even at a very low concentration (i.e., 20 nM), thus providing the potential for the determination of phenolic compounds in practical applications.

Microporous Materials of Metal Carboxylates

NASA Astrophysics Data System (ADS)

Mori, Wasuke; Takamizawa, Satoshi

2000-06-01

Copper(II) terephthalate absorbs a large amount of gases such as N2, Ar, O2, and Xe. The maximum amounts of absorption of gases were 1.8, 1.9, 2.2, and 0.9 mole per mole of the copper(II) salt for N2, Ar, O2, and Xe, respectively, indicating that the gases were not adsorbed on the surface but occluded within the solid. Other microporous copper(II) dicarboxylates are also reviewed. The porous structure of copper(II) terephthalate, in which the gas is occluded, is deduced from the temperature dependence of magnetic susceptibilities and the linear structure of terephthalate. Microporous molybdenum(II) and ruthenium(II, III) dicarboxylates are discussed. We describe that rhodium(II) monocarboxylate bridged by pyrazine form stable micropores by self-assembly of infinite linear chain complexes.

Luminescence quenching of tris(2,2'-bipyridine)ruthenium(II) by 2,6-dimethylphenol and 4-bromo-2,6-dimethylphenol in sol-gel-processed silicate thin films.

PubMed

Altamirano, M; Senz, A; Gsponer, H E

2004-02-15

The luminescence properties of tris(1,2-bipyridine)ruthenium(II) (Ru(bpy)(3)(2+)), included in different organically modified silicate gel matrixes were investigated. Spin and dip-coated thin films were prepared from methyltrimethoxysilane (MTMOS) and methyltriethoxysilane (MTEOS). A blue shift in the emission spectrum of the MLCT excited state of Ru(bpy)(3)(2+) with respect to the aqueous solution was observed in all the films, practically independent of the reaction pH used to prepare the "sol," silane-derived precursor, and procedure used (dip-coating or spin-coating) to obtain the film. A bimodal distribution of probe sites in the films was obtained from modeling of the emission decays by a double exponential and from application of the exponential series method. The parameters of the decay components depended principally on the thermal treatment used in the processing of the films. The lifetimes decreased with the increase in the drying temperature of the films; at the same time, the emission spectra showed a red shift and the luminescence efficiency decreased. A luminescence quenching of the ruthenium complex in the films by 4-bromo-2,6-dimethylphenol and 2,6-dimethylphenol in aerated aqueous solution at pH 12 in contact with the film was also observed. The quenching plots obtained from luminescence intensities or luminescence intensity decay measurements showed a downward curvature. These plots could be fitted satisfactorily by a sum of two Stern-Volmer terms with quenching constants K(SV1) and K(SV2) associated with two different binding sites of the ruthenium complex. This result is indicative of the matrix microheterogeneity in the films and is fully consistent with the biexponential nature of the luminescence intensity decay profiles. The Stern-Volmer parameter values for both sites in the films suggest that only a low percentage of the probe is accessible to the quencher and its respective constant K(SV1) is lower than in water.

Synergistic oxygen atom transfer by ruthenium complexes with non-redox metal ions.

PubMed

Lv, Zhanao; Zheng, Wenrui; Chen, Zhuqi; Tang, Zhiming; Mo, Wanling; Yin, Guochuan

2016-07-28

Non-redox metal ions can affect the reactivity of active redox metal ions in versatile biological and heterogeneous oxidation processes; however, the intrinsic roles of these non-redox ions still remain elusive. This work demonstrates the first example of the use of non-redox metal ions as Lewis acids to sharply improve the catalytic oxygen atom transfer efficiency of a ruthenium complex bearing the classic 2,2'-bipyridine ligand. In the absence of Lewis acid, the oxidation of ruthenium(ii) complex by PhI(OAc)2 generates the Ru(iv)[double bond, length as m-dash]O species, which is very sluggish for olefin epoxidation. When Ru(bpy)2Cl2 was tested as a catalyst alone, only 21.2% of cyclooctene was converted, and the yield of 1,2-epoxycyclooctane was only 6.7%. As evidenced by electronic absorption spectra and EPR studies, both the oxidation of Ru(ii) by PhI(OAc)2 and the reduction of Ru(iv)[double bond, length as m-dash]O by olefin are kinetically slow. However, adding non-redox metal ions such as Al(iii) can sharply improve the oxygen transfer efficiency of the catalyst to 100% conversion with 89.9% yield of epoxide under identical conditions. Through various spectroscopic characterizations, an adduct of Ru(iv)[double bond, length as m-dash]O with Al(iii), Ru(iv)[double bond, length as m-dash]O/Al(iii), was proposed to serve as the active species for epoxidation, which in turn generated a Ru(iii)-O-Ru(iii) dimer as the reduced form. In particular, both the oxygen transfer from Ru(iv)[double bond, length as m-dash]O/Al(iii) to olefin and the oxidation of Ru(iii)-O-Ru(iii) back to the active Ru(iv)[double bond, length as m-dash]O/Al(iii) species in the catalytic cycle can be remarkably accelerated by adding a non-redox metal, such as Al(iii). These results have important implications for the role played by non-redox metal ions in catalytic oxidation at redox metal centers as well as for the understanding of the redox mechanism of ruthenium catalysts in the oxygen atom transfer reaction.

Using Organic Light-Emitting Electrochemical Thin-Film Devices to Teach Materials Science

ERIC Educational Resources Information Center

Sevian, Hannah; Muller, Sean; Rudmann, Hartmut; Rubner, Michael F.

2004-01-01

Materials science can be taught by applying organic light-emitting electrochemical thin-film devices and in this method students were allowed to make a light-emitting device by spin coating a thin film containing ruthenium (II) complex ions onto a glass slide. Through this laboratory method students are provided with the opportunity to learn about…

Development and application of a ruthenium(II) complex-based photoluminescent and electrochemiluminescent dual-signaling probe for nitric oxide.

PubMed

Zhang, Wenzhu; Zhang, Jingmei; Zhang, Hailei; Cao, Liyan; Zhang, Run; Ye, Zhiqiang; Yuan, Jingli

2013-11-15

A ruthenium(II) complex, [Ru(bpy)2(DA-phen)](PF6)2 (bpy: 2,2'-bipyridine; DA-phen: 5,6-diamino-1,10-phenanthroline), has been developed as a photoluminescent (PL) and electrochemiluminescent (ECL) dual-signaling probe for the highly sensitive and selective detection of nitric oxide (NO) in aqueous and biological samples. Due to the presence of electron transfer process from diamino group to the excited-state of the Ru(II) complex, the PL and ECL intensities of the probe are very weak. After the probe was reacted with NO in physiological pH aqueous media under aerobic conditions to afford its triazole derivative, [Ru(bpy)2(TA-phen)](2+) (TA-phen: 5,6-triazole-1,10-phenanthroline), the electron transfer process was inhibited, so that the PL and ECL efficiency of the Ru(II) complex was remarkably increased. The PL and ECL responses of the probe to NO in physiological pH media are highly sensitive with the detection limits at low micromolar concentration level, and highly specific without the interferences of other reactive oxygen/nitrogen species (ROS/RNS) and metal ions. Moreover, the probe has good cell-membrane permeability, and can be rapidly transferred into living cells for trapping the intracellular NO molecules. These features enabled the probe to be successfully used for the monitoring of the endogenous NO production in living biological cell and tissue samples with PL and ECL dual-modes. Copyright © 2013 Elsevier B.V. All rights reserved.

Ruthenium red-induced bundling of bacterial cell division protein, FtsZ.

PubMed

Santra, Manas Kumar; Beuria, Tushar K; Banerjee, Abhijit; Panda, Dulal

2004-06-18

The assembly of FtsZ plays a major role in bacterial cell division, and it is thought that the assembly dynamics of FtsZ is a finely regulated process. Here, we show that ruthenium red is able to modulate FtsZ assembly in vitro. In contrast to the inhibitory effects of ruthenium red on microtubule polymerization, we found that a substoichiometric concentration of ruthenium red strongly increased the light-scattering signal of FtsZ assembly. Further, sedimentable polymer mass was increased by 1.5- and 2-fold in the presence of 2 and 10 microm ruthenium red, respectively. In addition, ruthenium red strongly reduced the GTPase activity and prevented dilution-induced disassembly of FtsZ polymers. Electron microscopic analysis showed that 4-10 microm of ruthenium red produced thick bundles of FtsZ polymers. The significant increase in the light-scattering signal and pelletable polymer mass in the presence of ruthenium red seemed to be due to the bundling of FtsZ protofilaments into larger polymers rather than the actual increase in the level of polymeric FtsZ. Furthermore, ruthenium red was found to copolymerize with FtsZ, and the copolymerization of substoichiometric amounts of ruthenium red with FtsZ polymers promoted cooperative assembly of FtsZ that produced large bundles. Calcium inhibited the binding of ruthenium red to FtsZ. However, a concentration of calcium 1000-fold higher than that of ruthenium red was required to produce similar effects on FtsZ assembly. Ruthenium red strongly modulated FtsZ polymerization, suggesting the presence of an important regulatory site on FtsZ and suggesting that a natural ligand, which mimics the action of ruthenium red, may regulate the assembly of FtsZ in bacteria.

IR-doped ruthenium oxide catalyst for oxygen evolution

NASA Technical Reports Server (NTRS)

Valdez, Thomas I. (Inventor); Narayanan, Sekharipuram R. (Inventor)

2012-01-01

A method for preparing a metal-doped ruthenium oxide material by heating a mixture of a doping metal and a source of ruthenium under an inert atmosphere. In some embodiments, the doping metal is in the form of iridium black or lead powder, and the source of ruthenium is a powdered ruthenium oxide. An iridium-doped or lead-doped ruthenium oxide material can perform as an oxygen evolution catalyst and can be fabricated into electrodes for electrolysis cells.

Syntheses, structures and luminescence for zinc coordination polymers based on a multifunctional 4‧-(3-carboxyphenyl)- 3,2‧:6‧,3″-terpyridine ligand

NASA Astrophysics Data System (ADS)

Cheng, Yue; Yang, Meng-Lin; Hu, Huai-Ming; Xu, Bing; Wang, Xiaofang; Xue, Ganglin

2016-07-01

Six new coordination polymers, [ZnLCl]n(1), [ZnL2]n·2nH2O (2), [Zn2L(o-bdc)(OH)]n·0.5nH2O (3), [Zn2L(m-bdc)(OH)]n·nH2O (4), [Zn2L2(p-bdc) (H2O)2]n·nH2O (5), [Zn2L(1,2,4-btc)(H2O)]n(6), (HL=4‧-(3-carboxyphenyl)- 3,2‧:6‧,3″-terpyridine, H2(o-bdc)= benzene-1,2-dicarboxylic acid, H2(m-bdc)= benzene-1,3-dicarboxylic acid, H2(p-bdc)= benzene-1,4-dicarboxylic acid, H3(1,2,4-btc)= benzene-1,2,4-tricarboxylic acid) have been synthesized under the hydrothermal conditions. Compound 1 displays a 3-connected 2D network structure with point symbol of {82.10}. Compound 2 exhibits 1D infinite loop chain structure. Compound 3 possesses a (3,8)-connected 3D framework composed of tetranuclear units with point symbol of {43}2{46.618.84}. Compound 4 features a typical 2D hcb network based on tetranuclear zinc(II) units with point symbol of {44.62}. Compound 5 presents a classical two-fold penetration sql network with point symbol of {63}. Compound 6 can be seen as a (3,3,6)-connected 3D net with point symbol of {42.64.89}{42.6}{63}. The thermal stability and luminescent properties of compounds 1-6 in the solid state are discussed in detail.

RECOVERY OF RUTHENIUM VALUES

DOEpatents

Grummitt, W.E.; Hardwick, W.H.

1961-01-01

A process is given for the recovery of ruthenium from its aqueous solutions by oxidizing the ruthenium to the octavalent state and subsequently extracting the ruthenium into a halogen-substituted liquid paraffin.

Excited-state redox properties of ruthenium(II) phthalocyanine from electron-transfer quenching

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

Prasad, D.R.; Ferraudi, G.

1982-09-30

Electron-transfer reactions between the lowest-lying triplet state, /sup 3/..pi pi../sup */, of ruthenium (phthalocyanine)(pyridine)/sub 2/ and various nitroaromatic compounds have been studied by laser and conventional flash photolysis. Quenching rate constants determined for the oxidation of the excited state have been treated according to the Marcus-Hush theory. A self-exchange rate constant K approx. 10/sup 7/ M/sup -1/ x/sup -1/ was determined for the self-exchange reaction between the /sup 3/..pi pi../sup */ and radical cation, Ru(ph)(py)/sub 2//sup +/. Such a value indicates that the major component to the Franck-Condon reorganizational energy is the outer-sphere contribution. The photochemical properties of the phthalocyaninesmore » are discussed in terms of the redox potentials estimate for various excited states.« less

Static and Wind-on Performance of Polymer-Based Pressure-Sensitive Paints Using Platinum and Ruthenium as the Luminophore

PubMed Central

Lo, Kin Hing; Kontis, Konstantinos

2016-01-01

An experimental study has been conducted to investigate the static and wind-on performance of two in-house-developed polymer-based pressure-sensitive paints. Platinum tetrakis (pentafluorophenyl) porphyrin and tris-bathophenanthroline ruthenium II are used as the luminophores of these two polymer-based pressure-sensitive paints. The pressure and temperature sensitivity and the photo-degradation rate of these two pressure-sensitive paints have been investigated. In the wind tunnel test, it was observed that the normalised intensity ratio of both polymer-based pressure-sensitive paints being studied decreases with increasing the number of wind tunnel runs. The exact reason that leads to the occurrence of this phenomenon is unclear, but it is deduced that the luminophore is either removed or deactivated by the incoming flow during a wind tunnel test. PMID:27128913

μ3-Carbonato-κ3 O:O′:O′′-tris­{(η6-ben­zene)[(R)-1-(1-amino­ethyl)naphthyl-κ2 C 2,N]ruthenium(II)} hexa­fluorido­phosphate dichloro­methane solvate

PubMed Central

Sortais, Jean-Baptiste; Brelot, Lydia; Pfeffer, Michel; Barloy, Laurent

2008-01-01

The title compound, [Ru3(C12H12N)3(CO3)(C6H6)3]PF6·CH2Cl2, was obtained unintentionally as the product of an attempted deprotonation of the monomeric parent ruthenium complex [Ru(C12H12N)(C6H6)(C2H3N)]PF6. The carbonate ligand bridges three half-sandwich cyclo­ruthenated fragments, each of them exhibiting a pseudo-tetra­hedral geometry. The configuration of the Ru atoms is S. The naphthyl groups of the enanti­opure cyclo­ruthenated benzylic amine ligands point in the same direction, adopting a propeller shape. PMID:21201869

Structure-Antiplatelet Activity Relationships of Novel Ruthenium (II) Complexes: Investigation of Its Molecular Targets.

PubMed

Hsia, Chih-Hsuan; Jayakumar, Thanasekaran; Sheu, Joen-Rong; Tsao, Shin-Yi; Velusamy, Marappan; Hsia, Chih-Wei; Chou, Duen-Suey; Chang, Chao-Chien; Chung, Chi-Li; Khamrang, Themmila; Lin, Kao-Chang

2018-02-22

The regulation of platelet function by pharmacological agents that modulate platelet signaling has proven to be a positive approach to the prevention of thrombosis. Ruthenium complexes are fascinating for the development of new drugs, as they possess numerous chemical and biological properties. The present study aims to evaluate the structure-activity relationship (SAR) of newly synthesized ruthenium (II) complexes, TQ-1, TQ-2 and TQ-3 in agonists-induced washed human platelets. Silica gel column chromatography, aggregometry, immunoblotting, NMR, and X-ray analyses were performed in this study. Of the three tested compounds, TQ-3 showed a concentration (1-5 μM) dependent inhibitory effect on platelet aggregation induced by collagen (1 μg/mL) and thrombin (0.01 U/mL) in washed human platelets; however, TQ-1 and TQ-2 had no response even at 250 μM of collagen and thrombin-induced aggregation. TQ-3 was effective with inhibiting collagen-induced ATP release, calcium mobilization ([Ca 2+ ]i) and P-selectin expression without cytotoxicity. Moreover, TQ-3 significantly abolished collagen-induced Lyn-Fyn-Syk, Akt-JNK and p38 mitogen-activated protein kinases (p38 MAPKs) phosphorylation. The compound TQ-3 containing an electron donating amino group with two phenyl groups of the quinoline core could be accounted for by its hydrophobicity and this nature might be the reason for the noted antiplatelet effects of TQ-3. The present results provide a molecular basis for the inhibition by TQ-3 in collagen-induced platelet aggregation, through the suppression of multiple machineries of the signaling pathway. These results may suggest that TQ-3 can be considered a potential agent for the treatment of vascular diseases.

In vitro evaluation of the cyto-genotoxic potential of Ruthenium(II) SCAR complexes: a promising class of antituberculosis agents.

PubMed

De Grandis, Rone Aparecido; Resende, Flávia Aparecida; da Silva, Monize Martins; Pavan, Fernando Rogério; Batista, Alzir Azevedo; Varanda, Eliana Aparecida

2016-03-01

Tuberculosis is a top infectious disease killer worldwide, caused by the bacteria Mycobacterium tuberculosis. Increasing incidences of multiple drug-resistance (MDR) strains are emerging as one of the major public health threats. However, the drugs in use are still incapable of controlling the appalling upsurge of MDR. In recent years a marked number of research groups have devoted their attention toward the development of specific and cost-effective antimicrobial agents against targeted MDR-Tuberculosis. In previous studies, ruthenium(II) complexes (SCAR) have shown a promising activity against MDR-Tuberculosis although few studies have indeed considered ruthenium toxicity. Therefore, within the preclinical requirements, we have sought to determine the cyto-genotoxicity of three SCAR complexes in this present study. The treatment with the SCARs induced a concentration-dependent decrease in cell viability in CHO-K1 and HepG2 cells. Based on the clonogenic survival, SCAR 5 was found to be more cytotoxic while SCAR 6 exhibited selectivity action on tumor cells. Although SCAR 4 and 5 did not indicate any mutagenic activity as evidenced by the Ames and Cytokinesis block micronucleus cytome assays, the complex SCAR 6 was found to engender a frameshift mutation detected by Salmonella typhimurium in the presence of S9. Similarly, we observed a chromosomal damage in HepG2 cells with significant increases of micronuclei and nucleoplasmic bridges. These data indicate that SCAR 4 and 5 complexes did not show genotoxicity in our models while SCAR 6 was considered mutagenic. This study presented a comprehensive genotoxic evaluation of SCAR complexes were shown to be genotoxic in vitro. All in all, further studies are required to fully elucidate how the properties can affect human health. Copyright © 2016 Elsevier B.V. All rights reserved.

Deposition of RuO 4 on various surfaces in a nuclear reactor containment

NASA Astrophysics Data System (ADS)

Holm, Joachim; Glänneskog, Henrik; Ekberg, Christian

2009-07-01

During a severe nuclear reactor accident with air ingress, ruthenium can be released from the nuclear fuel in the form of ruthenium tetroxide. Hence, it is important to investigate how the reactor containment is able to reduce the source term of ruthenium. The aim of this work was to investigate the deposition of gaseous ruthenium tetroxide on aluminium, copper and zinc, which all appear in relatively large amounts in reactor containment. The experiments show that ruthenium tetroxide is deposited on all the metal surfaces, especially on the copper and zinc surfaces. A large deposition of ruthenium tetroxide also appeared on the relatively inert glass surfaces in the experimental set-ups. The analyses of the different surfaces, with several analytical methods, showed that the form of deposited ruthenium was mainly ruthenium dioxide.

Elucidation of the role of metal-to-ring charge-transfer excited states in the deactivation of photoexcited ruthenium porphyrin carbonyl complexes

NASA Astrophysics Data System (ADS)

Rodriguez, Juan; McDowell, Lynda; Holten, Dewey

1988-06-01

Deactivation of the lowest excited triplet state, 3(π, π*), of the Ru(II) porphyrins RuP(CO)(L) is more strongly dependent on temperature than decay of 3(π, π*) in Pt(II)P and H 2P (metal-free) complexes containing the same macrocycle P. This and other observations support the proposal that 3(π, π*) in the RuP(CO)(L) complexes decays in part via a metal-to-ring (d, π*) charge-transfer excited state at higher energy.

Surfactant-enhanced singlet energy transfer from the charge-transfer excited state of tris(2,2-bipyridine) ruthenium(II)

NASA Astrophysics Data System (ADS)

Mandal, Krishnagopal; Demas, J. N.

1981-12-01

Very efficient (45-75%) sodium lauryl sulfate (NaLS) enhanced singlet enengy transfer has been demonstrated from the spin-orbit charge-transfer excited state of [Ru(bpy) 3] 2+ (bpy = 2,2'-bipyridine) to the xxx violet, oxazine 1, and rhodamine 101 at concentrations of 10 -5 M, Energy transfer occurs in xxx.

The determination of psilocin and psilocybin in hallucinogenic mushrooms by HPLC utilizing a dual reagent acidic potassium permanganate and tris(2,2'-bipyridyl)ruthenium(II) chemiluminescence detection system.

PubMed

Anastos, Nicole; Lewis, Simon W; Barnett, Neil W; Sims, D Noel

2006-01-01

This paper describes a procedure for the determination of psilocin and psilocybin in mushroom extracts using high-performance liquid chromatography with postcolumn chemiluminescence detection. A number of extraction methods for psilocin and psilocybin in hallucinogenic mushrooms were investigated, with a simple methanolic extraction being found to be most effective. Psilocin and psilocybin were extracted from a variety of hallucinogenic mushrooms using methanol. The analytes were separated on a C12 column using a (95:5% v/v) methanol:10 mM ammonium formate, pH 3.5 mobile phase with a run time of 5 min. Detection was realized through a dual reagent chemiluminescence detection system of acidic potassium permanganate and tris(2,2'-bipyridyl)ruthenium(II). The chemiluminescence detection system gave improved detectability when compared with UV absorption at 269 nm, with detection limits of 1.2 x 10(-8) and 3.5 x 10(-9) mol/L being obtained for psilocin and psilocybin, respectively. The procedure was applied to the determination of psilocin and psilocybin in three Australian species of hallucinogenic mushroom.

Simple chemiluminescence determination of ketotifen using tris(1,10 phenanthroline)ruthenium(II)- Ce(IV) system.

PubMed

Mokhtari, Ali; Ghazaeian, Mehrgan; Maghsoudi, Mahdieh; Keyvanfard, Mohsen; Emami, Iraj

2015-11-01

A new method using chemiluminescence (CL) detection has been developed for the simple determination of ketotifen fumarate (KF). The method is based on the catalytic effect of KF in the CL reaction of tris(1,10 phenanthroline)ruthenium(II), Ru(phen)3 (2+), with Ce(IV) in sulfuric acid medium. The CL response was detected using a lab-made chemiluminometer. Effects of chemical variables were investigated and under optimum conditions, the CL intensity was proportional to the concentration of the drug over the range 0.34-34.00 µg mL(-1) KF. The limit of detection (S/N=3) was 0.09 µg mL(-1). Effects of common ingredients were investigated and the method was applied successfully for determining KF in pharmaceutical formulations and human plasma. The percent of relative standard deviation (n=11) at level of 3.4 µg mL(-1) of KF was 4.6% and the minimum sampling rate was 70 samples per hour. The possible CL mechanism is proposed based on the kinetic characteristic of the CL reaction, CL spectrum, UV-Vis and phosphorescence spectra. Copyright © 2015 John Wiley & Sons, Ltd.

Luminescence-Functionalized Metal-Organic Frameworks Based on a Ruthenium(II) Complex: A Signal Amplification Strategy for Electrogenerated Chemiluminescence Immunosensors.

PubMed

Xiong, Cheng-Yi; Wang, Hai-Jun; Liang, Wen-Bin; Yuan, Ya-Li; Yuan, Ruo; Chai, Ya-Qin

2015-06-26

Novel luminescence-functionalized metal-organic frameworks (MOFs) with superior electrogenerated chemiluminescence (ECL) properties were synthesized based on zinc ions as the central ions and tris(4,4'-dicarboxylicacid-2,2'-bipyridyl)ruthenium(II) dichloride ([Ru(dcbpy)3](2+)) as the ligands. For potential applications, the synthesized MOFs were used to fabricate a "signal-on" ECL immunosensor for the detection of N-terminal pro-B-type natriuretic peptide (NT-proBNP). As expected, enhanced ECL signals were obtained through a simple fabrication strategy because luminescence-functionalized MOFs not only effectively increased the loading of [Ru(dcbpy)3](2+), but also served as a loading platform in the ECL immunosensor. Furthermore, the proposed ECL immunosensor had a wide linear range from 5 pg mL(-1) to 25 ng mL(-1) and a relatively low detection limit of 1.67 pg mL(-1) (signal/noise=3). The results indicated that luminescence-functionalized MOFs provided a novel amplification strategy in the construction of ECL immunosensors and might have great prospects for application in bioanalysis. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis, characterization and cytotoxicity studies of palladium(II)-proflavine complexes.

PubMed

Polyanskaya, Tatyana V; Kazhdan, Irene; Motley, D Michelle; Walmsley, Judith A

2010-11-01

An investigation of the reaction of Pd(II) complexes with proflavine (3,6-diaminoacridine) resulted in the isolation of the compounds [Pd(terpy)(proflavine)](NO(3))(HSO(4))*3H(2)O, 1, (terpy = 2,2':6',2″-terpyridine), [Pd(en)(proflavineH))](NO(3))(SO(4)), 2, (en = ethylenediamine), and [Pd(proflavineH)Cl(2)](SO(4))(0.5)*H(2)O, 3. They have been isolated and characterized by NMR, IR, and electro-spray ionization mass spectrometry techniques and by elemental analyses. The proflavine was bonded to the Pd(II) through the endocyclic nitrogen in 1, but through the proflavine NH(2) in 2. Compound 3 appeared to be polymeric in the solid state with a 1:1 mole ratio of Pd(II):proflavine. Upon solution of 3 in DMSO, two unique species were formed. In one species the Pd(II) was bonded to two proflavines through the endocyclic nitrogen (1:2 mole ratio) and in the other species, a Pd(II) was bonded to each NH(2) group of a single proflavine (2:1 mole ratio). Molecular modeling of the equilibrium geometry by Spartan 8 produced structures which were consistent with the experimental data on the solutions of the three compounds. In vitro cytotoxicity testing against two breast cancer cell lines and one ovarian cancer cell line showed that compounds 1 and 3 had significant activity. Copyright © 2010 Elsevier Inc. All rights reserved.

SEPARATION OF RUTHENIUM FROM AQUEOUS SOLUTIONS

DOEpatents

Beederman, M.; Vogler, S.; Hyman, H.H.

1959-07-14

The separation of rathenium from a rathenium containing aqueous solution is described. The separation is accomplished by adding sodium nitrite, silver nitrate and ozone to the ruthenium containing aqueous solution to form ruthenium tetroxide and ihen volatilizing off the ruthenium tetroxide.

Ruthenium(η⁶,η¹-arene-CH₂-NHC) Catalysts for Direct Arylation of 2-Phenylpyridine with (Hetero)Aryl Chlorides in Water.

PubMed

Kaloğlu, Nazan; Özdemir, İsmail; Gürbüz, Nevin; Arslan, Hakan; Dixneuf, Pierre H

2018-03-13

A series of new benzimidazolium halides were synthesized in good yields as unsymmetrical N -heterocyclic carbene (NHC) precursors containing the N-CH₂-arene group. The benzimidazolium halides were readily converted into ruthenium(II)-NHC complexes with the general formula [RuCl₂(η⁶,η¹-arene-CH₂-NHC)]. The structures of all new compounds were characterized by ¹H NMR (Nuclear Magnetic Resonance), 13 C NMR, FT-IR (Fourier Transform Infrared) spectroscopy and elemental analysis techniques. The single crystal structure of one benzimidazole ruthenium complex, 2b , was determined. The complex is best thought of as containing an octahedrally coordinated Ru center with the arene residue occupying three sites, the remaining sites being occupied by a (carbene)C-Ru bond and two Ru-Cl bonds. The catalytic activity of [RuCl₂(η⁶,η ¹ -arene-CH₂-NHC)] complexes was evaluated in the direct (hetero)arylation of 2-phenylpyridine with (hetero)aryl chlorides in water as the nontoxic reaction medium. These results show that catalysts 2a and 2b were the best for monoarylation with simple phenyl and tolyl chlorides. For functional aryl chlorides, 2d , 2e , and 2c appeared to be the most efficient.

Electronic structure of the indium tin oxide/nanocrystalline anatase (TiO2)/ruthenium-dye interfaces in dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Lyon, J. E.; Rayan, M. K.; Beerbom, M. M.; Schlaf, R.

2008-10-01

The electronic structure of two interfaces commonly found in dye-sensitized photovoltaic cells based on nanocrystalline anatase TiO2 ("Grätzel cells") was investigated using photoemission spectroscopy (PES). X-ray photoemission spectroscopy (XPS) and ultraviolet photoemission spectroscopy (UPS) measurements were carried out on the indium tin oxide (ITO)/TiO2 and the TiO2/cis-bis(isothiocyanato)bis(2,2'-bipyridyl-4,4'-dicarboxylato)-ruthenium(II)bis-tetrabutylammonium dye ("N719" or "Ruthenium 535-bisTBA") interfaces. Both contacts were investigated using a multistep deposition procedure where the entire structure was prepared in vacuum using electrospray deposition. In between deposition steps the surface was characterized with XPS and UPS resulting in a series of spectra, allowing the determination of the orbital and band lineup at the interfaces. The results of these efforts confirm previous PES measurements on TiO2/dye contacts prepared under ambient conditions, suggesting that ambient contamination might not have significant influence on the electronic structure at the dye/TiO2 interface. The results also demonstrate that there may be a significant barrier for electron injection at the sputtered ITO/TiO2 interface and that this interface should be viewed as a semiconductor heterojunction rather than as metal-semiconductor (Schottky) contact.

Dependence of intramolecular electron-transfer rates on driving force, pH, and temperature in ammineruthenium-modified ferrocytochromes c

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

Wishart, J.F.; Sun, J.; Su, C.

1997-01-23

Several ruthenium ammine complexes were used to modify horse-heart cytochrome c at histidine-33, creating a series of (NH{sub 3}){sub 4}(L)Ru-Cyt c derivatives (L = H{sub 2}O/OH{sup -}, ammonia, 4-ethylpyridine, 3,5-lutidine, pyridine, isonicotinamide, N-methylpyrazinium) with a wide range of driving forces for Fe-to-Ru electron transfer (-{Delta}G{degree} = -0.125 to +0.46 eV). Electron-transfer rates and activation parameters were measured by pulse radiolysis using azide or carbonate radicals. The driving-force dependence of electron-transfer rates between redox centers of the same charge types obeys Marcus-Hush theory. The activationless rate limit for all of the ruthenium derivatives except the N-methylpyrazinium complex is 3.9x10{sup 5} s{supmore » -1}. Thermodynamic parameters obtained from nonisothermal differential pulse voltammetry show that the electron-transfer reactions are entropy-driven. The thermodynamic and kinetic effects of phosphate ion binding to the ruthenium center are examined. The rate of intramolecular electron transfer in (NH{sub 3}){sub 4}(isn)Ru{sup III}-Cyt c{sup II} decreases at high pH, with a midpoint at pH 9.1. 28 refs., 4 figs., 3 tabs.« less

Ruthenium Catalyzed Hydrohydroxyalkylation of Acrylates with Diols and α-Hydroxycarbonyl Compounds to Form Spiro- and α-Methylene-γ-Butyrolactones

PubMed Central

McInturff, Emma L.; Mowat, Jeffrey; Waldeck, Andrew R.; Krische, Michael J.

2013-01-01

Under the conditions of ruthenium(0) catalyzed hydrohydroxyalkylation, vicinal diols 1a–1l and methyl acrylate 2a are converted to the corresponding lactones 3a–3l in good to excellent yield. The reaction of methyl acrylate 2a with hydrobenzoin 1f, benzoin didehydro-1f, and benzil tetradehydro-1f form the same lactone 3f product, demonstrating that this process may be deployed in a redox level-independent manner. A variety of substituted acrylic esters 2a–2h participate in spirolactone formation, as illustrated in the conversion of N-benzyl-3-hydroxyoxindole 1o to cycloadducts 4a–4h. Hydrohydroxyalkylation of hydroxyl-substituted methacrylate 2i with diols 1b, 1f, 1j and 1l forms α-exo-methylene-γ-butyrolactones 5b, 5f, 5j and 5l in moderate to good yield. A catalytic cycle involving 1,2-dicarbonyl-acrylate oxidative coupling to form oxaruthenacyclic intermediates is postulated. A catalytically competent mononuclear ruthenium(II) complex was characterized by single crystal X-ray diffraction. The influence of electronic effects on regioselectivity in reactions of nonsymmetric diols were probed using para-substituted 1-phenyl-1,2-propanediols 1g, 1m and 1n and density functional theory (DFT) calculations. PMID:24187991

A series of terpyridine containing flexible amino diethylacetate derivatives with large two-photon action cross-sections for effective mitochondrial imaging in living liver cancerous cells

NASA Astrophysics Data System (ADS)

Jia, Ran; Zhu, Yingying; Hu, Lei; Xiong, Qiru; Zhao, Meng; Zhang, Mingzhu; Tian, Xiaohe

2018-01-01

Small molecules possess large two-photon action cross sections (Φσ) are highly demanded for biological purpose. Herein, three novel terpyridine containing flexible amino diethylacetate organic small molecules (A1, A2 and A3) were rationally designed and their photophysical properties were investigated both experimentally and theoretically. The results revealed that the three chromophores possess large Φσ and remarkable Stokes' shift in high polar solvents, which are particularly benefit for further biological imaging application. One chromophore (A1) displayed an effective intracellular uptake against lung cancerous living cells A549. Colocalization studies suggested the internalized subcellular compartment was mitochondria. Consequently, chromophore A1 provides a promising platform to directly monitor mitochondria in living cells under two-photon confocal laser scanning microscopy.

Transfer hydrogenation catalysis in cells as a new approach to anticancer drug design

PubMed Central

Soldevila-Barreda, Joan J.; Romero-Canelón, Isolda; Habtemariam, Abraha; Sadler, Peter J.

2015-01-01

Organometallic complexes are effective hydrogenation catalysts for organic reactions. For example, Noyori-type ruthenium complexes catalyse reduction of ketones by transfer of hydride from formate. Here we show that such catalytic reactions can be achieved in cancer cells, offering a new strategy for the design of safe metal-based anticancer drugs. The activity of ruthenium(II) sulfonamido ethyleneamine complexes towards human ovarian cancer cells is enhanced by up to 50 × in the presence of low non-toxic doses of formate. The extent of conversion of coenzyme NAD+ to NADH in cells is dependent on formate concentration. This novel reductive stress mechanism of cell death does not involve apoptosis or perturbation of mitochondrial membrane potentials. In contrast, iridium cyclopentadienyl catalysts cause cancer cell death by oxidative stress. Organometallic complexes therefore have an extraordinary ability to modulate the redox status of cancer cells. PMID:25791197

Metalorganic Chemical Vapor Deposition of Ruthenium-Doped Diamond like Carbon Films

NASA Technical Reports Server (NTRS)

Sunkara, M. K.; Ueno, M.; Lian, G.; Dickey, E. C.

2001-01-01

We investigated metalorganic precursor deposition using a Microwave Electron Cyclotron Resonance (ECR) plasma for depositing metal-doped diamondlike carbon films. Specifically, the deposition of ruthenium doped diamondlike carbon films was investigated using the decomposition of a novel ruthenium precursor, Bis(ethylcyclopentadienyl)-ruthenium (Ru(C5H4C2H5)2). The ruthenium precursor was introduced close to the substrate stage. The substrate was independently biased using an applied RF power. Films were characterized using Fourier Transform Infrared Spectroscopy (FTIR), Transmission Electron Microscopy (TEM) and Four Point Probe. The conductivity of the films deposited using ruthenium precursor showed strong dependency on the deposition parameters such as pressure. Ruthenium doped sample showed the presence of diamond crystallites with an average size of approx. 3 nm while un-doped diamondlike carbon sample showed the presence of diamond crystallites with an average size of 11 nm. TEM results showed that ruthenium was atomically dispersed within the amorphous carbon network in the films.

Total enantioselectivity in the DNA binding of the dinuclear ruthenium(II) complex [[Ru(Me2bpy)2]2(mu-bpm)]4+ [bpm = 2,2'-bipyrimidine; Me2bpy = 4,4'-dimethyl-2,2'-bipyridine].

PubMed

Smith, Jayden A; Collins, J Grant; Patterson, Bradley T; Keene, F Richard

2004-05-07

The binding of the three stereoisomers (DeltaDelta-, LambdaLambda- and DeltaLambda-) of the dinuclear ruthenium(II) complex [[Ru(Me2bpy)2]2(mu-bpm)]4+ [Me2bpy = 4,4'-dimethyl-2,2'-bipyridine; bpm = 2,2'-bipyrimidine] to a tridecanucleotide containing a single adenine bulge has been studied by 1H NMR spectroscopy. The addition of the DeltaDelta-isomer to d(CCGAGAATTCCGG)2 induced significant chemical shift changes for the base and sugar resonances of the residues at the bulge site (G3A4G5/C11C10), whereas small shifts were observed upon addition of the enantiomeric LambdaLambda-form. NOESY spectra of the tridecanucleotide bound with the DeltaDelta-isomer revealed intermolecular NOE's between the metal complex and the nucleotide residues at the bulge site, while only weak NOE's were observed to terminal residues to the LambdaLambda-form. Competitive binding studies were performed where both enantiomers were simultaneously added to the tridecanucleotide, and for all ratios of the two stereoisomers the DeltaDelta-isomer remained selectively bound at the bulge site with the LambdaLambda-enantiomer localised at the terminal regions of the tridecanucleotide. The meso-diastereoisomer (DeltaLambda) was found to bind to the tridecanucleotide with characteristics intermediate between the DeltaDelta- and LambdaLambda-enantiomers of the rac form. Two distinct sets of metal complex resonances were observed, with one set having essentially the same shift as the free metal complex, whilst the other set of resonances exhibited significant shifts. The NOE data indicated that the meso-diastereoisomer does not bind as selectively as the DeltaDelta-isomer, with NOE's observed to a greater number of nucleotide residues compared to the DeltaDelta-form. This study provides a rare example of total enantioselectivity in the binding of an inert transition metal complex to DNA, produced by the shape recognition of both ruthenium(II) centres.

Characterization And Dissolution Properties Of Ruthenium Oxides

EPA Science Inventory

Ruthenium oxides (RuO₂•1.10H₂O and RuO₂) have been synthesized by forced hydrolysis and oxidation of ruthenium chloride. The resulting materials were extensively characterized to determine the crystallinity, surface area, and ruthenium oxidation ...

cis-Bis(O-methyl­dithio­carbonato-κ2 S,S′)bis­(tri­phenyl­phosphane-κP)ruthenium(II)

PubMed Central

Valerio-Cárdenas, Cintya; Hernández-Ortega, Simón; Reyes-Martínez, Reyna; Morales-Morales, David

2013-01-01

In the title compound, [Ru(CH3OCS2)2(C18H15P)2], the RuII atom is in a distorted octa­hedral coordination by two xanthate anions (CH3OCS2) and two tri­phenyl­phosphane (PPh3) ligands. Both bidentate xanthate ligands coordinate the RuII atom with two slightly different Ru—S bond lengths but with virtually equal bite angles [71.57 (4) and 71.58 (3)°]. The packing of the complexes is assured by C—H⋯O and C—H⋯π inter­actions. PMID:24046578

Metal oxide films on metal

DOEpatents

Wu, Xin D.; Tiwari, Prabhat

1995-01-01

A structure including a thin film of a conductive alkaline earth metal oxide selected from the group consisting of strontium ruthenium trioxide, calcium ruthenium trioxide, barium ruthenium trioxide, lanthanum-strontium cobalt oxide or mixed alkaline earth ruthenium trioxides thereof upon a thin film of a noble metal such as platinum is provided.

Kinetics and Photochemistry of Ruthenium Bisbipyridine Diacetonitrile Complexes: An Interdisciplinary Inorganic and Physical Chemistry Laboratory Exercise

ERIC Educational Resources Information Center

Rapp, Teresa L.; Phillips, Susan R.; Dmochowski, Ivan J.

2016-01-01

The study of ruthenium polypyridyl complexes can be widely applied across disciplines in the undergraduate curriculum. Ruthenium photochemistry has advanced many fields including dye-sensitized solar cells, photoredox catalysis, lightdriven water oxidation, and biological electron transfer. Equally promising are ruthenium polypyridyl complexes…

Systematic syntheses and metalloligand doping of flexible porous coordination polymers composed of a Co(III)-metalloligand.

PubMed

Kobayashi, Atsushi; Suzuki, Yui; Ohba, Tadashi; Ogawa, Tomohiro; Matsumoto, Takeshi; Noro, Shin-ichiro; Chang, Ho-Chol; Kato, Masako

2015-03-16

A series of flexible porous coordination polymers (PCPs) RE-Co, composed of a Co(III)-metalloligand [Co(dcbpy)3](3-) (Co; H2dcbpy = 4,4'-dicarboxy-2,2'-bipyridine) and lanthanide cations (RE(3+) = La(3+), Ce(3+), Pr(3+), Nd(3+), Sm(3+), Eu(3+), Gd(3+), Tb(3+), Er(3+)), was systematically synthesized. X-ray crystallographic analysis revealed that the six carboxylates at the top of each coordination octahedron of Co(III)-metalloligand were commonly bound to RE(3+) cations to form a rock-salt-type porous coordination framework. When RE-Co contains a smaller and heavier RE(3+) cation than Nd(3+), the RE-Co crystallized in the cubic Fm-3m space group, whereas the other three RE-Co with larger RE(3+) crystallized in the lower symmetrical orthorhombic Fddd space group, owing to the asymmetric 10-coordinated bicapped square antiprism structure of the larger RE(3+) cation. Powder X-ray diffraction and vapor-adsorption isotherm measurements revealed that all synthesized RE-Co PCPs show reversible amorphous-crystalline transitions, triggered by water-vapor-adsorption/desorption. This transition behavior strongly depends on the kind of RE(3+); the transition of orthorhombic RE-Co was hardly observed under exposure to CH3OH vapor, but the RE-Co with smaller cations such as Gd(3+) showed the transition under exposure to CH3OH vapors. Further tuning of vapor-adsorption property was examined by doping of Ru(II)-metalloligands, [Ru(dcbpy)3](4-), [Ru(dcbpy)2Cl2](4-), [Ru(dcbpy)(tpy)Cl](-), and [Ru(dcbpy)(dctpy)](3-) (abbreviated as RuA, RuB, RuC, and RuD, respectively; tpy = 2,2':6',2″-terpyridine, H2dctpy = 4,4″-dicarboxy-2,2':6',2″-terpyridine), into the Co(III)-metalloligand site of Gd-Co to form the Ru(II)-doped PCP RuX@Gd-Co (X = A, B, C, or D). Three Ru(II)-metalloligands, RuA, RuB, and RuD dopants, were found to be uniformly incorporated into the Gd-Co framework by replacing the original Co(III)-metalloligand, whereas the doping of RuC failed probably because of the less number of coordination sites. In addition, we found that the RuA doping into the Gd-Co PCP had a large effect on vapor-adsorption due to the electrostatic interaction originating from the negatively charged RuA sites in the framework and the charge-compensating Li(+) cations in the porous channel.

Charge Transfer Between Quantum Dots and Peptide-Coupled Redox Complexes

DTIC Science & Technology

2009-01-01

labeled with reactive metal complexes includ- ing a ruthenium chelate (Ru), a bis-bipyridine ruthe- nium chelate (ruthenium-bpy), and a ferrocene metal...of unconjugated QDs and the metal complex–labeled peptides immobilized on indium tin oxide (ITO) electrodes. The ruthenium and ferrocene peptide...Ag/AgCI E v s. N H E E v s. v ac uu m (e V ) Ruthenium Ferrocene Ruthenium-bpy DHLA QDs DHLA-PEG QDs Quantum dot Metal complex CB VB E0X of QDs Fe

Cation Effects on the Electron-Acceptor Side of Photosystem II.

PubMed

Khan, Sahr; Sun, Jennifer S; Brudvig, Gary W

2015-06-18

The normal pathway of electron transfer on the electron-acceptor side of photosystem II (PSII) involves electron transfer from quinone A, QA, to quinone B, QB. It is possible to redirect electrons from QA(-) to water-soluble Co(III) complexes, which opens a new avenue for harvesting electrons from water oxidation by immobilization of PSII on electrode surfaces. Herein, the kinetics of electron transfer from QA(-) to [Co(III)(terpy)2](3+) (terpy = 2,2';6',2″-terpyridine) are investigated with a spectrophotometric assay revealing that the reaction follows Michaelis-Menten saturation kinetics, is inhibited by cations, and is not affected by variation of the QA reduction potential. A negatively charged site on the stromal surface of the PSII protein complex, composed of glutamic acid residues near QA, is hypothesized to bind cations, especially divalent cations. The cations are proposed to tune the redox properties of QA through electrostatic interactions. These observations may thus explain the molecular basis of the effect of divalent cations like Ca(2+), Sr(2+), Mg(2+), and Zn(2+) on the redox properties of the quinones in PSII, which has previously been attributed to long-range conformational changes propagated from divalent cations binding to the Ca(II)-binding site in the oxygen-evolving complex on the lumenal side of the PSII complex.

NADH Electrooxidation Using Bis(1,10-phenanthroline-5,6-dione) (2,2′-bipyridine)ruthenium(II)-Exchanged Zirconium Phosphate Modified Carbon Paste Electrodes

PubMed Central

Santiago, Mitk’El B.; Vélez, Meredith M.; Borrero, Solmarie; Díaz, Agustín; Casillas, Craig A.; Hofmann, Cristina; Guadalupe, Ana R.; Colón, Jorge L.

2007-01-01

We present a carbon paste electrode (CPE) modified using the electron mediator bis(1,10-phenanthroline-5,6-dione) (2,2′-bipyridine)ruthenium(II) ([Ru(phend)2bpy]2+) exchanged into the inorganic layered material zirconium phosphate (ZrP). X-Ray powder diffraction showed that the interlayer distance of ZrP increases upon [Ru(phend)2bpy]2+ intercalation from 10.3 Å to 14.2 Å. The UV-vis and IR spectroscopies results showed the characteristic peaks expected for [Ru(phend)2bpy]2+. The UV-vis spectrophotometric results indicate that the [Ru(phend)2bpy]2+ concentration inside the ZrP layers increased as a function of the loading level. The exchanged [Ru(phend)2bpy]2+ exhibited luminescence even at low concentration. Modified CPEs were constructed and analyzed using cyclic voltammetry. The intercalated mediator remained electroactive within the layers (E°′ = −38.5 mV vs. Ag/AgCl, 3.5 M NaCl) and electrocatalysis of NADH oxidation was observed. The kinetics of the modified CPE shows a Michaelis –Menten behavior. This CPE was used for the oxidation of NADH in the presence of Bakers’ yeast alcohol dehydrogenase. A calibration plot for ethanol is presented. PMID:18516242

Unveiling magnetic interactions of ruthenium trichloride via constraining direction of orbital moments: Potential routes to realize a quantum spin liquid

NASA Astrophysics Data System (ADS)

Hou, Y. S.; Xiang, H. J.; Gong, X. G.

2017-08-01

Recent experiments reveal that the honeycomb ruthenium trichloride α -RuC l3 is a prime candidate of the Kitaev quantum spin liquid (QSL). However, there is no theoretical model which can properly describe its experimental dynamical response due to the lack of a full understanding of its magnetic interactions. Here, we propose a general scheme to calculate the magnetic interactions in systems (e.g., α -RuC l3 ) with nonnegligible orbital moments by constraining the directions of orbital moments. With this scheme, we put forward a minimal J1-K1-Γ1-J3-K3 model for α -RuC l3 and find that: (I) The third nearest neighbor (NN) antiferromagnetic Heisenberg interaction J3 stabilizes the zigzag antiferromagnetic order; (II) The NN symmetric off-diagonal exchange Γ1 plays a pivotal role in determining the preferred direction of magnetic moments and generating the spin wave gap. An exact diagonalization study on this model shows that the Kitaev QSL can be realized by suppressing the NN symmetric off-diagonal exchange Γ1 and the third NN Heisenberg interaction J3. Thus, we not only propose a powerful general scheme for investigating the intriguing magnetism of Jeff=1 /2 magnets, but also point out future directions for realizing the Kitaev QSL in the honeycomb ruthenium trichloride α -RuC l3 .

Ruthenium(II) 2,2'-bibenzimidazole complex as a second-sphere receptor for anions interaction and colorimeter.

PubMed

Cui, Ying; Niu, Yan-Li; Cao, Man-Li; Wang, Ke; Mo, Hao-Jun; Zhong, Yong-Rui; Ye, Bao-Hui

2008-07-07

A ruthenium(II) complex [Ru(bpy) 2(H 2bbim)](PF 6) 2 ( 1) as anions receptor has been exploited, where Ru(II)-bpy moiety acts as a chromophore and the H 2bbim ligand as an anion binding site. A systematic study suggests that 1 interacts with the Cl (-), Br (-), I (-), NO 3 (-), HSO 4 (-), and H 2PO 4 (-) anions via the formation of hydrogen bonds. Whereas 1 undergoes a stepwise process with the addition of F (-) and OAc (-) anions: formation of the monodeprotonated complex [Ru(bpy) 2(Hbbim)] with a low anion concentration, followed by the double-deprotonated complex [Ru(bpy) 2(bbim)], in the presence of a high anion concentration. These stepwise processes concomitant with the changes of vivid colors from yellow to orange brown and then to violet can be used for probing the F (-) and OAc (-) anions by naked eye. The deprotonation processes are not only determined by the basicity of the anion but also related to the strength of hydrogen bonding, as well as the stability of the formed compounds. Moreover, a double-deprotonated complex [Ru(bpy) 2(bbim)].CH 3OH.H 2O ( 3) has been synthesized, and the structural changes induced by the deprotonation has also been investigated. In addition, complexes [Ru(bpy) 2(Hbbim)] 2(HOAc) 3Cl 2.12H 2O ( 2), [Ru(bpy) 2(Hbbim)](HCCl 3CO 2)(CCl 3CO 2).2H 2O ( 4), and [Ru(bpy) 2(H 2bbim)](CF 3CO 2) 2.4H 2O ( 5) have been synthesized to observe the second sphere coordination between the Ru(II)-H 2bbim moiety and carboxylate groups via hydrogen bonds in the solid state.

Intramolecular electron transfer in cyanide bridged adducts comprising Ru(II)/Ru(III) tetracarboxylate and [Mn(I)(CO)(CN)((t)BuNC)(4)] units.

PubMed

Imhof, Wolfgang; Sterzik, Anke; Krieck, Sven; Schwierz, Markus; Hoffeld, Thomas; Spielberg, Eike T; Plass, Winfried; Patmore, Nathan

2010-07-21

Reaction of mixed valence ruthenium tetracarboxylates [Ru(2)(II,III)(R(1)COO)(2)(R(2)COO)(2)Cl] (R(1) = Me, R(2) = 2,4,6-(i)Pr-Ph or R(1) = R(2) = (t)Bu) with two equivalents of the octahedral manganese complex [Mn(I)(CO)(CN)((t)BuNC)(4)] leads to the formation of cyanide bridged heteronuclear coordination compounds of the general formula {[Ru(2)(II,III)(R(1)COO)(2)(R(2)COO)(2)][Mn(I)(CO)(CN)((t)BuNC)(4)](2)}Cl. In solution an intramolecular electron transfer from manganese towards the multiply bonded Ru(2) core occurs that is verified by EPR and IR spectroscopy, magnetic measurements and DFT calculations. Nevertheless, disproportionation of an initially formed {Mn(I)-Ru(2)(II,III)-Mn(I)}(+) adduct into {Mn(II)-Ru(2)(II,III)-Mn(I)}(2+) and {Mn(I)-Ru(2)(II,II)-Mn(I)} species cannot be completely ruled out.

Co-sensitization of ruthenium(II) dye-sensitized solar cells by coumarin based dyes

NASA Astrophysics Data System (ADS)

Athanas, Anish Babu; Thangaraj, Shankar; Kalaiyar, Swarnalatha

2018-05-01

Co-sensitization technique has been appraised for attaining enhanced performance in dye-sensitized solar cells (DSSCs). DSSCs are fabricated with a heteroleptic Ru(II) sensitizer (RDAB1) containing 4,4‧-diamino-2,2‧-bipyridine (dabpy) ligand, co-sensitized with electron donor-acceptor type coumarin containing thiophene (CT) and indole (CI) moieties. The individual overall power conversion efficiency of the sensitizer is 5.44%. Enhanced power conversion efficiencies of 6.34% and 7.09% were observed when RDAB1 was co-sensitized with Coumarin containing CI and CT respectively. The enhanced PCE can be attributed to the presence of co-sensitizers which effectively overcome the light absorption by I-/I3-, dye aggregation and charge recombination.

Cell cycle, apoptosis, cellular uptake and whole-transcriptome microarray gene expression analysis of HeLa cells treated with a ruthenium(II)-arene complex with an isoquinoline-3-carboxylic acid ligand.

PubMed

Jovanović, Katarina K; Tanić, Miljana; Ivanović, Ivanka; Gligorijević, Nevenka; Dojčinović, Biljana P; Radulović, Siniša

2016-10-01

Ruthenium(II)-arene complexes are promising drug candidates for the therapy of solid tumors. In previous work, seven new compounds of the general formula [Ru(η 6 -p-cymene)(L 1-7 )Cl] were synthesized and characterized, of which the complex with L=isoquinoline-3-carboxylic acid (RuT 7 ) was two times as active on HeLa cells compared to normal cell line MRC-5, as indicated by IC 50 values determined after 48h of incubation (45.4±3.0 vs. 84.2±5.7μM, respectively). In the present study, cell cycle analysis of HeLa cells treated with RuT 7 showed S phase arrest and an increase in sub-G1 population. The apoptotic potential of the title compound was confirmed with the Annexin V-FITC/PI assay together with a morphological evaluation of cells using fluorescent microscopy. Analysis of the intracellular accumulation of ruthenium showed 8.9ng Ru/10 6 cells after 6h of incubation. To gain further insight in the molecular mechanism of action of RuT 7 on HeLa cells, a whole-transcriptome microarray gene expression analysis was performed. Analysis of functional categories and signaling and biochemical pathways associated with the response of HeLa cells to treatment with RuT 7 showed that it leads the cells through the intrinsic (mitochondrial) apoptotic pathway, via indirect DNA damage due to the action of reactive oxygen species, and through direct DNA binding of RuT 7 . Statistical analysis for enrichment of gene sets associated with known drug-induced toxicities identified fewer associated toxicity profiles in RuT 7 -treated cells compared to cisplatin treatment. Altogether these results provide the basis for further development of RuT 7 in animal and pre-clinical studies as a potential drug candidate. Copyright © 2016 Elsevier Inc. All rights reserved.

METABOLISM OF RUTHENIUM IN THE RAT. Technical Documentary Report

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

Traynor, J.E.; Leeper, S.W.

1961-12-01

Seventeen Sprague-Dawley rats were injected intramuscularly and intraperitoneally with ruthenium-106. The amount of this isotope was determined daily for 5 weeks in the urine and feces. Animals were sacrificed at intervals and the various organs were analyzed for ruthenium. It was noted from this experiment that the pathways of absorption, metabolism, and excretion are dependent on the route of administration of ruthenium. (auth)

Synthesis of PVP-stabilized ruthenium colloids with low boiling point alcohols.

PubMed

Zhang, Yuqing; Yu, Jiulong; Niu, Haijun; Liu, Hanfan

2007-09-15

A route to the preparation of poly(N-vinyl-2-pyrrolidone) (PVP)-stabilized ruthenium colloids by refluxing ruthenium(III) chloride in low boiling point alcohols was developed. Deep purple colloids with shuttle-like ruthenium particles were also synthesized. XPS measurement verified the nanoparticles were in the metallic state. The morphology of metal nanoparticles was characterized by UV-visible absorption spectrophotometry, TEM and XRD.

Hydrogen Bonding Rescues Overpotential in Seven-Coordinated Ru Water Oxidation Catalysts

DOE PAGES

Matheu, Roc; Ertem, Mehmed Z.; Gimbert-Surinach, Carolina; ...

2017-08-15

In this paper, we describe the synthesis, structural characterization, and redox properties of two new Ru complexes containing the dianionic potentially pentadentate [2,2':6',2"-terpyridine]-6,6"-dicarboxylate (tda 2–) ligand that coordinates Ru at the equatorial plane and with additional pyridine or dmso acting as monondentate ligand in the axial positions: [Ru II(tda-κ-N 3O)(py)(dmso)], 1 II and [Ru III(tda-κ-N 3O 2)(py)(H 2O) ax] +, 2 III(H 2O) +. Complex 1 II has been characterized by single-crystal XRD in the solid state and in solution by NMR spectroscopy. The redox properties of 1 II and 2 III(H 2O) + have been thoroughly investigated by meansmore » of cyclic voltammetry and differential pulse voltammetry. Complex 2 II(H 2O) displays poor catalytic activity with regard to the oxidation of water to dioxygen, and its properties have been analyzed on the basis of foot of the wave analysis and catalytic Tafel plots. The activity of 2 II(H 2O) has been compared with related water oxidation catalysts (WOCs) previously described in the literature. Despite its moderate activity, 2 II(H 2O) constitutes the cornerstone that has triggered the rationalization of the different factors that govern overpotentials as well as efficiencies in molecular WOCs. The present work uncovers the interplay between different parameters, namely, coordination number, number of anionic groups bonded to the first-coordination sphere of the metal center, water oxidation catalysis overpotential, p K a and hydrogen bonding, and the performance of a given WOC. It thus establishes the basic principles for the design of efficient WOCs operating at low overpotentials.« less

Alkene metathesis: the search for better catalysts.

PubMed

Deshmukh, Prashant H; Blechert, Siegfried

2007-06-28

Alkene metathesis catalyst development has made significant progress over recent years. Research in metathesis catalyst design has endeavoured to tackle three key issues: those of (i) catalyst efficiency and activity, (ii) substrate scope and selectivity--particularly stereoselective metathesis reactions--and (iii) the minimization of metal impurities and catalyst recycling. This article describes a brief history of metathesis catalyst development, followed by a survey of more recent research, with a particular emphasis on ruthenium catalysts.

Wavelength Independent Optical Lithography.

DTIC Science & Technology

1986-06-06

lamp because it has a smooth, broadband output in the visible and near UV. High Density Optical Intormation Storage The NSOM concept can be combined...stringent control can be maintained over the temperature of the entire apparatus. Ideally, both of these methods should be used. - . * S P. .~ V: -:V- TwT ...DNA helixes : enantiomers of tris(4, 7-diphenylpheanthroline)ruthenium (II). Proc. Natl. Acad. Sci. U.S.A. 81, 7 (1984). 27. J.M. Fernandez, E. Neher

Microsensors based on GaN semiconductors covalently functionalized with luminescent Ru(II) complexes.

PubMed

López-Gejo, Juan; Arranz, Antonio; Navarro, Alvaro; Palacio, Carlos; Muñoz, Elías; Orellana, Guillermo

2010-02-17

Covalent tethering of a Ru(II) dye to gallium nitride surfaces has been accomplished as a key step in the development of innovative sensing devices in which the indicator support (semiconductor) plays the role of both support and excitation source. Luminescence emission decays and time-resolved emission spectra confirm the presence of the dye on the semiconductor surfaces, while X-ray photoelectron spectroscopy proves its covalent bonding. The O(2) sensitivity of the new device is comparable to those of other ruthenium-based sensor systems. This achievement paves the way to a new generation of integrable ultracompact microsensors that combine semiconductor emitter-probe assemblies.

Ring-rearrangement metathesis of nitroso Diels-Alder cycloadducts.

PubMed

Vincent, Guillaume; Kouklovsky, Cyrille

2011-03-01

Strained nitroso Diels-Alder bicyclo[2.2.1] or [2.2.2] adducts functionalized with alkene side chains of diverse length undergo a ring-rearrangement metathesis process with external alkenes and Grubbs II or Hoveyda-Grubbs II ruthenium catalysts, under microwave irradiation or classical heating, to deliver cis-fused bicycles of various ring sizes, which contain a N-O bond. These scaffolds are of synthetic relevance for the generation of molecular diversity and to the total synthesis of alkaloids. The observation of unexpected reactions, such as epimerization or one-carbon homologation of the alkene side chain, is also reported. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electron-transfer quenching vs. exciplex-mediated quenching of the low-lying excited states in phthalocyanines

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

Prasad, D.R.; Ferraudi, G.

1983-05-25

Oxidative electron-transfer quenching of the lowest ligand-centered /sup 3/..pi pi..* of ruthenium (RU) phthalocyanines (pc)L/sub 2/, L = dimethylformamide (dmf) or pyridine (py), by a series of nitroaromatic compounds, viologen salts, and metal complexes has been investigated by laser and conventional flash photolysis. The quenching rate constants, treated according to Marcus-Hush and Rehm-Weller equations, gave self-exchange rate constants, k/sub exch/ approx. 10/sup 7/ M/sup -1/ s/sup -1/, for the electron exchange between the /sup 3/..pi pi..* and the ruthenium(II) ligand radical. The excited states of a number of phthalocyanines, e.g. Ru(pc)(dimethyl sulfoxide(Me/sub 2/SO)/sub 2/), Ru(pc)(dmf)CO, Ru(pc)(py)CO, and Rh(pc)(methanol(CH/sub 3/OH)chloride), undergomore » quenching mediated by exciplex formation. The formation of exciplexes is discussed in terms of the related exciplexes of the porphyrins.« less

Evaluation of optical excitation conditions for ruthenium complex for biosensor optodes

NASA Astrophysics Data System (ADS)

Pieper, Sean; Zhong, Zhong; Lear, Kevin L.; Reardon, Ken

2007-03-01

Development of a fiber optic biosensor incorporating genetically engineered enzymes which catalyze chlorinated ethenes in an oxygen-consuming reaction for in situ monitoring of groundwater contaminants motivates optimization of optode excitation conditions. These conditions affect the sensitivity, signal-to-noise, and optode service life impacting the quality of the overall biosensor. Optodes are generally comprised of a fluorophore conjugated with a polymer as a substrate cross linked at the distal end of a fiber optic. We investigate the excitation conditions of tris(4,7-diphenyl-1,10-phenanthroline) ruthenium(II) chloride (Ru(dpp)3) conjugated with poly(vinyl alcohol) (PVOH) as an optode. A reported advantage of Ru(dpp)3 is that it has no emission spectral shift occurring under varying chemical and environmental conditions. Photostability degradation due to photobleaching of Ru(dpp)3 with PVOH as a substrate is explored by varying the optical irradiance of the fluorophore containing optode. Other issues relating to practical implementation of Ru(dpp)3 as oxygen sensitive biosensors will be discussed.

Hydrogen storage and delivery: the carbon dioxide - formic acid couple.

PubMed

Laurenczy, Gábor

2011-01-01

Carbon dioxide and the carbonates, the available natural C1 sources, can be easily hydrogenated into formic acid and formates in water; the rate of this reduction strongly depends on the pH of the solution. This reaction is catalysed by ruthenium(II) pre-catalyst complexes with a large variety of water-soluble phosphine ligands; high conversions and turnover numbers have been realised. Although ruthenium(II) is predominant in these reactions, the iron(II) - tris[(2-diphenylphosphino)-ethyl]phosphine (PP3) complex is also active, showing a new perspective to use abundant and inexpensive iron-based compounds in the CO2 reduction. In the catalytic hydrogenation cycles the in situ formed metal hydride complexes play a key role, their structures with several other intermediates have been proven by multinuclear NMR spectroscopy. In the other hand safe and convenient hydrogen storage and supply is the fundamental question for the further development of the hydrogen economy; and carbon dioxide has been recognised to be a viable H2 vector. Formic acid--containing 4.4 weight % of H2, that is 53 g hydrogen per litre--is suitable for H2 storage; we have shown that in aqueous solutions it can be selectively decomposed into CO-free (CO < 10 ppm) CO2 and H2. The reaction takes place under mild experimental conditions and it is able to generate high pressure H2 (up to 600 bar). The cleavage of HCOOH is catalysed by several hydrophilic Ru(II) phosphine complexes (meta-trisulfonated triphenylphosphine, mTPPTS, being the most efficient one), either in homogeneous systems or as immobilised catalysts. We have also shown that the iron(II)--hydrido tris[(2-diphenylphosphino)ethyl]phosphine complex catalyses with an exceptionally high rate and efficiency (turnover frequency, TOF = 9425 h(-1)mol(-1); turnover number, TON = 92400) the formic acid cleavage, in environmentally friendly propylene carbonate solution, opening the way to use cheap, non-noble metal based catalysts for this reaction, too.

Design, synthesis, DNA-binding affinity, cytotoxicity, apoptosis, and cell cycle arrest of Ru(II) polypyridyl complexes.

PubMed

Venkat Reddy, Putta; Reddy, Mallepally Rajender; Avudoddi, Srishailam; Praveen Kumar, Yata; Nagamani, Chintakuntla; Deepika, Nancherla; Nagasuryaprasad, K; Singh, Surya Satyanarayana; Satyanarayana, Sirasani

2015-09-15

A novel polypyridyl ligand CNPFIP (CNPFIP=2-(5(4-chloro-2-nitrophenyl)furan-2-yl)-1H-imidazo[4,5f][1,10]phenanthroline) and its mononuclear Ru(II) polypyridyl complexes of [Ru(phen)2CNPFIP](2+)(1) (phen=1,10-phenanthroline), [Ru(bpy)2CNPFIP](2+)(2) (bpy=2,2'-bipyridine), and [Ru(dmb)2CNPFIP](2+)(3) (dmb=4,4'-dimethyl-2,2'-bipyridine) have been synthesized successfully and characterized thoroughly by elemental analysis, UV/Vis, IR, NMR, and ESI-MS. The interaction of the Ru(II) complexes with calf thymus DNA (CT-DNA) was investigated by absorption titration, fluorescence, viscosity measurements. The experimental results suggest that three complexes bind to CT-DNA through an intercalative mode and the DNA-binding affinity of complex 1 is greater than that of complexes 2 and 3. The photocleavage of plasmid pBR322 DNA by ruthenium complexes 1, 2, and 3 was investigated. We have also tested three complexes for their antimicrobial activity against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) bacteria. The in vitro cytotoxicity of these complexes was evaluated by MTT assay, and complex 1 shows higher cytotoxicity than 2 and 3 on HeLa cells. The induced apoptosis and cell cycle arrest of HeLa cells were investigated by flow cytometry for 24h. The molecular docking of ruthenium complexes 1, 2, and 3 with the active site pocket residues of human DNA TOP1 was performed using LibDock. Copyright © 2015 Elsevier Inc. All rights reserved.

Ferrocene and (arene)ruthenium(II) complexes of the natural anticancer naphthoquinone plumbagin with enhanced efficacy against resistant cancer cells and a genuine mode of action.

PubMed

Spoerlein-Guettler, Cornelia; Mahal, Katharina; Schobert, Rainer; Biersack, Bernhard

2014-09-01

A series of ferrocene and (arene)ruthenium(II) complexes attached to the naturally occurring anticancer naphthoquinones plumbagin and juglone was tested for efficacy against various cancer cell lines and for alterations in the mode of action. The plumbagin ferrocene and (p-cymene)Ru(II) conjugates 1c and 2a overcame the multi-drug drug resistance of KB-V1/Vbl cervix carcinoma cells and showed IC50 (72 h) values around 1 μM in growth inhibition assays using 3-(4,5-dimethyl-2-yl)-2,5-diphenyltetrazolium bromide (MTT). They were further investigated for their influence on the cell cycle of KB-V1/Vbl and HCT-116 colon carcinoma cells, on the generation of reactive oxygen species (ROS) by the latter cell line, for their substrate character for the P-glycoprotein drug eflux pump via the calcein-AM efflux assays, and for DNA affinity by the electrophoretic mobility shift assay (EMSA). The derivatives 1c and 2a increased the number of dead cancer cells (sub-G0/G1 fraction) in a dose- and time-dependent manner. ROS levels were significantly increased upon treatment with 1c and 2a. These compounds also showed a greater affinity to linear DNA than plumbagin. While plumbagin did not affect calcein-AM transport by P-glycoprotein the derivatives 1c and 2a exhibited a 50% or 80% inhibition of the P-glycoprotein-mediated calcein-AM efflux relative to the clinically established sensitizer verapamil. Copyright © 2014 Elsevier Inc. All rights reserved.

A novel dual-functioning ruthenium(II)-arene complex of an anti-microbial ciprofloxacin derivative - Anti-proliferative and anti-microbial activity.

PubMed

Ude, Ziga; Romero-Canelón, Isolda; Twamley, Brendan; Fitzgerald Hughes, Deirdre; Sadler, Peter J; Marmion, Celine J

2016-07-01

7-(4-(Decanoyl)piperazin-1-yl)-ciprofloxacin, CipA, (1) which is an analogue of the antibiotic ciprofloxacin, and its ruthenium(II) complex [Ru(η(6)-p-cymene)(CipA-H)Cl], (2) have been synthesised and the x-ray crystal structures of 1·1.3H2O·0.6CH3OH and 2·CH3OH·0.5H2O determined. The complex adopts a typical pseudo-octahedral 'piano-stool' geometry, with Ru(II) π-bonded to the p-cymene ring and σ-bonded to a chloride and two oxygen atoms of the chelated fluoroquinolone ligand. The complex is highly cytotoxic in the low μM range and is as potent as the clinical drug cisplatin against the human cancer cell lines A2780, A549, HCT116, and PC3. It is also highly cytotoxic against cisplatin- and oxaliplatin-resistant cell lines suggesting a different mechanism of action. The complex also retained low μM cytotoxicity against the human colon cancer cell line HCT116p53 in which the tumour suppressor p53 had been knocked out, suggesting that the potent anti-proliferative properties associated with this complex are independent of the status of p53 (in contrast to cisplatin). The complex also retained moderate anti-bacterial activity in two Escherichia coli, a laboratory strain and a clinical isolate resistant to first, second and third generation β-lactam antibiotics. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

A series of Ln-p-chlorobenzoic acid–terpyridine complexes: lanthanide contraction effects, supramolecular interactions and luminescent behavior

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

Carter, Korey P.; Pope, Simon J. A.; Cahill, Christopher L.

Fifteen new lanthanide p-chlorobenzoic acid complexes, [PrL3(terpy)(H2O)]2 (1), [LnL3(terpy)(H2O)]2 (Ln = Nd (2), Sm (3), and Eu (4)), and [LnL3(terpy)(H2O)] (Ln = Sm (3'), Eu (4'), Gd (5), Tb (6), Dy (7), Ho (8), Er (9), Tm (10), Yb (11), Lu (12), and Y (13); HL: p-chlorobenzoic acid; terpy: 2,2':6',2''-terpyridine), have been synthesized hydrothermally at varying temperatures and structurally characterized by single crystal and powder X-ray diffraction. The series is comprised of binuclear molecular units (Pr–Eu) that give way to mononuclear molecular complexes (Sm–Y) as the lanthanide contraction takes effect. All fifteen complexes feature a tridentate terpyridine ligand, p-chlorobenzoic acidmore » ligands exhibiting multiple binding modes, bidentate, bridging bidentate, and monodentate, and a bound water molecule. Binuclear complexes 1–4 are stitched together via intermolecular interactions: aromatic–aromatic interactions for 1, halogen•••halogen interactions for 2–4, to form 1D chains. Mononuclear complexes 3', 4', and 5–13 utilize supramolecular hydrogen and halogen bonding to form 2D sheets. Visible and near-IR solid state luminescence studies were performed on complexes 2, 3, 3', 4, 4', 6, 7 and 11 and the characteristic visible luminescence of Sm(III), Eu(III), Tb(III), and Dy(III) was exhibited. The near-IR spectra of the Nd(III) and Yb(III) complexes exhibit weak characteristic luminescence, showing that terpy can act as a sensitizing chromophore in these systems.« less

A ruthenium anticancer compound interacts with histones and impacts differently on epigenetic and death pathways compared to cisplatin

PubMed Central

Capuozzo, Antonelle; Ali, Moussa; Santamaria, Rita; Armant, Olivier; Delalande, Francois; Dorsselaer, Alain Van; Cianferani, Sarah; Spencer, John; Pfeffer, Michel; Mellitzer, Georg; Gaiddon, Christian

2017-01-01

Ruthenium complexes are considered as potential replacements for platinum compounds in oncotherapy. Their clinical development is handicapped by a lack of consensus on their mode of action. In this study, we identify three histones (H3.1, H2A, H2B) as possible targets for an anticancer redox organoruthenium compound (RDC11). Using purified histones, we confirmed an interaction between the ruthenium complex and histones that impacted on histone complex formation. A comparative study of the ruthenium complex versus cisplatin showed differential epigenetic modifications on histone H3 that correlated with differential expression of histone deacetylase (HDAC) genes. We then characterized the impact of these epigenetic modifications on signaling pathways employing a transcriptomic approach. Clustering analyses showed gene expression signatures specific for cisplatin (42%) and for the ruthenium complex (30%). Signaling pathway analyses pointed to specificities distinguishing the ruthenium complex from cisplatin. For instance, cisplatin triggered preferentially p53 and folate biosynthesis while the ruthenium complex induced endoplasmic reticulum stress and trans-sulfuration pathways. To further understand the role of HDACs in these regulations, we used suberanilohydroxamic acid (SAHA) and showed that it synergized with cisplatin cytotoxicity while antagonizing the ruthenium complex activity. This study provides critical information for the characterization of signaling pathways differentiating both compounds, in particular, by the identification of a non-DNA direct target for an organoruthenium complex. PMID:27935863

Septipyridines as conformationally controlled substitutes for inaccessible bis(terpyridine)-derived oligopyridines in two-dimensional self-assembly

PubMed Central

Caterbow, Daniel; Künzel, Daniela; Mavros, Michael G; Groß, Axel; Landfester, Katharina

2011-01-01

Summary The position of the peripheral nitrogen atoms in bis(terpyridine)-derived oligopyridines (BTPs) has a strong impact on their self-assembly behavior at the liquid/HOPG (highly oriented pyrolytic graphite) interface. The intermolecular hydrogen bonding interactions in these peripheral pyridine units show specific 2D structures for each BTP isomer. From nine possible constitutional isomers only four have been described in the literature. The synthesis and self-assembling behavior of an additional isomer is presented here, but the remaining four members of the series are synthetically inaccessible. The self-assembling properties of three of the missing four BTP isomers can be mimicked by making use of the energetically preferred N–C–C–N transoid conformation between 2,2'-bipyridine subunits in a new class of so-called septipyridines. The structures are investigated by scanning tunneling microscopy (STM) and a combination of force-field and first-principles electronic structure calculations. PMID:22003448

pH-Stable Eu- and Tb-organic-frameworks mediated by an ionic liquid for the aqueous-phase detection of 2,4,6-trinitrophenol (TNP).

PubMed

Qin, Jian-Hua; Wang, Hua-Rui; Han, Min-Le; Chang, Xin-Hong; Ma, Lu-Fang

2017-11-14

Two pH-stable luminescent metal-organic frameworks (LMOFs), {[Ln 2 (L) 2 (OH)(HCOO)]·[H 2 O]} n (Ln = Eu 1, Tb 2), based on a new π-conjugated organic building block involving both carboxylate and terpyridine groups were rationally synthesized under a combination of hydro/solvothermal and ionothermal conditions (H 2 L = 4'-(4-(3,5-dicarboxylphenoxy)phenyl)-4,2':6',4''-terpyridine). 1 and 2 are isostructural and feature noninterpenetrated open 3D condensed frameworks constructed by rod-shaped lanthanide-carboxylate building units. Their excellent water-stability and pH-stability allow them to be used in aquatic systems. 1 and 2 both exhibit selective and sensitive aqueous phase detection of the well-known nitroaromatic explosive environmental pollutant 2,4,6-trinitrophenol (TNP), which is highly desirable for practical applications. The presence of a free pyridine group on the LMOF particle surface was strategically utilized for the purpose of exclusive TNP-sensing.

Organometallic ruthenium anticancer complexes inhibit human glutathione-S-transferase π.

PubMed

Lin, Yu; Huang, Yongdong; Zheng, Wei; Wang, Fuyi; Habtemariam, Abraha; Luo, Qun; Li, Xianchan; Wu, Kui; Sadler, Peter J; Xiong, Shaoxiang

2013-11-01

The organometallic ruthenium(II) anticancer complexes [(η(6)-arene)Ru(en)Cl](+) (arene = p-cymene (1), biphenyl (2) or 9,10-dihydrophenanthrene (3); en = ethylenediamine), exhibit in vitro and in vivo anticancer activities. In the present work, we show that they inhibit human glutathione-S-transferase π (GSTπ) with IC50 values of 59.4 ± 1.3, 63.2 ± 0.4 and 37.2 ± 1.1 μM, respectively. Mass spectrometry revealed that complex 1 binds to the S-donors of Cys15, Cys48 within the G-site and Cys102 at the interface of the GSTπ dimer, while complex 2 binds to Cys48 and Met92 at the dimer interface and complex 3 to Cys15, Cys48 and Met92. Moreover, the binding of complex 1 to Cys15 and Cys102, complex 2 to Cys48 and complex 3 to Cys15 induces the irreversible oxidation of the coordinated thiolates to sulfenates. Molecular modeling studies indicate that the coordination of the {(arene)Ru(en)}(2+) fragment to Cys48 blocks the hydrophilic G-site sterically, perhaps preventing substrate from proper positioning and accounting for the reduction in enzymatic activity of ruthenated GSTπ. The binding of the ruthenium arene complexes to Cys102 or Met92 disrupts the dimer interface which is an essential structural feature for the proper functioning of GSTπ, perhaps also contributing to the inhibition of GSTπ. © 2013.

Solvothermal growth of a ruthenium metal-organic framework featuring HKUST-1 structure type as thin films on oxide surfaces.

PubMed

Kozachuk, Olesia; Yusenko, Kirill; Noei, Heshmat; Wang, Yuemin; Walleck, Stephan; Glaser, Thorsten; Fischer, Roland A

2011-08-14

Phase-pure crystalline thin films of a mixed-valence Ru(2)(II,III) metal-organic framework with 1,3,5-benzenetricarboxylate (btc) as a linker were solvothermally grown on amorphous alumina and silica surfaces. Based on the Rietveld refinement, the structure of Ru-MOF was assigned to be analogous to [Cu(3)(btc)(2)] (HKUST-1). This journal is © The Royal Society of Chemistry 2011

DNA interaction, antioxidant activity, and bioactivity studies of two ruthenium(II) complexes

NASA Astrophysics Data System (ADS)

Han, Bing-Jie; Jiang, Guang-Bin; Yao, Jun-Hua; Li, Wei; Wang, Ji; Huang, Hong-Liang; Liu, Yun-Jun

2015-01-01

Two new ruthenium(II) polypyridyl complexes [Ru(dmb)2(dcdppz)](ClO4)2 (1) and [Ru(bpy)2(dcdppz)](ClO4)2 (2) were prepared and characterized. The crystal structure of the complex 2 was solved by single crystal X-ray diffraction. The complex crystallizes in the monoclinic system, space group P21/n with a = 12.9622(14) Å, b = 17.1619(19) Å, c = 22.7210(3) Å, β = 100.930(2)°, R = 0.0536, Rω = 0.1111. The DNA-binding constants for complexes 1 and 2 were determined to be 1.92 × 105 (s = 1.72) and 2.24 × 105 (s = 1.86) M-1, respectively. The DNA-binding behaviors showed that complexes 1 and 2 interact with DNA by intercalative mode. The antioxidant activities of the ligand and the complexes were performed. Ligand, dcdppz, has no cytotoxicity against the selected cell lines. Complex 1 shows higher cytotoxicity than complex 2, but lower than cisplatin toward selected cell lines. The apoptosis and cell cycle arrest were investigated, and the apoptotic mechanism of BEL-7402 cells was studied by reactive oxygen species (ROS), mitochondrial membrane potential and western blot analysis. Complex 1 induces apoptosis in BEL-7402 cells through ROS-mediated mitochondrial dysfunction pathway and by regulating the expression of Bcl-2 family proteins.

Synthesis, Characterization, Cytotoxic Activity, and Interactions with CT-DNA and BSA of Cationic Ruthenium(II) Complexes Containing Dppm and Quinoline Carboxylates

PubMed Central

da Silva, Edinaldo N.; da Silva, Paulo A. B.; Graminha, Angélica E.; de Oliveira, Pollyanna F.; Damasceno, Jaqueline L.; Tavares, Denise C.; Batista, Alzir A.

2017-01-01

The complexes cis-[Ru(quin)(dppm)2]PF6 and cis-[Ru(kynu)(dppm)2]PF6 (quin = quinaldate; kynu = kynurenate; dppm = bis(diphenylphosphino)methane) were prepared and characterized by elemental analysis, electronic, FTIR, 1H, and 31P{1H} NMR spectroscopies. Characterization data were consistent with a cis arrangement for the dppm ligands and a bidentate coordination through carboxylate oxygens of the quin and kynu anions. These complexes were not able to intercalate CT-DNA as shown by circular dichroism spectroscopy. On the other hand, bovine serum albumin (BSA) binding constants and thermodynamic parameters suggest spontaneous interactions with this protein by hydrogen bonds and van der Waals forces. Cytotoxicity assays were carried out on a panel of human cancer cell lines including HepG2, MCF-7, and MO59J and one normal cell line GM07492A. In general, the new ruthenium(II) complexes displayed a moderate to high cytotoxicity in all the assayed cell lines with IC50 ranging from 10.1 to 36 µM and were more cytotoxic than the precursor cis-[RuCl2(dppm)2]. The cis-[Ru(quin)(dppm)2]PF6 were two to three times more active than the reference metallodrug cisplatin in the MCF-7 and MO59J cell lines. PMID:28814948

Ruthenium(II) piano stool coordination compounds with aminomethylphosphanes: Synthesis, characterisation and preliminary biological study in vitro.

PubMed

Płotek, Michał; Starosta, Radosław; Komarnicka, Urszula K; Skórska-Stania, Agnieszka; Kołoczek, Przemysław; Kyzioł, Agnieszka

2017-05-01

Reaction of {[Ru(η 6 -p-cymene)Cl] 2 (μ-Cl) 2 } (1) with aminomethylphosphane derived from morpholine (P{CH 2 N(CH 2 CH 2 ) 2 O} 3 (A), PPh 2 {CH 2 N(CH 2 CH 2 ) 2 O} (B)) or piperazine (P{CH 2 N(CH 2 CH 2 ) 2 NCH 2 CH 3 } 3 (C), PPh 2 {CH 2 N(CH 2 CH 2 ) 2 NCH 2 CH 3 } (D)) results in four new piano stool ruthenium(II) coordination compounds: [Ru(η 6 -p-cymene)Cl 2 (A)] (2A), [Ru(η 6 -p-cymene)Cl 2 (B)] (2B), [Ru(η 6 -p-cymene)Cl 2 (C)] (2C) and [Ru(η 6 -p-cymene)Cl 2 (D)] (2D). Every complex was fully characterized using spectroscopic methods ( 1 H, 13 C{ 1 H}, 31 P{ 1 H} NMR and ESI-MS), elemental analysis, X-ray single crystal diffraction and DFT calculations. Preliminary studies of in vitro cytotoxicity on the A549 (human lung adenocarcinoma) and MCF7 (human breast adenocarcinoma) cell lines revealed 2A-2D activity in the same order of magnitude as in the case of cisplatin. Additionally, the study confirmed the ability of 2A-2D to interact with DNA helix and transferrin. Copyright © 2017 Elsevier Inc. All rights reserved.

Electrospinning processed nanofibrous TiO2 membranes for photovoltaic applications

NASA Astrophysics Data System (ADS)

Onozuka, Katsuhiro; Ding, Bin; Tsuge, Yosuke; Naka, Takayuki; Yamazaki, Michiyo; Sugi, Shinichiro; Ohno, Shingo; Yoshikawa, Masato; Shiratori, Seimei

2006-02-01

We have recently fabricated dye-sensitized solar cells (DSSCs) comprising nanofibrous TiO2 membranes as electrode materials. A thin TiO2 film was pre-deposited on fluorine doped tin oxide (FTO) coated conducting glass substrate by immersion in TiF4 aqueous solution to reduce the electron back-transfer from FTO to the electrolyte. The composite polyvinyl acetate (PVac)/titania nanofibrous membranes can be deposited on the pre-deposited thin TiO2 film coated FTO by electrospinning of a mixture of PVac and titanium isopropoxide in N,N-dimethylformamide (DMF). The nanofibrous TiO2 membranes were obtained by calcining the electrospun composite nanofibres of PVac/titania as the precursor. Spectral sensitization of the nanofibrous TiO2 membranes was carried out with a ruthenium (II) complex, cis-dithiocyanate-N,N'-bis(2,2'-bipyridyl-4,4'-dicarboxylic acid) ruthenium (II) dihydrate. The results indicated that the photocurrent and conversion efficiency of electrodes can be increased with the addition of the pre-deposited TiO2 film and the adhesion treatment using DMF. Additionally, the dye loading, photocurrent, and efficiency of the electrodes were gradually increased by increasing the average thickness of the nanofibrous TiO2 membranes. The efficiency of the fibrous TiO2 photoelectrode with the average membrane thickness of 3.9 µm has a maximum value of 4.14%.

Using ruthenium sawhorse based decarboxylation to produce industrial materials from oleic acid

USDA-ARS?s Scientific Manuscript database

Ruthenium catalyzed isomerization and decarboxylation of 9-cis-octadecenoic acid are reported as part of the effort to produce valuable industrial materials from biobased sources. Initial studies have demonstrated the efficacy of ruthenium sawhorse materials and further mechanistic studies uncovered...

Metal-metal interactions in linear tri-, penta-, hepta-, and nona-nuclear ruthenium string complexes.

PubMed

Niskanen, Mika; Hirva, Pipsa; Haukka, Matti

2012-05-01

Density functional theory (DFT) methodology was used to examine the structural properties of linear metal string complexes: [Ru(3)(dpa)(4)X(2)] (X = Cl(-), CN(-), NCS(-), dpa = dipyridylamine(-)), [Ru(5)(tpda)(4)Cl(2)], and hypothetical, not yet synthesized complexes [Ru(7)(tpta)(4)Cl(2)] and [Ru(9)(ppta)(4)Cl(2)] (tpda = tri-α-pyridyldiamine(2-), tpta = tetra-α-pyridyltriamine(3-), ppta = penta-α-pyridyltetraamine(4-)). Our specific focus was on the two longest structures and on comparison of the string complexes and unsupported ruthenium backboned chain complexes, which have weaker ruthenium-ruthenium interactions. The electronic structures were studied with the aid of visualized frontier molecular orbitals, and Bader's quantum theory of atoms in molecules (QTAIM) was used to study the interactions between ruthenium atoms. The electron density was found to be highest and distributed most evenly between the ruthenium atoms in the hypothetical [Ru(7)(tpta)(4)Cl(2)] and [Ru(9)(ppta)(4)Cl(2)] string complexes.

Ligand-to-ligand charge-transfer transitions of platinum(II) complexes with arylacetylide ligands with different chain lengths: spectroscopic characterization, effect of molecular conformations, and density functional theory calculations.

PubMed

Tong, Glenna So Ming; Law, Yuen-Chi; Kui, Steven C F; Zhu, Nianyong; Leung, King Hong; Phillips, David Lee; Che, Chi-Ming

2010-06-11

The complexes [Pt(tBu(3)tpy){C[triple bond]C(C(6)H(4)C[triple bond]C)(n-1)R}](+) (n = 1: R = alkyl and aryl (Ar); n = 1-3: R = phenyl (Ph) or Ph-N(CH(3))(2)-4; n = 1 and 2, R = Ph-NH(2)-4; tBu(3)tpy = 4,4',4''-tri-tert-butyl-2,2':6',2''-terpyridine) and [Pt(Cl(3)tpy)(C[triple bond]CR)](+) (R = tert-butyl (tBu), Ph, 9,9'-dibutylfluorene, 9,9'-dibutyl-7-dimethyl-amine-fluorene; Cl(3)tpy = 4,4',4''-trichloro-2,2':6',2''-terpyridine) were prepared. The effects of substituent(s) on the terpyridine (tpy) and acetylide ligands and chain length of arylacetylide ligands on the absorption and emission spectra were examined. Resonance Raman (RR) spectra of [Pt(tBu(3)tpy)(C[triple bond]CR)](+) (R = n-butyl, Ph, and C(6)H(4)-OCH(3)-4) obtained in acetonitrile at 298 K reveal that the structural distortion of the C[triple bond]C bond in the electronic excited state obtained by 502.9 nm excitation is substantially larger than that obtained by 416 nm excitation. Density functional theory (DFT) and time-dependent DFT (TDDFT) calculations on [Pt(H(3)tpy)(C[triple bond]CR)](+) (R = n-propyl (nPr), 2-pyridyl (Py)), [Pt(H(3)tpy){C[triple bond]C(C(6)H(4)C[triple bond]C)(n-1)Ph}](+) (n = 1-3), and [Pt(H(3)tpy){C[triple bond]C(C(6)H(4)C[triple bond]C)(n-1)C(6)H(4)-N(CH(3))(2)-4}](+)/+H(+) (n = 1-3; H(3)tpy = nonsubstituted terpyridine) at two different conformations were performed, namely, with the phenyl rings of the arylacetylide ligands coplanar ("cop") with and perpendicular ("per") to the H(3)tpy ligand. Combining the experimental data and calculated results, the two lowest energy absorption peak maxima, lambda(1) and lambda(2), of [Pt(Y(3)tpy)(C[triple bond]CR)](+) (Y = tBu or Cl, R = aryl) are attributed to (1)[pi(C[triple bond]CR)-->pi*(Y(3)tpy)] in the "cop" conformation and mixed (1)[d(pi)(Pt)-->pi*(Y(3)tpy)]/(1)[pi(C[triple bond]CR)-->pi*(Y(3)tpy)] transitions in the "per" conformation. The lowest energy absorption peak lambda(1) for [Pt(tBu(3)tpy){C[triple bond]C(C(6)H(4)C[triple bond]C)(n-1)C(6)H(4)-H-4}](+) (n = 1-3) shows a redshift with increasing chain length. However, for [Pt(tBu(3)tpy){C[triple bond]C(C6H4C[triple bond]C)(n-1)C(6)H(4)-N(CH(3))(2)-4}](+) (n = 1-3), lambda(1) shows a blueshift with increasing chain length n, but shows a redshift after the addition of acid. The emissions of [Pt(Y(3)tpy)(C[triple bond]CR)](+) (Y = tBu or Cl) at 524-642 nm measured in dichloromethane at 298 K are assigned to the (3)[pi(C[triple bond]CAr)-->pi*(Y(3)tpy)] excited states and mixed (3)[d(pi)(Pt)-->pi*(Y(3)tpy)]/(3)[pi(C[triple bond]C)-->pi*(Y(3)tpy)] excited states for R = aryl and alkyl groups, respectively. [Pt(tBu(3)tpy){C[triple bond]C(C(6)H(4)C[triple bond]C)(n-1)C(6)H(4)-N(CH(3))(2)-4}](+) (n = 1 and 2) are nonemissive, and this is attributed to the small energy gap between the singlet ground state (S(0)) and the lowest triplet excited state (T(1)).

Ruthenium on chitosan: A recyclable heterogeneous catalyst for aqueous hydration of nitriles to amides

EPA Science Inventory

Ruthenium has been immobilized over chitosan by simply stirring an aqueous suspension of chitosan in water with ruthenium chloride and has been utilized for the oxidation of nitriles to amides; the hydration of nitriles occurs in high yield and excellent selectivity, which procee...

Magnetic Silica-Supported Ruthenium Nanoparticles: An Efficient Catalyst for Transfer Hydrogenation of Carbonyl Compounds

EPA Science Inventory

One-pot synthesis of ruthenium nanoparticles on magnetic silica is described which involve the in situ generation of magnetic silica (Fe3O4@ SiO2) and ruthenium nano particles immobilization; the hydration of nitriles and transfer hydrogenation of carbonyl compounds occurs in hi...

PROCESS FOR DECONTAMINATING THORIUM AND URANIUM WITH RESPECT TO RUTHENIUM

DOEpatents

Meservey, A.A.; Rainey, R.H.

1959-10-20

The control of ruthenium extraction in solvent-extraction processing of neutron-irradiated thorium is presented. Ruthenium is rendered organic-insoluble by the provision of sulfite or bisulfite ions in the aqueous feed solution. As a result the ruthenium remains in the aqueous phase along with other fission product and protactinium values, thorium and uranium values being extracted into the organic phase. This process is particularly applicable to the use of a nitrate-ion-deficient aqueous feed solution and to the use of tributyl phosphate as the organic extractant.

Photoinduced oxidation of a water-soluble manganese(III) porphyrin

PubMed Central

Maliyackel, Anthony C.; Otvos, John W.; Spreer, Larry O.; Calvin, Melvin

1986-01-01

The photoinduced oxidation of tetra(N-methyl-4-pyridyl)porphyrinmanganese(III) has been achieved in homogeneous solution. The manganese porphyrin was used as an electron donor in a three-component system with tris-(2,2′-bipyridine)ruthenium(II) as the photosensitizer and chloropentaamminecobalt(III) as the electron acceptor. The photooxidized manganese porphyrin is unstable in aqueous solution, reverting to the starting manganese(III) porphyrin. The oxidation of manganese(III) porphyrin and the subsequent reduction of the oxidized porphyrin can be cycled repeatedly. PMID:16593699

Molecular recognition in protein modification with rhodium metallopeptides

PubMed Central

Ball, Zachary T.

2015-01-01

Chemical manipulation of natural, unengineered proteins is a daunting challenge which tests the limits of reaction design. By combining transition-metal or other catalysts with molecular recognition ideas, it is possible to achieve site-selective protein reactivity without the need for engineered recognition sequences or reactive sites. Some recent examples in this area have used ruthenium photocatalysis, pyridine organocatalysis, and rhodium(II) metallocarbene catalysis, indicating that the fundamental ideas provide opportunities for using diverse reactivity on complex protein substrates and in complex cell-like environments. PMID:25588960

An estrogen receptor targeted ruthenium complex as a two-photon photodynamic therapy agent for breast cancer cells.

PubMed

Zhao, Xueze; Li, Mingle; Sun, Wen; Fan, Jiangli; Du, Jianjun; Peng, Xiaojun

2018-06-21

In this study, we reported a tamoxifen modified Ru(ii) polypyridyl complex (Ru-tmxf) as an estrogen receptor (ER) targeted photosensitizer. Ru-tmxf displays enhanced cellular uptake and PDT efficiency toward breast cancer cells with high ER expression due to the specific targeting of tamoxifen to ER and finally localizes in lysosomes. Moreover, Ru-tmxf can be activated by two-photon excitation, generating 1O2 to damage lysosomes and result in cell death.

Preparation and reactivity of mixed-ligand ruthenium(II) hydride complexes with phosphites and polypyridyls.

PubMed

Albertin, Gabriele; Antoniutti, Stefano; Bacchi, Alessia; D'Este, Claudia; Pelizzi, Giancarlo

2004-02-23

Chloro complexes [RuCl(N-N)P3]BPh4 (1-3) [N-N = 2,2'-bipyridine, bpy; 1,10-phenanthroline, phen; 5,5'-dimethyl-2,2'-bipyridine, 5,5'-Me2bpy; P = P(OEt)3, PPh(OEt)2 and PPh2OEt] were prepared by allowing the [RuCl4(N-N)].H2O compounds to react with an excess of phosphite in ethanol. The bis(bipyridine) [RuCl(bpy)2[P(OEt)3

Synthesis and spectroscopic studies of Ru(II) complexes of steroidal thiosemicarbazones by multi step reaction: As anti-bacterial agents.

PubMed

Khan, Salman A; Asiri, Abdullah M

2017-08-01

Ru(II) steroidal metal complexes were synthesized by the reaction of dichlorodicarbonyl ruthenium(II) [Ru(CO) 2 Cl 2 ] n with Steroidal thiosemicarbazones. Coordination via the thionic sulfur and the azomethine nitrogen atom of the thiosemicarbazone to the Ru(II) metal. Steroidal thiosemicarbazone derivatives were obtained by the thiosemicarbazide with steroidal ketones. Structures of the steroidal thiosemicarbazone and their metal complexes were confirmed by the FT-IR, 1 H NMR, 13 C NMR, Fab-Mass spectroscopy and elemental analysis. The antibacterial activity of these compounds were first tested in vitro by the disk diffusion assay against two Gram-positive and two Gram-negative bacteria, and then the minimum inhibitory concentration (MIC) was determined. The results showed that steroidal Ru(II) complexes are better inhibit growth as compared to steroidal thiosemicarbazones of both types of the bacteria (gram-positive and gram-negative). Copyright © 2017 Elsevier Inc. All rights reserved.

Ultrasensitive apurinic/apyrimidinic endonuclease 1 immunosensing based on self-enhanced electrochemiluminescence of a Ru(II) complex.

PubMed

Zhuo, Ying; Liao, Ni; Chai, Ya-Qin; Gui, Guo-Feng; Zhao, Min; Han, Jing; Xiang, Yun; Yuan, Ruo

2014-01-21

An alternative "signal on" immunosensor for ultrasensitive detection of apurinic/apyrimidinic endonuclease 1 (APE-1) was designed utilizing the self-enhanced electrochemiluminescence (ECL) of a novel Ru(II) complex functionalized coil-like nanocomposite as signal labels. The desirable self-enhanced ECL luminophore was achieved by combining the coreactant of poly(ethylenimine) (PEI) and the luminophor of bis(2,2'-bipyridine)-5-amino-1,10-phenanthroline ruthenium(II) [Ru(bpy)2(5-NH2-1,10-phen)(2+)] to form one novel Ru(II) complex, which exhibited significantly enhanced ECL efficiency and stability. Moreover, the carbon nanotubes (CNTs) were employed as nanocarriers for self-enhanced Ru(II) complex loading via π-π stacking to obtain the coil-like nanocomposite to act as signal probe. Compared with traditional ECL immunoassay, our proposed strategy is simple and sensitive, avoiding the adding of any coreactant into testing solution for signal amplification, and shows a detection limit down to subfemtogram per milliliter level under the optimized experimental condition.

Ruthenium(II) bipyridine complexes bearing new keto-enol azoimine ligands: synthesis, structure, electrochemistry and DFT calculations.

PubMed

Al-Noaimi, Mousa; Awwadi, Firas F; Mansi, Ahmad; Abdel-Rahman, Obadah S; Hammoudeh, Ayman; Warad, Ismail

2015-01-25

The novel azoimine ligand, Ph-NH-N=C(COCH3)-NHPh(C≡CH) (H2L), was synthesized and its molecular structure was determined by X-ray crystallography. Catalytic hydration of the terminal acetylene of H2L in the presence of RuCl3·3H2O in ethanol at reflux temperature yielded a ketone (L1=Ph-N=N-C(COCH3)=N-Ph(COCH3) and an enol (L2=Ph-N=N-C(COCH3)=N-PhC(OH)=CH2) by Markovnikov addition of water. Two mixed-ligand ruthenium complexes having general formula, trans-[Ru(bpy)(Y)Cl2] (1-2) (where Y=L1 (1) and Y=L2 (2), bpy is 2.2'-bipyrdine) were achieved by the stepwise addition of equimolar amounts of (H2L) and bpy ligands to RuCl3·3H2O in absolute ethanol. Theses complexes were characterized by elemental analyses and spectroscopic (IR, UV-Vis, and NMR (1D (1)H NMR, (13)C NMR, (DEPT-135), (DEPT-90), 2D (1)H-(1)H and (13)C-(1)H correlation (HMQC) spectroscopy)). The two complexes exhibit a quasi-reversible one electron Ru(II)/Ru(III) oxidation couple at 604 mV vs. ferrocene/ferrocenium (Cp2Fe(0/+)) couple along with one electron ligand reduction at -1010 mV. The crystal structure of complex 1 showed that the bidentate ligand L1 coordinates to Ru(II) by the azo- and imine-nitrogen donor atoms. The complex adopts a distorted trans octahedral coordination geometry of chloride ligands. The electronic spectra of 1 and 1+ in dichloromethane have been modeled by time-dependent density functional theory (TD-DFT). Copyright © 2014 Elsevier B.V. All rights reserved.

Design and development of novel MRI compatible zirconium- ruthenium alloys with ultralow magnetic susceptibility.

PubMed

Li, H F; Zhou, F Y; Li, L; Zheng, Y F

2016-04-19

In the present study, novel MRI compatible zirconium-ruthenium alloys with ultralow magnetic susceptibility were developed for biomedical and therapeutic devices under MRI diagnostics environments. The results demonstrated that alloying with ruthenium into pure zirconium would significantly increase the strength and hardness properties. The corrosion resistance of zirconium-ruthenium alloys increased significantly. High cell viability could be found and healthy cell morphology observed when culturing MG 63 osteoblast-like cells and L-929 fibroblast cells with zirconium-ruthenium alloys, whereas the hemolysis rates of zirconium-ruthenium alloys are <1%, much lower than 5%, the safe value for biomaterials according to ISO 10993-4 standard. Compared with conventional biomedical 316L stainless steel, Co-Cr alloys and Ti-based alloys, the magnetic susceptibilities of the zirconium-ruthenium alloys (1.25 × 10(-6) cm(3)·g(-1)-1.29 × 10(-6) cm(3)·g(-1) for zirconium-ruthenium alloys) are ultralow, about one-third that of Ti-based alloys (Ti-6Al-4V, ~3.5 × 10(-6) cm(3)·g(-1), CP Ti and Ti-6Al-7Nb, ~3.0 × 10(-6) cm(3)·g(-1)), and one-sixth that of Co-Cr alloys (Co-Cr-Mo, ~7.7 × 10(-6) cm(3)·g(-1)). Among the Zr-Ru alloy series, Zr-1Ru demonstrates enhanced mechanical properties, excellent corrosion resistance and cell viability with lowest magnetic susceptibility, and thus is the optimal Zr-Ru alloy system as therapeutic devices under MRI diagnostics environments.

A facile one-pot synthesis of ruthenium hydroxide nanoparticles on magnetic silica: Aqueous hydration of nitriles to amides

EPA Science Inventory

One-pot synthesis of ruthenium hydroxide nanoparticles on magnetic silica is described which involve the in situ generation of magnetic silica (Fe3O4@ SiO2) and ruthenium hydroxide immobilization; the hydration of nitriles occurs in high yield and excellent selectivity using this...

Synergy between the metal nanoparticles and the support for the hydrogenation of functionalized carboxylic acids to diols on Ru/TiO2.

PubMed

Primo, Ana; Concepción, Patricia; Corma, Avelino

2011-03-28

Ruthenium nanoparticles supported on titania are over three times more active than conventional ruthenium on carbon for the hydrogenation of lactic acid. This superior catalytic activity can be due to a combined action of small ruthenium nanoparticles and the titania support.

Platinum-ruthenium-palladium fuel cell electrocatalyst

DOEpatents

Gorer, Alexander

2006-02-07

A catalyst suitable for use in a fuel cell, especially as an anode catalyst, that contains platinum at a concentration that is between about 20 and about 60 atomic percent, ruthenium at a concentration that is between about 20 and about 60 atomic percent, palladium at a concentration that is between about 5 and about 45 atomic percent, and having an atomic ratio of platinum to ruthenium that is between about 0.7 and about 1.2. Alternatively, the catalyst may contain platinum at a concentration that is between about 25 and about 50 atomic percent, ruthenium at a concentration that is between about 25 and about 55 atomic percent, palladium at a concentration that is between about 5 and about 45 atomic percent, and having a difference between the concentrations of ruthenium and platinum that is no greater than about 20 atomic percent.

Photodamage of a Mn(III/IV)-oxo mixed-valence compound and photosystem II: evidence that a high-valent manganese species is responsible for UV-induced photodamage of the oxygen-evolving complex in photosystem II.

PubMed

Wei, Zi; Cady, Clyde W; Brudvig, Gary W; Hou, Harvey J M

2011-01-01

The Mn cluster in photosystem II (PS II) is believed to play an important role in the UV photoinhibition of green plants, but the mechanism is still not clear at a molecular level. In this work, the photochemical stability of [Mn(III)(O)(2)Mn(IV)(H(2)O)(2)(Terpy)(2)](NO(3))(3) (Terpy=2,2':6',2''-terpyridine), designated as Mn-oxo mixed-valence dimer, a well characterized functional model of the oxygen-evolving complex in PS II, was examined in aqueous solution by exposing the complex to excess light irradiation at six different wavelengths in the range of 250 to 700 nm. The photodamage of the Mn-oxo mixed-valence dimer was confirmed by the decrease of its oxygen-evolution activity measured in the presence of the chemical oxidant oxone. Ultraviolet light irradiation induced a new absorption peak at around 400-440 nm of the Mn-oxo mixed-valence dimer. Visible light did not have the same effect on the Mn-oxo mixed-valence dimer. We speculate that the spectral change may be caused by conversion of the Mn(III)O(2)Mn(IV) dimer into a new structure--Mn(IV)O(2)Mn(IV). In the processes, the appearance of a 514 nm fluorescence peak was observed in the solution and may be linked to the hydration or protonation of Terpy ligand in the Mn-oxo dimer. In comparing the response of the PS II functional model compound and the PS II complex to excess light radiation, our results support the idea that UV photoinhibition is triggered at the Mn(4)Ca center of the oxygen-evolution complex in PS II by forming a modified structure, possibly a Mn(IV) species, and that the reaction of Mn ions is likely the initial step. Published by Elsevier B.V.

Design, Synthesis and Characterisation of New Chimeric Ruthenium(II)-Gold(I) Complexes as Improved Cytotoxic Agents

PubMed Central

Massai, Lara; Fernández-Gallardo, Jacob; Guerri, Annalisa; Arcangeli, Annarosa; Pillozzi, Serena

2015-01-01

Two heterobimetallic complexes, i.e. [RuCl2(p-cymene)(µ-dppm)AuC] (1) and [RuCl2(p-cymene)(µ-dppm)Au S(thiazoline)] (3), based on known cytotoxic [Ru(p-cymene)Cl2(PR3)] and [AuX(PR3)] (X = Cl, SR) molecular scaffolds, with the diphosphane linker 1,1-bis(diphenylphosphino) methane, dppm, were conveniently prepared and characterised. Remarkably, the new compounds manifested a more favourable in vitro pharmacological profile toward cancer cells than individual ruthenium and gold species being either more cytotoxic or more selective. The interactions of the study compounds with (pBR322) DNA and their inhibitory effects on cathepsin B were also assessed. In addition, their reactivity toward suitable models of protein targets was explored and clear evidence gained for disruption of the bimetallic motif and for protein binding of monometallic fragments. Overall, the data reported here strongly support the concept of multifunctional heterometallic compounds as “improved” candidate agents for cancer treatment. The mechanistic and pharmacological implications of the present findings are discussed. PMID:25996553

Protein Surface Mimetics: Understanding How Ruthenium Tris(Bipyridines) Interact with Proteins.

PubMed

Hewitt, Sarah H; Filby, Maria H; Hayes, Ed; Kuhn, Lars T; Kalverda, Arnout P; Webb, Michael E; Wilson, Andrew J

2017-01-17

Protein surface mimetics achieve high-affinity binding by exploiting a scaffold to project binding groups over a large area of solvent-exposed protein surface to make multiple cooperative noncovalent interactions. Such recognition is a prerequisite for competitive/orthosteric inhibition of protein-protein interactions (PPIs). This paper describes biophysical and structural studies on ruthenium(II) tris(bipyridine) surface mimetics that recognize cytochrome (cyt) c and inhibit the cyt c/cyt c peroxidase (CCP) PPI. Binding is electrostatically driven, with enhanced affinity achieved through enthalpic contributions thought to arise from the ability of the surface mimetics to make a greater number of noncovalent interactions than CCP with surface-exposed basic residues on cyt c. High-field natural abundance 1 H, 15 N HSQC NMR experiments are consistent with surface mimetics binding to cyt c in similar manner to CCP. This provides a framework for understanding recognition of proteins by supramolecular receptors and informing the design of ligands superior to the protein partners upon which they are inspired. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

A dye-sensitized photoelectrochemical tandem cell for light driven hydrogen production from water

DOE PAGES

Sherman, Benjamin D.; Sheridan, Matthew V.; Wee, Kyung -Ryang; ...

2016-12-02

Here, tandem junction photoelectrochemical water-splitting devices, whereby two light absorbing electrodes targeting separate portions of the solar spectrum generate the voltage required to convert water to oxygen and hydrogen, enable much higher possible efficiencies than single absorber systems. We report here on the development of a tandem system consisting of a dye-sensitized photoelectrochemical cell (DSPEC) wired in series with a dye-sensitized solar cell (DSC). The DSPEC photoanode incorporates a tris(bipyridine)ruthenium(II)-type chromophore and molecular ruthenium based water oxidation catalyst. The DSPEC was tested with two more-red absorbing DSC variations, one utilizing N719 dye with an I 3 –/I – redox mediatormore » solution and the other D35 dye with a tris(bipyridine)cobalt ([Co(bpy) 3] 3+/2+) based mediator. The tandem configuration consisting of the DSPEC and D35/[Co(bpy) 3] 3+/2+ based DSC gave the best overall performance and demonstrated the production of H 2 from H 2O with the only energy input from simulated solar illumination.« less

Design, synthesis and characterisation of new chimeric ruthenium(II)-gold(I) complexes as improved cytotoxic agents.

PubMed

Massai, Lara; Fernández-Gallardo, Jacob; Guerri, Annalisa; Arcangeli, Annarosa; Pillozzi, Serena; Contel, María; Messori, Luigi

2015-06-28

Two heterobimetallic complexes, i.e. [RuCl2(p-cymene)(μ-dppm)AuC] (1) and [RuCl2(p-cymene)(μ-dppm)Au(S-thiazoline)] (3), based on known cytotoxic [Ru(p-cymene)Cl2(PR3)] and [AuX(PR3)] (X = Cl, SR) molecular scaffolds, with the diphosphane linker 1,1-bis(diphenylphosphino)methane, dppm, were conveniently prepared and characterised. Remarkably, the new compounds manifested a more favourable in vitro pharmacological profile toward cancer cells than individual ruthenium and gold species being either more cytotoxic or more selective. The interactions of the studied compounds with (pBR322) DNA and their inhibitory effects on cathepsin B were also assessed. In addition, their reactivity toward suitable models of protein targets was explored and clear evidence gained for disruption of the bimetallic motif and for protein binding of monometallic fragments. Overall, the data reported here strongly support the concept of multifunctional heterometallic compounds as "improved" candidate agents for cancer treatment. The mechanistic and pharmacological implications of the present findings are discussed.

Coordination-Driven Self-Assembly of M3L2 Trigonal Cages from Pre-organized Metalloligands Incorporating Octahedral Metal Centers and Fluorescent Detection of Nitroaromatics

PubMed Central

Wang, Ming; Vajpayee, Vaishali; Shanmugaraju, Sankarasekaran; Zheng, Yao-Rong; Zhao, Zhigang; Kim, Hyunuk

2011-01-01

The design and preparation of novel M3L2 trigonal cages via coordination-driven self-assembly of pre-organized metalloligands containing octahedral aluminum(III), gallium(III), or ruthenium(II) centers is described. By employing tritopic or dinuclear linear metalloligands and appropriate complementary subunits, M3L2 trigonal-bipyramidal and trigonal prismatic cages are self-assembled under mild conditions. These 3-D cages were characterized with multinuclear NMR spectroscopy (1H and 31P) and high-resolution electronic spray mass spectrometry (HR-ESI-MS). The structure of one such trigonal prismatic cage, self-assembled from an arene ruthenium metalloligand, was confirmed via single-crystal X-ray crystallography. The fluorescent nature of these prisms, due to the presence of their electron-rich ethynyl functionalities, prompted photophysical studies which revealed that electron-deficient nitroaromatics are effective quenchers of the cages' emission. Excited state charge transfer from the prisms to the nitroaromatic substrates can be used as the basis for developing selective and discriminatory turn-off fluorescent sensors for nitroaromatics. PMID:21214171

Tuning the Electronic Structure of Fe(II) Polypyridines via Donor Atom and Ligand Scaffold Modifications: A Computational Study.

PubMed

Bowman, David N; Bondarev, Alexey; Mukherjee, Sriparna; Jakubikova, Elena

2015-09-08

Fe(II) polypyridines are an important class of pseudo-octahedral metal complexes known for their potential applications in molecular electronic switches, data storage and display devices, sensors, and dye-sensitized solar cells. Fe(II) polypyridines have a d(6) electronic configuration and pseudo-octahedral geometry and can therefore possess either a high-spin (quintet) or a low-spin (singlet) ground state. In this study, we investigate a series of complexes based on [Fe(tpy)2](2+) (tpy = 2,2';6',2″-terpyridine) and [Fe(dcpp)2](2+) (dcpp = 2,6-bis(2-carboxypyridyl)pyridine). The ligand field strength in these complexes is systematically tuned by replacing the central pyridine with five-membered (N-heterocyclic carbene, pyrrole, furan) or six-membered (aryl, thiazine-1,1-dioxide, 4-pyrone) moieties. To determine the impact of ligand substitutions on the relative energies of metal-centered states, the singlet, triplet, and quintet states of the Fe(II) complexes were optimized in water (PCM) using density functional theory at the B3LYP+D2 level with 6-311G* (nonmetals) and SDD (Fe) basis sets. It was found that the dcpp ligand scaffold allows for a more ideal octahedral coordination environment in comparison to the tpy ligand scaffold. The presence of six-membered central rings also allows for a more ideally octahedral coordination environment relative to five-membered central rings, regardless of the ligand scaffold. We find that the ligand field strength in the Fe(II) polypyridines can be tuned by altering the donor atom identity, with C donor atoms providing the strongest ligand field.

Highly sensitive catalytic spectrophotometric determination of ruthenium

NASA Astrophysics Data System (ADS)

Naik, Radhey M.; Srivastava, Abhishek; Prasad, Surendra

2008-01-01

A new and highly sensitive catalytic kinetic method (CKM) for the determination of ruthenium(III) has been established based on its catalytic effect on the oxidation of L-phenylalanine ( L-Pheala) by KMnO 4 in highly alkaline medium. The reaction has been followed spectrophotometrically by measuring the decrease in the absorbance at 526 nm. The proposed CKM is based on the fixed time procedure under optimum reaction conditions. It relies on the linear relationship where the change in the absorbance (Δ At) versus added Ru(III) amounts in the range of 0.101-2.526 ng ml -1 is plotted. Under the optimum conditions, the sensitivity of the proposed method, i.e. the limit of detection corresponding to 5 min is 0.08 ng ml -1, and decreases with increased time of analysis. The method is featured with good accuracy and reproducibility for ruthenium(III) determination. The ruthenium(III) has also been determined in presence of several interfering and non-interfering cations, anions and polyaminocarboxylates. No foreign ions interfered in the determination ruthenium(III) up to 20-fold higher concentration of foreign ions. In addition to standard solutions analysis, this method was successfully applied for the quantitative determination of ruthenium(III) in drinking water samples. The method is highly sensitive, selective and very stable. A review of recently published catalytic spectrophotometric methods for the determination of ruthenium(III) has also been presented for comparison.

Ruthenium Catalyzed Diastereo- and Enantioselective Coupling of Propargyl Ethers with Alcohols: Siloxy-Crotylation via Hydride Shift Enabled Conversion of Alkynes to π-Allyls

PubMed Central

Liang, Tao; Zhang, Wandi; Chen, Te-Yu; Nguyen, Khoa D.; Krische, Michael J.

2015-01-01

The first enantioselective carbonyl crotylations through direct use of alkynes as chiral allylmetal equivalents are described. Chiral ruthenium(II) complexes modified by Josiphos (SL-J009-1) catalyze the C-C coupling of TIPS-protected propargyl ether 1a with primary alcohols 2a-2o to form products of carbonyl siloxy-crotylation 3a-3o, which upon silyl deprotection-reduction deliver 1,4-diols 5a-5o with excellent control of regio-, anti-diastereo- and enantioselectivity. Structurally related propargyl ethers 1b and 1c bearing ethyl- and phenyl-substituents engage in diastereo- and enantioselective coupling, as illustrated in the formation of adducts 5p and 5q, respectively. Selective mono-tosylation of diols 5a, 5c, 5e, 5f, 5k and 5m is accompanied by spontaneous cyclization to deliver the trans-2,3-disubstituted furans 6a, 6c, 6e, 6f, 6k and 6m, respectively. Primary alcohols 2a, 2l and 2p were converted to the siloxy-crotylation products 3a, 3l and 3p, which upon silyl deprotection-lactol oxidation were transformed to the trans-4,5-disubstituted γ-butyrolactones 7a, 7l and 7p. The formation of 7p represents a total synthesis of (+)-trans-whisky lactone. Unlike closely related ruthenium catalyzed alkyne-alcohol C-C couplings, deuterium labeling studies provide clear evidence of a novel 1,2-hydride shift mechanism that converts metal-bound alkynes to π-allyls in the absence of intervening allenes. PMID:26418572

Synthesis and Catalytic Activity of Ruthenium-Indenylidene Complexes for Olefin Metathesis: Microscale Experiments for the Undergraduate Inorganic or Organometallic Laboratories

ERIC Educational Resources Information Center

Pappenfus, Ted M.; Hermanson, David L.; Ekerholm, Daniel P.; Lilliquist, Stacie L.; Mekoli, Megan L.

2007-01-01

A series of experiments for undergraduate laboratory courses (e.g., inorganic, organometallic or advanced organic) have been developed. These experiments focus on understanding the design and catalytic activity of ruthenium-indenylidene complexes for olefin metathesis. Included in the experiments are the syntheses of two ruthenium-indenylidene…

Design and development of novel MRI compatible zirconium- ruthenium alloys with ultralow magnetic susceptibility

PubMed Central

Li, H.F.; Zhou, F.Y.; Li, L.; Zheng, Y.F.

2016-01-01

In the present study, novel MRI compatible zirconium-ruthenium alloys with ultralow magnetic susceptibility were developed for biomedical and therapeutic devices under MRI diagnostics environments. The results demonstrated that alloying with ruthenium into pure zirconium would significantly increase the strength and hardness properties. The corrosion resistance of zirconium-ruthenium alloys increased significantly. High cell viability could be found and healthy cell morphology observed when culturing MG 63 osteoblast-like cells and L-929 fibroblast cells with zirconium-ruthenium alloys, whereas the hemolysis rates of zirconium-ruthenium alloys are <1%, much lower than 5%, the safe value for biomaterials according to ISO 10993-4 standard. Compared with conventional biomedical 316L stainless steel, Co–Cr alloys and Ti-based alloys, the magnetic susceptibilities of the zirconium-ruthenium alloys (1.25 × 10−6 cm3·g−1–1.29 × 10−6 cm3·g−1 for zirconium-ruthenium alloys) are ultralow, about one-third that of Ti-based alloys (Ti–6Al–4V, ~3.5 × 10−6 cm3·g−1, CP Ti and Ti–6Al–7Nb, ~3.0 × 10−6 cm3·g−1), and one-sixth that of Co–Cr alloys (Co–Cr–Mo, ~7.7 × 10−6 cm3·g−1). Among the Zr–Ru alloy series, Zr–1Ru demonstrates enhanced mechanical properties, excellent corrosion resistance and cell viability with lowest magnetic susceptibility, and thus is the optimal Zr–Ru alloy system as therapeutic devices under MRI diagnostics environments. PMID:27090955

Selective deposition of nanostructured ruthenium oxide using Tobacco mosaic virus for micro-supercapacitors in solid Nafion electrolyte

NASA Astrophysics Data System (ADS)

Gnerlich, Markus; Ben-Yoav, Hadar; Culver, James N.; Ketchum, Douglas R.; Ghodssi, Reza

2015-10-01

A three-dimensional micro-supercapacitor has been developed using a novel bottom-up assembly method combining genetically modified Tobacco mosaic virus (TMV-1Cys), photolithographically defined micropillars and selective deposition of ruthenium oxide on multi-metallic microelectrodes. The three-dimensional microelectrodes consist of a titanium nitride current collector with two functionalized areas: (1) gold coating on the active electrode area promotes TMV-1Cys adhesion, and (2) sacrificial nickel pads dissolve in ruthenium tetroxide plating solution to produce ruthenium oxide on all electrically connected areas. The microfabricated electrodes are arranged in an interdigitated pattern, and the capacitance per electrode has been measured as high as 203 mF cm-2 with solid Nafion electrolyte. The process integration of bio-templated ruthenium oxide with microfabricated electrodes and solid electrolyte is an important advance towards the energy storage needs of mass produced self-sufficient micro-devices.

Graphene/Ruthenium Active Species Aerogel as Electrode for Supercapacitor Applications.

PubMed

Gigot, Arnaud; Fontana, Marco; Pirri, Candido Fabrizio; Rivolo, Paola

2017-12-30

Ruthenium active species containing Ruthenium Sulphide (RuS₂) is synthesized together with a self-assembled reduced graphene oxide (RGO) aerogel by a one-pot hydrothermal synthesis. Ruthenium Chloride and L-Cysteine are used as reactants. The hydrothermal synthesis of the innovative hybrid material occurs at 180 °C for 12 h, by using water as solvent. The structure and morphology of the hybrid material are fully characterized by Raman, XRD, XPS, FESEM and TEM. The XRD and diffraction pattern obtained by TEM display an amorphous nanostructure of RuS₂ on RGO crystallized flakes. The specific capacitance measured in planar configuration in 1 M NaCl electrolyte at 5 mV s -1 is 238 F g -1 . This supercapacitor electrode also exhibits perfect cyclic stability without loss of the specific capacitance after 15,000 cycles. In summary, the RGO/Ruthenium active species hybrid material demonstrates remarkable properties for use as active material for supercapacitor applications.

Selective deposition of nanostructured ruthenium oxide using Tobacco mosaic virus for micro-supercapacitors in solid Nafion electrolyte

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

Gnerlich, Markus; Ben-Yoav, Hadar; Culver, James N.

A three-dimensional micro-supercapacitor has been developed using a novel bottom-up assembly method combining genetically modified Tobacco mosaic virus (TMV-1Cys), photolithographically defined micropillars and selective deposition of ruthenium oxide on multi-metallic microelectrodes. The three-dimensional microelectrodes consist of a titanium nitride current collector with two functionalized areas: (1) gold coating on the active electrode area promotes TMV-1Cys adhesion, and (2) sacrificial nickel pads dissolve in ruthenium tetroxide plating solution to produce ruthenium oxide on all electrically connected areas. The microfabricated electrodes are arranged in an interdigitated pattern, and the capacitance per electrode has been measured as high as 203 mF cm-2 withmore » solid Nafion electrolyte. The process integration of bio-templated ruthenium oxide with microfabricated electrodes and solid electrolyte is an important advance towards the energy storage needs of mass produced self-sufficient micro-devices.« less

Enhanced electrochemiluminescence sensor from tris(2,2'-bipyridyl)ruthenium(II) incorporated into MCM-41 and an ionic liquid-based carbon paste electrode.

PubMed

Li, Jing; Huang, Minghua; Liu, Xiaoqing; Wei, Hui; Xu, Yuanhong; Xu, Guobao; Wang, Erkang

2007-07-01

The electrochemiluminescence (ECL) of tris(2,2'-bipyridyl)ruthenium(II) [Ru(bpy)(3)(2+)] ion-exchanged in the sulfonic-functionalized MCM-41 silicas was developed with tripropylamine (TPrA) as a co-reactant in a carbon paste electrode (CPE) using a room temperature ionic liquid (IL) as a binder. The sulfonic-functionalized silicas MCM-41 were used for preparing an ECL sensor by the electrostatic interactions between Ru(bpy)(3)(2+) cations and sulfonic acid groups. We used the IL as a binder to construct the CPE (IL-CPE) to replace the traditional binder of the CPE (T-CPE)--silicone oil. The results indicated that the MCM-41-modified IL-CPE had more open structures to allow faster diffusion of Ru(bpy)(3)(2+) and that the ionic liquid also acted as a conducting bridge to connect TPrA with Ru(bpy)(3)(2+) sites immobilized in the electrode, resulting in a higher ECL intensity compared with the MCM-41-modified T-CPE. Herein, the detection limit for TPrA of the MCM-41-modified IL-CPE was 7.2 nM, which was two orders of magnitude lower than that observed at the T-CPE. When this new sensor was used in flow injection analysis (FIA), the MCM-41-modified IL-CPE ECL sensor also showed good reproducibility. Furthermore, the sensor could also be renewed easily by mechanical polishing whenever needed.

Determination of ultra-trace formaldehyde in air using ammonium sulfate as derivatization reagent and capillary electrophoresis coupled with on-line electrochemiluminescence detection.

PubMed

Deng, Biyang; Liu, Yang; Yin, Huihui; Ning, Xi; Lu, Hua; Ye, Li; Xu, Quanxiu

2012-03-15

The reaction between formaldehyde and ammonium ion to produce hexamethylenetetramine is well known. The reaction conditions are very easily controlled in situ and the experiment operation is very simple. However, such derivatization reaction for trace formaldehyde determination using capillary electrophoresis (CE) electrochemiluminescence (ECL) has not been reported before. In this study, the application of ammoniun sulfate as derivatization reagent to in-situ determination of formaldehyde in air was reported. Based on ECL enhancement of tris(2,2'-bipyridyl)ruthenium(II) with hexamethylenetetramine, a novel approach for the determination of ultra-trace formaldehyde in air using CE coupled with on-line ECL of tris(2,2'-bipyridyl)ruthenium(II) has been developed. The parameters affecting separation and detection such as detection potential, concentration and pH of phosphate buffer, and electrokinetic voltage, were investigated. Under the optimal conditions, the linear concentration range of formaldehyde in air was from 0.48 μg/m(3) to 96 mg/m(3) (linear range covering 5 orders of magnitude). The limit of detection (3σ) was 0.15 μg/m(3). The relative standard deviations of peak height and migration time for six consecutive injection of 1 ng/mL formaldehyde derivative were 0.9% and 0.8%, respectively. The recoveries of formaldehyde in air were between 99.3% and 101%. Copyright © 2012 Elsevier B.V. All rights reserved.

A novel ruthenium (II)-derived organometallic compound, TQ-6, potently inhibits platelet aggregation: Ex vivo and in vivo studies.

PubMed

Hsia, Chih-Hsuan; Velusamy, Marappan; Sheu, Joen-Rong; Khamrang, Themmila; Jayakumar, Thanasekaran; Lu, Wan-Jung; Lin, Kuan-Hung; Chang, Chao-Chien

2017-08-25

Arterial thrombosis plays a key role in cardiovascular diseases. Hence, developing more effective antithrombotic agents is necessary. We designed a ruthenium (II)-derived complex, [Ru(η 6 -cymene)2-(1H-benzoimidazol-2-yl)-quinoline Cl]BF 4 (TQ-6), as a new antiplatelet drug. TQ-6 (0.3 µM) exhibited extremely strong inhibitory activity against platelet aggregation, Src, and Syk phosphorylation stimulated by agonists in human platelets. In collagen-activated platelets, TQ-6 also inhibited ATP-release, [Ca +2 ]i, P-selectin expression, FITC-PAC-1 binding, and hydroxyl radical formation, as well as the phosphorylation of phospholipase Cγ2, protein kinase C, mitogen-activated protein kinases, and Akt. Neither FITC-JAQ1 nor FITC-triflavin binding or integrin β 3 phosphorylation stimulated by immobilized fibrinogen were diminished by TQ-6. Furthermore, TQ-6 had no effects in cyclic nucleotide formation. Moreover, TQ-6 substantially prolonged the closure time in whole blood, increased the occlusion time of thrombotic platelet plug formation and bleeding time in mice. In conclusion, TQ-6 has a novel role in inhibiting platelet activation through the inhibition of the agonist receptors-mediated inside-out signaling such as Src-Syk-PLCγ2 cascade and subsequent suppression of granule secretion, leading to disturb integrin α IIb β 3 -mediated outside-in signaling, and ultimately inhibiting platelet aggregation. Therefore, TQ-6 has potential to develop as a therapeutic agent for preventing or treating thromboembolic disorders.

Light-triggered self-assembly of triarylamine-based nanospheres

NASA Astrophysics Data System (ADS)

Moulin, Emilie; Niess, Frédéric; Fuks, Gad; Jouault, Nicolas; Buhler, Eric; Giuseppone, Nicolas

2012-10-01

Tailored triarylamine units modified with terpyridine ligands were coordinated to Zn2+ ions and characterized as discrete dimeric entities. Interestingly, when these complexes were subsequently irradiated with simple visible light in chloroform, they readily self-assembled into monodisperse spheres with a mean diameter of 160 nm.Tailored triarylamine units modified with terpyridine ligands were coordinated to Zn2+ ions and characterized as discrete dimeric entities. Interestingly, when these complexes were subsequently irradiated with simple visible light in chloroform, they readily self-assembled into monodisperse spheres with a mean diameter of 160 nm. Electronic supplementary information (ESI) available: Synthetic procedures and products' characterization (2-4 and 6-9). 1H NMR titration of compound 6 by Zn(OTf)2 to form complex 7. Kinetic measurements by UV-Vis-NIR spectroscopy. Transmission electron microscopy imaging for complexes 8 and 9. UV-Vis-NIR for an Fe2+ analogue of complex 7. Dynamic light scattering and time autocorrelation function for self-assembly of complexes 7-9. Copies of 1H and 13C NMR spectra for compounds 2-4 and 6. See DOI: 10.1039/c2nr32168h

6,6″-Dimethyl-2,2':6',2″-terpyridine revisited: new fluorescent silver(I) helicates with in vitro antiproliferative activity via selective nucleoli targeting.

PubMed

Fik, Marta A; Gorczyński, Adam; Kubicki, Maciej; Hnatejko, Zbigniew; Fedoruk-Wyszomirska, Agnieszka; Wyszko, Eliza; Giel-Pietraszuk, Małgorzata; Patroniak, Violetta

2014-10-30

6,6″-Dimethyl-2,2':6',2″-terpyridine ligand (L) reacts in equimolar ratio with Ag(I) ions what results in formation of dinuclear double helicates, which differ in terms of framework and complexity in accordance to counterions and solvent applied. Obtained complexes were thoroughly studied in terms of their biological activity, with the positive antiproliferative outcome on three human cancer cell lines: human breast cancer (T47D), human cervical carcinoma (HeLa) and human lung cancer (A-549). Performed DNA binding experiments showed that given Ag(I) species specifically interact with DNA double helix via intercalation and were visualized by confocal microscopy to specifically bind to the nuclei. All newly synthesized helical systems exhibit promising antimicrobial activity against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus bacterial strains. Spectrophotometric properties were described as fulfilment of structural studies of newly presented complexes confirming their helical structure in solution. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Role of Thermal Process on Self-Assembled Structures of 4′-([2,2′:6′,2″-Terpyridin]-4′-Yl)-[1,1′-Biphenyl]-4-Carboxylic Acid on Au(III)

PubMed Central

Liu, Xiaoqing; Wang, Yongli; Song, Xin; Chen, Feng; Ouyang, Hongping; Zhang, Xueao; Cai, Yingxiang; Liu, Xiaoming; Wang, Li

2013-01-01

The role of dynamic processes on self-assembled structures of 4′-([2,2′:6′, 2″-terpyridin]-4′-yl)-[1,1′-biphenyl]-4-carboxylic acid (l) molecules on Au(III) has been studied by scanning tunneling microscopy. The as-deposited monolayer is closed-packed and periodic in a short-range due to dipole forces. A thermal annealing process at 110 degrees drives such disordered monolayer into ordered chain-like structures, determined by the combination of the dipole forces and hydrogen bonding. Further annealing at 130 degrees turns the whole monolayer into a bowknot-like structure in which hydrogen bonding plays the dominant role in the formation of assembled structures. Such dependence of an assembled structure on the process demonstrates that an assembled structure can be regulated and controlled not only by the molecular structure but also by the thermal process to form the assembled structure. PMID:23478440

Cross-couplings in the elaboration of luminescent bis-terpyridyl iridium complexes: the effect of extended or inhibited conjugation on emission.

PubMed

Leslie, Wendy; Batsanov, Andrei S; Howard, Judith A K; Williams, J A Gareth

2004-02-21

The utility of Suzuki cross-coupling methodology for the in situ elaboration of bromo-functionalised bis-terpyridyl iridium(III) complexes has been explored. The complex [Ir(tpy)(tpy-phi-Br)]3+ [tpy-phi-Br = 4'-(4-bromophenyl)-2,2':6',2''-terpyridine] undergoes palladium-catalysed cross-coupling with aryl boronic acids to yield biaryl-substituted complexes directly. The biphenyl and 4-cyanobiphenyl-substituted products display relatively intense, long-lived (tau > 100 mus) yellow emission in degassed aqueous solution at room temperature, assigned to a 3pi-pi* state. A 4-aminobiphenyl-substituted analogue displays an additional low energy absorbance band, attributed to an intraligand charge-transfer (ILCT) excited state, and is scarcely emissive under the same conditions. The iridium(III) complex of 4'-mesityl-terpyridine is also reported. Its emission is much shorter-lived, with a spectral profile resembling that of unsubstituted [Ir(tpy)2]3+, confirming the need for the attainment of a roughly coplanar geometry for stabilisation of the 3pi-pi* excited state.

Poly(ε-caprolactone) decorated with one room-temperature red-emitting ruthenium(II) complex: synthesis, characterization, thermal and optical properties.

PubMed

Schulze, Marcus; Jäger, Michael; Schubert, Ulrich S

2012-04-13

The incorporation of room-temperature red-emissive [Ru(II)(dqp)(dqp-CH(2) OH)](2+) (dqp is 2,6-di(quinolin-8-yl)pyridine) in poly(ε-caprolactone) (PCL) is explored following two routes. First, the ring-opening polymerization of ε-caprolactone is investigated using the free ligand and the complex as initiators. Alternatively, the complexation strategy utilizing PCL-dqp as a macroligand is detailed. Both routes yield room-temperature emissive polymers centered at 400 nm (free ligand) and 680 nm (complex) in aerated solvent. DSC and TGA showed the typical properties of PCL, for example, the melting point (59 °C). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis, characterization, and anticancer activity of a series of ketone-N(4)-substituted thiosemicarbazones and their ruthenium(II) arene complexes.

PubMed

Su, Wei; Qian, Quanquan; Li, Peiyuan; Lei, Xiaolin; Xiao, Qi; Huang, Shan; Huang, Chusheng; Cui, Jianguo

2013-11-04

A series of ketone-N(4)-substituted thiosemicarbazone (TSC) compounds (L1-L9) and their corresponding [(η(6)-p-cymene)Ru(II)(TSC)Cl](+/0) complexes (1-9) were synthesized and characterized by NMR, IR, elemental analysis, and HR-ESI-mass spectrometry. The molecular structures of L4, L9, 1-6, and 9 were determined by single-crystal X-ray diffraction analysis. The compounds were further evaluated for their in vitro antiproliferative activities against the SGC-7901 human gastric cancer, BEL-7404 human liver cancer, and HEK-293T noncancerous cell lines. Furthermore, the interactions of the compounds with DNA were followed by electrophoretic mobility spectrometry studies.

Influence of the π-coordinated arene on the anticancer activity of ruthenium(II) carbohydrate organometallic complexes

NASA Astrophysics Data System (ADS)

Hanif, Muhammad; Meier, Samuel; Nazarov, Alexey; Risse, Julie; Legin, Anton; Casini, Angela; Jakupec, Michael; Keppler, Bernhard; Hartinger, Christian

2013-10-01

The synthesis and in vitro cytotoxicity of a series of RuII(arene) complexes with carbohydrate-derived phosphite ligands and various arene co-ligands is described. The arene ligand has a strong influence on the in vitro anticancer activity of this series of compounds, which correlates fairly well with cellular accumulation. The most lipophilic compound bearing a biphenyl moiety and a cyclohexylidene-protected carbohydrate is the most cytotoxic with unprecedented IC50 values for the compound class in three human cancer cell lines. This compound shows reactivity to the DNA model nucleobase 9-ethylguanine, but does not alter the secondary structure of plasmid DNA indicating that other biological targets are responsible for its cytotoxic effect.

Comparison of physical and photophysical properties of monometallic and bimetallic ruthenium(II) complexes containing structurally altered diimine ligands

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

Macatangay, A.; Jackman, D.C.; Merkert, J.W.

1996-11-06

The physical and photophysical properties of a series of monometallic, [Ru(bpy){sub 2}(dmb)]{sup 2+}, [Ru(bpy){sub 2}(BPY)]{sup 2+}, [Ru(bpy)(Obpy)]{sup 2+} and [Ru(bpy){sub 2}(Obpy)] {sup 2+}, and bimetallic, [(Ru(bpy){sub 2}){sub 2}(BPY)]{sup 4+} and [(Ru(bpy){sub 2}){sub 2}(Obpy)]{sup 4+}, complexes are examined, where bpy is 2,2{prime}-bipyridine, dmb is 4,4{prime}-dimethyl-2,2{prime}-bipyridine, BPY is 1,2-bis(4-methyl-2,2{prime}-bipyridin-4{prime}-yl)ethane, and Obpy is 1,2-bis(2,2{prime}-bipyridin-6-yl)ethane. The complexes display metal-to-ligand charge transfer transitions in the 450 nmn region, intraligand {pi}{yields}{pi}* transitions at energies greater than 300 nm, a reversible oxidation of the ruthenium(II) center in the 1.25-1.40 V vs SSCE region, a series of three reductions associated with each coordinated ligand commencing at {minus}1.3 Vmore » and ending at {approximately}{minus}1.9 V, and emission from a {sup 3}MLCT state having energy maxima between 598 and 610 nm. The Ru{sup III}/Ru{sup II} oxidation of the two bimetallic complexes is a single, two one-electron process. Relative to [Ru(bpy){sub 2}(BPY)]{sup 2+}, the Ru{sup III}/Ru{sup II} potential for [Ru-(bpy){sub 2}(Obpy)]{sup 2+} increases from 1.24 to 1.35 V, the room temperature emission lifetime decreases from 740 to 3ns, and the emission quantum yield decreases from 0.078 to 0.000 23. Similarly, relative to [(Ru(bpy){sub 2}){sub 2}(BPY)]{sup 4+}, the Ru{sup III}/Ru{sup II} potential for [(Ru(bpy){sub 2}){sub 2}(Obpy)]{sup 4+} increases from 1.28 to 1.32 V, the room temperature emission lifetime decreases from 770 to 3 ns, and the room temperature emission quantum yield decreases from 0.079 to 0.000 26.« less

Crystal and molecular structures of pentaammine(pyrazine)ruthenium(II) tetrafluoroborate and pentaammine(pyrazine)ruthenium(III) trifluoromethanesulfonate monohydrate

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

Gress, M.E.; Creutz, C.; Quicksall, C.O.

1981-05-01

For (Ru(NH/sub 3/)/sub 5/(C/sub 4/N/sub 2/H/sub 4/))(BF/sub 4/)/sub 2/ the space group is P2/sub 1/2/sub 1/2/sub 1/ with cell parameters a = 12.615 (2) A, b = 15.610 (3) A, c = 7.965 (2) A, and Z = 4. For (Ru(NH/sub 3/)/sub 5/(C/sub 4/N/sub 2/H/sub 4/))(CF/sub 3/SO/sub 3/)/sub 3/.H/sub 2/O the space group is Pnma with cell parameters a = 23.795 (4) A, b = 8.062 (2) A, c = 12.848 (2) A, and Z = 4. The geometries of both the Ru(NH/sub 3/)/sub 5/pz/sup 2 +/ (pz = pyrazine) and Ru(NH/sub 3/)/sub 5/pz/sup 3 +/ cations are approximately octahedral,more » with the plane of the pyrazine ring intersecting at a 45/sup 0/ angle the equatorial plane containing the bound pyrazine N and the three N atoms of the NH/sub 3/ groups, as is expected from steric considerations. The Ru-NH/sub 3/ bond lengths are similar to those found in other ammine complexes: Ru(II)-NH/sub 3/, 2.15 to 2.17 A; Ru(III)-NH/sub 3/, 2.10 to 2.13 A. By contrast the Ru(II)-pz bond (2.006 A) is shorter than the Ru(III)-pz bond (2.076 A) by 0.07 A. This is attributed to ..pi.. back-bonding between Ru(II) and pyrazine. The dimensions of the mononuclear ions Ru(NH/sub 3/)/sub 5/pz/sup 2 +/ and Ru(NH/sub 3/)/sub 5/pz/sup 3 +/ are used to model the structure of valence-localized Ru/sup II/(NH/sub 3/)/sub 5/pzRu/sup III/(NH/sub 3/)/sub 5//sup 5 +/. The observed properties of this ion are then compared with those predicted from Marcus-Hush electron-transfer theory.« less

A novel ruthenium(II)-cobaloxime supramolecular complex for photocatalytic H2 evolution: Synthesis, characterisation, and mechanistic studies

PubMed Central

Cropek, Donald M.; Metz, Anja; Müller, Astrid M.; Gray, Harry B.; Horne, Toyketa; Horton, Dorothy C.; Poluektov, Oleg; Tiede, David M.; Weber, Ralph T.; Jarrett, William L.; Phillips, Joshua D.

2012-01-01

We report the synthesis and characterization of novel mixed-metal binuclear ruthenium(II)-cobalt(II) photocatalysts for hydrogen evolution in acidic acetonitrile. First, 2-(2′-pyridyl)benzothiazole (pbt), 1, was reacted with RuCl3·xH2O to produce [Ru(pbt)2Cl2] ·0.25CH3COCH3, 2, which was then reacted with 1,10-phenanthroline-5,6-dione (phendione), 3 in order to produce [Ru(pbt)2(phendione)](PF6)2·4H2O, 4. Compound 4 was then reacted with 4-pyridinecarboxaldehyde in order to produce [Ru(pbt)2(L-pyr)](PF6)2·9.5H2O, 5 (where L-pyr = (4-pyridine)oxazolo[4,5-f]phenanthroline). Compound 5 was then reacted with [Co(dmgBF2)2(H2O)2] (where dmgBF2 = difluorboryldimethylglyoximate) in order to produce the mixed-metal binuclear complex, [Ru(pbt)2(L-pyr)Co(dmgBF2)2(H2O)](PF6)2·11H2O·1.5CH3COCH3, 6. [Ru(Me2bpy)2(L-pyr)Co(dmgBF2)2(OH2)](PF6)2, 7 (where Me2bpy = 1,10-phenanthroline, 4,4′-dimethyl-2,2′-bipyridine) and [Ru(phen)2(L-pyr)Co(dmgBF2)2(OH2)](PF6)2, 8 were also synthesised. All complexes were characterized by elemental analysis, UV-visible absorption, 11B, 19F, and 59Co NMR, ESR spectroscopy, and cyclic voltammetry, where appropriate. Photocatalytic studies carried out in acidified acetonitrile demonstrated constant hydrogen generation longer than a 42 hour period as detected by gas chromatography. Time resolved spectroscopic measurements were performed on compound 6, which proved an intramolecular electron transfer from an excited Ru(II) metal centre to the Co(II) metal centre via the bridging L-pyr ligand. This resulted in the formation of a cobalt(I)-containing species that is essential for the production of H2 gas in the presence of H+ ions. A proposed mechanism for the generation of hydrogen is presented. PMID:23001132

Copper(II)-Catalyzed Conversion of Aryl/Heteroaryl Boronic Acids, Boronates, and Trifluoroborates into the Corresponding Azides: Substrate Scope and Limitations.

PubMed

Grimes, Kimberly D; Gupte, Amol; Aldrich, Courtney C

2010-05-01

We report the copper(II)-catalyzed conversion of organoboron compounds into the corresponding azide derivatives. A systematic series of phenylboronic acid derivatives is evaluated to examine the importance of steric and electronic effects of the substituents on reaction yield as well as functional group compatibility. Heterocyclic substrates are also shown to participate in this mild reaction while compounds incorporating B-C(sp(3)) bonds are unreactive under the reaction conditions. The copper(II)-catalyzed boronic acid-azide coupling reaction is further extended to both boronate esters and potassium organotrifluoroborate salts. The method described herein complements existing procedures for the preparation of aryl azides from the respective amino, triazene, and halide derivatives and we expect that it will greatly facilitate copper- and ruthenium-catalyzed azide-alkyne cycloaddition reactions for the preparation of diversely functionalized 1-aryl- or 1-heteroaryl-1,2,3-triazoles derivatives.

Protein modification via alkyne hydrosilylation using a substoichiometric amount of ruthenium(ii) catalyst† †Dedicated to Professor Stuart L. Schreiber on the occasion of his 60th birthday. ‡ ‡Electronic supplementary information (ESI) available. See DOI: 10.1039/c6sc05313k Click here for additional data file.

PubMed Central

Kwan, Terence T.-L.; Boutureira, Omar; Frye, Elizabeth C.; Walsh, Stephen J.; Gupta, Moni K.; Wallace, Stephen; Wu, Yuteng; Zhang, Fengzhi; Sore, Hannah F.; Galloway, Warren R. J. D.; Chin, Jason W.; Welch, Martin; Bernardes, Gonçalo J. L.

2017-01-01

Transition metal catalysis has emerged as a powerful strategy to expand synthetic flexibility of protein modification. Herein, we report a cationic Ru(ii) system that enables the first example of alkyne hydrosilylation between dimethylarylsilanes and O-propargyl-functionalized proteins using a substoichiometric amount or low-loading of Ru(ii) catalyst to achieve the first C–Si bond formation on full-length substrates. The reaction proceeds under physiological conditions at a rate comparable to other widely used bioorthogonal reactions. Moreover, the resultant gem-disubstituted vinylsilane linkage can be further elaborated through thiol–ene coupling or fluoride-induced protodesilylation, demonstrating its utility in further rounds of targeted modifications. PMID:28966779

A facile one-pot synthesis of ruthenium hydroxide nanoparticles on magnetic silica: aqueous hydration of nitriles to amides.

PubMed

Baig, R B Nasir; Varma, Rajender S

2012-06-25

One-pot synthesis of ruthenium hydroxide nanoparticles on magnetic silica is described which involves the in situ generation of magnetic silica (Fe(3)O(4)@SiO(2)) and ruthenium hydroxide immobilization; the hydration of nitriles occurs in high yield and excellent selectivity using this catalyst which proceeds exclusively in aqueous medium under neutral conditions.

Recent advances in ruthenium complex-based light-driven water oxidation catalysts.

PubMed

Xue, Long-Xin; Meng, Ting-Ting; Yang, Wei; Wang, Ke-Zhi

2015-11-01

The light driven splitting of water is one of the most attractive approaches for direct conversion of solar energy into chemical energy in the future. Ruthenium complexes as the water oxidation catalysts (WOCs) and light sensitizers have attracted increasing attention, and have made a great progress. This mini-review highlights recent progress on ruthenium complex-based photochemical and photoelectrochemical water oxidation catalysts. The recent representative examples of these ruthenium complexes that are in homogeneous solution or immobilized on solid electrodes, are surveyed. In particular, special attention has been paid on the supramolecular dyads with photosensitizer and WOC being covalently hold together, and grafted onto the solid electrode. Copyright © 2015 Elsevier B.V. All rights reserved.

Emission switching of ferrocenyl Schiff bases and a representative ruthenium complex in alkaline DMSO: Absorption, electrochemical and microstructural studies

NASA Astrophysics Data System (ADS)

Mishra, Lallan; Dubey, Santosh Kumar

2007-10-01

N,N'-Bis(4-ferrocenyl)- p-phenylene/octamethylene-diimines (L 1/L 2) and a representative Ru(II) complex [Ru(DMSO) 2Cl 2L 1]·2H 2O were prepared and characterized which showed many fold enhancement in their luminescence in alkaline dimethylsulfoxide (DMSO) solution. Spectral and electrochemical properties of these compounds have been studied. Microstructure (SEM) of L 1 and its complex showed single-phase porous material of crystal size ˜1 μm.

Substituent Effects and Bonding Characteristics in o- Benzoquinonediiminebis(bipyrdine) Ruthenium(II) Complexes

DTIC Science & Technology

1992-10-23

C.; Dei, A.; Gatteschi , D.; Pardi, L Inorg. Chem. 1989, 2L 1476; (b) Benel, C.; Dei, A.; Gatteschi , D.; Ckdel, H. U.; Pardi, L Inorg. Ckem. 1989, 28...3091; (c) Benelli, C.; Dei, A.; Gatteschi , D.; Pardi, L Inorg.Chem. 1990,2& 3409. 16. Bruni, S.; Cariati, F.; Dei, A.; Gatteschi , D. Inog Cbim. Ata...1991, 186 157. 17. Dei, A.; Gatteschi , D.; Pardi, L; Barra, A. L; Brunel, L C. Chem, Py. Lett.. 1990, 175. 589; Dei, A.; Pardi, L Inorg, Chim.Acta

Construction of New Coordination Polymers from 4'-(2,4-disulfophenyl)- 3,2':6'3"-terpyridine: Polymorphism, pH-dependent syntheses, structures, and properties

NASA Astrophysics Data System (ADS)

Zhang, Li; Li, Chao-Jie; He, Jia-En; Chen, Yin-Yu; Zheng, Sheng-Run; Fan, Jun; Zhang, Wei-Guang

2016-01-01

Nine new coordination compounds, namely, [Co(HDSPTP)2(H2O)4]·4H2O (H2DSPTP=4'-(2,4-disulfophenyl)-3,2':6'3"-terpyridine, 1 and 2), {[Ni(DSPTP)(H2O)4]·3H2O}n (3), {[Cu(HDSPTP)2(H2O)3]·8H2O}n (4), {[Cu(HDSPTP)2(H2O)3]·6H2O}n (5), {[Cu(DSPTP)(H2O)2]·H2O}n (6), {[Zn(DSPTP)(H2O)2]·2H2O}n (7), {[Cd(DSPTP)(H2O)2]·2H2O}n (8), and [Ag2(DSPTP)(H2O)]n (9), were constructed based on a new ligand containing both terpyridyl and sulfo groups. The reactions of H2DSPTP with Co(NO3)2.6H2O resulted in two mononuclear complexes (compounds 1 and 2). They are polymorphisms that display different hydrogen bonding networks. They are selectively synthesized by altering the added alkalis. The reaction of H2DSPTP with Ni(NO3)2·6H2O resulted in a 1D "S-shaped" coordination chain (compound 3). The reactions of Cu(II) with H2DSPTP at different pH value resulted in the following three compounds: two kinds of 1D chains obtained at pH 3.0 and 4.0 for compounds 4 and 5, respectively, and a 3D framework based on binuclear ring units with 4-connected sra topology (Compound 6). The reactions of H2DSPTP with ds-block ions resulted in the following three compounds: a Zn(II) (compound 7) and a Cd(II) (compound 8) 3D frameworks with structures similar to that in compound 6, and a 3D framework based on tetranuclear Ag(I) SBUs with binodal (4,8)-connected flu type 3D framework topology. The structural diversity is mainly attributed to the rich coordination modes (from monodentate to μ7-mode) and conformations (cis-cis and cis-trans) of HDSPTP-/DSPTP2- ligands and the metal center and can be controllable synthesized by altering the alkalis, and pH value. Thermal stability of all compounds was performed, and the thermal behaviors of compounds 6 and 8 were further explored by PXRD. Compound 6 exhibits low thermal stability and undergo a crystalline-crystalline-amorphous phase transition as temperature increases from 25 °C to 200 °C, and show amorphous-crystalline phase transition when rehydrated. However, compound 8 exhibits high thermal stability above 500 °C. Its crystalline phase can retain above 300 °C and undergo a crystalline-crystalline phase transition as temperature increased to 400 °C, and transit back to compound 8 when rehydrated. Moreover, luminescence properties of compounds 7-9 were also investigated.

Graphene/Ruthenium Active Species Aerogel as Electrode for Supercapacitor Applications

PubMed Central

Gigot, Arnaud; Fontana, Marco; Pirri, Candido Fabrizio; Rivolo, Paola

2017-01-01

Ruthenium active species containing Ruthenium Sulphide (RuS2) is synthesized together with a self-assembled reduced graphene oxide (RGO) aerogel by a one-pot hydrothermal synthesis. Ruthenium Chloride and L-Cysteine are used as reactants. The hydrothermal synthesis of the innovative hybrid material occurs at 180 °C for 12 h, by using water as solvent. The structure and morphology of the hybrid material are fully characterized by Raman, XRD, XPS, FESEM and TEM. The XRD and diffraction pattern obtained by TEM display an amorphous nanostructure of RuS2 on RGO crystallized flakes. The specific capacitance measured in planar configuration in 1 M NaCl electrolyte at 5 mV s−1 is 238 F g−1. This supercapacitor electrode also exhibits perfect cyclic stability without loss of the specific capacitance after 15,000 cycles. In summary, the RGO/Ruthenium active species hybrid material demonstrates remarkable properties for use as active material for supercapacitor applications. PMID:29301192

SOLVENT EXTRACTION OF RUTHENIUM

DOEpatents

Hyman, H.H.; Leader, G.R.

1959-07-14

The separation of rathenium from aqueous solutions by solvent extraction is described. According to the invention, a nitrite selected from the group consisting of alkali nitrite and alkaline earth nitrite in an equimolecular quantity with regard to the quantity of rathenium present is added to an aqueous solution containing ruthenium tetrantrate to form a ruthenium complex. Adding an organic solvent such as ethyl ether to the resulting mixture selectively extracts the rathenium complex.

C-H functionalization of phenols using combined ruthenium and photoredox catalysis: in situ generation of the oxidant.

PubMed

Fabry, David C; Ronge, Meria A; Zoller, Jochen; Rueping, Magnus

2015-02-23

A combination of ruthenium and photoredox catalysis allowed the ortho olefination of phenols. Using visible light, the direct C-H functionalization of o-(2-pyridyl)phenols occurred, and diverse phenol ethers were obtained in good yields. The regeneration of the ruthenium catalyst was accomplished by a photoredox-catalyzed oxidative process. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Method for forming monolayer graphene-boron nitride heterostructures

DOEpatents

Sutter, Peter Werner; Sutter, Eli Anguelova

2016-08-09

A method for fabricating monolayer graphene-boron nitride heterostructures in a single atomically thin membrane that limits intermixing at boundaries between graphene and h-BN, so as to achieve atomically sharp interfaces between these materials. In one embodiment, the method comprises exposing a ruthenium substrate to ethylene, exposing the ruthenium substrate to oxygen after exposure to ethylene and exposing the ruthenium substrate to borazine after exposure to oxygen.

Ruthenium on rutile catalyst, catalytic system, and method for aqueous phase hydrogenations

DOEpatents

Elliot, Douglas C.; Werpy, Todd A.; Wang, Yong; Frye, Jr., John G.

2001-01-01

An essentially nickel- and rhenium-free catalyst is described comprising ruthenium on a titania support where the titania is greater than 75% rutile. A catalytic system containing a nickel-free catalyst comprising ruthenium on a titania support where the titania is greater than 75% rutile, and a method using this catalyst in the hydrogenation of an organic compound in the aqueous phase is also described.

Antiproliferative effects of ruthenium-based nucleolipidic nanoaggregates in human models of breast cancer in vitro: insights into their mode of action

PubMed Central

Irace, Carlo; Misso, Gabriella; Capuozzo, Antonella; Piccolo, Marialuisa; Riccardi, Claudia; Luchini, Alessandra; Caraglia, Michele; Paduano, Luigi; Montesarchio, Daniela; Santamaria, Rita

2017-01-01

Looking for new metal-based anticancer treatments, in recent years many ruthenium complexes have been proposed as effective and safe potential drugs. In this context we have recently developed a novel approach for the in vivo delivery of Ru(III) complexes, preparing stable ruthenium-based nucleolipidic nanoaggregates endowed with significant antiproliferative activity. Herein we describe the cellular response to our ruthenium-containing formulations in selected models of human breast cancer. By in vitro bioscreens in the context of preclinical studies, we have focused on their ability to inhibit breast cancer cell proliferation by the activation of the intrinsic apoptotic pathway, possibly via mitochondrial perturbations involving Bcl-2 family members and predisposing to programmed cell death. In addition, the most efficient ruthenium-containing cationic nanoaggregates we have hitherto developed are able to elicit both extrinsic and intrinsic apoptosis, as well as autophagy. To limit chemoresistance and counteract uncontrolled proliferation, multiple cell death pathways activation by metal-based chemotherapeutics is a challenging, yet very promising strategy for targeted therapy development in aggressive cancer diseases, such as triple-negative breast cancer with limited treatment options. These outcomes provide valuable, original knowledge on ruthenium-based candidate drugs and new insights for future optimized cancer treatment protocols. PMID:28349991

The inhibition of mitochondrial calcium transport by lanthanides and Ruthenium Red

PubMed Central

Reed, Ken C.; Bygrave, Fyfe L.

1974-01-01

An EGTA (ethanedioxybis(ethylamine)tetra-acetic acid)-quench technique was developed for measuring initial rates of 45Ca2+ transport by rat liver mitochondria. This method was used in conjunction with studies of Ca2+-stimulated respiration to examine the mechanisms of inhibition of Ca2+ transport by the lanthanides and Ruthenium Red. Ruthenium Red inhibits Ca2+ transport non-competitively with Ki 3×10−8m; there are 0.08nmol of carrier-specific binding sites/mg of protein. The inhibition by La3+ is competitive (Ki=2×10−8m); the concentration of lanthanide-sensitive sites is less than 0.001nmol/mg of protein. A further difference between their modes of action is that lanthanide inhibition diminishes with time whereas that by Ruthenium Red does not. Binding studies showed that both classes of inhibitor bind to a relatively large number of external sites (probably identical with the `low-affinity' Ca2+-binding sites). La3+ competes with Ruthenium Red for most of these sites, but a small fraction of the bound Ruthenium Red (less than 2nmol/mg of protein) is not displaced by La3+. The results are discussed briefly in relation to possible models for a Ca2+ carrier. PMID:4375957

A rational repeating template method for synthesis of 2D hexagonally ordered mesoporous precious metals.

PubMed

Takai, Azusa; Doi, Yoji; Yamauchi, Yusuke; Kuroda, Kazuyuki

2011-03-01

A repeating template method is presented for the synthesis of mesoporous metals with 2D hexagonal mesostructures. First, a silica replica (i.e., silica nanorods arranged periodically) is prepared by using 2D hexagonally ordered mesoporous carbon as the template. After that, the obtained silica replica is used as the second template for the preparation of mesoporous ruthenium. After the ruthenium species are introduced into the silica replica, the ruthenium species are then reduced by a vapor-infiltration method by using the reducing agent dimethylamine borane. After the ruthenium deposition, the silica is chemically removed. Analysis by transmission and scanning electron microscopies, a nitrogen-adsorption-desorption isotherm, and small-angle X-ray scattering revealed that the mesoporous ruthenium had a 2D hexagonal mesostructure, although the mesostructural ordering is decreased compared to that of the original mesoporous carbon template. This method is widely applicable to other metal systems. By changing the metal species introduced into the silica replica, several mesoporous metals (palladium and platinum) can be synthesized. Ordered mesoporous ruthenium and palladium, which are not easily attainable by the soft-templating methods, can be prepared. This study has overcome the composition variation limitations of the soft-templating method. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Iridium-Doped Ruthenium Oxide Catalyst for Oxygen Evolution

NASA Technical Reports Server (NTRS)

Valdez, Thomas I.; Narayan, Sri R.; Billings, Keith J.

2011-01-01

NASA requires a durable and efficient catalyst for the electrolysis of water in a polymer-electrolyte-membrane (PEM) cell. Ruthenium oxide in a slightly reduced form is known to be a very efficient catalyst for the anodic oxidation of water to oxygen, but it degrades rapidly, reducing efficiency. To combat this tendency of ruthenium oxide to change oxidation states, it is combined with iridium, which has a tendency to stabilize ruthenium oxide at oxygen evolution potentials. The novel oxygen evolution catalyst was fabricated under flowing argon in order to allow the iridium to preferentially react with oxygen from the ruthenium oxide, and not oxygen from the environment. Nanoparticulate iridium black and anhydrous ruthenium oxide are weighed out and mixed to 5 18 atomic percent. They are then heat treated at 300 C under flowing argon (in order to create an inert environment) for a minimum of 14 hours. This temperature was chosen because it is approximately the creep temperature of ruthenium oxide, and is below the sintering temperature of both materials. In general, the temperature should always be below the sintering temperature of both materials. The iridium- doped ruthenium oxide catalyst is then fabricated into a PEM-based membrane- electrode assembly (MEA), and then mounted into test cells. The result is an electrolyzer system that can sustain electrolysis at twice the current density, and at the same efficiency as commercial catalysts in the range of 100-200 mA/sq cm. At 200 mA/sq cm, this new system operates at an efficiency of 85 percent, which is 2 percent greater than commercially available catalysts. Testing has shown that this material is as stable as commercially available oxygen evolution catalysts. This means that this new catalyst can be used to regenerate fuel cell systems in space, and as a hydrogen generator on Earth.

Perspectives of ruthenium(ii) polyazaaromatic photo-oxidizing complexes photoreactive towards tryptophan-containing peptides and derivatives.

PubMed

Estalayo-Adrián, S; Garnir, K; Moucheron, C

2018-01-04

Ru II polyazaaromatic complexes have been studied with the aim of developing molecular tools for DNA and oligonucleotides. In this context, Ru II -TAP (TAP = 1,4,5,8-tetraazaphenanthrene) complexes have been developed as specific photoreagents targeting the genetic material. The advantage of such compounds is due to the formation of photo-addition products between the Ru-TAP complex and the biomolecule, originating from a photo-induced electron transfer process that takes place between the excited Ru-TAP complex and guanine (G) bases of DNA. This photo-addition has been more recently extended to amino acids in view of applications involving peptides, such as inhibition or photocontrol of proteins. More particularly, tryptophan (Trp) and Trp-containing peptides are also able to be photo-oxidized by Ru II -TAP complexes, leading to the formation of photo-addition products. This mini review focuses on recent advances in the search for Ru II polyazaaromatic photo-oxidizing complexes of interest as molecular tools and photoreagents for Trp-containing peptides and proteins. Different possible future directions in this field are also discussed.

Electronic structure investigation of atomic layer deposition ruthenium(oxide) thin films using photoemission spectroscopy

NASA Astrophysics Data System (ADS)

Schaefer, Michael; Schlaf, Rudy

2015-08-01

Analyzing and manipulating the electronic band line-up of interfaces in novel micro- and nanoelectronic devices is important to achieve further advancement in this field. Such band alignment modifications can be achieved by introducing thin conformal interfacial dipole layers. Atomic layer deposition (ALD), enabling angstrom-precise control over thin film thickness, is an ideal technique for this challenge. Ruthenium (Ru0) and its oxide (RuO2) have gained interest in the past decade as interfacial dipole layers because of their favorable properties like metal-equivalent work functions, conductivity, etc. In this study, initial results of the electronic structure investigation of ALD Ru0 and RuO2 films via photoemission spectroscopy are presented. These experiments give insight into the band alignment, growth behavior, surface structure termination, and dipole formation. The experiments were performed in an integrated vacuum system attached to a home-built, stop-flow type ALD reactor without exposing the samples to the ambient in between deposition and analysis. Bis(ethylcyclopentadienyl)ruthenium(II) was used as precursor and oxygen as reactant. The analysis chamber was outfitted with X-ray photoemission spectroscopy (LIXPS, XPS). The determined growth modes are consistent with a strong growth inhibition situation with a maximum average growth rate of 0.21 Å/cycle for RuO2 and 0.04 Å/cycle for Ru.0 An interface dipole of up to -0.93 eV was observed, supporting the assumption of a strongly physisorbed interface. A separate experiment where the surface of a RuO film was sputtered suggests that the surface is terminated by an intermediate, stable, non-stoichiometric RuO2/OH compound whose surface is saturated with hydroxyl groups.

Direct grafting of long-lived luminescent indicator dyes to GaN light-emitting diodes for chemical microsensor development.

PubMed

López-Gejo, Juan; Navarro-Tobar, Álvaro; Arranz, Antonio; Palacio, Carlos; Muñoz, Elías; Orellana, Guillermo

2011-10-01

Two new methods for covalent functionalization of GaN based on plasma activation of its surface are presented. Both of them allow attachment of sulfonated luminescent ruthenium(II) indicator dyes to the p- and n-type semiconductor as well as to the surface of nonencapsulated chips of GaN light-emitting diodes (blue LEDs). X-ray photoelectron spectroscopy analysis of the functionalized semiconductor confirms the formation of covalent bonds between the GaN surface and the dye. Confocal fluorescence microscopy with single-photon-timing (SPT) detection has been used for characterization of the functionalized surfaces and LED chips. While the ruthenium complex attached to p-GaN under an oxygen-free atmosphere gives significantly long mean emission lifetimes for the indicator dye (ca. 2000 ns), the n-GaN-functionalized surfaces display surprisingly low values (600 ns), suggesting the occurrence of a quenching process. A photoinduced electron injection from the dye to the semiconductor conduction band, followed by a fast back electron transfer, is proposed to be responsible for the excited ruthenium dye deactivation. This process invalidates the use of the n-GaN/dye system for sensing applications. However, for p-GaN/dye materials, the luminescence decay accelerates in the presence of O(2). The moderate sensitivity is attributed to the fact that only a monolayer of indicator dye is anchored to the semiconductor surface but serves as a demonstrator device. Moreover, the luminescence decays of the functionalized LED chip measured with excitation of either an external (laser) source or the underlying LED emission (from p-GaN/InGaN quantum wells) yield the same mean luminescence lifetime. These results pave the way for using advanced LEDs to develop integrateable optochemical microsensors for gas analysis. © 2011 American Chemical Society

Ruthenium(II) arene complexes with chelating chloroquine analogue ligands: Synthesis, characterization and in vitro antimalarial activity†

PubMed Central

Glans, Lotta; Ehnbom, Andreas; de Kock, Carmen; Martínez, Alberto; Estrada, Jesús; Smith, Peter J.; Haukka, Matti; Sánchez-Delgado, Roberto A.; Nordlander, Ebbe

2012-01-01

Three new ruthenium complexes with bidentate chloroquine analogue ligands, [Ru(η6-cym)(L1)Cl]Cl (1, cym = p-cymene, L1 = N-(2-((pyridin-2-yl)methylamino)ethyl)-7-chloroquinolin-4-amine), [Ru(η6-cym)(L2)Cl]Cl (2, L2 = N-(2-((1-methyl-1H-imidazol-2-yl)methylamino)ethyl)-7-chloroquinolin-4-amine) and [Ru(η6-cym)(L3)Cl] (3, L3 = N-(2-((2-hydroxyphenyl)methylimino)ethyl)-7-chloroquinolin-4-amine) have been synthesized and characterized. In addition, the X-ray crystal structure of 2 is reported. The antimalarial activity of complexes 1–3 and ligands L1, L2 and L3, as well as the compound N-(2-(bis((pyridin-2-yl)methyl)amino)ethyl)-7-chloroquinolin-4-amine (L4), against chloroquine sensitive and chloroquine resistant Plasmodium falciparum malaria strains was evaluated. While 1 and 2 are less active than the corresponding ligands, 3 exhibits high antimalarial activity. The chloroquine analogue L2 also shows good activity against both the choloroquine sensitive and the chloroquine resistant strains. Heme aggregation inhibition activity (HAIA) at an aqueous buffer/n-octanol interface (HAIR50) and lipophilicity (D, as measured by water/n-octanol distribution coefficients) have been measured for all ligands and metal complexes. A direct correlation between the D and HAIR50 properties cannot be made because of the relative structural diversity of the complexes, but it may be noted that these properties are enhanced upon complexation of the inactive ligand L3 to ruthenium, to give a metal complex (3) with promising antimalarial activity. PMID:22249579

Nonproductive events in ring-closing metathesis using ruthenium catalysts.

PubMed

Stewart, Ian C; Keitz, Benjamin K; Kuhn, Kevin M; Thomas, Renee M; Grubbs, Robert H

2010-06-30

The relative TONs of productive and nonproductive metathesis reactions of diethyl diallylmalonate are compared for eight different ruthenium-based catalysts. Nonproductive cross metathesis is proposed to involve a chain-carrying ruthenium methylidene. A second more-challenging substrate (dimethyl allylmethylallylmalonate) that forms a trisubstituted olefin product is used to further delineate the effect of catalyst structure on the relative efficiencies of these processes. A steric model is proposed to explain the observed trends.

Dye molecular structure device open-circuit voltage correlation in Ru(II) sensitizers with heteroleptic tridentate chelates for dye-sensitized solar cells.

PubMed

Wu, Kuan-Lin; Li, Cheng-Hsuan; Chi, Yun; Clifford, John N; Cabau, Lydia; Palomares, Emilio; Cheng, Yi-Ming; Pan, Hsiao-An; Chou, Pi-Tai

2012-05-02

Dicarboxyterpyridine chelates with π-conjugated pendant groups attached at the 5- or 6-position of the terminal pyridyl unit were synthesized. Together with 2,6-bis(5-pyrazolyl)pyridine, these were used successfully to prepare a series of novel heteroleptic, bis-tridentate Ru(II) sensitizers, denoted as TF-11-14. These dyes show excellent performance in dye-sensitized solar cells (DSCs) under AM1.5G simulated sunlight at a light intensity of 100 mW cm(-2) in comparison with a reference device containing [Ru(Htctpy)(NCS)(3)][TBA](3) (N749), where H(3)tctpy and TBA are 4,4',4"-tricarboxy-2,2':6',2"-terpyridine and tetra-n-butylammonium cation, respectively. In particular, the sensitizer TF-12 gave a short-circuit photocurrent of 19.0 mA cm(-2), an open-circuit voltage (V(OC)) of 0.71 V, and a fill factor of 0.68, affording an overall conversion efficiency of 9.21%. The increased conjugation conferred to the TF dyes by the addition of the π-conjugated pendant groups increases both their light-harvesting and photovoltaic energy conversion capability in comparison with N749. Detailed recombination processes in these devices were probed by various spectroscopic and dynamics measurements, and a clear correlation between the device V(OC) and the cell electron lifetime was established. In agreement with several other recent studies, the results demonstrate that high efficiencies can also be achieved with Ru(II) sensitizers that do not contain thiocyanate ancillaries. This bis-tridentate, dual-carboxy anchor configuration thus serves as a prototype for future omnibearing design of highly efficient Ru(II) sensitizers suited for use in DSCs. © 2012 American Chemical Society

N-Tosylhydrazone directed annulation via C-H/N-N bond activation in Ru(ii)/PEG-400 as homogeneous recyclable catalytic system: a green synthesis of isoquinolines.

PubMed

Deshmukh, Dewal S; Bhanage, Bhalchandra M

2018-06-21

A green and sustainable methodology for the synthesis of isoquinolines using Ru(ii)/PEG-400 as a homogeneous recyclable catalytic system has been demonstrated. N-Tosylhydrazone, a rarely explored directing group, has been successfully employed for an annulation type of reaction with alkynes via C-H/N-N activation. A short reaction time with a simple extraction procedure, a wide substrate scope with high yields of products, easily prepared substrates, biodegradable solvent, and scalability up to the gram level enhance the efficiency and sustainability of the proposed protocol. Further, the expensive ruthenium-based homogeneous catalytic system could be reused up to a fourth consecutive cycle without any loss in its activity.

Ruthenium-Catalyzed Cycloaddition of 1-Haloalkynes with Nitrile Oxides and Organic Azides; Synthesis of 4-Halo Isoxazoles and 5-Halo Triazoles

PubMed Central

Oakdale, James S.; Sit, Rakesh K.

2015-01-01

(Cyclopentadienyl)(cyclooctadiene) ruthenium(II) chloride [CpRuCl(cod)] catalyzes the reaction between nitrile oxides and electronically deficient 1-choro-, 1-bromo- and 1-iodoalkynes leading to 4-haloisoxazoles. Organic azides are also suitable 1,3-dipoles, resulting in 5-halo-1,2,3-triazoles. These air tolerant reactions can be performed at room temperature with 1.25 equiv of the respective 1,3-dipole relative to the alkyne component. Reactive 1-haloalkynes include propiolic amides, esters, ketones and phosphonates. Post-functionalization of the halogenated azole products can be accomplished using palladium-catalyzed cross-coupling reactions as well as via manipulation of reactive amide groups. The lack of catalysis observed with Cp*RuCl(cod) is attributed to steric demands of the Cp* (η5-C5Me5) ligand in comparison to the parent Cp (η5-C5H5). This hypothesis is supported by the poor reactivity of (η5-C5Me4CF3)RuCl(cod), which serves as a an isosteric mimic of Cp* and as an isoelectronic analog of Cp. PMID:25059647

Oxidative addition of allylic halides to ruthenium(II) compounds. Preparation, reactions, and X-ray crystallographic structure of ruthenium(IV)-allyl complexes

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

Nagashima, Hideo; Mukai, Katsunori; Shiota, Yusuke

1990-03-01

The oxidative addition of allylic halides to (C{sub 5}R{sub 5})RuL{sub 2}X (R = H, Me; L = CO, PPh{sub 3}) gave new Ru(IV)-{eta}{sup 3}-allyl complexes, (C{sub 5}R{sub 5})RuX{sub 2}({eta}{sup 3}-allyl). An X-ray structure determination was carried out on (C{sub 5}Me{sub 5})RuBr{sub 2}({eta}{sup 3}-C{sub 3}H{sub 5}), indicating a pseudo-piano-stool structure having two Br atoms and two terminal carbons of the endo-{eta}{sup 3}-allyl ligand located at the basal positions. There is a crystal mirror plane bisecting the pentamethylcyclopentadienyl and the {pi}-allyl ligands. Crystal data: orthorhombic, space group P2{sub 1}2{sub 1}2{sub 1}, a = 22.738 (1) {angstrom}, b = 13.367 (7) {angstrom}, cmore » = 9.383 (1) {angstrom}, Z = 4., data refined to R = 0.0695. Its {sup 1}H and {sup 13}C NMR spectra showed symmetric allyl signals, supporting that the above-described piano-stool structure is maintained even in solution.« less

Charge transfer from an adsorbed ruthenium-based photosensitizer through an ultra-thin aluminium oxide layer and into a metallic substrate

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

Gibson, Andrew J.; Temperton, Robert H.; Handrup, Karsten

2014-06-21

The interaction of the dye molecule N3 (cis-bis(isothiocyanato)bis(2,2-bipyridyl-4,4′-dicarbo-xylato) -ruthenium(II)) with the ultra-thin oxide layer on a AlNi(110) substrate, has been studied using synchrotron radiation based photoelectron spectroscopy, resonant photoemission spectroscopy, and near edge X-ray absorption fine structure spectroscopy. Calibrated X-ray absorption and valence band spectra of the monolayer and multilayer coverages reveal that charge transfer is possible from the molecule to the AlNi(110) substrate via tunnelling through the ultra-thin oxide layer and into the conduction band edge of the substrate. This charge transfer mechanism is possible from the LUMO+2 and 3 in the excited state but not from the LUMO,more » therefore enabling core-hole clock analysis, which gives an upper limit of 6.0 ± 2.5 fs for the transfer time. This indicates that ultra-thin oxide layers are a viable material for use in dye-sensitized solar cells, which may lead to reduced recombination effects and improved efficiencies of future devices.« less

Hybrid TiO2 -Ruthenium Nano-photosensitizer Synergistically Produces Reactive Oxygen Species in both Hypoxic and Normoxic Conditions.

PubMed

Gilson, Rebecca C; Black, Kvar C L; Lane, Daniel D; Achilefu, Samuel

2017-08-28

Photodynamic therapy (PDT) is widely used to treat diverse diseases, but its dependence on oxygen to produce cytotoxic reactive oxygen species (ROS) diminishes the therapeutic effect in a hypoxic environment, such as solid tumors. Herein, we developed a ROS-producing hybrid nanoparticle-based photosensitizer capable of maintaining high levels of ROS under both normoxic and hypoxic conditions. Conjugation of a ruthenium complex (N3) to a TiO 2 nanoparticle afforded TiO 2 -N3. Upon exposure of TiO 2 -N3 to light, the N3 injected electrons into TiO 2 to produce three- and four-fold more hydroxyl radicals and hydrogen peroxide, respectively, than TiO 2 at 160 mmHg. TiO 2 -N3 maintained three-fold higher hydroxyl radicals than TiO 2 under hypoxic conditions via N3-facilitated electron-hole reduction of adsorbed water molecules. The incorporation of N3 transformed TiO 2 from a dual type I and II PDT agent to a predominantly type I photosensitizer, irrespective of the oxygen content. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Anti-tumor activity and mechanism of apoptosis of A549 induced by ruthenium complex.

PubMed

Sun, Dongdong; Mou, Zhipeng; Li, Nuan; Zhang, Weiwei; Wang, Yazhe; Yang, Endong; Wang, Weiyun

2016-12-01

Two new ruthenium (II) polypyridyl complexes [Ru(MeIm) 4 (pip)] 2+ (1) and [Ru(MeIm) 4 (4-npip)] 2+ (2) were synthesized under the guidance of computational studies (DFT). Their binding property to human telomeric G-quadruplex studied by UV-Vis absorption spectroscopy, the fluorescent resonance energy transfer (FRET) melting assay and circular dichroism (CD) spectroscopy for validating the theoretical prediction. Both of them were evaluated for their potential anti-proliferative activity against four human tumor cell lines. Complex 2 shows growth inhibition against all the cell lines tested, especially the human lung tumor cell (A549). The RTCA analysis not only validated the inhibition activity but also showed the ability of reducing A549 cells' migration. DNA-flow cytometric analysis, mitochondrial membrane potential (ΔΨm) and the scavenger measurements of reactive oxygen species (ROS) analysis carried out to investigate the mechanism of cell growth inhibition and apoptosis-inducing effect of complex 2. The results demonstrated that complex 2 induces tumor cells apoptosis by acting on both mitochondrial homeostasis destruction and death receptor signaling pathways. And those suggested that complex 2 could be a candidate for further evaluation as a chemotherapeutic agent against human tumor.

Synthesis, molecular structure, and C-C coupling reactions of carbeneruthenium(II) complexes with C5H5Ru(=CRR') and C5Me5Ru(=CRR') as molecular units.

PubMed

Braun, Thomas; Münch, Gerhard; Windmüller, Bettina; Gevert, Olaf; Laubender, Matthias; Werner, Helmut

2003-06-06

The ethene derivatives [(eta(5)-C(5)R(5))RuX(C(2)H(4))(PPh(3))] with R=H and Me, which have been prepared from the eta(3)-allylic compounds [(eta(5)-C(5)R(5))Ru(eta(3)-2-MeC(3)H(4))(PPh(3))] (1, 2) and acids HX under an ethene atmosphere, are excellent starting materials for the synthesis of a series of new halfsandwich-type ruthenium(II) complexes. The olefinic ligand is replaced not only by CO and pyridine, but also by internal and terminal alkynes to give (for X=Cl) alkyne, vinylidene, and allene compounds of the general composition [(eta(5)-C(5)R(5))RuCl(L)(PPh(3))] with L=C(2)(CO(2)Me)(2), Me(3)SiC(2)CO(2)Et, C=CHCO(2)R, and C(3)H(4). The allenylidene complex [(eta(5)-C(5)H(5))RuCl(=C=C=CPh(2))(PPh(3))] is directly accessible from 1 (R=H) in two steps with the propargylic alcohol HC triple bond CC(OH)Ph(2) as the precursor. The reactions of the ethene derivatives [(eta(5)-C(5)H(5))RuX(C(2)H(4))(PPh(3))] (X=Cl, CF(3)CO(2)) with diazo compounds RR'CN(2) yield the corresponding carbene complexes [(eta(5)-C(5)R(5))RuX(=CRR')(PPh(3))], while with ethyl diazoacetate (for X=Cl) the diethyl maleate compound [(eta(5)-C(5)H(5))RuCl[eta(2)-Z-C(2)H(2)(CO(2)Et)(2)](PPh(3))] is obtained. Halfsandwich-type ruthenium(II) complexes [(eta(5)-C(5)R(5))RuCl(=CHR')(PPh(3))] with secondary carbenes as ligands, as well as cationic species [(eta(5)-C(5)H(5))Ru(=CPh(2))(L)(PPh(3))]X with L=CO and CNtBu and X=AlCl(4) and PF(6), have also been prepared. The neutral compounds [(eta(5)-C(5)H(5))RuCl(=CRR')(PPh(3))] react with phenyllithium, methyllithium, and the vinyl Grignard reagent CH(2)=CHMgBr by displacement of the chloride and subsequent C-C coupling to generate halfsandwich-type ruthenium(II) complexes with eta(3)-benzyl, eta(3)-allyl, and substituted olefins as ligands. Protolytic cleavage of the metal-allylic bond in [(eta(5)-C(5)H(5))Ru(eta(3)-CH(2)CHCR(2))(PPh(3))] with acetic acid affords the corresponding olefins R(2)C=CHCH(3). The by-product of this process is the acetato derivative [(eta(5)-C(5)H(5))Ru(kappa(2)-O(2)CCH(3))(PPh(3))], which can be reconverted to the carbene complexes [(eta(5)-C(5)H(5))RuCl(=CR(2))(PPh(3))] in a one-pot reaction with R(2)CN(2) and Et(3)NHCl.

Ceria-supported ruthenium nanoparticles as highly active and long-lived catalysts in hydrogen generation from the hydrolysis of ammonia borane.

PubMed

Akbayrak, Serdar; Tonbul, Yalçın; Özkar, Saim

2016-07-05

Ruthenium(0) nanoparticles supported on ceria (Ru(0)/CeO2) were in situ generated from the reduction of ruthenium(iii) ions impregnated on ceria during the hydrolysis of ammonia borane. Ru(0)/CeO2 was isolated from the reaction solution by centrifugation and characterized by ICP-OES, BET, XRD, TEM, SEM-EDS and XPS techniques. All the results reveal that ruthenium(0) nanoparticles were successfully supported on ceria and the resulting Ru(0)/CeO2 is a highly active, reusable and long-lived catalyst for hydrogen generation from the hydrolysis of ammonia borane with a turnover frequency value of 361 min(-1). The reusability tests reveal that Ru(0)/CeO2 is still active in the subsequent runs of hydrolysis of ammonia borane preserving 60% of the initial catalytic activity even after the fifth run. Ru(0)/CeO2 provides a superior catalytic lifetime (TTO = 135 100) in hydrogen generation from the hydrolysis of ammonia borane at 25.0 ± 0.1 °C before deactivation. The work reported here includes the formation kinetics of ruthenium(0) nanoparticles. The rate constants for the slow nucleation and autocatalytic surface growth of ruthenium(0) nanoparticles were obtained using hydrogen evolution as a reporter reaction. An evaluation of rate constants at various temperatures enabled the estimation of activation energies for both the reactions, Ea = 60 ± 7 kJ mol(-1) for the nucleation and Ea = 47 ± 2 kJ mol(-1) for the autocatalytic surface growth of ruthenium(0) nanoparticles, as well as the activation energy of Ea = 51 ± 2 kJ mol(-1) for the catalytic hydrolysis of ammonia borane.

Tin-decorated ruthenium nanoparticles: a way to tune selectivity in hydrogenation reaction

NASA Astrophysics Data System (ADS)

Bonnefille, Eric; Novio, Fernando; Gutmann, Torsten; Poteau, Romuald; Lecante, Pierre; Jumas, Jean-Claude; Philippot, Karine; Chaudret, Bruno

2014-07-01

Two series of ruthenium nanoparticles stabilized either by a polymer (polyvinylpyrrolidone; Ru/PVP) or a ligand (bisdiphenylphosphinobutane; Ru/dppb) were reacted with tributyltin hydride [(n-C4H9)3SnH] leading to tin-decorated ruthenium nanoparticles, Ru/PVP/Sn and Ru/dppb/Sn. The Sn/Ru molar ratio was varied in order to study the influence of the surface tin content on the properties of these new nanoparticles, by comparison with Ru/PVP and Ru/dppb. Besides HRTEM and WAXS analyses, spectroscopic techniques (IR, NMR and Mössbauer) combined with theoretical calculations and a simple catalytic test (styrene hydrogenation) allowed us to evidence the formation of μ3-bridging ``SnR'' groups on the ruthenium surface as well as to rationalize their influence on surface chemistry and catalytic activity.Two series of ruthenium nanoparticles stabilized either by a polymer (polyvinylpyrrolidone; Ru/PVP) or a ligand (bisdiphenylphosphinobutane; Ru/dppb) were reacted with tributyltin hydride [(n-C4H9)3SnH] leading to tin-decorated ruthenium nanoparticles, Ru/PVP/Sn and Ru/dppb/Sn. The Sn/Ru molar ratio was varied in order to study the influence of the surface tin content on the properties of these new nanoparticles, by comparison with Ru/PVP and Ru/dppb. Besides HRTEM and WAXS analyses, spectroscopic techniques (IR, NMR and Mössbauer) combined with theoretical calculations and a simple catalytic test (styrene hydrogenation) allowed us to evidence the formation of μ3-bridging ``SnR'' groups on the ruthenium surface as well as to rationalize their influence on surface chemistry and catalytic activity. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr00791c

Nitric acid recovery from waste solutions

DOEpatents

Wilson, A. S.

1959-04-14

The recovery of nitric acid from aqueous nitrate solutions containing fission products as impurities is described. It is desirable to subject such solutions to concentration by evaporation since nitric acid is regenerated thereby. A difficulty, however, is that the highly radioactive fission product ruthenium is volatilized together with the nitric acid. It has been found that by adding nitrous acid, ruthenium volatilization is suppressed and reduced to a negligible degree so that the distillate obtained is practically free of ruthenium.

Selective catalytic reduction system and process for treating NOx emissions using a palladium and rhodium or ruthenium catalyst

DOEpatents

Sobolevskiy, Anatoly [Orlando, FL; Rossin, Joseph A [Columbus, OH; Knapke, Michael J [Columbus, OH

2011-07-12

A process for the catalytic reduction of nitrogen oxides (NOx) in a gas stream (29) in the presence of H.sub.2 is provided. The process comprises contacting the gas stream with a catalyst system (38) comprising zirconia-silica washcoat particles (41), a pre-sulfated zirconia binder (44), and a catalyst combination (40) comprising palladium and at least one of rhodium, ruthenium, or a mixture of ruthenium and rhodium.

Terpyridine derivatives as "turn-on" fluorescence chemosensors for the selective and sensitive detection of Zn2+ ions in solution and in live cells.

PubMed

Mandal, Tripti; Hossain, Anowar; Dhara, Anamika; Al Masum, Abdulla; Konar, Saugata; Manna, Saikat Kumar; Seth, Saikat Kumar; Pathak, Sudipta; Mukhopadhyay, Subrata

2018-06-20

A terpyridine based compound L1 was designed and synthesized as an "off-on" chemosensor for the detection of Zn2+. Chemosensor L1 showed excellent selectivity and sensitivity toward Zn2+ by exhibiting a large fluorescence enhancement (∼51-fold) at 370 nm whereas other competitive metal ions did not show any noticeable change in the emission spectra of chemosensor L1. The chemosensor (L1) was shown to detect Zn2+ ions down to 9.76 μM at pH 7.4. However, chemosensor L1 binds Zn2+ in a 1 : 2 ratio (receptor : metal) with an association constant of 1.85 × 104 (R2 = 0.993) and this 1 : 2 stoichiometric fashion is established on the basis of a Job plot and mass spectroscopy. DFT/TD-DFT calculations were carried out to understand the binding nature, coordination features and electronic properties of L1 and the L1-2Zn2+ complex. In addition, this "turn-on" fluorescence probe was effectively used to image intracellular Zn2+ ions in cultured MDA-MB-468 cells.

Competing supramolecular interactions give a new twist to terpyridyl chemistry: anion- and solvent-induced formation of spiral arrays in silver(I) complexes of a simple terpyridine.

PubMed

Hannon, Michael J; Painting, Claire L; Plummer, Edward A; Childs, Laura J; Alcock, Nathaniel W

2002-05-17

Multiple competing molecular interactions (metal-ligand, pi-stacking and hydrogen-bonding) in the silver(I) complexes of 4'-thiomethyl-2,2':6',2"-terpyridine give rise to a range of different molecular architectures, in which the metal-ligand coordination requirements are satisfied in quite different ways. Polynuclear supramolecular spirals, aggregated mononuclear and aggregated dinuclear units are all structurally characterised. The metallo-supramolecular architecture obtained displays a remarkable dependence both on the choice of non-coordinated anion and the type of solvent used (coordinating or non-coordinating). The anion dependence is particularly surprising, since the anions are not integrated into the centre of the supramolecular structure. The solution behaviour is also solvent and anion dependent, with aggregation of planar mononuclear cations observed in acetonitrile, but oligonuclear spiral species implicated in nitromethane. The extraordinarily variable geometries of these systems suggest that they provide a novel example of the "frustration" principle, in which opposing tendencies cannot simultaneously be satisfied and identify an alternative approach to the design of metallo-supramolecular systems whose structure is responsive to external agents.

Kinetics and Photochemistry of Ruthenium Bisbipyridine Diacetonitrile Complexes: An Interdisciplinary Inorganic and Physical Chemistry Laboratory Exercise.

PubMed

Rapp, Teresa L; Phillips, Susan R; Dmochowski, Ivan J

2016-12-13

The study of ruthenium polypyridyl complexes can be widely applied across disciplines in the undergraduate curriculum. Ruthenium photochemistry has advanced many fields including dye-sensitized solar cells, photoredox catalysis, light-driven water oxidation, and biological electron transfer. Equally promising are ruthenium polypyridyl complexes that provide a sterically bulky, photolabile moiety for transiently "caging" biologically active molecules. Photouncaging involves the use of visible (1-photon) or near-IR (2-photon) light to break one or more bonds between ruthenium and coordinated ligand(s), which can occur on short time scales and in high quantum yields. In this work we demonstrate the use of a model "caged" acetonitrile complex, Ru(2,2'-bipyridine) 2 (acetonitrile) 2 , or RuMeCN in an advanced synthesis and physical chemistry laboratory. Students made RuMeCN in an advanced synthesis laboratory course and performed UV-vis spectroscopy and electrochemistry. The following semester students investigated RuMeCN photolysis kinetics in a physical chemistry laboratory. These two exercises may also be combined to create a 2-week module in an advanced undergraduate laboratory course.

Kinetics and Photochemistry of Ruthenium Bisbipyridine Diacetonitrile Complexes: An Interdisciplinary Inorganic and Physical Chemistry Laboratory Exercise

PubMed Central

2016-01-01

The study of ruthenium polypyridyl complexes can be widely applied across disciplines in the undergraduate curriculum. Ruthenium photochemistry has advanced many fields including dye-sensitized solar cells, photoredox catalysis, light-driven water oxidation, and biological electron transfer. Equally promising are ruthenium polypyridyl complexes that provide a sterically bulky, photolabile moiety for transiently “caging” biologically active molecules. Photouncaging involves the use of visible (1-photon) or near-IR (2-photon) light to break one or more bonds between ruthenium and coordinated ligand(s), which can occur on short time scales and in high quantum yields. In this work we demonstrate the use of a model “caged” acetonitrile complex, Ru(2,2′-bipyridine)2(acetonitrile)2, or RuMeCN in an advanced synthesis and physical chemistry laboratory. Students made RuMeCN in an advanced synthesis laboratory course and performed UV–vis spectroscopy and electrochemistry. The following semester students investigated RuMeCN photolysis kinetics in a physical chemistry laboratory. These two exercises may also be combined to create a 2-week module in an advanced undergraduate laboratory course. PMID:28649139

Iodide Ion Pairing with Highly Charged Ruthenium Polypyridyl Cations in CH3CN.

PubMed

Swords, Wesley B; Li, Guocan; Meyer, Gerald J

2015-05-04

A series of three highly charged cationic ruthenium(II) polypyridyl complexes of the general formula [Ru(deeb)3-x(tmam)x](PF6)2x+2, where deeb is 4,4'-diethyl ester-2,2'-bipyridine and tmam is 4,4'-bis[(trimethylamino)methyl]-2,2'-bipyridine, were synthesized and characterized and are referred to as 1, 2, or 3 based on the number of tmam ligands. Crystals suitable for X-ray crystallography were obtained for the homoleptic complex 3, which was found to possess D3 symmetry over the entire ruthenium complex. The complexes displayed visible absorption spectra typical of metal-to-ligand charge-transfer (MLCT) transitions. In acetonitrile, quasi-reversible waves were assigned to Ru(III/II) electron transfer, with formal reduction potentials that shifted negative as the number of tmam ligands was increased. Room temperature photoluminescence was observed in acetonitrile with quantum yields of ϕ ∼ 0.1 and lifetimes of τ ∼ 2 μs. The spectroscopic and electrochemical data were most consistent with excited-state localization on the deeb ligand for 1 and 2 and on the tmam ligand for 3. The addition of tetrabutylammonium iodide to the complexes dissolved in a CH3CN solution led to changes in the UV-vis absorption spectra consistent with ion pairing. A Benesi-Hildebrand-type analysis of these data revealed equilibrium constants that increased with the cationic charge 1 < 2 < 3 with K = 4000, 4400, and 7000 M(-1). (1)H NMR studies in CD3CN also revealed evidence for iodide ion pairs and indicated that they occur predominantly with iodide localization near the tmam ligand(s). The diastereotopic H atoms on the methylene carbon that link the amine to the bipyridine ring were uniquely sensitive to the presence of iodide; analysis revealed that an iodide "binding pocket" exists wherein iodide forms an adduct with the 3 and 3' bipyridyl H atoms and the quaternized amine. The MLCT excited states were efficiently quenched by iodide. Time-resolved photoluminescence measurements of 1 revealed a static component consistent with rapid electron transfer from iodide in the "binding pocket" to the Ru metal center in the excited state, ket > 10(8) s(-1). The possible relevance of this work to solar energy conversion and dye-sensitized solar cells is discussed.

Long-Range Intramolecular Electronic Communication in a Trinuclear Ruthenium Tropolonate Complex.

PubMed

Yoshida, Jun; Kuwahara, Kyohei; Suzuki, Kota; Yuge, Hidetaka

2017-02-20

Dinuclear and trinuclear ruthenium complexes, [Ru(trop) 2 (C 2 trop)Ru(dppe)Cp] [2b; trop = tropolonato, C 2 trop = ethynyltropolonato, dppe = 1,2-bis(diphenylphosphino)ethane] and [Ru(trop){(C 2 trop)Ru(dppe)Cp} 2 ] (3), were synthesized, and their electronic and electrochemical properties were investigated in comparison with our previously reported complex [Ru(acac) 2 (C 2 trop)Ru(dppe)Cp] (2a). The electron-donating Ru II (dppe)Cp unit and electron-accepting Ru III O 6 unit are connected by C 2 trop in these complexes. 2a incorporates acetylacetonate as an ancillary ligand, while 2b and 3 incorporate tropolonate as an ancillary ligand. Every complex, 2a, 2b, and 3, exhibits similar UV-vis-near-IR (NIR) absorption spectra, demonstrating the lack of explicit intramolecular electronic communication between the units at least in the neutral state. The weak NIR absorption in 2a further diminished upon electrochemical oxidation, indicating almost no electronic communication between the units. In contrast, 2b and 3 exhibit broad NIR absorptions upon oxidation. Additionally, 3 exhibits four stepwise redox couples in the electrochemical study, which are formally attributed to [Ru II (trop) 3 ] - /[Ru III (trop) 3 ], two [Ru II (dppe)Cp]/[Ru III (dppe)Cp] + , and [Ru III (trop) 3 ]/[Ru IV (trop) 3 ] + couples. Clear separation of the redox couples attributed to the two terminal [Ru(dppe)Cp] units demonstrates the thermodynamic stability of the intermediate oxidation states with respect to disproportionation. Further electrochemical studies using an electrolyte including perfluorinated weakly coordinating anions and density functional theory/time-dependent density functional theory calculations confirmed the effect of ancillary ligands, acetylacetonate and tropolonate. In the case of 2a, electronic delocalization over the whole complex, especially over the [Ru(acac) 2 (trop)] unit, appears to be small. In contrast, the electronic communication between [Ru(dppe)Cp] and [Ru(trop) 3 ] units in 3 seems to be enhanced upon oxidation, resulting in the long-range intramolecular electronic communication.

Vascular response of ruthenium tetraamines in aortic ring from normotensive rats.

PubMed

Conceição-Vertamatti, Ana Gabriela; Ramos, Luiz Alberto Ferreira; Calandreli, Ivy; Chiba, Aline Nunes; Franco, Douglas Wagner; Tfouni, Elia; Grassi-Kassisse, Dora Maria

2015-03-01

Ruthenium (Ru) tetraamines are being increasingly used as nitric oxide (NO) carriers. In this context, pharmacological studies have become highly relevant to better understand the mechanism of action involved. To evaluate the vascular response of the tetraamines trans-[Ru(II)(NH3)4(Py)(NO)](3+), trans-[Ru(II)(Cl)(NO) (cyclan)](PF6)2, and trans-[Ru(II)(NH3)4(4-acPy)(NO)](3+). Aortic rings were contracted with noradrenaline (10(-6) M). After voltage stabilization, a single concentration (10(-6) M) of the compounds was added to the assay medium. The responses were recorded during 120 min. Vascular integrity was assessed functionally using acetylcholine at 10(-6) M and sodium nitroprusside at 10(-6) M as well as by histological examination. Histological analysis confirmed the presence or absence of endothelial cells in those tissues. All tetraamine complexes altered the contractile response induced by norepinephrine, resulting in increased tone followed by relaxation. In rings with endothelium, the inhibition of endothelial NO caused a reduction of the contractile effect caused by pyridine NO. No significant responses were observed in rings with endothelium after treatment with cyclan NO. In contrast, in rings without endothelium, the inhibition of guanylate cyclase significantly reduced the contractile response caused by the pyridine NO and cyclan NO complexes, and both complexes caused a relaxing effect. The results indicate that the vascular effect of the evaluated complexes involved a decrease in the vascular tone induced by norepinephrine (10(-6) M) at the end of the incubation period in aortic rings with and without endothelium, indicating the slow release of NO from these complexes and suggesting that the ligands promoted chemical stability to the molecule. Moreover, we demonstrated that the association of Ru with NO is more stable when the ligands pyridine and cyclan are used in the formulation of the compound.

Dinuclear RuII(bipy)2 Derivatives: Structural, Biological, and in Vivo Zebrafish Toxicity Evaluation.

PubMed

Lenis-Rojas, Oscar A; Roma-Rodrigues, Catarina; Fernandes, Alexandra R; Marques, Fernanda; Pérez-Fernández, David; Guerra-Varela, Jorge; Sánchez, Laura; Vázquez-García, Digna; López-Torres, Margarita; Fernández, Alberto; Fernández, Jesús J

2017-06-19

Ruthenium-based drugs exhibit interesting properties as potential anticancer pharmaceuticals. We herein present the synthesis and characterization of a new family of ruthenium complexes with formulas [{Ru(bipy) 2 } 2 (μ-L)][CF 3 SO 3 ] 4 (L = bptz, 1a) and [{Ru(bipy) 2 } 2 (μ-L)][CF 3 SO 3 ] 2 (L = arphos, 2a; dppb, 3a; dppf, 4a), which were synthesized from the Ru(II) precursor compound cis-Ru(bipy) 2 Cl 2 . The complexes were characterized by elemental analysis, mass spectrometry, 1 H and 31 P{ 1 H} NMR, IR spectroscopy, and conductivity measurements. The molecular structures for three Ru(II) compounds were determined by single-crystal X-ray diffraction. The newly developed compounds interact with CT-DNA by intercalation, in particular, 2a, 3a, and 4a, which also seemed to induce some extent of DNA degradation. This effect seemed to be related with the formation of reactive oxygen species. The cytotoxic activity was evaluated against A2780, MCF7, and MDAMB231 human tumor cells. Compounds 2a and 4a were the most cytotoxic with activity compared to cisplatin (∼2 μM, 72 h) in the A2780 cisplatin sensitive cells. All the compounds induced A2780 cell death by apoptosis, however, to a lesser extent for compounds 4a and 2a. For these compounds, the mechanism of cell death in addition to apoptosis seemed to involve autophagy. In vivo toxicity was evaluated using the zebrafish embryo model. LC 50 estimates varied from 5.397 (3a) to 39.404 (1a) mg/L. Considering the in vivo toxicity in zebrafish embryos and the in vitro cytotoxicity in cancer cells, compound 1a seems to be the safest having no effect on dechirionation and presenting a good antiproliferative activity against ovarian carcinoma cells.

Nickel/ruthenium catalyst and method for aqueous phase reactions

DOEpatents

Elliott, D.C.; Sealock, J.L.

1998-09-29

A method of hydrogenation is described using a catalyst in the form of a plurality of porous particles wherein each particle is a support having nickel metal catalytic phase or reduced nickel deposited thereon in a first dispersed phase and an additional ruthenium metal deposited onto the support in a second dispersed phase. The additional ruthenium metal is effective in retarding or reducing agglomeration or sintering of the nickel metal catalytic phase thereby increasing the life time of the catalyst during hydrogenation reactions. 2 figs.

Dual function catalysts. Dehydrogenation and asymmetric intramolecular Diels-Alder cycloaddition of N-hydroxy formate esters and hydroxamic acids: evidence for a ruthenium-acylnitroso intermediate.

PubMed

Chow, Chun P; Shea, Kenneth J

2005-03-23

The chiral ruthenium salen complex, 13b, functions as an efficient catalyst for the sequential oxidation and asymmetric Diels-Alder cycloaddition of hydroxamic acids and N-hydroxy formate esters. This result provides evidence for the formation of a ruthenium-nitroso formate (acyl nitroso) intermediate. The Diels-Alder precursors are prepared from simple building blocks, and the cycloadducts, bridged oxazinolactams, can serve as useful intermediates in organic synthesis.

Nickel/ruthenium catalyst and method for aqueous phase reactions

DOEpatents

Elliott, Douglas C.; Sealock, John L.

1998-01-01

A method of hydrogenation using a catalyst in the form of a plurality of porous particles wherein each particle is a support having nickel metal catalytic phase or reduced nickel deposited thereon in a first dispersed phase and an additional ruthenium metal deposited onto the support in a second dispersed phase. The additional ruthenium metal is effective in retarding or reducing agglomeration or sintering of the nickel metal catalytic phase thereby increasing the life time of the catalyst during hydrogenation reactions.

Synthesis, structure and in vitro cytostatic activity of ferrocene-Cinchona hybrids.

PubMed

Kocsis, László; Szabó, Ildikó; Bősze, Szilvia; Jernei, Tamás; Hudecz, Ferenc; Csámpai, Antal

2016-02-01

Exploring copper(I)- and ruthenium(II)-catalyzed azide-alkyne cycloadditions and a Sonogashira protocol, novel cytostatic ferrocene-cinchona hybrids were synthetized displaying significant in vitro activity on HepG-2 and HT-29 cells. Preliminary SAR studies disclosed that compounds incorporating linkers with 1,2,3-triazole and chalchone residues can be considered as promising lead structures. According to the best of our knowledge this is the first letter on the incorporation of ferrocene nucleus in the reputed cinchona family via triazole and chalcone linkers with established pharmaceutical profile. Copyright © 2015 Elsevier Ltd. All rights reserved.

Platinum-ruthenium-palladium alloys for use as a fuel cell catalyst

DOEpatents

Gorer, Alexander

2002-01-01

A noble metal alloy composition for a fuel cell catalyst, a ternary alloy composition containing platinum, ruthenium and palladium. The alloy shows increased activity as compared to well-known catalysts.

Platinum-ruthenium-nickel fuel cell electrocatalyst

DOEpatents

Gorer, Alexander

2005-07-26

A catalyst suitable for use in a fuel cell, especially as an anode catalyst, that contains platinum, ruthenium, and nickel, wherein the nickel is at a concentration that is less than about 10 atomic percent.

Ruthenium nanoparticles in ionic liquids: structural and stability effects of polar solutes.

PubMed

Salas, Gorka; Podgoršek, Ajda; Campbell, Paul S; Santini, Catherine C; Pádua, Agílio A H; Costa Gomes, Margarida F; Philippot, Karine; Chaudret, Bruno; Turmine, Mireille

2011-08-14

Ionic liquids are a stabilizing medium for the in situ synthesis of ruthenium nanoparticles. Herein we show that the addition of molecular polar solutes to the ionic liquid, even in low concentrations, eliminates the role of the ionic liquid 3D structure in controlling the size of ruthenium nanoparticles, and can induce their aggregation. We have performed the synthesis of ruthenium nanoparticles by decomposition of [Ru(COD)(COT)] in 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [C(1)C(4)Im][NTf(2)], under H(2) in the presence of varying amounts of water or 1-octylamine. For water added during the synthesis of metallic nanoparticles, a decrease of the solubility in the ionic liquid was observed, showed by nanoparticles located at the interface between aqueous and ionic phases. When 1-octylamine is present during the synthesis, stable nanoparticles of a constant size are obtained. When 1-octylamine is added after the synthesis, aggregation of the ruthenium nanoparticles is observed. In order to explain these phenomena, we have explored the molecular interactions between the different species using (13)C-NMR and DOSY (Diffusional Order Spectroscopy) experiments, mixing calorimetry, surface tension measurements and molecular simulations. We conclude that the behaviour of the ruthenium nanoparticles in [C(1)C(4)Im][NTf(2)] in the presence of 1-octylamine depends on the interaction between the ligand and the nanoparticles in terms of the energetics but also of the structural arrangement of the amine at the nanoparticle's surface.

Water-Soluble Ruthenium (II) Chiral Heteroleptic Complexes with Amoebicidal in Vitro and in Vivo Activity.

PubMed

Toledano-Magaña, Yanis; García-Ramos, Juan C; Torres-Gutiérrez, Carolina; Vázquez-Gasser, Cristina; Esquivel-Sánchez, José M; Flores-Alamo, Marcos; Ortiz-Frade, Luis; Galindo-Murillo, Rodrigo; Nequiz, Mario; Gudiño-Zayas, Marco; Laclette, Juan P; Carrero, Julio C; Ruiz-Azuara, Lena

2017-02-09

Three water-soluble Ru(II) chiral heteroleptic coordination compounds [Ru(en)(pdto)]Cl 2 (1), [Ru(gly)(pdto)]Cl (2), and [Ru(acac)(pdto)]Cl (3), where pdto = 2,2'-[1,2-ethanediylbis-(sulfanediyl-2,1-ethanediyl)]dipyridine, en = ethylendiamine, gly = glycinate, and acac = acetylacetonate, have been synthezised and fully characterized. The crystal structures of compounds 1-3 are described. The IC 50 values for compounds 1-3 are within nanomolar range (14, 12, and 6 nM, respectively). The cytotoxicity for human peripheral blood lymphocytes is extremely low (>100 μM). Selectivity indexes for Ru(II) compounds are in the range 700-1300. Trophozoites exposed to Ru(II) compounds die through an apoptotic pathway triggered by ROS production. The orally administration to infected mice induces a total elimination of the parasite charge in mice faeces 1-2-fold faster than metronidazole. Besides, all compounds inhibit the trophozoite proliferation in amoebic liver abscess induced in hamster. All our results lead us to propose these compounds as promising candidates as antiparasitic agents.

Crystal structure of (2,2′-bi­pyridine-κ2 N,N′)bis­(3,5-di-tert-butyl-o-benzo­quinonato-κ2 O,O′)ruthenium(II)

PubMed Central

Ali, Akram; Potaskalov, Vadim A.

2017-01-01

In the title mononuclear complex, [Ru(C14H20O2)2(C10H8N2)], the RuII ion has a distorted octa­hedral coordination environment defined by two N atoms of the chelating 2,2′-bi­pyridine ligand and four O atoms from two 3,5-di-tert-butyl-o-benzo­quinone ligands. In the crystal, the complex mol­ecules are linked by inter­molecular C—H⋯O hydrogen bonds and π–π stacking inter­actions between the 2,2′-bi­pyridine ligands [centroid–centroid distance = 3.538 (3) Å], resulting in a layer structure extending parallel to the ab plane. PMID:28316832

Photosensitization of different ruthenium(II) complex dyes on TiO 2 for photocatalytic H 2 evolution under visible-light

NASA Astrophysics Data System (ADS)

Peng, Tianyou; Dai, Ke; Yi, Huabing; Ke, Dingning; Cai, Ping; Zan, Ling

2008-07-01

Hydrogen production over dye-sensitized Pt/P25 under visible-light irradiation was investigated by using methanol or TEOA as an electron donor. Ru 2(bpy) 4L 1-PF 6 shows the best photosensitization due to its largest conjugation system, widest range of visible-light and 'antenna effect' among the used three Ru(II)-bipyridyl dyes. Ru 2(bpy) 4L 1-PF 6 loosely linked with TiO 2 also exhibit more steady and higher increases in H 2 evolution upon prolonging the irradiation time than the tightly linked N719. The dynamic equilibrium between the linkage of ground dye and divorce of oxidized dye from TiO 2 can enhance the electron-injection and hinder the backward transfer, and then improve the H 2 evolution efficiency.

Dithia[3.3]paracyclophane-based monometal ruthenium acetylide complexes: synthesis, characterization and substituent effects.

PubMed

Zhu, Xingxun; Ou, Yaping; Zhang, Jing; Xia, Jian-Long; Yin, Jun; Yu, Guang-Ao; Liu, Sheng Hua

2013-05-21

A series of dithia[3.3]metaparacyclophane-based monometal ruthenium acetylide complexes have been synthesized. All of the complexes have been fully characterised by NMR spectrometry, X-ray crystallography and elemental analyses. At the same time, their basic optical properties, such as UV/Vis absorption spectra, and electrochemical properties have been determined. (1)H NMR and X-ray crystal structure studies reveal that there are intramolecular C-H···π interactions in these ruthenium complexes, in both solution and solid states. Electrochemical studies reveal that the substituted groups on the dithia[3.3]paracyclophane ring can clearly affect the oxidation activities of the ruthenium center by way of the intramolecular C-H···π interaction. In addition, electron-donating groups facilitate the oxidation of the ruthenium center compared with electron-deficient groups. UV/Vis absorption and IR spectra of some complexes in neutral and oxidized states also have been studied. IR spectra studies indicated that the substituents in the cyclophane have some effects on the ν(C≡C) bands of these complexes in the neutral state and little effect on ν(C≡C) of these complexes in the oxidized state.

cis,cis,cis-(Acetato-κ(2) O,O')bis-[1,2-bis-(diphenyl-phosphan-yl)ethane-κ(2) P,P']ruthenium(II) 0.75-trifluoro-methane-sulfonate 0.25-chloride.

PubMed

Figueira, João; Rodrigues, João; Valkonen, Arto

2013-04-01

In the title Ru(II) carboxyl-ate compound, [Ru(C2H3O2)(C26H24P2)2](CF3O3S)0.75Cl0.25, the distorted tris-bidentate octa-hedral stereochemistry about the Ru(II) atom in the complex cation comprises four P-atom donors from two 1,2-bis-(diphenyl-phosphan-yl)ethane ligands [Ru-P = 2.2881 (13)-2.3791 (13) Å] and two O-atom donors from the acetate ligand [Ru-O = 2.191 (3) and 2.202 (3) Å]. The disordered counter-anions are located on the same site in the structure in a 3:1 ratio, the expanded formula comprising four complex cations, three trifluoro-methane-sulfonate anions and one chloride anion, with two such formula units in the unit cell.

PROCESS FOR REMOVING NOBLE METALS FROM URANIUM

DOEpatents

Knighton, J.B.

1961-01-31

A pyrometallurgical method is given for purifying uranium containing ruthenium and palladium. The uranium is disintegrated and oxidized by exposure to air and then the ruthenium and palladium are extracted from the uranium with molten zinc.

Formation of polycyclic lactones through a ruthenium-catalyzed ring-closing metathesis/hetero-Pauson-Khand reaction sequence.

PubMed

Finnegan, David F; Snapper, Marc L

2011-05-20

Processes that form multiple carbon-carbon bonds in one operation can generate molecular complexity quickly and therefore be used to shorten syntheses of desirable molecules. We selected the hetero-Pauson-Khand (HPK) cycloaddition and ring-closing metathesis (RCM) as two unique carbon-carbon bond-forming reactions that could be united in a tandem ruthenium-catalyzed process. In doing so, complex polycyclic products can be obtained in one reaction vessel from acyclic precursors using a single ruthenium additive that can catalyze sequentially two mechanistically distinct transformations.

"Off-On"switching electrochemiluminescence biosensor for mercury(II) detection based on molecular recognition technology.

PubMed

Cheng, Lin; Wei, BingGuo; He, Ling Ling; Mao, Ling; Zhang, Jie; Ceng, JinXiang; Kong, DeRong; Chen, ChaDan; Cui, HanFeng; Hong, Nian; Fan, Hao

2017-02-01

A novel "off-On" electrogenerated chemiluminescence (ECL) biosensor has been developed for the detection of mercury(II) based on molecular recognition technology. The ECL mercury(II) biosensor comprises two main parts: an ECL substrate and an ECL intensity switch. The ECL substrate was made by modifying the complex of Ruthenium(II) tris-(bipyridine)(Ru(bpy) 3 2+ )/Cyclodextrins-Au nanoparticles(CD-AuNps)/Nafion on the surface of glass carbon electrode (GCE), and the ECL intensity switch is the single hairpin DNA probe designed according to the "molecular recognition" strategy which was functionalized with ferrocene tag at one end and attached to Cyclodextrins (CD) on modified GCE through supramolecular noncovalent interaction. We demonstrated that, in the absence of Hg(II) ion, the probe keeps single hairpin structure and resulted in a quenching of ECL of Ru(bpy) 3 2+ . Whereas, in the presence of Hg(II) ion, the probe prefers to form the T-Hg(II)-T complex and lead to an obvious recovery of ECL of Ru(bpy) 3 2+ , which provided a sensing platform for the detection of Hg(II) ion. Using this sensing platform, a simple, rapid and selective "off-On" ECL biosensor for the detection of mercury(II) with a detection limit of 0.1 nM has been developed. Copyright © 2016. Published by Elsevier Inc.

Feasibility of processing the experimental breeder reactor-II driver fuel from the Idaho National Laboratory through Savannah River Site's H-Canyon facility

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

Magoulas, V. E.

Savannah River National Laboratory (SRNL) was requested to evaluate the potential to receive and process the Idaho National Laboratory (INL) uranium (U) recovered from the Experimental Breeder Reactor II (EBR-II) driver fuel through the Savannah River Site’s (SRS) H-Canyon as a way to disposition the material. INL recovers the uranium from the sodium bonded metallic fuel irradiated in the EBR-II reactor using an electrorefining process. There were two compositions of EBR-II driver fuel. The early generation fuel was U-5Fs, which consisted of 95% U metal alloyed with 5% noble metal elements “fissium” (2.5% molybdenum, 2.0% ruthenium, 0.3% rhodium, 0.1% palladium,more » and 0.1% zirconium), while the later generation was U-10Zr which was 90% U metal alloyed with 10% zirconium. A potential concern during the H-Canyon nitric acid dissolution process of the U metal containing zirconium (Zr) is the explosive behavior that has been reported for alloys of these materials. For this reason, this evaluation was focused on the ability to process the lower Zr content materials, the U-5Fs material.« less

Preparation of olefins from synthesis gas using ruthenium supported on ceric oxide

DOEpatents

Pierantozzi, Ronald

1985-01-01

A catalyst comprising a ruthenium carbonyl compound deposited on a cerium oxide-containing support material provides for the selective synthesis of low molecular weight olefinic hydrocarbons from mixtures of hydrogen and carbon monoxide.

Preparation of olefins from synthesis gas using ruthenium supported on ceric oxide

DOEpatents

Pierantozzi, R.

1985-04-09

A catalyst comprising a ruthenium carbonyl compound deposited on a cerium oxide-containing support material provides for the selective synthesis of low molecular weight olefinic hydrocarbons from mixtures of hydrogen and carbon monoxide.

Cu(II) and Cu(I) complexes with 1,2-dithiosquarate as a ligand; from molecular compounds to supramolecular network structures

NASA Astrophysics Data System (ADS)

Calatayud, M. Luisa; Castro, Isabel; Julve, Miguel; Sletten, Jorunn

2008-03-01

Four new complexes of copper(II) and/or copper(I) with 1,2-dtsq as a ligand have been synthesized and characterized by single crystal X-ray diffraction methods, [Cu II(terpy)(1,2-dtsq)] ( 1), [Cu II(dmen)(1,2-dtsq)] n ( 2), {[Cu II(dmen) 2][Cu I(1,2-dtsq)] 2} n·2nH 2O( 3) and {[Cu II(men) 2][Cu I (1,2-dtsq)] 2} n·nH 2O ( 4) (1,2-dtsq = 1,2-dithiosquarate, dianion of 3,4-dimercapto-1-cyclobutene-1,2-dione; dmen = N, N-dimethylethylenediamine; men = N-methylethylenediamine, terpy = 2,2':6,2″-terpyridine). Compound 1 consists of neutral [Cu II(terpy)(1,2-dtsq)] mononuclear units which are held together by O⋯H-C and van der Waals interactions. Compound 2 is built of neutral [Cu II(dmen)(1,2-dtsq)] entities which are connected through weak Cu-S (pairs) and Cu-O (single) interactions into a layer structure. The structures of 3 and 4 feature polynuclear [Cu(1,2-dtsq)]nn- chains, in which dtsq groups are linking copper(I) ions in the μ-1,1, μ-1,1,1 and μ-1,2 bridging modes. The dtsq groups in these chains connect to the copper(II) ions of the [Cu IIL 2] 2+ cations [L being the bidentate dmen ( 3) and men ( 4) ligands], but in different manners in the two structures. The connections in compound 3 are unsymmetrical, so that columns of {[Cu II(dmen) 2][Cu I(1,2-dtsq)] 2} n where the copper(II) ions bind to 1,2-dtsq oxygen atoms with relatively strong axial bonds may be identified. These columns are further connected to each other through weak axial Cu II⋯S interactions, creating a three-dimensional (3D) network with channels containing the solvent water. In compound 4, on the other hand, the two crystallographically independent cations each forms a symmetrical link between the anionic chains through, respectively, O-Cu II-O and S-Cu II-S axial bonds, again creating a 3D structure with channels running parallel to the chain axis. The reduction of copper(II) to copper(I) by 1,2-dtsq is precluded when the coordination sphere of the copper(II) ion is partially blocked with the tridentate terpy ligand whereas this process occurs when the blocking ligands are the bidentate dmen and men groups.

Ruthenium-cobalt nanoalloys encapsulated in nitrogen-doped graphene as active electrocatalysts for producing hydrogen in alkaline media

NASA Astrophysics Data System (ADS)

Su, Jianwei; Yang, Yang; Xia, Guoliang; Chen, Jitang; Jiang, Peng; Chen, Qianwang

2017-04-01

The scalable production of hydrogen could conveniently be realized by alkaline water electrolysis. Currently, the major challenge confronting hydrogen evolution reaction (HER) is lacking inexpensive alternatives to platinum-based electrocatalysts. Here we report a high-efficient and stable electrocatalyst composed of ruthenium and cobalt bimetallic nanoalloy encapsulated in nitrogen-doped graphene layers. The catalysts display remarkable performance with low overpotentials of only 28 and 218 mV at 10 and 100 mA cm-2, respectively, and excellent stability of 10,000 cycles. Ruthenium is the cheapest platinum-group metal and its amount in the catalyst is only 3.58 wt.%, showing the catalyst high activity at a very competitive price. Density functional theory calculations reveal that the introduction of ruthenium atoms into cobalt core can improve the efficiency of electron transfer from alloy core to graphene shell, beneficial for enhancing carbon-hydrogen bond, thereby lowing ΔGH* of HER.

Determination of folates by HPLC-chemiluminescence using a ruthenium(II)-cerium(IV) system, and its application to pharmaceutical preparations and supplements.

PubMed

Ikeda, Rie; Ichiyama, Kosuke; Tabuchi, Naoto; Wada, Mitsuhiro; Kuroda, Naotaka; Nakashima, Kenichiro

2014-11-01

A chemiluminescence (CL) reaction of folic acid (FA) with ruthenium (II) and cerium (IV) was applied to quantify FA-related compounds such as FA, dihydrofolic acid, tetrahydrofolic acid, 5-methyltetrahydrofolic acid, 5-formyltetrahydrofolic acid and methotrexate (MTX). Among the FAs, 5-methyltetrahydrofolic acid provided the highest CL intensity. HPLC-CL detection of FA was applied to quantify FA in pharmaceutical preparations and supplements. Analytical samples were separated on a semi-micro ODS column with a mixture of 20 mM phosphate buffer (pH 5.7) and acetonitrile (94 : 6, v/v %). The separated samples were mixed with a post-column CL reagent consisting of 1.5 mM Ru(bipy)3 (2+) and 1.0 mM Ce(SO4)2 , then the generated CL was monitored. The calibration range for FA was 10-100 μM and the limit of detection was 1.34 μM (signal-to-noise ratio of 3). Repeatabilities were 4.2, 4.6 and 5.0 RSD% (10, 25, 50 μM), and the recoveries for FA supplement, vitamin B complex supplement and FA-containing medication (tablet) were 102.4 ± 10.5, 103.3 ± 13.3 and 100.3 ± 8.5%, respectively. The described method is robust against changes in the chromatographic parameters of ± 3.3 or ± 1.5%. The measured FA content corresponded well to the labeled content of FA-containing products (100.6-104.9%), demonstrating the precision and accuracy of this method for the evaluation of FA pharmaceutical preparations. Copyright © 2014 John Wiley & Sons, Ltd.

Concentration Dependent Dimensionality of Resonance Energy Transfer in a Postsynthetically Doped Morphologically Homologous Analogue of UiO-67 MOF with a Ruthenium(II) Polypyridyl Complex

DOE PAGES

Maza, William A.; Padilla, Roberto; Morris, Amanda J.

2015-06-04

In this study, a method is described here by which to dope ruthenium(II) bis(2,2'-bipyridine) (2,2'-bipyridyl-5,5'-dicarboxylic acid), RuDCBPY, into a UiO-67 metal–organic framework (MOF) derivative in which 2,2'-bipyridyl-5,5'-dicarboxylic acid, UiO-67-DCBPY, is used in place of 4,4'-biphenyldicarboxylic acid. Emission lifetime measurements of the RuDCBPY triplet metal-to-ligand charge transfer, 3MLCT, excited state as a function of RuDCBPY doping concentration in UiO-67-DCBPY are discussed in light of previous results for RuDCBPY-UiO-67 doped powders in which quenching of the 3MLCT was said to be due to dipole–dipole homogeneous resonance energy transfer, RET. The bulk distribution of RuDCBPY centers within MOF crystallites are also estimated withmore » the use of confocal fluorescence microscopy. In the present case, it is assumed that the rate of RET between RuDCBPY centers has an r –6 separation distance dependence characteristic of Förster RET. The results suggest (1) the dimensionality in which RET occurs is dependent on the RuDCBPY concentration ranging from one-dimensional at very low concentrations up to three-dimensional at high concentration, (2) the occupancy of RuDCBPY within UiO-67-DCBPY is not uniform throughout the crystallites such that RuDCBPY densely populates the outer layers of the MOF at low concentrations, and (3) the average separation distance between RuDCBPY centers is ~21 Å.« less

Singlet oxygen sensitizing materials based on porous silicone: photochemical characterization, effect of dye reloading and application to water disinfection with solar reactors.

PubMed

Manjón, Francisco; Santana-Magaña, Montserrat; García-Fresnadillo, David; Orellana, Guillermo

2010-06-01

Photogeneration of singlet molecular oxygen ((1)O(2)) is applied to organic synthesis (photooxidations), atmosphere/water treatment (disinfection), antibiofouling materials and in photodynamic therapy of cancer. In this paper, (1)O(2) photosensitizing materials containing the dyes tris(4,4'-diphenyl-2,2'-bipyridine)ruthenium(II) (1, RDB(2+)) or tris(4,7-diphenyl-1,10-phenanthroline)ruthenium(II) (2, RDP(2+)), immobilized on porous silicone (abbreviated RDB/pSil and RDP/pSil), have been produced and tested for waterborne Enterococcus faecalis inactivation using a laboratory solar simulator and a compound parabolic collector (CPC)-based solar photoreactor. In order to investigate the feasibility of its reuse, the sunlight-exposed RDP/pSil sensitizing material (RDP/pSil-a) has been reloaded with RDP(2+) (RDP/pSil-r). Surprisingly, results for bacteria inactivation with the reloaded material have demonstrated a 4-fold higher efficiency compared to those of either RDP/pSil-a, unused RDB/pSil and the original RDP/pSil. Surface and bulk photochemical characterization of the new material (RDP/pSil-r) has shown that the bactericidal efficiency enhancement is due to aggregation of the silicone-supported photosensitizer on the surface of the polymer, as evidenced by confocal fluorescence lifetime imaging microscopy (FLIM). Photogenerated (1)O(2) lifetimes in the wet sensitizer-doped silicone have been determined to be ten times longer than in water. These facts, together with the water rheology in the solar reactor and the interfacial production of the biocidal species, account for the more effective disinfection observed with the reloaded photosensitizing material. These results extend and improve the operational lifetime of photocatalytic materials for point-of-use (1)O(2)-mediated solar water disinfection.

Kinetic effects of sulfur oxidation on catalytic nitrile hydration: nitrile hydratase insights from bioinspired ruthenium(II) complexes.

PubMed

Kumar, Davinder; Nguyen, Tho N; Grapperhaus, Craig A

2014-12-01

Kinetic investigations inspired by the metalloenzyme nitrile hydratase were performed on a series of ruthenium(II) complexes to determine the effect of sulfur oxidation on catalytic nitrile hydration. The rate of benzonitrile hydration was quantified as a function of catalyst, nitrile, and water concentrations. Precatalysts L(n)RuPPh3 (n = 1-3; L(1) = 4,7-bis(2'-methyl-2'-mercapto-propyl)-1-thia-4,7-diazacyclononane; L(2) = 4-(2'-methyl-2'-sulfinatopropyl)-7-(2'-methyl-2'-mercapto-propyl)-1-thia-4,7-diazacyclononane; L(3) = 4-(2'-methyl-2'-sulfinatopropyl)-7-(2'-methyl-2'-sulfenato-propyl)-1-thia-4,7-diazacyclononane) were activated by substitution of triphenylphosphine with substrate in hot dimethylformamide solution. Rate measurements are consistent with a dynamic equilibrium between inactive aqua (L(n)Ru-OH2) and active nitrile (L(n)Ru-NCR) derivatives with K = 21 ± 1, 9 ± 0.9, and 23 ± 3 for L(1) to L(3), respectively. Subsequent hydration of the L(n)Ru-NCR intermediate yields the amide product with measured hydration rate constants (k's) of 0.37 ± 0.01, 0.82 ± 0.07, and 1.59 ± 0.12 M(-1) h(-1) for L(1) to L(3), respectively. Temperature dependent studies reveal that sulfur oxidation lowers the enthalpic barrier by 27 kJ/mol, but increases the entropic barrier by 65 J/(mol K). Density functional theory (DFT) calculations (B3LYP/LanL2DZ (Ru); 6-31G(d) (all other atoms)) support a nitrile bound catalytic cycle with lowering of the reaction barrier as a consequence of sulfur oxidation through enhanced nitrile binding and attack of the water nucleophile through a highly organized transition state.

Synthesis, DNA Cleavage Activity, Cytotoxicity, Acetylcholinesterase Inhibition, and Acute Murine Toxicity of Redox-Active Ruthenium(II) Polypyridyl Complexes.

PubMed

Alatrash, Nagham; Narh, Eugenia S; Yadav, Abhishek; Kim, Mahn-Jong; Janaratne, Thamara; Gabriel, James; MacDonnell, Frederick M

2017-07-06

Four mononuclear [(L-L) 2 Ru(tatpp)] 2+ and two dinuclear [(L-L) 2 Ru(tatpp)Ru(L-L) 2 ] 4+ ruthenium(II) polypyridyl complexes (RPCs) containing the 9,11,20,22-tetraazatetrapyrido[3,2-a:2',3'-c:3'',2''-l:2''',3'''-n]pentacene (tatpp) ligand were synthesized, in which L-L is a chelating diamine ligand such as 2,2'-bipyridine (bpy), 1,10-phenanthroline (phen), 3,4,7,8-tetramethyl-1,10-phenanthroline (Me 4 phen) or 4,7-diphenyl-1,10-phenanthroline (Ph 2 phen). These Ru-tatpp analogues all undergo reduction reactions with modest reducing agents, such as glutathione (GSH), at pH 7. These, plus several structurally related but non-redox-active RPCs, were screened for DNA cleavage activity, cytotoxicity, acetylcholinesterase (AChE) inhibition, and acute mouse toxicity, and their activities were examined with respect to redox activity and lipophilicity. All of the redox-active RPCs show single-strand DNA cleavage in the presence of GSH, whereas none of the non-redox-active RPCs do. Low-micromolar cytotoxicity (IC 50 ) against malignant H358, CCL228, and MCF7 cultured cell lines was mainly restricted to the redox-active RPCs; however, they were substantially less toxic toward nonmalignant MCF10 cells. The IC 50 values for AChE inhibition in cell-free assays and the acute toxicity of RPCs in mice revealed that whereas most RPCs show potent inhibitory action against AChE (IC 50 values <15 μm), Ru-tatpp complexes as a class are surprisingly well tolerated in animals relative to other RPCs. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Lipophilicity-dependent ruthenium N-heterocyclic carbene complexes as potential anticancer agents.

PubMed

Lv, Gaochao; Guo, Liubin; Qiu, Ling; Yang, Hui; Wang, Tengfei; Liu, Hong; Lin, Jianguo

2015-04-28

Five Ru(II)-N-heterocyclic carbenes (NHC) (1-5) were synthesized by reacting the appropriately substituted imidazolium chlorides with Ag2O, forming the NHC-silver chloride in situ followed by transmetalation with dimeric p-cymene ruthenium(II) dichloride. All the complexes were characterized by NMR and ESI-MS, and complex 1 was also characterized by single-crystal X-ray diffraction. The IC50 values of these five complexes were determined by the MTT-based assay on four human cancer cell lines, SKOV-3 (ovarian), PC-3 (prostate), MDA-MB-231 (breast) and EC109 (esophagus). The cytotoxicities of these complexes changed from a moderate effect to a fine one, corresponding to the increasing lipophilicity order of the complex of 2 < 1 < 3 < 4 < 5 (0.91, 0.88, 1.36, 1.85 and 2.62 for 1–5 respectively). Complex 5 showed the most cytotoxicity with the IC50 values 10.3 ± 0.3 μM for SKOV-3, 2.9 ± 0.1 μM for PC-3, 8.2 ± 0.6 μM for MDA-MB-231, 6.4 ± 0.2 μM for EC109 cell lines. Due to the superior cytotoxicity of complex 5 against the PC-3 cell lines, further biological evaluations were carried out to elucidate its action mechanism. The morphologic changes and cell cycle analysis showed that complex 5 can inhibit PC-3 cell lines by inducing cell cycle arrest at the G2/M phase. The DNA binding experiments further demonstrate that complex 5 has a better binding ability for DNA (Kb = 2.2 × 10(6) M(-1)) than complexes 1-4 (3.8 × 10(5), 7.0 × 10(5), 5.7 × 10(5), and 1.9 × 10(5) respectively).

Ruthenium or osmium complexes and their uses as catalysts for water oxidation

DOEpatents

Corbea, Javier Jesus Concepcion; Chen, Zuofeng; Jurss, Jonah Wesley; Templeton, Joseph L.; Hoertz, Paul; Meyer, Thomas J.

2013-09-03

The present invention provides ruthenium or osmium complexes and their uses as a catalyst for catalytic water oxidation. Another aspect of the invention provides an electrode and photo-electrochemical cells for electrolysis of water molecules.

Ruthenium or osmium complexes and their uses as catalysts for water oxidation

DOEpatents

Concepcion Corbea, Javier Jesus; Chen, Zuofeng; Jurss, Jonah Wesley; Templeton, Joseph L; Hoertz, Paul; Meyer, Thomas J

2014-10-28

The present invention provides ruthenium or osmium complexes and their uses as a catalyst for catalytic water oxidation. Another aspect of the invention provides an electrode and photo-electrochemical cells for electrolysis of water molecules.

Ruthenium carbonyl catalyst supported on ceric oxide for preparation of olefins from synthesis gas

DOEpatents

Pierantozzi, R.

1985-04-02

A catalyst comprising a ruthenium carbonyl compound deposited on a cerium oxide-containing support material provides for the selective synthesis of low molecular weight olefinic hydrocarbons from mixtures of hydrogen and carbon monoxide.

Ruthenium carbonyl catalyst supported on ceric oxide for preparation of olefins from synthesis gas

DOEpatents

Pierantozzi, Ronald

1985-01-01

A catalyst comprising a ruthenium carbonyl compound deposited on a cerium oxide-containing support material provides for the selective synthesis of low molecular weight olefinic hydrocarbons from mixtures of hydrogen and carbon monoxide.

Growth kinetics of disk-shaped copper islands in electrochemical deposition.

PubMed

Guo, Lian; Zhang, Shouliang; Searson, Peter

2009-05-01

The ability to independently dictate the shape and crystal orientation of islands in electrocrystallization remains a significant challenge. The main reason for this is that the complex interplay between the substrate, nucleation, and surface chemistry is not fully understood. Here we report on the kinetics of island growth for copper on ruthenium oxide. The small nucleation overpotential leads to enhanced lateral growth and the formation of hexagonal disk-shaped islands. The amorphous substrate allows the nuclei to achieve the thermodynamically favorable orientation, i.e., a 111 surface normal. Island growth follows power law kinetics in both lateral and vertical directions. At shorter times, the two growth exponents are equal to 1/2 whereas at longer times lateral growth slows down while vertical growth speeds up. We propose a growth mechanism, wherein the lateral growth of disk-shaped islands is initiated by attachment of Cu adatoms on the ruthenium oxide surface onto the island periphery while vertical growth is initiated by two-dimensional nucleation on the top terrace and followed by lateral step propagation. These results indicate three criteria for enhanced lateral growth in electrodeposition: (i) a substrate that leads to a small nucleation overpotential, (ii) fast adatom surface diffusion on substrate to promote lateral growth, and (iii) preferential anion adsorption to stabilize the basal plane.

Concentration and removal of tritium and/or deuterium from water contaminated with tritium and/or deuterium

DOEpatents

Meyer, Thomas J.; Narula, Poonam M.

2001-01-01

Concentration of tritium and/or deuterium that is a contaminant in H.sub.2 O, followed by separation of the concentrate from the H.sub.2 O. Employed are certain metal oxo complexes, preferably with a metal from Group VIII. For instance, [Ru.sup.IV (2,2',6',2"-terpyridine)(2,2'-bipyridine)(O)](ClO.sub.4).sub.2 is very suitable.

THE ROLE OF COMPETITION EFFECT IN THE SELF-ASSEMBLY STRUCTURE OF 3,5-DIPHENYLBENZOIC ACID AND 2,2‧:6‧,2″-TERPYRIDINE-4‧-CARBOXYLIC ACID ON Ag(110)

NASA Astrophysics Data System (ADS)

Hu, Yufen; Li, Wei; Lu, Yan; Wang, Zhongping; Leng, Xinli; Liao, Qinghua; Liu, Xiaoqing; Wang, Li

The self-assembly structures of 2,2‧:6‧,2‧‧-terpyridine-4‧-carboxylic acid (C16H11N3O2; YN) molecules and 3,5-diphenylbenzoic acid (C19H14O2; YC) molecules on Ag(110) surface have been investigated by scanning tunneling microscopy (STM) and Density Functional Theory (DFT) calculation. The YC molecules form two different well-organized structures due to the π-π stacking and dipole-dipole interactions. When three C atoms of YC molecules are replaced by three N atoms to form YN molecules, the main driving force to form ordered assembly structures of YN molecule is changed to metal-organic coordination bond and hydrogen bond. The dramatic changes of main driving force between YC/Ag(110) and YN/Ag(110) system demonstrate that the N atoms are apt to form metal-organic coordination bond and hydrogen bond but dipole-dipole interactions and π-π stacking are relative to C atoms. These findings further reveal that the optimization design of organic molecules could vary the main driving force and then lead to the change of the molecular self-assembly structures.

Eu3+ complex of ligand4’-(4-carboxyphenyl)-2,2’:6’,2″-terpyridine as fluorosensor of heavy metals

NASA Astrophysics Data System (ADS)

Zulys, A.; Rachmawati, N.

2017-04-01

Ligand 4’-(4-carboxyphenyl)-2,2’:6’,2″-terpyridine (2-Hcptpy) has been synthesized by modification of Kröhnke method. The synthesize was performed using aldol condensation reaction. The white precipitate was collected and produced 62% yield (1.062 gr). Ligand 2-Hcptpy has been characterized by FTIR, Elemental analyzer, H-NMR, UV-vis, and UV-DRS spectrometer. It was then reacted with lanthanide group (Eu3+) to form a complex by hydrothermal process. The result of Eu3+ complex was 0.352 gr. of white yellowish precipitate. The application of this research is for the fluorosensor of heavy metals (Pb2+dan Cd2+). The data of fluorescence showed two types of fluorescence, either turn on or turn off fluorosensor. Ligand 2-Hcptpy has an on-off type with the addition of Pb2+ and Cd2+, while complex Eu3+ has two types of fluorosensor. The complex showed turn on-off and turn on-off by addition of Pb2+ and type of turn off by addition of Cd2+. Either ligand or complex, showed fluorescence intensity by adding heavy metals up to concentration 5×10-8 M.

Enantioselective synthesis of allylic esters via asymmetric allylic substitution with metal carboxylates using planar-chiral cyclopentadienyl ruthenium catalysts.

PubMed

Kanbayashi, Naoya; Onitsuka, Kiyotaka

2010-02-03

An asymmetric allylic substitution with sodium carboxylate using a planar-chiral cyclopentadienyl ruthenium complex has been developed. Optically active allylic esters were prepared in good yields with high regio- and enantioselectivities.

Ruthenium-Catalyzed Cascade Annulation of Indole with Propargyl Alcohols.

PubMed

Kaufmann, Julia; Jäckel, Elisabeth; Haak, Edgar

2018-05-14

Cascade transformations forming multiple bonds and one-pot procedures provide rapid access to natural-product-like scaffolds from simple precursors. These atom-economic processes are valuable tools in organic synthesis and drug discovery. Herein, we report on ruthenium-catalyzed cascade annulations of indole with readily available propargyl alcohols. These provide rapid access to diverse carbazoles, cyclohepta[b]indoles, and further fused polycycles with high selectivity. A bifunctional ruthenium complex featuring a redox-coupled cyclopentadienone ligand acts as a common catalyst for the different cascade processes. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Determination of oxygen diffusion kinetics during thin film ruthenium oxidation

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

Coloma Ribera, R., E-mail: r.colomaribera@utwente.nl; Kruijs, R. W. E. van de; Yakshin, A. E.

2015-08-07

In situ X-ray reflectivity was used to reveal oxygen diffusion kinetics for thermal oxidation of polycrystalline ruthenium thin films and accurate determination of activation energies for this process. Diffusion rates in nanometer thin RuO{sub 2} films were found to show Arrhenius behaviour. However, a gradual decrease in diffusion rates was observed with oxide growth, with the activation energy increasing from about 2.1 to 2.4 eV. Further exploration of the Arrhenius pre-exponential factor for diffusion process revealed that oxidation of polycrystalline ruthenium joins the class of materials that obey the Meyer-Neldel rule.

Hydrogenation of Carbon Dioxide to Methane by Ruthenium Nanoparticles in Ionic Liquid.

PubMed

Melo, Catarina I; Szczepańska, Anna; Bogel-Łukasik, Ewa; Nunes da Ponte, Manuel; Branco, Luís C

2016-05-23

The efficient transformation of carbon dioxide into fuels can be an excellent alternative to sequestration. In this work, we describe CO2 hydrogenation to methane in imidazolium-based ionic liquid media, using ruthenium nanoparticles prepared in situ as catalyst. The best yield of methane (69 %) was achieved using 0.24 mol % ruthenium catalyst (in [omim][NTf2 ], 1-octyl-3-methylimidazolium bistrifluoromethanesulfonylimide, at 40 bar of hydrogen pressure plus 40 bar of CO2 pressure, and at 150 °C. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ruthenium(III) catalyzed oxidation of sugar alcohols by dichloroisocyanuric acid—A kinetic study

NASA Astrophysics Data System (ADS)

Lakshman Kumar, Y.; Venkata Nadh, R.; Radhakrishnamurti, P. S.

2016-02-01

Kinetics of ruthenium(III) catalyzed oxidation of biologically important sugar alcohols (myo-inositol, D-sorbitol, and D-mannitol) by dichloroisocyanuric acid was carried out in aqueous acetic acid—perchloric medium. The reactions were found to be first order in case of oxidant and ruthenium(III). Zero order was observed with the concentrations of sorbitol and mannitol whereas, a positive fractional order was found in the case of inositol concentration. An inverse fractional order was observed with perchloric acid in oxidation of three substrates. Arrhenius parameters were calculated and a plausible mechanism was proposed.

Investigation of Ruthenium Dissolution in Advanced Membrane Electrode Assemblies for Direct Methanol Based Fuel Cell Stacks

NASA Technical Reports Server (NTRS)

Valdez, Thomas I.; Firdosy, S.; Koel, B. E.; Narayanan, S. R.

2005-01-01

Dissolution of ruthenium was observed in the 80-cell stack. Duration testing was performed in single cell MEAs to determine the pathway of cell degradation. EDAX analysis on each of the single cell MEAs has shown that the Johnson Matthey commercial catalyst is stable in DMFC operation for 250 hours, no ruthenium dissolution was observed. Changes in the hydrophobicity of the cathode backing papers was minimum. Electrode polarization analysis revealed that the MEA performance loss is attributed to changes in the cathode catalyst layer. Ruthenium migration does not seem to occur during cell operation but can occur when methanol is absent from the anode compartment, the cathode compartment has access to air, and the cells in the stack are electrically connected to a load (Shunt Currents). The open-to-air cathode stack design allowed for: a) The MEAs to have continual access to oxygen; and b) The stack to sustain shunt currents. Ruthenium dissolution in a DMFC stack can be prevented by: a) Developing an internally manifolded stacks that seal reactant compartments when not in operation; b) Bringing the cell voltages to zero quickly when not in operation; and c) Limiting the total number of cells to 25 in an effort to limit shunt currents.

A new approach to synthesize supported ruthenium phosphides for hydrodesulfurization

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

Wang, Qingfang; Key Laboratory of Advanced Energy Materials Chemistry; Wang, Zhiqiang

2016-02-15

Highlights: • We bring out a new method to synthesize noble metal phosphides at low temperature. • Both RuP and Ru{sub 2}P were synthesized using triphenylphosphine as phosphorus sources. • Ru{sub 2}P was the better active phase for HDS than RuP and metal Ru. • RuP/SiO{sub 2} prepared by new method had better HDS activity to that by TPR method. - Abstract: Supported noble metal ruthenium phosphides were synthesized by one-step H{sub 2}-thermal treatment method using triphenylphosphine (TPP) as phosphorus sources at low temperatures. Two phosphides RuP and Ru{sub 2}P can be prepared by this method via varying the molarmore » ratio of metal salt and TPP. The as-prepared phosphides were characterized by X-ray powder diffraction (XRD), low-temperature N{sub 2} adsorption, CO chemisorption and transmission electronic microscopy (TEM). The supported ruthenium phosphides prepared by new method and conventional method together with contradistinctive metallic ruthenium were evaluated in hydrodesulfurization (HDS) of dibenzothiophene (DBT). The catalytic results showed that metal-rich Ru{sub 2}P was the better active phase for HDS than RuP and metal Ru. Besides this, ruthenium phosphide catalyst prepared by new method exhibited superior HDS activity to that prepared by conventional method.« less

Probing the structural evolution of ruthenium doped germanium clusters: Photoelectron spectroscopy and density functional theory calculations

PubMed Central

Jin, Yuanyuan; Lu, Shengjie; Hermann, Andreas; Kuang, Xiaoyu; Zhang, Chuanzhao; Lu, Cheng; Xu, Hongguang; Zheng, Weijun

2016-01-01

We present a combined experimental and theoretical study of ruthenium doped germanium clusters, RuGen− (n = 3–12), and their corresponding neutral species. Photoelectron spectra of RuGen− clusters are measured at 266 nm. The vertical detachment energies (VDEs) and adiabatic detachment energies (ADEs) are obtained. Unbiased CALYPSO structure searches confirm the low-lying structures of anionic and neutral ruthenium doped germanium clusters in the size range of 3 ≤ n ≤ 12. Subsequent geometry optimizations using density functional theory (DFT) at PW91/LANL2DZ level are carried out to determine the relative stability and electronic properties of ruthenium doped germanium clusters. It is found that most of the anionic and neutral clusters have very similar global features. Although the global minimum structures of the anionic and neutral clusters are different, their respective geometries are observed as the low-lying isomers in either case. In addition, for n > 8, the Ru atom in RuGen−/0 clusters is absorbed endohedrally in the Ge cage. The theoretically predicted vertical and adiabatic detachment energies are in good agreement with the experimental measurements. The excellent agreement between DFT calculations and experiment enables a comprehensive evaluation of the geometrical and electronic structures of ruthenium doped germanium clusters. PMID:27439955

Catalytic oxidation of waste materials

NASA Technical Reports Server (NTRS)

Jagow, R. B.

1977-01-01

Aqueous stream of human waste is mixed with soluble ruthenium salts and is introduced into reactor at temperature where ruthenium black catalyst forms on internal surfaces of reactor. This provides catalytically active surface to convert oxidizable wastes into breakdown products such as water and carbon dioxide.

Synthesis of CuO by Cu-CPPs with the determination of Cu(II) coordination modes from a novel complex of [Cu(terpyOH){sub 2}]·(HBTC)·2H{sub 2}O

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

Wang, Yu, E-mail: wangyu1012@hit.edu.cn; Chen, Gang, E-mail: gchen@hit.edu.cn; Han, Li

2013-10-15

In this study, we investigated the synthesis of CuO microrods by simple calcination of copper-based coordination polymer particles (Cu-CPPs) at high temperature in air. The photocatalytic activity of the CuO microrods was tested by the decomposition of aqueous solution of RhB, which was completely decomposed by irradiation with light. To analyze the relationship of metal ions and ligands in the Cu-CPPs, the single crystal of [Cu(terpyOH){sub 2}]∙(HBTC)∙2H{sub 2}O (1) (terpyOH=4′-hydroxy-2,2′:6′,2″-terpyridine, BTC=1,3,5-benzene tricarboxylate) was first prepared and characterized by X-ray single crystal structural analysis. A variety of hydrogen bonds constructing the 3D complex structure in [Cu(terpyOH){sub 2}]∙(HBTC)∙2H{sub 2}O (1) were observed.more » - Graphical abstract: Demonstrating a general method to synthesize CuO microrods via simple calcination of Cu-CPPs and Cu(II) coordination modes from a novel complex of [Cu(terpyOH){sub 2}]∙(HBTC)·2H{sub 2}O constructed by hydrogen bonding. Display Omitted - Highlights: • The formation of microrods CuO from thermal treatment of Cu-CPPs through an “escape-by-crafty-scheme” strategy has been studied. • Determination of Cu(II) coordination modes in Cu-CPPs from a novel complex of [Cu(terpyOH){sub 2}]∙(HBTC) 2H{sub 2}O. • Invested the behave of hydrogen bonding to construct the 3D complex structure. • Commendable photodegradation performance was observed.« less

Pressure-Sensitive Paint: Effect of Substrate

PubMed Central

Quinn, Mark Kenneth; Yang, Leichao; Kontis, Konstantinos

2011-01-01

There are numerous ways in which pressure-sensitive paint can be applied to a surface. The choice of substrate and application method can greatly affect the results obtained. The current study examines the different methods of applying pressure-sensitive paint to a surface. One polymer-based and two porous substrates (anodized aluminum and thin-layer chromatography plates) are investigated and compared for luminescent output, pressure sensitivity, temperature sensitivity and photodegradation. Two luminophores [tris-Bathophenanthroline Ruthenium(II) Perchlorate and Platinum-tetrakis (pentafluorophenyl) Porphyrin] will also be compared in all three of the substrates. The results show the applicability of the different substrates and luminophores to different testing environments. PMID:22247685

Estimation of the outer-sphere contribution to the activation volume for electron exchange reactions using the mean spherical approximation

NASA Astrophysics Data System (ADS)

Takagi, Hideo D.; Swaddle, Thomas W.

1996-01-01

The outer-sphere contribution to the volume of activation of homogeneous electron exchange reactions is estimated for selected solvents on the basis of the mean spherical approximation (MSA), and the calculated values are compared with those estimated by the Strank-Hush-Marcus (SHM) theory and with activation volumes obtained experimentally for the electron exchange reaction between tris(hexafluoroacetylacetonato)ruthenium(III) and -(II) in acetone, acetonitrile, methanol and chloroform. The MSA treatment, which recognizes the molecular nature of the solvent, does not improve significantly upon the continuous-dielectric SHM theory, which represents the experimental data adequately for the more polar solvents.

Electrochemiluminescent DNA sensor based on controlled Zn-mediated grafting of diazonium precursors.

PubMed

Torréns, Mabel; Ortiz, Mayreli; Bejarano-Nosas, Diego; O'Sullivan, Ciara K

2015-07-01

Controlled Zn-mediated grafting of a thin layer of a diazonium salt was used to functionalise a carbon electrode with ruthenium(II)-tris-bipyridine (Ru)-labelled DNA for use as a capture probe in an electrochemiluminescent genosensor. A secondary reporter probe was labelled with a ferrocene (Fc) molecule, and in the presence of the single-stranded DNA target a genocomplex formed, where the Fc-label effectively quenched the electrochemiluminescence of the signal emitted from the Ru-label. The spacing of the labels for maximum sensitivity and minimum detection limit was optimised, and the signal reproducibility and stability of the method was established.

Light-activated protein inhibition through photoinduced electron transfer of a ruthenium(II)–cobalt(III) bimetallic complex

DOE PAGES

Holbrook, Robert J.; Weinberg, David J.; Peterson, Mark D.; ...

2015-02-11

In this paper, we describe a mechanism of light activation that initiates protein inhibitory action of a biologically inert Co(III) Schiff base (Co(III)-sb) complex. Photoinduced electron transfer (PET) occurs from a Ru(II) bipyridal complex to a covalently attached Co(III) complex and is gated by conformational changes that occur in tens of nanoseconds. Reduction of the Co(III)-sb by PET initiates displacement of the inert axial imidazole ligands, promoting coordination to active site histidines of α-thrombin. Upon exposure to 455 nm light, the rate of ligand exchange with 4-methylimidazole, a histidine mimic, increases by approximately 5-fold, as observed by NMR spectroscopy. Similarly,more » the rate of α-thrombin inhibition increases over 5-fold upon irradiation. Finally, these results convey a strategy for light activation of inorganic therapeutic agents through PET utilizing redox-active metal centers.« less

Recommendation of ruthenium source for sludge batch flowsheet studies

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

Woodham, W.

Included herein is a preliminary analysis of previously-generated data from sludge batches 7a, 7b, 8, and 9 sludge simulant and real-waste testing, performed to recommend a form of ruthenium for future sludge batch simulant testing under the nitric-formic flowsheet. Focus is given to reactions present in the Sludge Receipt and Adjustment Tank cycle, given that this cycle historically produces the most changes in chemical composition during Chemical Process Cell processing. Data is presented and analyzed for several runs performed under the nitric-formic flowsheet, with consideration given to effects on the production of hydrogen gas, nitrous oxide gas, consumption of formate,more » conversion of nitrite to nitrate, and the removal and recovery of mercury during processing. Additionally, a brief discussion is given to the effect of ruthenium source selection under the nitric-glycolic flowsheet. An analysis of data generated from scaled demonstration testing, sludge batch 9 qualification testing, and antifoam degradation testing under the nitric-glycolic flowsheet is presented. Experimental parameters of interest under the nitric-glycolic flowsheet include N2O production, glycolate destruction, conversion of glycolate to formate and oxalate, and the conversion of nitrite to nitrate. To date, the number of real-waste experiments that have been performed under the nitric-glycolic flowsheet is insufficient to provide a complete understanding of the effects of ruthenium source selection in simulant experiments with regard to fidelity to real-waste testing. Therefore, a determination of comparability between the two ruthenium sources as employed under the nitric-glycolic flowsheet is made based on available data in order to inform ruthenium source selection for future testing under the nitric-glycolic flowsheet.« less

Acetate- and thiol-capped monodisperse ruthenium nanoparticles: XPS, XAS, and HRTEM studies.

PubMed

Chakroune, Nassira; Viau, Guillaume; Ammar, Souad; Poul, Laurence; Veautier, Delphine; Chehimi, Mohamed M; Mangeney, Claire; Villain, Françoise; Fiévet, Fernand

2005-07-19

Monodisperse ruthenium nanoparticles were prepared by reduction of RuCl3 in 1,2-propanediol. The mean particle size was controlled by appropriate choice of the reduction temperature and the acetate ion concentration. Colloidal solutions in toluene were obtained by coating the metal particles with dodecanethiol. High-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and X-ray absorption spectroscopy (XANES and EXAFS for the Ru K-absorption edge) were performed on particles of two different diameters, 2 and 4 nm, and in different environments, polyol/acetate or thiol. For particles stored in polyol/acetate XPS studies revealed superficial oxidation limited to one monolayer and a surface coating containing mostly acetate ions. Analysis of the EXAFS spectra showed both oxygen and ruthenium atoms around the ruthenium atoms with a Ru-Ru coordination number N smaller than the bulk value, as expected for fine particles. In the case of 2 nm acetate-capped particles N is consistent with particles made up of a metallic core and an oxidized monolayer. For 2 nm thiol-coated particles, a Ru-S bond was evidenced by XPS and XAS. For the 4 nm particles XANES and XPS studies showed that most of the ruthenium atoms are in the zerovalent state. Nevertheless, in both cases, when capped with thiol, the Ru-Ru coordination number inferred from EXAFS is much smaller than for particles of the same size stored in polyol. This is attributed to a structural disorganization of the particles by thiol chemisorption. HRTEM studies confirm the marked dependence of the structural properties of the ruthenium particles on their chemical environment; they show the acetate-coated particles to be single crystals, whereas the thiol-coated particles appear to be polycrystalline.

Ruthenium-catalyzed regioselective allylic amination of 2,3,3-trifluoroallylic carbonates.

PubMed

Isobe, Shin-Ichi; Terasaki, Shou; Hanakawa, Taisyun; Mizuno, Shota; Kawatsura, Motoi

2017-04-05

We demonstrated the ruthenium-catalyzed allylic amination of 2,3,3-trifluoroallylic carbonates with several types of amines. The reactions proceeded with several types of amines, and succeeded in obtaining polyfluorinated terminal alkenes possessing branched allylic amines as a single regioisomer.

Parameters governing ruthenium sawhorse-based decarboxylation of oleic acid

USDA-ARS?s Scientific Manuscript database

Ruthenium-catalyzed decarboxylation of 9-cisoctadecenoic is a path to produce biobased olefins. Here, a mechanistic study of this reaction was undertaken utilizing a closed reaction system and a pressure reactor. The proposed mechanism of an isomerization followed by a decarboxylation reaction was c...

Decarboxylation of cinnamic acids using a ruthenium sawhorse

USDA-ARS?s Scientific Manuscript database

The ruthenium sawhorse has proven effective in the conversion of trans-cinnamic acid, and substituted trans-cinnamic acids, giving an effective source of biobased styrene and styrene analogues. The reaction is especially versatile, as it achieves product without utilising co-reagents. However, the o...

Mononuclear ruthenium(III) complexes containing chelating thiosemicarbazones: Synthesis, characterization and catalytic property

NASA Astrophysics Data System (ADS)

Raja, N.; Ramesh, R.

2010-02-01

Mononuclear ruthenium(III) complexes of the type [RuX(EPh 3) 2(L)] (E = P or As; X = Cl or Br; L = dibasic terdentate dehydroacetic acid thiosemicarbazones) have been synthesized from the reaction of thiosemicarbazone ligands with ruthenium(III) precursors, [RuX 3(EPh 3) 3] (where E = P, X = Cl; E = As, X = Cl or Br) and [RuBr 3(PPh 3) 2(CH 3OH)] in benzene. The compositions of the complexes have been established by elemental analysis, magnetic susceptibility measurement, FT-IR, UV-vis and EPR spectral data. These complexes are paramagnetic and show intense d-d and charge transfer transitions in dichloromethane. The complexes show rhombic EPR spectra at LNT which are typical of low-spin distorted octahedral ruthenium(III) species. All the complexes are redox active and display an irreversible metal centered redox processes. Complex [RuCl(PPh 3) 2(DHA-PTSC)] ( 5) was used as catalyst for transfer hydrogenation of ketones in the presence of isopropanol/KOH and was found to be the active species.

Tunable emission in lanthanide coordination polymer gels based on a rationally designed blue emissive gelator.

PubMed

Sutar, Papri; Suresh, Venkata M; Maji, Tapas Kumar

2015-06-18

Rational design and synthesis of a new low molecular weight gelator (LMWG) having 9,10-diphenylanthracene core and terminal terpyridine is reported. Tb(III) and Eu(III) ion coordination to a LMWG results in green and pink emissive coordination polymer gels, respectively, with coiled nanofiber morphology. Further, control over stoichiometry of LMWG:Tb(III):Eu(III) leads to yellow and white light emitting bimetallic gels.

Complex of transferrin with ruthenium for medical applications

DOEpatents

Richards, Powell; Srivastava, Suresh C.; Meinken, George E.

1984-05-15

A novel Ruthenium-transferrin complex, prepared by reacting iron-free human transferrin dissolved in a sodium acetate solution at pH 7 with ruthenium by heating at about 40.degree. C. for about 2 hours, and purifying said complex by means of gel chromotography with pH 7 sodium acetate as eluent. The mono- or di-metal complex produced can be used in nuclear medicine in the diagnosis and/or treatment of tumors and abscesses. Comparative results with Ga-67-citrate, which is the most widely used tumor-localizing agent in nuclear medicine, indicate increased sensitivity of detection and greater tumor uptake with the Ru-transferrin complex.

An Atom-Economic and Selective Ruthenium-Catalyzed Redox Isomerization of Propargylic Alcohols. An Efficient Strategy for the Synthesis of Leukotrienes

PubMed Central

Trost, Barry M.; Livingston, Robert C.

2008-01-01

Catalytic ruthenium complexes in conjunction with an indium cocatalyst and Bronsted acid isomerize primary and secondary propargylic alcohols in good yields to provide trans enals and enones exclusively. Readily available indenylbis(triphenylphosphine)ruthenium chloride in the presence of indium triflate and camphorsulfonic acid give the best turnover numbers and reactivity with the broadest range of substrates. Deuterium labeling experiments suggest that the process occurs through propargylic hydride migration followed by protic cleavage of the resultant vinylruthenium intermediate. Application of this method to the synthesis of leukotriene B4 demonstrates its utility and extraordinary selectivity. PMID:18702463

In Vitro Effects of Novel Ruthenium Complexes in Neospora caninum and Toxoplasma gondii Tachyzoites

PubMed Central

Barna, Fabienne; Debache, Karim; Küster, Tatiana

2013-01-01

Upon the screening of 16 antiproliferative compounds against Toxoplasma gondii and Neospora caninum, two hydrolytically stable ruthenium complexes (compounds 16 and 18) exhibited 50% inhibitory concentrations of 18.7 and 41.1 nM (T. gondii) and 6.7 and 11.3 nM (N. caninum). To achieve parasiticidal activity with compound 16, long-term treatment (22 to 27 days at 80 to 160 nM) was required. Transmission electron microscopy demonstrated the rapid impact on and ultrastructural alterations in both parasites. These preliminary findings suggest that the potential of ruthenium-based compounds should thus be further exploited. PMID:23979747

URANIUM DECONTAMINATION

DOEpatents

Buckingham, J.S.; Carroll, J.L.

1959-12-22

A process is described for reducing the extractability of ruthenium, zirconium, and niobium values into hexone contained in an aqueous nitric acid uranium-containing solution. The solution is made acid-deficient, heated to between 55 and 70 deg C, and at that temperature a water-soluble inorganic thiosulfate is added. By this, a precipitate is formed which carries the bulk of the ruthenium, and the remainder of the ruthenium as well as the zirconium and niobium are converted to a hexone-nonextractable form. The rutheniumcontaining precipitate can either be removed from the solu tion or it can be dissolved as a hexone-non-extractable compound by the addition of sodium dichromate prior to hexone extraction.

Posttranscriptional regulation of alpha-amylase II-4 expression by gibberellin in germinating rice seeds.

PubMed

Nanjo, Yohei; Asatsuma, Satoru; Itoh, Kimiko; Hori, Hidetaka; Mitsui, Toshiaki; Fujisawa, Yukiko

2004-06-01

Hormonal regulation of expression of alpha-amylase II-4 that lacks the gibberellin-response cis-element (GARE) in the promoter region of the gene was studied in germinating rice (Oryza sativa L.) seeds. Temporal and spatial expression of alpha-amylase II-4 in the aleurone layer were essentially identical to those of alpha-amylase I-1 whose gene contains GARE, although these were distinguishable in the embryo tissues at the early stage of germination. The gibberellin-responsible expression of alpha-amylase II-4 was also similar to that of alpha-amylase I-1. However, the level of alpha-amylase II-4 mRNA was not increased by gibberellin, indicating that the transcriptional enhancement of alpha-amylase II-4 expression did not occur in the aleurone. Gibberellin stimulated the accumulation of 45Ca2+ into the intracellular secretory membrane system. In addition, several inhibitors for Ca2+ signaling, such as EGTA, neomycin, ruthenium red (RuR), and W-7 prevented the gibberellin-induced expression of alpha-amylase II-4 effectively. While the gibberellin-induced expression of alpha-amylase II-4 occurred normally in the aleurone layer of a rice dwarf mutant d1 which is defective in the alpha subunit of the heterotrimeric G protein. Based on these results, it was concluded that the posttranscriptional regulation of alpha-amylase II-4 expression by gibberellin operates in the aleurone layer of germinating rice seed, which is mediated by Ca2+ but not the G protein.

Improvement of ruthenium based decarboxylation of carboxylic acids

USDA-ARS?s Scientific Manuscript database

The removal of oxygen atoms from biobased carboxylic acids is an attractive route to provide the drop in replacement feedstocks that industry needs to continue to provide high performance products. Through the use of ruthenium catalysis, an efficient method where this process can be accomplished on ...

Oxidation-reduction catalyst and its process of use

NASA Technical Reports Server (NTRS)

Schryer, Jacqueline L. (Inventor); Oglesby, Donald M. (Inventor); Jordan, Jeffrey D. (Inventor); Watkins, Anthony Neal (Inventor)

2008-01-01

This invention relates generally to a ruthenium stabilized oxidation-reduction catalyst useful for oxidizing carbon monoxide, and volatile organic compounds, and reducing nitrogen oxide species in oxidizing environments, substantially without the formation of toxic and volatile ruthenium oxide species upon said oxidizing environment being at high temperatures.

Method for producing electricity using a platinum-ruthenium-palladium catalyst in a fuel cell

DOEpatents

Gorer, Alexander

2004-01-27

A method for producing electricity using a fuel cell that utilizes a ternary alloy composition as a fuel cell catalyst, the ternary alloy composition containing platinum, ruthenium and palladium. The alloy shows increased activity as compared to well-known catalysts.

Ruthenium-catalyzed aerobic oxidative decarboxylation of amino acids: a green, zero-waste route to biobased nitriles.

PubMed

Claes, Laurens; Verduyckt, Jasper; Stassen, Ivo; Lagrain, Bert; De Vos, Dirk E

2015-04-18

Oxidative decarboxylation of amino acids into nitriles was performed using molecular oxygen as terminal oxidant and a heterogeneous ruthenium hydroxide-based catalyst. A range of amino acids was oxidized in very good yield, using water as the solvent.

Catalytic oxidation of dimethyl ether

DOEpatents

Zelenay, Piotr; Wu, Gang; Johnston, Christina M.; Li, Qing

2016-05-10

A composition for oxidizing dimethyl ether includes an alloy supported on carbon, the alloy being of platinum, ruthenium, and palladium. A process for oxidizing dimethyl ether involves exposing dimethyl ether to a carbon-supported alloy of platinum, ruthenium, and palladium under conditions sufficient to electrochemically oxidize the dimethyl ether.

Thermodynamic properties of gaseous ruthenium species.

PubMed

Miradji, Faoulat; Souvi, Sidi; Cantrel, Laurent; Louis, Florent; Vallet, Valérie

2015-05-21

The review of thermodynamic data of ruthenium oxides reveals large uncertainties in some of the standard enthalpies of formation, motivating the use of high-level relativistic correlated quantum chemical methods to reduce the level of discrepancies. The reaction energies leading to the formation of ruthenium oxides RuO, RuO2, RuO3, and RuO4 have been calculated for a series of reactions. The combination of different quantum chemical methods has been investigated [DFT, CASSCF, MRCI, CASPT2, CCSD(T)] in order to predict the geometrical parameters, the energetics including electronic correlation and spin-orbit coupling. The most suitable method for ruthenium compounds is the use of TPSSh-5%HF for geometry optimization, followed by CCSD(T) with complete basis set (CBS) extrapolations for the calculation of the total electronic energies. SO-CASSCF seems to be accurate enough to estimate spin-orbit coupling contributions to the ground-state electronic energies. This methodology yields very accurate standard enthalpies of formations of all species, which are either in excellent agreement with the most reliable experimental data or provide an improved estimate for the others. These new data will be implemented in the thermodynamical databases that are used by the ASTEC code (accident source term evaluation code) to build models of ruthenium chemistry behavior in severe nuclear accident conditions. The paper also discusses the nature of the chemical bonds both from molecular orbital and topological view points.

Inhibition of ammonia poisoning by addition of platinum to Ru/α-Al2 O3 for preferential CO oxidation in fuel cells.

PubMed

Sato, Katsutoshi; Yagi, Sho; Zaitsu, Shuhei; Kitayama, Godai; Kayada, Yuto; Teramura, Kentaro; Takita, Yusaku; Nagaoka, Katsutoshi

2014-12-01

In polymer electrolyte fuel cell (PEFC) systems, small amounts of ammonia (NH3 ) present in the reformate gas deactivate the supported ruthenium catalysts used for preferential oxidation (PROX) of carbon monoxide (CO). In this study, we investigated how the addition of a small amount of platinum to a Ru/α-Al2 O3 catalyst (Pt/Ru=1:9 w/w) affected the catalyst's PROX activity in both the absence and the presence of NH3 (130 ppm) under conditions mimicking the reformate conditions during steam reforming of natural gas. The activity of undoped Ru/α-Al2 O3 decreased sharply upon addition of NH3 , whereas Pt/Ru/α-Al2 O3 exhibited excellent PROX activity even in the presence of NH3 . Ruthenium K-edge X-ray absorption near-edge structure (XANES) spectra indicated that in the presence of NH3 , some of the ruthenium in the undoped catalyst was oxidized in the presence of NH3 , whereas ruthenium oxidation was not observed with Pt/Ru/α-Al2 O3 . These results suggest that ruthenium oxidation is retarded by the platinum, so that the catalyst shows high activity even in the presence of NH3 . © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

SORPTION OF LEAD ON A RUTHENIUM COMPOUND: A MACROSCOPIC AND MICROSCOPIC STUDY

EPA Science Inventory

The objective of this study was to elucidate the sorption mechanism of Pb on the high-affinity ruthenium compound with time at pH 6 employing batch methods and X-ray absorption fine structure (XAFS) and X-ray diffraction (XRD) spectroscopies. For the spectroscopic studies, Pb so...

Arsenate Adsorption On Ruthenium Oxides: A Spectroscopic And Kinetic Investigation

EPA Science Inventory

Arsenate adsorption on amorphous (RuO₂•1.1H₂O) and crystalline (RuO₂) ruthenium oxides was evaluated using spectroscopic and kinetic methods to elucidate the adsorption mechanism. Extended X-ray absorption fine structure spectroscopy (EXAFS) was ...

Room temperature aerobic oxidation of amines by a nanocrystalline ruthenium oxide pyrochlore nafion composite catalyst.

PubMed

Venkatesan, Shanmuganathan; Kumar, Annamalai Senthil; Lee, Jyh-Fu; Chan, Ting-Shan; Zen, Jyh-Myng

2012-05-14

The aerobic oxidation of primary amines to their respective nitriles has been carried out at room temperature using a highly reusable nanocrystalline ruthenium oxide pyrochlore Nafion composite catalyst (see figure). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

SEPARATION OF URANYL AND RUTHENIUM VALUES BY THE TRIBUTYL PHOSPHATE EXTRACTION PROCESS

DOEpatents

Wilson, A.S.

1961-05-01

A process is given for separating uranyl values from ruthenium values contained in an aqueous 3 to 4 M nitric acid solution. After the addition of hydrogen peroxide to obtain a concentration of 0.3 M, the uranium is selectively extracted with kerosene-diluted tributyl phosphate.

Magnetically Recoverable Supported Ruthenium Catalyst for Hydrogenation of Alkynes and Transfer Hydrogenation of Carbonyl Compounds

EPA Science Inventory

A ruthenium (Ru) catalyst supported on magnetic nanoparticles (NiFe2O4) has been successfully synthesized and used for hydrogenation of alkynes at room temperature as well as transfer hydrogenation of a number of carbonyl compounds under microwave irradiation conditions. The cata...

Detailed electrochemical studies of the tetraruthenium polyoxometalate water oxidation catalyst in acidic media: identification of an extended oxidation series using Fourier transformed alternating current voltammetry.

PubMed

Lee, Chong-Yong; Guo, Si-Xuan; Murphy, Aidan F; McCormac, Timothy; Zhang, Jie; Bond, Alan M; Zhu, Guibo; Hill, Craig L; Geletii, Yurii V

2012-11-05

The electrochemistry of the water oxidation catalyst, Rb(8)K(2)[{Ru(4)O(4)(OH)(2)(H(2)O)(4)}(γ-SiW(10)O(36))(2)] (Rb(8)K(2)-1(0)) has been studied in the presence and absence of potassium cations in both hydrochloric and sulfuric acid solutions by transient direct current (dc) cyclic voltammetry, a steady state dc method in the rotating disk configuration and the kinetically sensitive technique of Fourier transformed large-amplitude alternating current (ac) voltammetry. In acidic media, the presence of potassium ions affects the kinetics (apparent rate of electron transfer) and thermodynamics (reversible potentials) of the eight processes (A'/A to H/H') that are readily detected under dc voltammetric conditions. The six most positive processes (A'/A to F/F'), each involve a one electron ruthenium based charge transfer step (A'/A, B'/B are Ru(IV/V) oxidation and C/C' to F/F' are Ru(IV/III) reduction). The apparent rate of electron transfer of the ruthenium centers in sulfuric acid is higher than in hydrochloric acid. The addition of potassium cations increases the apparent rates and gives rise to a small shift of reversible potential. Simulations of the Fourier transformed ac voltammetry method show that the B'/B, E/E', and F/F' processes are quasi-reversible, while the others are close to reversible. A third Ru(IV/V) oxidation process is observed just prior to the positive potential limit via dc methods. Importantly, the ability of the higher harmonic components of the ac method to discriminate against the irreversible background solvent process allows this (process I) as well as an additional fourth reversible ruthenium based process (J) to be readily identified. The steady-state rotating disk electrode (RDE) method confirmed that all four Ru-centers in Rb(8)K(2)-1(0) are in oxidation state IV. The dc and ac data indicate that reversible potentials of the four ruthenium centers are evenly spaced, which may be relevant to understanding of the water oxidation electrocatalysis. A profound effect of the potassium cation is observed for the one-electron transfer process (G/G') assigned to Ru(III/II) reduction and the multiple electron transfer reduction process (H/H') that arise from the tungstate polyoxometalate framework. A significant shift of E°' to a more positive potential value for process H/H' was observed on removal of K(+) (~100 mV in H(2)SO(4) and ~50 mV in HCl).

Crystal structure of bis-[μ-(4-meth-oxy-phen-yl)methane-thiol-ato-κ(2) S:S]bis-[chlorido-(η(6)-1-isopropyl-4-methyl-benzene)-ruthenium(II)] chloro-form disolvate.

PubMed

Stíbal, David; Süss-Fink, Georg; Therrien, Bruno

2015-10-01

The mol-ecular structure of the title complex, [Ru2(C8H9OS)2Cl2(C10H14)2]·2CHCl3 or (p-MeC6H4Pr (i) )2Ru2(SCH2-p-C6H5-OCH3)2Cl2·2CHCl3, shows inversion symmetry. The two symmetry-related Ru(II) atoms are bridged by two 4-meth-oxy-α-toluene-thiol-ato [(4-meth-oxy-phen-yl)methane-thiol-ato] units. One chlorido ligand and the p-cymene ligand complete the typical piano-stool coordination environment of the Ru(II) atom. In the crystal, the CH moiety of the chloro-form mol-ecule inter-acts with the chlorido ligand of the dinuclear complex, while one Cl atom of the solvent inter-acts more weakly with the methyl group of the bridging 4-meth-oxy-α-toluene-thiol-ato unit. This assembly leads to the formation of supra-molecular chains extending parallel to [021].

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.

In-situ XPS analysis of oxidized and reduced plasma deposited ruthenium-based thin catalytic films

NASA Astrophysics Data System (ADS)

Balcerzak, Jacek; Redzynia, Wiktor; Tyczkowski, Jacek

2017-12-01

A novel in-situ study of the surface molecular structure of catalytically active ruthenium-based films subjected to the oxidation (in oxygen) and reduction (in hydrogen) was performed in a Cat-Cell reactor combined with a XPS spectrometer. The films were produced by the plasma deposition method (PEMOCVD). It was found that the films contained ruthenium at different oxidation states: metallic (Ru0), RuO2 (Ru+4), and other RuOx (Ru+x), of which content could be changed by the oxidation or reduction, depending on the process temperature. These results allow to predict the behavior of the Ru-based catalysts in different redox environments.

Complex of transferrin with ruthenium for medical applications

DOEpatents

Richards, P.; Srivastava, S.C.; Meinken, G.E.

1984-05-15

A novel ruthenium-transferrin complex is disclosed which is prepared by reacting iron-free human transferrin dissolved in a sodium acetate solution at pH 7 with ruthenium by heating at about 40 C for about 2 hours. The complex is purified by means of gel chromotography with pH 7 sodium acetate as eluent. The mono- or di-metal complex produced can be used in nuclear medicine in the diagnosis and/or treatment of tumors and abscesses. Comparative results with Ga-67-citrate, which is the most widely used tumor-localizing agent in nuclear medicine, indicate increased sensitivity of detection and greater tumor uptake with the Ru-transferrin complex. No Drawings

Complex of transferrin with ruthenium for medical applications. [Ru 97, Ru 103

DOEpatents

Richards, P.; Srivastava, S.C.; Meinken, G.E.

1980-11-03

A novel Ruthenium-transferrin complex, prepared by reacting iron-free human transferrin dissolved in a sodium acetate solution at pH 7 with ruthenium by heating at about 40/sup 0/C for about 2 hours, and purifying said complex by means of gel chromatography with pH 7 sodium acetate as eluent. The mono- or di-metal complex produced can be used in nuclear medicine in the diagnosis and/or treatment of tumors and abscesses. Comparitive results with Ga-67-citrate, which is the most widely used tumor-localizing agent in nuclear medicine, indicate increased sensitivity of detection and greater tumor uptake with the Ru-transferrin complex.

Development of a ruthenium/phosphite catalyst system for domino hydroformylation-reduction of olefins with carbon dioxide.

PubMed

Liu, Qiang; Wu, Lipeng; Fleischer, Ivana; Selent, Detlef; Franke, Robert; Jackstell, Ralf; Beller, Matthias

2014-06-02

An efficient domino ruthenium-catalyzed reverse water-gas-shift (RWGS)-hydroformylation-reduction reaction of olefins to alcohols is reported. Key to success is the use of specific bulky phosphite ligands and triruthenium dodecacarbonyl as the catalyst. Compared to the known ruthenium/chloride system, the new catalyst allows for a more efficient hydrohydroxymethylation of terminal and internal olefins with carbon dioxide at lower temperature. Unwanted hydrogenation of the substrate is prevented. Preliminary mechanism investigations uncovered the homogeneous nature of the active catalyst and the influence of the ligand and additive in individual steps of the reaction sequence. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Tandem enyne metathesis-Diels-Alder reaction for construction of natural product frameworks.

PubMed

Rosillo, Marta; Domínguez, Gema; Casarrubios, Luis; Amador, Ulises; Pérez-Castells, Javier

2004-03-19

Enynes connected through aromatic rings are used as substrates for metathesis reactions. The reactivity of three ruthenium carbene complexes is compared. The resulting 1,3-dienes are suitable precursors of polycyclic structures via a Diels-Alder process. Some domino RCM-Diels-Alder reactions are performed, suggesting a possible beneficial effect of the ruthenium catalyst in the cycloaddition process. Other examples require Lewis acid cocatalyst. When applied to aromatic ynamines or enamines, a new synthesis of vinylindoles is achieved. Monitorization of several metathesis reactions with NMR shows the different behavior for ruthenium catalysts. New carbenic species are detected in some reactions with an important dependence on the solvent used.

Nucleophilic addition of amines to ruthenium carbenes: ortho-(alkynyloxy)benzylamine cyclizations towards 1,3-benzoxazines.

PubMed

González-Rodríguez, Carlos; Suárez, José Ramón; Varela, Jesús A; Saá, Carlos

2015-02-23

A new ruthenium-catalyzed cyclization of ortho-(alkynyloxy)benzylamines to dihydro-1,3-benzoxazines is reported. The cyclization is thought to take place via the vinyl ruthenium carbene intermediates which are easily formed from [Cp*RuCl(cod)] and N2 CHSiMe3 . The mild reaction conditions and the efficiency of the procedure allow the easy preparation of a broad range of new 2-vinyl-2-substituted 1,3-benzoxazine derivatives. Rearrangement of an internal C(sp) in the starting material into a tetrasubstituted C(sp(3) ) atom in the final 1,3-benzoxazine is highly remarkable. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ruthenium-Catalyzed Cascade C—H Functionalization of Phenylacetophenones**

PubMed Central

Mehta, Vaibhav P; García-López, José-Antonio; Greaney, Michael F

2014-01-01

Three orthogonal cascade C—H functionalization processes are described, based on ruthenium-catalyzed C—H alkenylation. 1-Indanones, indeno indenes, and indeno furanones were accessed through cascade pathways by using arylacetophenones as substrates under conditions of catalytic [{Ru(p-cymene)Cl2}2] and stoichiometric Cu(OAc)2. Each transformation uses C—H functionalization methods to form C—C bonds sequentially, with the indeno furanone synthesis featuring a C—O bond formation as the terminating step. This work demonstrates the power of ruthenium-catalyzed alkenylation as a platform reaction to develop more complex transformations, with multiple C—H functionalization steps taking place in a single operation to access novel carbocyclic structures. PMID:24453063

Surface-enhanced hyper-Raman spectroscopy with a picosecond laser: gold and copper colloids

NASA Astrophysics Data System (ADS)

Lipscomb, Leigh Ann; Nie, Shuming; Feng, Sibo; Yu, Nai-Teng

1990-07-01

We have obtained surface-enhanced hyper-Raman scattering (SEHRS) spectra of crystal violet, rhodamine 6G and Ru(trpy) (BPE) 32+ adsorbed on gold and copper colloidal surfaces (where trpy=2,2',2″-terpyridine, BPE=trans-bis(4-pyridyl)ethylene). Our results demonstrate that the SEHRS effect is not intrinsically restricted to a Ag substrate and that surface enhancements at the emitted hyper-Raman photon frequencies are not required for observing SEHRS signals.

Ruthenium supported on magnetic nanoparticles: An efficient and recoverable catalyst for hydrogenation of alkynes and transfer hydrogenation of carbonyl compounds

EPA Science Inventory

Ruthenium supported on surface modified magnetic nanoparticles (NiFe2O4) has been successfully synthesized and applied for hydrogenation of alkynes at room temperature as well as transfer hydrogenation of a number of carbonyl compounds under microwave irradiation conditions. The ...

Using ruthenium polypyridyl functionalized ZnO mesocrystals and gold nanoparticle dotted graphene composite for biological recognition and electrochemiluminescence biosensing

NASA Astrophysics Data System (ADS)

Liu, Suli; Zhang, Jinxing; Tu, Wenwen; Bao, Jianchun; Dai, Zhihui

2014-01-01

Using ruthenium polypyridyl functionalized ZnO mesocrystals as bionanolabels, a universal biological recognition and biosensing platform based on gold nanoparticle (AuNP) dotted reduced graphene oxide (rGO) composite was developed. AuNP-rGO accelerated electron transfer between the detection probe and the electrode, and increased the surface area of the working electrode to load greater amounts of the capture antibodies. The large surface area of ZnO mesocrystals was beneficial for loading a high content ruthenium polypyridyl complex, leading to an enhanced electrochemiluminescence signal. Using α-fetoprotein (AFP) as a model, a simple and sensitive sandwich-type electrochemiluminescence biosensor with tripropylamine (TPrA) as a coreactant for detection of AFP was constructed. The designed biosensor provided a good linear range from 0.04 to 500 ng mL-1 with a low detection limit of 0.031 ng mL-1 at a S/N of 3 for AFP determination. The proposed biological recognition and biosensing platform extended the application of ruthenium polypyridyl functionalized ZnO mesocrystals, which provided a new promising prospect.

Problems with the thermogravimetric determination of oxygen stoichiometries in pure and rare-earth substituted La2RuO5

NASA Astrophysics Data System (ADS)

Riegg, S.; Müller, T.; Ebbinghaus, S. G.

2013-06-01

The oxygen stoichiometries of pure and rare-earth substituted La2RuO5 have been investigated by thermogravimetry (TG) in reducing atmosphere. Assuming that the observed total weight loss is caused by the reduction of Ru4+ to Ru-metal, remarkable oxygen deficiencies were calculated. These would correspond to ruthenium oxidation states significantly lower than the ones experimentally observed by XANES. To explain this discrepancy we investigated the reduction products by X-ray absorption spectroscopy (XAS). EXAFS measurements at the Ru-K edge revealed the presence of an X-ray amorphous ruthenium oxide, indicating an incomplete reduction. The apparent oxygen deficiencies obtained for pure and rare-earth substituted samples correlate with the amount of remaining ruthenium oxide. The presence of a ruthenium oxide species was furthermore verified by Ru-LIII XANES investigations. Our results show that the determination of oxygen contents by thermogravimetry might fail even for the easily reducable nobel metal oxides and therefore has to be applied with caution if the reaction products cannot be identified unambiguously.

The Mystery of the Electronic Spectrum of Ruthenium Monophosphide

NASA Astrophysics Data System (ADS)

Adam, Allan G.; Christensen, Ryan M.; Dore, Jacob M.; Konder, Ricarda M.; Tokaryk, Dennis W.

2016-06-01

Using PH3 as a reactant gas and ruthenium as the target metal in the UNB laser ablation spectrometer, the ruthenium monophosphide molecule (RuP) has been detected. Dispersed fluorescence experiments have been performed to determine ground state vibrational frequencies and the presence of any low-lying electronic states. Rotationally resolved spectra of two vibrational bands at 577nm and 592nm have been taken; the bands have been identified as 1-0 and 0-0 bands based on isotopic shifts. Ruthenium has seven stable isotopes and rotational transitions have been observed for six of the RuP isotopologues. RuP is isoelectronic to RuN so it is expected that RuP will have a 2Σ+ ground state and low resolution spectra indicated a likely 2Σ+ - 2Σ+ electronic transition. Further investigation has led us to believe we are observing a 2Π - 2Σ+ transition but mysteriously some important rotational branches are missing. It is hoped that new data to be recorded on a second electronic system we have observed at 535nm will help shed light on this mystery.

Tracking the Oxygen Status in the Cell Nucleus with a Hoechst-Tagged Phosphorescent Ruthenium Complex.

PubMed

Hara, Daiki; Umehara, Yui; Son, Aoi; Asahi, Wataru; Misu, Sotaro; Kurihara, Ryohsuke; Kondo, Teruyuki; Tanabe, Kazuhito

2018-05-04

Molecular oxygen in living cells is distributed and consumed inhomogeneously, depending on the activity of each organelle. Therefore, tractable methods that can be used to monitor the oxygen status in each organelle are needed to understand cellular function. Here we report the design of a new oxygen-sensing probe for use in the cell nucleus. We prepared "Ru-Hoechsts", each consisting of a phosphorescent ruthenium complex linked to a Hoechst 33258 moiety, and characterized their properties as oxygen sensors. The Hoechst unit shows strong DNA-binding properties in the nucleus, and the ruthenium complex shows oxygen-dependent phosphorescence. Thus, Ru-Hoechsts accumulated in the cell nucleus and showed oxygen-dependent signals that could be monitored. Of the Ru-Hoechsts prepared in this study, Ru-Hoechst b, in which the ruthenium complex and the Hoechst unit were linked through a hexyl chain, showed the most suitable properties for monitoring the oxygen status. Ru-Hoechsts are probes with high potential for visualizing oxygen fluctuations in the nucleus. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

High-throughput determination of biochemical oxygen demand (BOD) by a microplate-based biosensor.

PubMed

Pang, Hei-Leung; Kwok, Nga-Yan; Chan, Pak-Ho; Yeung, Chi-Hung; Lo, Waihung; Wong, Kwok-Yin

2007-06-01

The use of the conventional 5-day biochemical oxygen demand (BOD5) method in BOD determination is greatly hampered by its time-consuming sampling procedure and its technical difficulty in the handling of a large pool of wastewater samples. Thus, it is highly desirable to develop a fast and high-throughput biosensor for BOD measurements. This paper describes the construction of a microplate-based biosensor consisting of an organically modified silica (ORMOSIL) oxygen sensing film for high-throughput determination of BOD in wastewater. The ORMOSIL oxygen sensing film was prepared by reacting tetramethoxysilane with dimethyldimethoxysilane in the presence of the oxygen-sensitive dye tris(4,7-diphenyl-1,10-phenanthroline)ruthenium-(II) chloride. The silica composite formed a homogeneous, crack-free oxygen sensing film on polystyrene microtiter plates with high stability, and the embedded ruthenium dye interacted with the dissolved oxygen in wastewater according to the Stern-Volmer relation. The bacterium Stenotrophomonas maltophilia was loaded into the ORMOSIL/ PVA composite (deposited on the top of the oxygen sensing film) and used to metabolize the organic compounds in wastewater. This BOD biosensor was found to be able to determine the BOD values of wastewater samples within 20 min by monitoring the dissolved oxygen concentrations. Moreover, the BOD values determined by the BOD biosensor were in good agreement with those obtained by the conventional BOD5 method.

Deposition and properties of cobalt- and ruthenium-based ultra-thin films

NASA Astrophysics Data System (ADS)

Henderson, Lucas Benjamin

Future copper interconnect systems will require replacement of the materials that currently comprise both the liner layer(s) and the capping layer. Ruthenium has previously been considered as a material that could function as a single material liner, however its poor ability to prevent copper diffusion makes it incompatible with liner requirements. A recently described chemical vapor deposition route to amorphous ruthenium-phosphorus alloy films could correct this problem by eliminating the grain boundaries found in pure ruthenium films. Bias-temperature stressing of capacitor structures using 5 nm ruthenium-phosphorus film as a barrier to copper diffusion and analysis of the times-to-failure at accelerated temperature and field conditions implies that ruthenium-phosphorus performs acceptably as a diffusion barrier for temperatures above 165°C. The future problems associated with the copper capping layer are primarily due to the poor adhesion between copper and the current Si-based capping layers. Cobalt, which adheres well to copper, has been widely proposed to replace the Si-based materials, but its ability to prevent copper diffusion must be improved if it is to be successfully implemented in the interconnect. Using a dual-source chemistry of dicobaltoctacarbonyl and trimethylphosphine at temperatures from 250-350°C, amorphous cobalt-phosphorus can be deposited by chemical vapor deposition. The films contain elemental cobalt and phosphorus, plus some carbon impurity, which is incorporated in the film as both graphitic and carbidic (bonded to cobalt) carbon. When deposited on copper, the adhesion between the two materials remains strong despite the presence of phosphorus and carbon at the interface, but the selectivity for growth on copper compared to silicon dioxide is poor and must be improved prior to consideration for application in interconnect systems. A single molecule precursor containing both cobalt and phosphorus atoms, tetrakis(trimethylphosphine)cobalt(0), yields cobalt-phosphorus films without any co-reactant. However, the molecule does not contain sufficient amounts of amorphizing agents to fully eliminate grain boundaries, and the resulting film is nanocrystalline.

A two-color fluorogenic carbene complex for tagging olefins via metathesis reaction

NASA Astrophysics Data System (ADS)

Wirtz, Marcel; Grüter, Andreas; Heib, Florian; Huch, Volker; Zapp, Josef; Herten, Dirk-Peter; Schmitt, Michael; Jung, Gregor

2015-12-01

We describe a fluorogenic ruthenium (II) carbene complex in which the chromophore is directly connected to the metal center. The compound introduces a boron dipyrromethene (BODIPY) moiety into target double bonds by metathesis. Tagging of terminal double bonds is demonstrated on immobilized styrene units on a glass surface. We also show that two compounds with distinguishable fluorescence properties are formed in the model reaction with styrene. The outcome of the metathesis reaction is characterized by 19F-NMR, optical spectroscopy, and, finally, single-molecule trajectories. This labeling scheme, in our perception, is of particular interest in the fields of interfacial science and biorthogonal ligation in combination with super-resolution imaging.

Developments and Applications of Electrogenerated Chemiluminescence Sensors Based on Micro- and Nanomaterials

PubMed Central

Hazelton, Sandra G.; Zheng, Xingwang; Zhao, Julia Xiaojun; Pierce, David T.

2008-01-01

A variety of recent developments and applications of electrogenerated chemiluminescence (ECL) for sensors are described. While tris(2,2′-bipyridyl)-ruthenium(II) and luminol have dominated and continue to pervade the field of ECL-based sensors, recent work has focused on use of these lumophores with micro- and nanomaterials. It has also extended to inherently luminescent nanomaterials, such as quantum dots. Sensor configurations including microelectrode arrays and microfluidics are reviewed and, with the recent trend toward increased use of nanomaterials, special attention has been given to sensors which include thin films, nanoparticles and nanotubes. Applications of ECL labels and examples of label-free sensing that incorporate nanomaterials are also discussed. PMID:27873850

Plasma-assisted oxide removal from ruthenium-coated EUV optics

NASA Astrophysics Data System (ADS)

Dolgov, A.; Lee, C. J.; Bijkerk, F.; Abrikosov, A.; Krivtsun, V. M.; Lopaev, D.; Yakushev, O.; van Kampen, M.

2018-04-01

An experimental study of oxide reduction at the surface of ruthenium layers on top of multilayer mirrors and thin Ru/Si films is presented. Oxidation and reduction processes were observed under conditions close to those relevant for extreme ultraviolet lithography. The oxidized ruthenium surface was exposed to a low-temperature hydrogen plasma, similar to the plasma induced by extreme ultraviolet radiation. The experiments show that hydrogen ions are the main reducing agent. Furthermore, the addition of hydrogen radicals increases the reduction rate beyond that expected from simple flux calculations. We show that low-temperature hydrogen plasmas can be effective for reducing oxidized top surfaces. Our proof-of-concept experiments show that an in situ, EUV-generated plasma cleaning technology is feasible.

Characterization of Self-Assembled Monolayers on a Ruthenium Surface

PubMed Central

2017-01-01

We have modified and stabilized the ruthenium surface by depositing a self-assembled monolayer (SAM) of 1-hexadecanethiol on a polycrystalline ruthenium thin film. The growth mechanism, dynamics, and stability of these monolayers were studied. SAMs, deposited under ambient conditions, on piranha-cleaned and piranha + H2SO4 cleaned substrates were compared to monolayers formed on H-radical-cleaned Ru surfaces. We found that alkanethiols on H-radical-cleaned Ru formed densely packed monolayers that remained stable when kept in a nitrogen atmosphere. X-ray photoelectron spectroscopy (XPS) shows a distinct sulfur peak (BE = 162.3 eV), corresponding to metal–sulfur bonding. When exposed to ambient conditions, the SAM decayed over a period of hours. PMID:28585831

Ruthenium-Catalyzed Aerobic Oxidation of Amines.

PubMed

Ray, Ritwika; Hazari, Arijit Singha; Lahiri, Goutam Kumar; Maiti, Debabrata

2018-01-18

Amine oxidation is one of the fundamental reactions in organic synthesis as it leads to a variety of value-added products such as oximes, nitriles, imines, and amides among many others. These products comprise the key N-containing building blocks in the modern chemical industry, and such transformations, when achieved in the presence of molecular oxygen without using stoichiometric oxidants, are much preferred as they circumvent the production of unwanted wastes. In parallel, the versatility of ruthenium catalysts in various oxidative transformations is well-documented. Herein, this review focuses on aerobic oxidation of amines specifically by using ruthenium catalysts and highlights the major achievements in this direction and challenges that still need to be addressed. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Carbon deposition in the Bosch process with ruthenium and ruthenium-iron alloy catalysts. M.S. Thesis. Final Report, Jan. 1981 - Jul. 1982

NASA Technical Reports Server (NTRS)

Manning, M. P.; Reid, R. C.; Sophonpanich, C.

1982-01-01

The effectiveness of ruthenium and the alloys 50Ru50Fe and 33Ru67Fe as alternatives to iron, nickel, and cobalt catalysts in recovering oxygen from metabolic carbon dioxide was investigated. Carbon deposition boundaries over the unsupported alloys are reported. Experiments were also carried out over 50Ru50Fe and 97Ru3Fe3 catalysts supported on gamma-alumina to determine their performance in the synthesis of low molecular weight olefins. High production of ethylene and propylene would be beneficial for an improvement of an overall Bosch process, as a gas phase containing high olefin content would enhance carbon deposition in a Bosch reactor.

Transition-metal chromophore as a new, sensitive spectroscopic tag for proteins. Selective covalent labeling of histidine residues in cytochromes c with chloro(2,2':6',2''-terpyridine)platinum(II) chloride

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

Ratilla, E.M.A.; Brothers, H.M. II; Kostic, N.M.

1987-07-22

Reactivity and selectivity of Pt(trpy)Cl/sup +/ toward proteins are studied with cytochromes c from horse and tuna as examples. The new transition-metal reagent is specific for histidine residues at pH 5. The reaction, facile one-step displacement of the Cl/sup -/ ligand by imidazole, produces good yield. The binding sites, His 26 and His 33 in the horse protein and His 26 in the tuna protein, are identified by UV-vis spectrophotometry and by peptide-mapping experiments. Model complexes with imidazole, histidine, histidine derivatives, and histidine-containing peptides are prepared and characterized. The covalently attached Pt(trpy)/sup 2 +/ labels allow easy separation of themore » protein derivatives by cation-exchange chromatography. The labels do not perturb the conformation and reduction potential of cytochrome c, as shown by UV-vis spectrophotometry, cyclic voltammetry, differential-pulse voltammetry, EPR spectroscopy, and /sup 1/H NMR spectroscopy. The selectivity of Pt(trpy)Cl/sup +/ is entirely opposite from that of PtCl/sub 4//sup 2 -/ although both of them are platinum(II)-chloro complexes. Owing to an interplay between the steric and electronic effects of the terpyridyl ligand, the new reagent is unreactive toward methionine (a thio ether) and cystine (a disulfide), which are otherwise highly nucleophilic ligands, but very reactive toward imidazole, which is otherwise a relatively weak ligand. Unusual and useful selectivity of preformed transition-metal complexes toward proteins evidently can be achieved by a judicious choice of ancillary ligands.« less

A Hard X-ray Study of a Manganese-Terpyridine Dimer Catalyst in a Chromium-based Metal Organic Framework - Oral Presentation

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

Ramsey, Alexandra

2015-08-25

Cleaner forms of energy are needed, and H 2 produced from water spliFng is a possible source. However, a robust catalyst is necessary to carry out the water oxidaKon reacKon. Plants uKlize Photosystem II to catalyze water oxidaKon as a part of photosynthesis, and many syntheKc water oxidaKon catalysts use Photosystem II as a model. In this study, the catalyst of interest was [(terpy)Mn(μ-O)2Mn(terpy)]3+ (MnTD), which was synthesized in a chromium-based Metal Organic Framework (MOF) to avoid degradaKon of MnTD molecules. Hard X-ray powder diffracKon was the primary method of analysis. The diffracKon data was used to detect the presencemore » of MOF in samples at different catalyKc stages, and laFce parameters were assigned to the samples containing MOF. Fourier maps were constructed to determine the contents of the MOF as preliminary studies suggested that MnTD may not be present. Results showed that MOF is present before catalysis occurs, but disappears in the iniKal stages of catalysis. Changes in the MOF’s laFce parameters suggest aWracKve interacKons between the MOF and catalyst; these interacKons may lead to the observed MOF degradaKon. Fourier maps also reveal limited, if any, amounts of MnTD in the system. Molecular manganese oxide may be the source of the high rate of water oxidaKon catalysis in the studied system.« less

Water oxidation catalyzed by the tetranuclear Mn complex [Mn(IV)4O5(terpy)4(H2O)2](ClO4)6.

PubMed

Gao, Yunlong; Crabtree, Robert H; Brudvig, Gary W

2012-04-02

The tetranuclear manganese complex [Mn(IV)(4)O(5)(terpy)(4)(H(2)O)(2)](ClO(4))(6) (1; terpy = 2,2':6',2″-terpyridine) gives catalytic water oxidation in aqueous solution, as determined by electrochemistry and GC-MS. Complex 1 also exhibits catalytic water oxidation when adsorbed on kaolin clay, with Ce(IV) as the primary oxidant. The redox intermediates of complex 1 adsorbed on kaolin clay upon addition of Ce(IV) have been characterized by using diffuse reflectance UV/visible and EPR spectroscopy. One of the products in the reaction on kaolin clay is Mn(III), as determined by parallel-mode EPR spectroscopic studies. When 1 is oxidized in aqueous solution with Ce(IV), the reaction intermediates are unstable and decompose to form Mn(II), detected by EPR spectroscopy, and MnO(2). DFT calculations show that the oxygen in the mono-μ-oxo bridge, rather than Mn(IV), is oxidized after an electron is removed from the Mn(IV,IV,IV,IV) tetramer. On the basis of the calculations, the formation of O(2) is proposed to occur by reaction of water with an electrophilic manganese-bound oxyl radical species, (•)O-Mn(2)(IV/IV), produced during the oxidation of the tetramer. This study demonstrates that [Mn(IV)(4)O(5)(terpy)(4)(H(2)O)(2)](ClO(4))(6) may be relevant for understanding the role of the Mn tetramer in photosystem II.

Theoretical study of photoinduced epoxidation of olefins catalyzed by ruthenium porphyrin.

PubMed

Ishikawa, Atsushi; Sakaki, Shigeyoshi

2011-05-12

Epoxidation of olefin by [Ru(TMP)(CO)(O)](-) (TMP = tetramesitylporphine), which is a key step of the photocatalyzed epoxidation of olefin by [Ru(TMP)(CO)], is studied mainly with the density functional theory (DFT) method, where [Ru(Por)(CO)] is employed as a model complex (Por = unsubstituted porphyrin). The CASSCF method was also used to investigate the electronic structure of important species in the catalytic cycle. In all of the ruthenium porphyrin species involved in the catalytic cycle, the weight of the main configuration of the CASSCF wave function is larger than 85%, suggesting that the static correlation is not very large. Also, unrestricted-DFT-calculated natural orbitals are essentially the same as CASSCF-calculated ones, here. On the basis of these results, we employed the DFT method in this work. Present computational results show characteristic features of this reaction, as follows: (i) The epoxidation reaction occurs via carboradical-type transition state. Neither carbocation-type nor concerted oxene-insertion-type character is observed in the transition state. (ii) Electron and spin populations transfer from the olefin moiety to the porphyrin ring in the step of the C-O bond formation. (iii) Electron and spin populations of the olefin and porphyrin moieties considerably change around the transition state. (iv) The atomic and spin populations of Ru change little in the reaction, indicating that the Ru center keeps the +II oxidation state in the whole catalytic cycle. (v) The stability of the olefin adduct [Ru(Por)(CO)(O)(olefin)](-) considerably depends on the kind of olefin, such as ethylene, n-hexene, and styrene. In particular, styrene forms a stable olefin adduct. And, (vi) interestingly, the difference in the activation barrier among these olefins is small in the quantitative level (within 5 kcal/mol), indicating that this catalyst can be applied to various substrates. This is because the stabilities and electronic structures of both the olefin adduct and the transition state are similarly influenced by the substituent of olefin.

Kinetics of photoinduced electron transfer reactions of ruthenium(II) complexes and phenols, tyrosine, N-acetyl-tyrosine and tryptophan in aqueous solutions measured with modulated fluorescence spectroscopy.

PubMed

Nguyen, Truong X; Landgraf, Stephan; Grampp, Günter

2017-01-01

Photooxidation kinetics of phenol, 1-naphthol, 2-naphthol, tyrosine (TyrOH) and N-acetyl-tyrosine (AcTyrOH), tryptophan (TrpH) by ruthenium(II) polypyridyl complexes: [Ru(bpy) 3 ]Cl 2 (1), [Ru(phen) 3 ]Cl 2 (2), [Ru(bpy)(phen)(bpg)]Cl 2 (3), and [Ru(dpq) 2 (bxbg)]Cl 2 (4) where bpy is 2,2'-bipyridine, phen - 1,10-phenanthroline, bpg - bipyridine-glycoluril, dpq - dipyrido[3,2-d:2',3'-f]quinoxaline, and bxbg - bis(o-xylene)bipyridine-glycoluril are investigated. Rate constants have been measured by steady-state luminescence and phase-modulation fluorometry in aqueous solutions at different pH's. The rates for the oxidation of the phenols and phenolic aromatic amino acids spreads over a wide range from 4.2×10 6 to 6.8×10 9 M -1 s -1 , depending on pH and the nature of solutes. At pH>pK a of the quenchers, the presence of reactive species (PhO - ) in the alkaline solutions is accounted for the rapid ET rates. In the pH range between 4 and 10 (pH

Electrochemical and surface analysis of the Fe-Cr-Ru system in non-oxidizing acid solutions

NASA Astrophysics Data System (ADS)

Tjong, S. C.

1990-03-01

The effect of ruthenium addition on the spontaneous passivation behaviour of Fe-40Cr alloy in 0.5M H 2SO 4 and 0.5M HCl acid solutions has been studied. Auger and XPS techniques were also used to investigate the surface chemistries of the spontaneously passivated film. Electrochemical measurements indicate that the Fe-40Cr-0.1Ru and Fe-40Cr-0.2Ru alloys exhibit spontaneous passivation upon exposing them in both hydrochloric and sulphuric acid solutions from 25 to 85 ° C. However, the transition time for spontaneous passivation reduces dramatically with an increase in the ruthenium content and solution temperature. Furthermore, this transition time also decreases for the investigated alloys exposed in a less aggressive sulphuric acid solution. AES results show that ruthenium and chromium are enriched in the spontaneous passive films formed on the Fe-40Cr-0.1Ru alloy in both hydrochloric and sulphuric acid solutions at 25 °C, and also in the spontaneous passive film formed on the Fe-40Cr-0.2Ru alloy in hydrochloric acid solution at 25 ° C. AES does not detect the presence of ruthenium in the spontaneous passive film formed on the Fe-40Cr-0.2Ru alloy in sulphuric acid solution. However, XPS analysis shows that ruthenium and chromium are incorporated into the spontaneous passive films formed on the Fe-40Cr-0.1Ru and Fe-40Cr-0.2Ru alloys in both hydrochloric and sulphuric acid solutions as Ru 4+ and Cr 3+ species.

Endoresection with adjuvant ruthenium brachytherapy for selected uveal melanoma patients - the Tuebingen experience.

PubMed

Süsskind, Daniela; Dürr, Carina; Paulsen, Frank; Kaulich, Theodor; Bartz-Schmidt, Karl U

2017-12-01

To evaluate the treatment of selected patients with uveal melanoma with endoresection and adjuvant ruthenium brachytherapy. Thirty-five patients with uveal melanoma not suitable for ruthenium plaque monotherapy were treated with endoresection and adjuvant ruthenium brachytherapy between January 2001 and October 2013. Recurrence-free survival, globe retention, course of visual acuity (VA), occurrence of therapy-related complications and metastasis-free and overall survival were analysed retrospectively. Eight patients (22.9%) had a tumour recurrence after a median follow-up of 49.5 months (range: 21-134 months). Enucleation was necessary in eight patients. Thirty-two patients (91%) had a loss of VA with a median loss of nine lines (range: 0 to -39 lines); VA was stable in three patients and no patients had a gain in VA. Four patients (11.4%) developed radiation retinopathy. Metastases were detected in seven patients (20.0%) during follow-up. The occurrence of metastasis was significantly associated with monosomy 3 (p < 0.0001). Twenty-four patients (68.6%) were alive at the end of follow-up. Five patients (14.3%) died because of uveal melanoma (UM) metastasis. Endoresection with adjuvant ruthenium brachytherapy is an option for selected patients with UM who cannot be treated with brachytherapy as monotherapy. About two-thirds of eyes can be retained long term without recurrences. Visual acuity cannot be maintained in most cases, and may even decrease considerably. Radiation complications are comparatively rare and not a significant problem. © 2016 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Investigation of Ruthenium Dissolution in Advanced Membrane Electrode Assemblies for Direct Methanol Based Fuel Cells Stacks

NASA Technical Reports Server (NTRS)

Valdez, T. I.; Firdosy, S.; Koel, B. E.; Narayanan, S. R.

2005-01-01

This viewgraph presentation gives a detailed review of the Direct Methanol Based Fuel Cell (DMFC) stack and investigates the Ruthenium that was found at the exit of the stack. The topics include: 1) Motivation; 2) Pathways for Cell Degradation; 3) Cell Duration Testing; 4) Duration Testing, MEA Analysis; and 5) Stack Degradation Analysis.

PRECIPITATION OF ZIRCONIUM, NIOBIUM, AND RUTHENIUM FROM AQUEOUS SOLUTIONS

DOEpatents

Wilson, A.S.

1958-08-12

An improvement on the"head end process" for decontaminating dissolver solutions of their Zr, Ni. and Ru values. The process consists in adding a water soluble symmetrical dialkyl ketone. e.g. acetone, before the formation of the manganese dioxide precipitate. The effect is that upon digestion, the ruthenium oxide does not volatilize, but is carried on the manganese dioxide precipitate.

Three-dimensional ruthenium-doped TiO 2 sea urchins for enhanced visible-light-responsive H 2 production

DOE PAGES

Nguyen-Phan, Thuy -Duong; Luo, Si; Vovchok, Dimitriy; ...

2016-05-23

Here, three-dimensional (3D) monodispersed sea urchin-like Ru-doped rutile TiO 2 hierarchical architectures composed of radially aligned, densely-packed TiO 2 nanorods have been successfully synthesized via an acid-hydrothermal method at low temperature without the assistance of any structure-directing agent and post annealing treatment. The addition of a minuscule concentration of ruthenium dopants remarkably catalyzes the formation of the 3D urchin structure and drives the enhanced photocatalytic H 2 production under visible light irradiation, not possible on undoped and bulk rutile TiO 2. Increasing ruthenium doping dosage not only increases the surface area up to 166 m 2 g –1 but alsomore » induces enhanced photoresponse in the regime of visible and near infrared light. The doping introduces defect impurity levels, i.e. oxygen vacancy and under-coordinated Ti 3+, significantly below the conduction band of TiO 2, and ruthenium species act as electron donors/acceptors that accelerate the photogenerated hole and electron transfer and efficiently suppress the rapid charge recombination, therefore improving the visible-light-driven activity.« less

Platinum-ruthenium nanotubes and platinum-ruthenium coated copper nanowires as efficient catalysts for electro-oxidation of methanol

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

Zheng, Jie; Cullen, David A.; Forest, Robert V.

2015-01-15

The sluggish kinetics of methanol oxidation reaction (MOR) is a major barrier to the commercialization of direct methanol fuel cells (DMFCs). In this study, we report a facile synthesis of platinum–ruthenium nanotubes (PtRuNTs) and platinum–ruthenium-coated copper nanowires (PtRu/CuNWs) by galvanic displacement reaction using copper nanowires as a template. The PtRu compositional effect on MOR is investigated; the optimum Pt/Ru bulk atomic ratio is about 4 and surface atomic ratio about 1 for both PtRuNTs and PtRu/CuNWs. Enhanced specific MOR activities are observed on both PtRuNTs and PtRu/CuNWs compared with the benchmark commercial carbon-supported PtRu catalyst (PtRu/C, Hispec 12100). Finally, x-raymore » photoelectron spectroscopy (XPS) reveals a larger extent of electron transfer from Ru to Pt on PtRu/CuNWs, which may lead to a modification of the d-band center of Pt and consequently a weaker bonding of CO (the poisoning intermediate) on Pt and a higher MOR activity on PtRu/CuNWs.« less

Unravelling the structural-electronic impact of arylamine electron-donating antennas on the performances of efficient ruthenium sensitizers for dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Chen, Wang-Chao; Kong, Fan-Tai; Ghadari, Rahim; Li, Zhao-Qian; Guo, Fu-Ling; Liu, Xue-Peng; Huang, Yang; Yu, Ting; Hayat, Tasawar; Dai, Song-Yuan

2017-04-01

We report a systematic research to understand the structural-electronic impact of the arylamine electron-donating antennas on the performances of the ruthenium complexes for dye-sensitized solar cells. Three ruthenium complexes functionalized with different arylamine electron-donating antennas (N,N-diethyl-aniline in RC-31, julolidine in RC-32 and N,N-dibenzyl-aniline in RC-36) are designed and synthesized. The photoelectric properties of RC dyes exhibit apparent discrepancy, which are ascribed to different structural nature and electronic delocalization ability of these arylamine electron-donating system. In conjunction with TiO2 microspheres photoanode and a typical coadsorbent DPA, the devices sensitized by RC-36 achieve the best conversion efficiency of 10.23%. The UV-Vis absorption, electrochemical measurement, incident photon-to-current conversion efficiency and transient absorption spectra confirm that the excellent performance of RC-36 is induced by synergistically structural-electronic impacts from enhanced absorption capacity and well-tuned electronic characteristics. These observations provide valuable insights into the molecular engineering methodology based on fine tuning structural-electronic impact of electron-donating antenna in efficient ruthenium sensitizers.

Synthesis, spectroscopic, structural and optical studies of Ru2S3 nanoparticles prepared from single-source molecular precursors

NASA Astrophysics Data System (ADS)

Mbese, Johannes Z.; Ajibade, Peter A.

2017-09-01

Homonuclear tris-dithiocarbamato ruthenium(III) complexes, [Ru(S2CNR2)3] were prepared and characterized by spectroscopic techniques and thermogravimetric analyses. The thermogravimetric analyses (TGA) of the ruthenium complexes showed that the complexes decompose to ruthenium(III) sulfide nanoparticles. The ruthenium(III) complexes were dispersed in oleic acid and thermolysed in hexadecylamine to prepared oleic acid/hexadecylamine capped Ru2S3 nanoparticles. FTIR revealed that Ru2S3 nanoparticles are capped through the interaction of the -NH2 group of hexadecylamine HDA adsorbed on the surfaces of nanoparticles and it also showed that oleic acid (OA) is acting as both coordinating stabilizing surfactant and capping agent. EDS spectra revealed that the prepared nanoparticles are mainly composed of Ru and S, confirming the formation of Ru2S3 nanoparticles. Powder XRD confirms that the nanoparticles are in cubic phase. The inner morphology of nanoparticles obtained from transmission electron microscopy (TEM) showed nanoparticles with narrow particle size distributions characterized by an average diameter of 8.45 nm with a standard deviation of 1.6 nm. The optical band gap (Eg) determined from Tauc plot are in the range 3.44-4.18 eV.

Comparative study of the anchorage and the catalytic properties of nanoporous TiO2 films modified with ruthenium (II) and rhenium (I) carbonyl complexes

NASA Astrophysics Data System (ADS)

Oyarzún, Diego P.; Chardon-Noblat, Sylvie; Linarez Pérez, Omar E.; López Teijelo, Manuel; Zúñiga, César; Zarate, Ximena; Shott, Eduardo; Carreño, Alexander; Arratia-Perez, Ramiro

2018-02-01

In this article we study the anchoring of cis-[Ru(bpyC4pyr)(CO)2(CH3CN)2]2+, cis-[Ru(bpy)2(CO)2]2+ and cis-[Ru(bpyac)(CO)2Cl2], onto nanoporous TiO2 employing electropolymerization, electrostatic interaction and chemical bonding. Also, the [Re(bpyac)(CO)3Cl] rhenium(I) complex for chemical anchorage was analyzed. The characterization of TiO2/Ru(II) and TiO2/Re(I) nanocomposite films was performed by field emission scanning electron microscopy (FESEM), electron dispersive X-ray spectroscopy (EDS) and Raman spectroscopy. In addition, for the more stable nanocomposites obtained, the catalytic properties (solar energy conversion and CO2 reduction) were evaluated. The efficiency improvement in redox process derived from the (photo)electrochemical evidence indicates that modified nanoporous TiO2 structures enhance the rate of charge transfer reactions.

The effects of linear assembly of two carbazole groups on acid-base and DNA-binding properties of a ruthenium(II) complex.

PubMed

Chen, Xi; Xue, Long-Xin; Ju, Chun-Chuan; Wang, Ke-Zhi

2013-07-01

A novel Ru(II) complex of [Ru(bpy)2(Hbcpip)](ClO4)2 {where bpy=2,2-bipyridine, Hbcpip=2-(4-(9H-3,9'-bicarbazol-9-yl)phenyl)-1H-imidazo[4,5-f][1,10]phenanthroline} is synthesized and characterized. Calf-thymus DNA-binding properties of the complex were studied by UV-vis absorption and luminescence titrations, steady-state emission quenching by [Fe(CN)6](4-), DNA competitive binding with ethidium bromide, thermal denaturation and DNA viscosity measurements. The results indicate that the complex partially intercalated into the DNA with a binding constant of (5.5±1.4)×10(5) M(-1) in buffered 50 mM NaCl. The acid-base properties of the complex were also studied by UV-visible and luminescence spectrophotometric pH titrations, and ground- and excited-state acidity ionization constant values were derived. Copyright © 2013 Elsevier B.V. All rights reserved.

Bioactive ruthenium(II)-arene complexes containing modified 18β-glycyrrhetinic acid ligands.

PubMed

Kong, Yaqiong; Chen, Feng; Su, Zhi; Qian, Yong; Wang, Fang-Xin; Wang, Xiuxiu; Zhao, Jing; Mao, Zong-Wan; Liu, Hong-Ke

2018-05-01

Metal-arene complexes containing bioactive natural-product derived ligands can have new and unusual properties. We report the synthesis, characterization and antiproliferative activity of two new Ru(II) arene complexes with imidazole (dichlorido complex 1) or bipyridyl (chlorido complex 2) ligands conjugated to 18β-glycyrrhetinic acid, an active triterpenoid metabolite of Glycyrrhiza glabra. In general, the conjugated ligands and complexes showed only moderate activity against HeLa (cervical), MCF-7 (breast) and A2780 (ovarian) cancer cells, although the activity of complex 2 in the former two cell lines approached that of the drug cisplatin. Complex 2 (in contrast to complex 1) also exhibited significant activity towards both Gram-positive S. aureus and Gram-negative E. coil bacteria. Complex 2 can induce condensation of DNA and enhances the generation of intracellular reactive oxygen species (ROS). The conjugation of natural products to ligands in organometallic half-sandwich complexes provides a strategy to enhance their biological activities. Copyright © 2018 Elsevier Inc. All rights reserved.

Spectroscopic, Electrochemical and Computational Characterisation of Ru Species Involved in Catalytic Water Oxidation: Evidence for a [Ru(V) (O)(Py2 (Me) tacn)] Intermediate.

PubMed

Casadevall, Carla; Codolà, Zoel; Costas, Miquel; Lloret-Fillol, Julio

2016-07-11

A new family of ruthenium complexes based on the N-pentadentate ligand Py2 (Me) tacn (N-methyl-N',N''-bis(2-picolyl)-1,4,7-triazacyclononane) has been synthesised and its catalytic activity has been studied in the water-oxidation (WO) reaction. We have used chemical oxidants (ceric ammonium nitrate and NaIO4 ) to generate the WO intermediates [Ru(II) (OH2 )(Py2 (Me) tacn)](2+) , [Ru(III) (OH2 )(Py2 (Me) tacn)](3+) , [Ru(III) (OH)(Py2 (Me) tacn)](2+) and [Ru(IV) (O)(Py2 (Me) tacn)](2+) , which have been characterised spectroscopically. Their relative redox and pH stability in water has been studied by using UV/Vis and NMR spectroscopies, HRMS and spectroelectrochemistry. [Ru(IV) (O)(Py2 (Me) tacn)](2+) has a long half-life (>48 h) in water. The catalytic cycle of WO has been elucidated by using kinetic, spectroscopic, (18) O-labelling and theoretical studies, and the conclusion is that the rate-determining step is a single-site water nucleophilic attack on a metal-oxo species. Moreover, [Ru(IV) (O)(Py2 (Me) tacn)](2+) is proposed to be the resting state under catalytic conditions. By monitoring Ce(IV) consumption, we found that the O2 evolution rate is redox-controlled and independent of the initial concentration of Ce(IV) . Based on these facts, we propose herein that [Ru(IV) (O)(Py2 (Me) tacn)](2+) is oxidised to [Ru(V) (O)(Py2 (Me) tacn)](2+) prior to attack by a water molecule to give [Ru(III) (OOH)(Py2 (Me) tacn)](2+) . Finally, it is shown that the difference in WO reactivity between the homologous iron and ruthenium [M(OH2 )(Py2 (Me) tacn)](2+) (M=Ru, Fe) complexes is due to the difference in the redox stability of the key M(V) (O) intermediate. These results contribute to a better understanding of the WO mechanism and the differences between iron and ruthenium complexes in WO reactions. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mo/Si multilayers with enhanced TiO II- and RuO II-capping layers

NASA Astrophysics Data System (ADS)

Yulin, Sergiy; Benoit, Nicolas; Feigl, Torsten; Kaiser, Norbert; Fang, Ming; Chandhok, Manish

2008-03-01

The lifetime of Mo/Si multilayer-coated projection optics is one of the outstanding issues on the road of commercialization of extreme-ultraviolet lithography (EUVL). The application of Mo/Si multilayer optics in EUVL requires both sufficient radiation stability and also the highest possible normal-incidence reflectivity. A serious problem of conventional high-reflective Mo/Si multilayers capped by silicon is the considerable degradation of reflective properties due to carbonization and oxidation of the silicon surface layer under exposure by EUV radiation. In this study, we focus on titanium dioxide (TiO II) and ruthenium dioxide (RuO II) as promising capping layer materials for EUVL multilayer coatings. The multilayer designs as well as the deposition parameters of the Mo/Si systems with different capping layers were optimized in terms of maximum peak reflectivity at the wavelength of 13.5 nm and longterm stability under high-intensive irradiation. Optimized TiO II-capped Mo/Si multilayer mirrors with an initial reflectivity of 67.0% presented a reflectivity drop of 0.6% after an irradiation dose of 760 J/mm2. The reflectivity drop was explained by the partial oxidation of the silicon sub-layer. No reflectivity loss after similar irradiation dose was found for RuO II-capped Mo/Si multilayer mirrors having initial peak reflectivity of 66%. In this paper we present data on improved reflectivity of interface-engineered TiO II- and RuO II-capped Mo/Si multilayer mirrors due to the minimization of both interdiffusion processes inside the multilayer stack and absorption loss in the oxide layer. Reflectivities of 68.5% at the wavelength of 13.4 nm were achieved for both TiO II- and RuO II-capped Mo/Si multilayer mirrors.

Ruthenium complexes containing 2-(2-nitrosoaryl)pyridine: structural, spectroscopic, and theoretical studies.

PubMed

Chan, Siu-Chung; Cheung, Ho-Yuen; Wong, Chun-Yuen

2011-11-21

Ruthenium complexes containing 2-(2-nitrosoaryl)pyridine (ON(^)N) and tetradentate thioether 1,4,8,11-tetrathiacyclotetradecane ([14]aneS4), [Ru(ON(^)N)([14]aneS4)](2+) [ON(^)N = 2-(2-nitrosophenyl)pyridine (2a), 10-nitrosobenzo[h]quinoline (2b), 2-(2-nitroso-4-methylphenyl)pyridine, (2c), 2-(2-nitrosophenyl)-5-(trifluoromethyl)pyridine (2d)] and analogues with the 1,4,7-trithiacyclononane ([9]aneS3)/tert-butylisocyanide ligand set, [Ru(ON(^)N)([9]aneS3)(C≡N(t)Bu)](2+) (4a and 4b), have been prepared by insertion of a nitrosonium ion (NO(+)) into the Ru-aryl bond of cyclometalated ruthenium(II) complexes. The molecular structures of the ON(^)N-ligated complexes 2a and 2b reveal that (i) the ON(^)N ligands behave as bidentate chelates via the two N atoms and the bite angles are 86.84(18)-87.83(16)° and (ii) the Ru-N(NO) and N-O distances are 1.942(5)-1.948(4) and 1.235(6)-1.244(5) Å, respectively. The Ru-N(NO) and N-O distances, together with ν(N═O), suggest that the coordinated ON(^)N ligands in this work are neutral moiety (ArNO)(0) rather than monoanionic radical (ArNO)(•-) or dianion (ArNO)(2-) species. The nitrosated complexes 2a-2d show moderately intense absorptions centered at 463-484 nm [ε(max) = (5-6) × 10(3) dm(3) mol(-1) cm(-1)] and a clearly discriminable absorption shoulder around 620 nm (ε(max) = (6-9) × 10(2) dm(3) mol(-1) cm(-1)), which tails up to 800 nm. These visible absorptions are assigned as a mixing of d(Ru) → ON(^)N metal-to-ligand charge-transfer and ON(^)N intraligand transitions on the basis of time-dependent density functional theory (TD-DFT) calculations. The first reduction couples of the nitrosated complexes range from -0.53 to -0.62 V vs Cp(2)Fe(+/0), which are 1.1-1.2 V less negative than that for [Ru(bpy)([14]aneS4)](2+) (bpy = 2,2'-bipyridine). Both electrochemical data and DFT calculations suggest that the lowest unoccupied molecular orbitals of the nitrosated complexes are ON(^)N-centered. Natural population analysis shows that the amount of positive charge on the Ru centers and the [Ru([14]aneS4)] moieties in 2a and 2b is larger than that in [Ru(bpy)([14]aneS4)](2+). According to the results of the structural, spectroscopic, electrochemical, and theoretical investigations, the ON(^)N ligands in this work have considerable π-acidic character and behave as better electron acceptors than bpy.

Engaging the Terminal: Promoting Halogen Bonding Interactions with Uranyl Oxo Atoms.

PubMed

Carter, Korey P; Kalaj, Mark; Surbella, Robert G; Ducati, Lucas C; Autschbach, Jochen; Cahill, Christopher L

2017-11-02

Engaging the nominally terminal oxo atoms of the linear uranyl (UO 2 2+ ) cation in non-covalent interactions represents both a significant challenge and opportunity within the field of actinide hybrid materials. An approach has been developed for promoting oxo atom participation in a range of non-covalent interactions, through judicious choice of electron donating equatorial ligands and appropriately polarizable halogen-donor atoms. As such, a family of uranyl hybrid materials was generated based on a combination of 2,5-dihalobenzoic acid and aromatic, chelating N-donor ligands. Delineation of criteria for oxo participation in halogen bonding interactions has been achieved by preparing materials containing 2,5-dichloro- (25diClBA) and 2,5-dibromobenzoic acid (25diBrBA) coupled with 2,2'-bipyridine (bipy) (1 and 2), 1,10-phenanthroline (phen) (3-5), 2,2':6',2''-terpyridine (terpy) (6-8), or 4'-chloro-2,2':6',2''-terpyridine (Cl-terpy) (9-10), which have been characterized through single crystal X-ray diffraction, Raman, Infrared (IR), and luminescence spectroscopy, as well as through density functional calculations of electrostatic potentials. Looking comprehensively, these results are compared with recently published analogues featuring 2,5-diiodobenzoic acid which indicate that although inclusion of a capping ligand in the uranyl first coordination sphere is important, it is the polarizability of the selected halogen atom that ultimately drives halogen bonding interactions with the uranyl oxo atoms. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electronic Interplay between TTF and Extended-TCNQ Electrophores along a Ruthenium Bis(acetylide) Linker.

PubMed

Vacher, Antoine; Auffray, Morgan; Barrière, Frédéric; Roisnel, Thierry; Lorcy, Dominique

2017-11-17

A bis(TTF-butadiynyl) ruthenium D-D'-D complex, with intramolecular electronic interplay between the three electron-donating electrophores, was easily converted through a cycloaddition-retroelectrocyclization with TCNQ into a D-A-D'-A-D pentad complex, which exhibits an intense intramolecular charge transfer together with an electronic interplay between the two acceptors along the conjugated organometallic bridge.

Inductively Coupled Plasma Mass Spectrometry: Sample Analysis of Zirconium and Ruthenium in Metal Organic Frameworks

DTIC Science & Technology

2018-02-01

international proficiency testing sponsored by the Organisation for the Prohibition of Chemical Weapons (The Hague, Netherlands). Traditionally...separate batch of standards at each level for a total of six analyses at each calibration level. Concentrations of the tested calibration levels are...and ruthenium at each calibration level. 11 REFERENCES 1. General Requirements for the Competence of Testing and Calibration Laboratories

Characteristics of a promising new thermoelectric material - Ruthenium silicide

NASA Technical Reports Server (NTRS)

Ohta, Toshitaka; Vining, Cronin B.; Allevato, Camillo E.

1991-01-01

A preliminary study on arc-melted samples has indicated that ruthenium silicide has the potential to obtain figure-of-merit values four times higher than that of conventional silicon-germanium material. In order to realize the high figure-of-merit values, high-quality crystal from the melt is needed. A Bridgman-like method has been employed and has realized much better crystals than arc-melted ones.

Asymmetric hydrogenation of aromatic ketones by new recyclable ionic tagged ferrocene-ruthenium catalyst system.

PubMed

Xu, Di; Zhou, Zhi-Ming; Dai, Li; Tang, Li-Wei; Zhang, Jun

2015-05-01

Newly developed ferrocene-oxazoline-phosphine ligands containing quaternary ammonium ionic groups exhibited excellent catalytic performance for the ruthenium-catalyzed hydrogenation of aromatic ketonic substrates to give chiral secondary alcohols with high levels of conversions and enantioselectivities. Simple manipulation process, water tolerance, high activity and good recyclable property make this catalysis practical and appealing. Copyright © 2015 Elsevier Ltd. All rights reserved.

Isomerization of 7-oxabenzonorbornadienes into naphthols catalyzed by [RuCl(2)(CO)(3)](2).

PubMed

Ballantine, Melissa; Menard, Michelle L; Tam, William

2009-10-02

Ruthenium-catalyzed isomerization of 7-oxanorbornadienes into naphthols was investigated. Among the various ruthenium catalysts tested, [RuCl(2)(CO)(3)](2) gave the highest yields in the isomerization, and various substituted naphthols were synthesized in moderate to excellent yields. Both symmetrical and unsymmetrical 7-oxanorbornadienes were employed in the study, and moderate to excellent regioselectivities were observed.

Ground and Excited-Electronic-State Dissociations of Hydrogen-Rich and Hydrogen-Deficient Tyrosine Peptide Cation Radicals

NASA Astrophysics Data System (ADS)

Viglino, Emilie; Lai, Cheuk Kuen; Mu, Xiaoyan; Chu, Ivan K.; Tureček, František

2016-09-01

We report a comprehensive study of collision-induced dissociation (CID) and near-UV photodissociation (UVPD) of a series of tyrosine-containing peptide cation radicals of the hydrogen-rich and hydrogen-deficient types. Stable, long-lived, hydrogen-rich peptide cation radicals, such as [AAAYR + 2H]+● and several of its sequence and homology variants, were generated by electron transfer dissociation (ETD) of peptide-crown-ether complexes, and their CID-MS3 dissociations were found to be dramatically different from those upon ETD of the respective peptide dications. All of the hydrogen-rich peptide cation radicals contained major (77%-94%) fractions of species having radical chromophores created by ETD that underwent photodissociation at 355 nm. Analysis of the CID and UVPD spectra pointed to arginine guanidinium radicals as the major components of the hydrogen-rich peptide cation radical population. Hydrogen-deficient peptide cation radicals were generated by intramolecular electron transfer in CuII(2,2 ':6 ',2 ″-terpyridine) complexes and shown to contain chromophores absorbing at 355 nm and undergoing photodissociation. The CID and UVPD spectra showed major differences in fragmentation for [AAAYR]+● that diminished as the Tyr residue was moved along the peptide chain. UVPD was found to be superior to CID in localizing Cα-radical positions in peptide cation radical intermediates.

Two luminescent d10 metal coordination polymers assembled from a semirigid terpyridyl carboxylate ligand with high selective detecting of Cu2+, Cr2O72- and acetone

NASA Astrophysics Data System (ADS)

Yuan, Fei; Wang, Ting-Ting; Hu, Huai-Ming; Li, Chuan-Ti; Zhou, Chun-Sheng; Wang, Xiaofang; Xue, Ganglin

2017-07-01

Using a carboxylic oligopyridine ligand, 4‧-(4-carboxyphenyl)-4,2‧:6‧,4″- terpyridine (Hcptpy), and imidazole-4,5-dicarboxylic acid (H3idc), two metal(II)-cptpy compounds formulated as [Zn2(cptpy)4]n·nH2O (1), [Zn2(cptpy)2(Hidc)(H2O)2]n·nH2O (2) have been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. Compound 1 shows a 2D +2D →3D supramolecular framework structure generated by two-fold interpenetrating 3-connected 2D framework (2D+2D→2D) with the sql topological net and the Schläfli symbol of {44·62}. Compound 2 displays a 1D ladder chain structure. The luminescent properties of 1 and the ones immersed in various kinds of organic compounds and nitrate@DMF solutions have been investigated. Importantly, 1 shows highly selective and sensitive response to acetone and Cu2+ through luminescence quenching effects, making it a promising luminescent sensor for acetone molecule and Cu2+. Meaningwhile, compound 2 shows highly selective sensitivity for Cr2O72-.

Surface Grafting of Ru(II) Diazonium-Based Sensitizers on Metal Oxides Enhances Alkaline Stability for Solar Energy Conversion.

PubMed

Bangle, Rachel; Sampaio, Renato N; Troian-Gautier, Ludovic; Meyer, Gerald J

2018-01-24

The electrografting of [Ru(ttt)(tpy-C 6 H 4 -N 2 + )] 3+ , where "ttt" is 4,4',4″-tri-tert-butyl-2,2':6',2″-terpyridine, was investigated on several wide band gap metal oxide surfaces (TiO 2 , SnO 2 , ZrO 2 , ZnO, In 2 O 3 :Sn) and compared to structurally analogous sensitizers that differed only by the anchoring group, i.e., -PO 3 H 2 and -COOH. An optimized procedure for diazonium electrografting to semiconductor metal oxides is presented that allowed surface coverages that ranged between 4.7 × 10 -8 and 10.6 × 10 -8 mol cm -2 depending on the nature of the metal oxide. FTIR analysis showed the disappearance of the diazonium stretch at 2266 cm -1 after electrografting. XPS analysis revealed a characteristic peak of Ru 3d at 285 eV as well as a peak at 531.6 eV that was attributed to O 1s in Ti-O-C bonds. Photocurrents were measured to assess electron injection efficiency of these modified surfaces. The electrografted sensitizers exhibited excellent stability across a range of pHs spanning from 1 to 14, where classical binding groups such as carboxylic and phosphonic derivatives were hydrolyzed.

Two Discrete RuCp* (Cp*=Pentamethylcyclopentadienyl) Binding Modes of N-Confused Porphyrins: Peripheral π Complex and Sitting Atop Ruthenocenophane Complex by Skeletal Transformation.

PubMed

Yamamoto, Takaaki; Mitsuno, Koki; Mori, Shigeki; Itoyama, Shuhei; Shiota, Yoshihito; Yoshizawa, Kazunari; Ishida, Masatoshi; Furuta, Hiroyuki

2018-05-07

Complexation of a RuCp* cation with N-confused tetraarylporphyrins (NCPs) forms directly bound ruthenium(II) pentamethylcyclopentadienyl (Cp*) π-complex on a specific meso-aryl group (e.g., phenyl) neighboring peripheral imino nitrogen of NCPs in high yields. In contrast, in the case of NCPs bearing bulky meso-substituents (e.g., 3,5-di-tert-butylphenyl), new ruthenocenophane-like complex embedded on an N-confused calix[4]phyrin was formed through multiple C-H bond activation of methyl groups of Cp* ligand. The mechanistic insight into the formation of the ruthenocenophane was derived from DFT calculations. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Enantioselective photochemistry via Lewis acid catalyzed triplet energy transfer

PubMed Central

Blum, Travis R.; Miller, Zachary D.; Bates, Desiree M.; Guzei, Ilia A.; Yoon, Tehshik P.

2017-01-01

Relatively few catalytic systems are able to control the stereochemistry of electronically excited organic intermediates. Here we report the discovery that a chiral Lewis acid complex can catalyze triplet energy transfer from an electronically excited photosensitizer. This strategy is applied to asymmetric [2+2] photocycloadditions of 2′-hydroxychalcones using tris(bipyridyl) ruthenium(II) as a sensitizer. A variety of electrochemical, computational, and spectroscopic data rule out substrate activation via photoinduced electron transfer and instead support a mechanism in which Lewis acid coordination dramatically lowers the triplet energy of the chalcone substrate. We expect that this approach will enable chemists to more broadly apply their detailed understanding of chiral Lewis acid catalysis to stereocontrol in reactions of electronically excited states. PMID:27980203

A TDDFT study of the ruthenium(II) polyazaaromatic complex [Ru(dppz)(phen) 2] 2+ in solution

NASA Astrophysics Data System (ADS)

Fantacci, Simona; De Angelis, Filippo; Sgamellotti, Antonio; Re, Nazzareno

2004-09-01

DFT/TDDFT calculations were performed to investigate the structural, electronic and optical properties of the [Ru(dppz)(phen) 2] 2+ complex in solution. TDDFT calculations in water show two groups of metal-to-ligand charge transfer (MLCT) transitions at ≈450 and 415 nm whose superposition gives account of the broad absorption band experimentally characterized at 440 nm. Also, a group of almost coincident MLCT transitions partially mixed with dppz intraligand π-π ∗ transitions centered at ≈380 nm is found to give rise to the narrow absorption band experimentally found at 380 nm. Our results provide insight into the hypochromic shifts experimentally characterized upon intercalation of the title complex into DNA.

Geochemical constraints on sustainable development: Can an advanced global economy achieve long-term stability?

NASA Astrophysics Data System (ADS)

Pickard, William F.

2008-04-01

The eighty-one stable chemical elements are examined individually with respect to (i) recent annual demand and (ii) worst case long-term availability in a distant future in which they must be extracted from the background sources of air, seawater, and ordinary rock. It is shown that, if a conventional use scenario is envisioned, the supplies of ruthenium, rhodium, palladium, tellurium, rhenium, osmium, iridium, platinum, gold, and especially phosphorus will be questionable while the supplies of copper, zinc, molybdenum, silver, cadmium, tin, antimony, tungsten, mercury, lead, and bismuth will be inadequate. It is therefore concluded that, in the long run, only the promotion of massive recycling and substitution technologies will suffice to maintain the global industrial society now developing.

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

Hartwig, J.F.

The products and mechanisms of the thermal reactions of several complexes of the general structure (PMe{sub 3}){sub 4}Ru(X)(Y) and (DMPM){sub 2}Ru(X)(Y) where X and Y are hydride, aryl, and benzyl groups, have been investigated. The mechanism of decomposition depends critically on the structure of the complex and the medium in which the thermolysis is carried out. The alkyl hydride complexes are do not react with alkane solvent, but undergo C-H activation processes with aromatic solvents by several different mechanisms. Thermolysis of (PMe{sub 3}){sub 4}Ru(Ph)(Me) or (PMe{sub 3}){sub 4}Ru(Ph){sub 2} leads to the ruthenium benzyne complex (PMe{sub 3}){sub 4}Ru({eta}{sup 2}-C{sub 6}H{submore » 4}) (1) by a mechanism which involves reversible dissociation of phosphine. In many ways its chemistry is analogous to that of early rather than late organo transition metal complexes. The synthesis, structure, variable temperature NMR spectroscopy and reactivity of ruthenium complexes containing aryloxide or arylamide ligands are reported. These complexes undergo cleavage of a P-C bond in coordinated trimethylphosphine, insertion of CO and CO{sub 2} and hydrogenolysis. Mechanistic studies on these reactions are described. The generation of a series of reactive ruthenium complexes of the general formula (PMe{sub 3}){sub 4}Ru(R)(enolate) is reported. Most of these enolates have been shown to bind to the ruthenium center through the oxygen atom. Two of the enolate complexes 8 and 9 exist in equilibrium between the O- and C-bound forms. The reactions of these compounds are reported, including reactions to form oxygen-containing metallacycles. The structure and reactivity of these ruthenium metallacycles is reported, including their thermal chemistry and reactivity toward protic acids, electrophiles, carbon monoxide, hydrogen and trimethylsilane. 243 refs., 10 tabs.« less

In vitro and in vivo antiproliferative and trypanocidal activities of ruthenium NO donors

PubMed Central

Silva, J J N; Osakabe, A L; Pavanelli, W R; Silva, J S; Franco, D W

2007-01-01

Background and purpose: Many compounds liberating NO (NO donors) have been used as therapeutic agents. Here we test two ruthenium nitrosyls, which release NO when activated by biological reducing agents, for their effects in vitro and in vivo against Trypanasoma cruzi, the agent responsible for the American trypanosomiasis (Chagas' disease). Experimental approach: Ruthenium NO donors were incubated with a partially drug-resistant strain of T. cruzi and the anti-proliferative and trypanocidal activities evaluated. In a mouse model of acute Chagas' disease, trypanocidal activity was evaluated by measuring parasitemia, survival rate of infected mice and elimination of amastigotes in myocardial tissue. Key results: In vitro, the observed anti-proliferative and trypanocidal activities of trans-[Ru(NO)(NH3)4isn](BF4)3 and trans-[Ru(NO)(NH3)4imN](BF4)3 were due to NO liberated upon reduction of these nitrosyls. Ru(NO)isn had a lower IC50epi (67 μM) than the NO donor, sodium nitroprusside (IC50epi=244 μM) and Ru(NO)imN (IC50try=52 μM) was more potent than gentian violet (IC50try=536 μM), currently used in the treatment of blood. Both ruthenium nitrosyls eliminated, in vivo, extracellular as well as intracellular forms of T. cruzi in the bloodstream and myocardial tissue and allowed survival of up to 80% of infected mice at a dose (100 nmol kg−1 day−1) much lower than the optimal dose for benznidazole (385 μmol kg−1 day−1). Conclusions and implications: Our data strongly suggest that NO liberated is responsible for the anti-proliferative and trypanocidal activities of the ruthenium NO donors and that these compounds are promising leads for novel and effective anti-parasitic drugs. PMID:17603548

Layer-by-layer grown scalable redox-active ruthenium-based molecular multilayer thin films for electrochemical applications and beyond.

PubMed

Kaliginedi, Veerabhadrarao; Ozawa, Hiroaki; Kuzume, Akiyoshi; Maharajan, Sivarajakumar; Pobelov, Ilya V; Kwon, Nam Hee; Mohos, Miklos; Broekmann, Peter; Fromm, Katharina M; Haga, Masa-aki; Wandlowski, Thomas

2015-11-14

Here we report the first study on the electrochemical energy storage application of a surface-immobilized ruthenium complex multilayer thin film with anion storage capability. We employed a novel dinuclear ruthenium complex with tetrapodal anchoring groups to build well-ordered redox-active multilayer coatings on an indium tin oxide (ITO) surface using a layer-by-layer self-assembly process. Cyclic voltammetry (CV), UV-Visible (UV-Vis) and Raman spectroscopy showed a linear increase of peak current, absorbance and Raman intensities, respectively with the number of layers. These results indicate the formation of well-ordered multilayers of the ruthenium complex on ITO, which is further supported by the X-ray photoelectron spectroscopy analysis. The thickness of the layers can be controlled with nanometer precision. In particular, the thickest layer studied (65 molecular layers and approx. 120 nm thick) demonstrated fast electrochemical oxidation/reduction, indicating a very low attenuation of the charge transfer within the multilayer. In situ-UV-Vis and resonance Raman spectroscopy results demonstrated the reversible electrochromic/redox behavior of the ruthenium complex multilayered films on ITO with respect to the electrode potential, which is an ideal prerequisite for e.g. smart electrochemical energy storage applications. Galvanostatic charge-discharge experiments demonstrated a pseudocapacitor behavior of the multilayer film with a good specific capacitance of 92.2 F g(-1) at a current density of 10 μA cm(-2) and an excellent cycling stability. As demonstrated in our prototypical experiments, the fine control of physicochemical properties at nanometer scale, relatively good stability of layers under ambient conditions makes the multilayer coatings of this type an excellent material for e.g. electrochemical energy storage, as interlayers in inverted bulk heterojunction solar cell applications and as functional components in molecular electronics applications.

Thermodynamic assessment of the rhodium-ruthenium-oxygen (Rh-Ru-O) system

NASA Astrophysics Data System (ADS)

Gossé, S.; Bordier, S.; Guéneau, C.; Brackx, E.; Domenger, R.; Rogez, J.

2018-03-01

Ruthenium (Ru) and rhodium (Rh) are abundant platinum-group metals formed during burn-up of nuclear fuels. Under normal operating conditions, Rh and Ru accumulate and predominantly form metallic precipitates with other fission products like Mo, Pd and Tc. In the framework of vitrification of high-level nuclear waste, these fission products are poorly soluble in molten glasses. They precipitate as metallic particles and oxide phases. Moreover, these Ru and Rh rich phases strongly depend on temperature and the oxygen fugacity of the glass melt. In case of severe accidental conditions with air ingress, oxidation of the Ru and Rh is possible. At low temperatures (T < 1422 K for rhodium sesquioxide and T < 1815 K for ruthenium dioxide), the formed oxides are relatively stable. On the other hand, at high temperatures (T > 1422 K for rhodium sesquioxide and T > 1815 K for ruthenium dioxide), they may decompose into (Rh)-FCC or (Ru)-HCP metallic phases and radiotoxic volatile gaseous species. A thermodynamic assessment of the Rh-Ru-O system will enable the prediction of: (1) the metallic and oxide phases that form during the vitrification of high-level nuclear wastes and (2) the release of volatile gaseous species during a severe accident. The Calphad method developed herein employs a thermodynamic approach in the investigation of the thermochemistry of rhodium and ruthenium at high temperatures. Current literature on the thermodynamic properties and phase diagram data enables preliminary thermodynamic assessments of the Rh-O and Ru-O systems. Additionally, select compositions in the ternary Rh-Ru-O system underwent experimental tests to complement data found in literature and to establish the phase equilibria in the ternary system.

Ruthenium complex Λ-WH0402 induces hepatocellular carcinoma LM6 (HCCLM6) cell death by triggering the Beclin-1-dependent autophagy pathway.

PubMed

Yuan, Jian; Lei, Zhinian; Wang, Xi; Zhu, Feng; Chen, Dongbo

2015-05-01

To evaluate the anticancer mechanism of the new ruthenium complex-Λ-WH0402 at the cellular level, the in vitro cytotoxicity of Λ-WH0402 was investigated on 10 human tumor cell lines. Λ-WH0402 was found to have higher anticancer activity than cisplatin toward human liver cancer HCCLM6 cells that have high tumor metastatic characteristics. Meanwhile, Λ-WH0402 showed an antimetastatic effect on HCCLM6 cells in vitro, mostly through its effect on cell adhesion, invasion and migration. In addition, Λ-WH0402 significantly reduced tumor metastasis to the lungs in orthotopic mouse hepatocellular cancer (HCC) models induced by HCCLM6 cells. Furthermore, Λ-WH0402 exerted an inhibitory effect on tumor cell growth and proliferation and induced dose-dependent cell cycle arrest in the S phase in HCCLM6 cells. Immunoblotting analysis showed that Λ-WH0402 not only decreased the expression of antiapoptotic protein Bcl-2 and nutrient-deprivation autophagy factor-1 (NAF-1), but also significantly increased the expression of Beclin-1 in HCCLM6 cells. More importantly, we identified that Λ-WH0402 treatment reduced the interaction between Bcl-2 and Beclin-1, and increased the expression of autophagic activation marker LC3B-II in HCCLM6 cells. On the whole, our results suggested that the anitcancer activity of Λ-WH0402 is mediated through promoting the Beclin-1-dependent autophagy pathway in HCCLM6 cells.

Tertiary to secondary reduction of aminomethylphosphane derived from 1-ethylpiperazine as a result of its coordination to ruthenium(II) centre - The first insight into the nature of process

NASA Astrophysics Data System (ADS)

Płotek, Michał; Starosta, Radosław; Komarnicka, Urszula K.; Skórska-Stania, Agnieszka; Kołoczek, Przemysław; Dudek, Karol; Kyzioł, Agnieszka

2016-10-01

Introduction of tertiary aminomethylphosphane P{CH2N(CH2CH2)2NCH2CH3}3 (B; tris{1-[4-ethyl(tetrahydro-1,4-diazino)]methyl}phosphane) to methanolic solution of [Ru(η5-C5H5)Cl(PPh3)2] (1) and NaBF4, instead of straightforward substitution of the chloride leads to concomitant cleavage of aminomethylphosphane's Psbnd CH2 bond. The obtained complex [Ru(η5-C5H5)PH{CH2N(CH2CH2)2NCH2CH3}2(PPh3)2]BF4 (2B‧) was fully characterized by spectroscopic methods ((NMR, IR, ESI-MS) and its solid state structure was determined with single crystal X-ray diffraction method. It was proven that the structure of 2B‧ is similar to the previously synthesized morpholine counterpart [Ru(η5-C5H5)PH{CH2N(CH2CH2)2O}2(PPh3)2]BF4 (2A‧). DFT calculations (B3LYP with the D95V(d,p) basis set for C, N, H and O and LanL2DZ with Los Alamos ECPs for Ru, P and Cl) revealed that the binding of aminomethylphosphanes to the ruthenium centre leads to the Psbnd C bonds elongation, which may finally result in breaking one of them and phosphane's reduction from tertiary to secondary ones.

In Situ FTIR and NMR Spectroscopic Investigations on Ruthenium-Based Catalysts for Alkene Hydroformylation.

PubMed

Kubis, Christoph; Profir, Irina; Fleischer, Ivana; Baumann, Wolfgang; Selent, Detlef; Fischer, Christine; Spannenberg, Anke; Ludwig, Ralf; Hess, Dieter; Franke, Robert; Börner, Armin

2016-02-18

Homogeneous ruthenium complexes modified by imidazole-substituted monophosphines as catalysts for various highly efficient hydroformylation reactions were characterized by in situ IR spectroscopy under reaction conditions and NMR spectroscopy. A proper protocol for the preformation reaction from [Ru3 (CO)12] is decisive to prevent the formation of inactive ligand-modified polynuclear complexes. During catalysis, ligand-modified mononuclear ruthenium(0) carbonyls were detected as resting states. Changes in the ligand structure have a crucial impact on the coordination behavior of the ligand and consequently on the catalytic performance. The substitution of CO by a nitrogen atom of the imidazolyl moiety in the ligand is not a general feature, but it takes place when structural prerequisites of the ligand are fulfilled. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Carbene based photochemical molecular assemblies for solar driven hydrogen generation.

PubMed

Peuntinger, Katrin; Pilz, T David; Staehle, Robert; Schaub, Markus; Kaufhold, Simon; Petermann, Lydia; Wunderlin, Markus; Görls, Helmar; Heinemann, Frank W; Li, Jing; Drewello, Thomas; Vos, Johannes G; Guldi, Dirk M; Rau, Sven

2014-09-28

Novel photocatalysts based on ruthenium complexes with NHC (N-heterocyclic carbene)-type bridging ligands have been prepared and structurally and photophysically characterised. The identity of the NHC-unit of the bridging ligand was established unambiguously by means of X-ray structural analysis of a heterodinuclear ruthenium-silver complex. The photophysical data indicate ultrafast intersystem crossing into an emissive and a non-emissive triplet excited state after excitation of the ruthenium centre. Exceptionally high luminescence quantum yields of up to 39% and long lifetimes of up to 2 μs are some of the triplet excited state characteristics. Preliminary studies into the visible light driven photocatalytic hydrogen formation show no induction phase and constant turnover frequencies that are independent on the concentration of the photocatalyst. In conclusion this supports the notion of a stable assembly under photocatalytic conditions.

Nobel Chemistry in the Laboratory: Synthesis of a Ruthenium Catalyst for Ring-Closing Olefin Metathesis--An Experiment for the Advanced Inorganic or Organic Laboratory

ERIC Educational Resources Information Center

Greco, George E.

2007-01-01

An experiment for the upper-level undergraduate laboratory is described in which students synthesize a ruthenium olefin metathesis catalyst, then use the catalyst to carry out the ring-closing metathesis of diethyl diallylmalonate. The olefin metathesis reaction was the subject of the 2005 Nobel Prize in chemistry. The catalyst chosen for this…

COMPLEX RUTHENIUM ACIDO-NITROS COMPOUNDS (in Russian)

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

Zvyagintsev, O.E.; Starostin, S.M.

1961-06-01

The chemical nature of the water in the complex ruthenium acidonitroso compounds is studied by measuring certain acid properties, reactions, and behaviors of the compounds in aqueous solution. The dependence of molecular electrical conductivity on time and dilution, variations of specific electroconductivity, the optical density, and the light absorption of the compounds at 200 to 800 m mu wave range were investigated and the dissociation constants were calculated. (R.V.J.)

Nanoparticle-supported and magnetically recoverable ruthenium hydroxide catalyst: efficient hydration of nitriles to amides in aqueous medium.

PubMed

Polshettiwar, Vivek; Varma, Rajender S

2009-01-01

Magnetic attraction not filtration: A magnetic nanoparticle-supported ruthenium hydroxide catalyst (see figure) was readily prepared from inexpensive starting materials and shown to catalyze the hydration of nitriles with excellent yield in a benign aqueous medium. Catalyst recovery using an external magnetic field, superior activity, and the inherent stability of the catalyst system are additional sustainable attributes of this protocol.

Synthesis, Structure and Antitumour Properties of a New 1,2-Propylenediaminetetraacetate-Ruthenium(III) Compound

PubMed Central

Vilaplana, R.; Romero, M. A.; Quirós, M.; Salas, J. M.

1995-01-01

A novel complex formed by ruthenium (III) and the sequestering ligand 1,2-propylenediaminetetraacetic acid (PDTA) has been synthetized and characterized. The structure of the monomeric compound, studied by X-ray diffraction , shows an almost symmetric octahedral geometry around the metal ion, with two chlorine atoms in a cis conformation. The antitumour activity against a variety of murine and human cancers is reported. PMID:18472768

Thiolate-bridged dinuclear ruthenium and iron complexes as robust and efficient catalysts toward oxidation of molecular dihydrogen in protic solvents.

PubMed

Yuki, Masahiro; Sakata, Ken; Hirao, Yoshifumi; Nonoyama, Nobuaki; Nakajima, Kazunari; Nishibayashi, Yoshiaki

2015-04-01

Thiolate-bridged dinuclear ruthenium and iron complexes are found to work as efficient catalysts toward oxidation of molecular dihydrogen in protic solvents such as water and methanol under ambient reaction conditions. Heterolytic cleavage of the coordinated molecular dihydrogen at the dinuclear complexes and the sequential oxidation of the produced hydride complexes are involved as key steps to promote the present catalytic reaction. The catalytic activity of the dinuclear complexes toward the chemical oxidation of molecular dihydrogen achieves up to 10000 TON (turnover number), and electrooxidation of molecular dihydrogen proceeds quite rapidly. The result of the density functional theory (DFT) calculation on the reaction pathway indicates that a synergistic effect between the two ruthenium atoms plays an important role to realize the catalytic oxidation of molecular dihydrogen efficiently. The present dinuclear ruthenium complex is found to work as an efficient organometallic anode catalyst for the fuel cell. It is noteworthy that the present dinuclear complex worked not only as an effective catalyst toward chemical and electrochemical oxidation of molecular dihydrogen but also as a good anode catalyst for the fuel cell. We consider that the result described in this paper provides useful and valuable information to develop highly efficient and low-cost transition metal complexes as anode catalysts in the fuel cell.

Chromium and Ruthenium-Doped Zinc Oxide Thin Films for Propane Sensing Applications

PubMed Central

Gómez-Pozos, Heberto; González-Vidal, José Luis; Torres, Gonzalo Alberto; Rodríguez-Baez, Jorge; Maldonado, Arturo; de la Luz Olvera, María; Acosta, Dwight Roberto; Avendaño-Alejo, Maximino; Castañeda, Luis

2013-01-01

Chromium and ruthenium-doped zinc oxide (ZnO:Cr) and (ZnO:Ru) thin solid films were deposited on soda-lime glass substrates by the sol-gel dip-coating method. A 0.6 M solution of zinc acetate dihydrate dissolved in 2-methoxyethanol and monoethanolamine was used as basic solution. Chromium (III) acetylacetonate and Ruthenium (III) trichloride were used as doping sources. The Ru incorporation and its distribution profile into the films were proved by the SIMS technique. The morphology and structure of the films were studied by SEM microscopy and X-ray diffraction measurements, respectively. The SEM images show porous surfaces covered by small grains with different grain size, depending on the doping element, and the immersions number into the doping solutions. The sensing properties of ZnO:Cr and ZnO:Ru films in a propane (C3H8) atmosphere, as a function of the immersions number in the doping solution, have been studied in the present work. The highest sensitivity values were obtained for films doped from five immersions, 5.8 and 900, for ZnO:Cr and ZnO:Ru films, respectively. In order to evidence the catalytic effect of the chromium (Cr) and ruthenium (Ru), the sensing characteristics of undoped ZnO films are reported as well. PMID:23482091

Iodine/iodide-free dye-sensitized solar cells.

PubMed

Yanagida, Shozo; Yu, Youhai; Manseki, Kazuhiro

2009-11-17

Dye-sensitized solar cells (DSSCs) are built from nanocrystalline anatase TiO(2) with a 101 crystal face (nc-TiO(2)) onto which a dye is absorbed, ruthenium complex sensitizers, fluid I(-)/I(3)(-) redox couples with electrolytes, and a Pt-coated counter electrode. DSSCs have now reached efficiencies as high as 11%, and G24 Innovation (Cardiff, U.K.) is currently manufacturing them for commercial use. These devices offer several distinct advantages. On the basis of the electron lifetime and diffusion coefficient in the nc-TiO(2) layer, DSSCs maintain a diffusion length on the order of several micrometers when the dyed-nc-TiO(2) porous layer is covered by redox electrolytes of lithium and/or imidazolium iodide and their polyiodide salts. The fluid iodide/iodine (I(-)/I(3)(-)) redox electrolytes can infiltrate deep inside the intertwined nc-TiO(2) layers, promoting the mobility of the nc-TiO(2) layers and serving as a hole-transport material of DSSCs. As a result, these materials eventually give a respectable photovoltaic performance. On the other hand, fluid I(-)/I(3)(-) redox shuttles have certain disadvantages: reduced performance control and long-term stability and incompatibility with some metallic component materials. The I(-)/I(3)(-) redox shuttle shows a significant loss in short circuit current density and a slight loss in open circuit voltage, particularly in highly viscous electrolyte-based DSSC systems. Iodine can also act as an oxidizing agent, corroding metals, such as the grid metal Ag and the Pt mediator on the cathode, especially in the presence of water and oxygen. In addition, the electrolytes (I(-)/I(3)(-)) can absorb visible light (lambda = approximately 430 nm), leading to photocurrent loss in the DSSC. Therefore, the introduction of iodide/iodine-free electrolytes or hole-transport materials (HTMs) could lead to cost-effective alternatives to TiO(2) DSSCs. In this Account, we discuss the iodide/iodine-free redox couple as a substitute for the fluid I(-)/I(3)(-) redox shuttle. We also review the adaptation of solid-state HTMs to the iodide/iodine-free solid-state DSSCs with an emphasis on their pore filling and charge mobility in devices and the relationship of those values to the performance of the resulting iodide/iodine-free DSSCs. We demonstrate how the structures of the sensitizing dye molecules and additives of lithium or imidazolium salts influence device performance. In addition, the self-organizing molecular interaction for electronic contact of HTMs to dye molecules plays an important role in unidirectional charge diffusion at interfaces. The poly(3,4-ethylenedioxythiophene) (PEDOT)-based DSSCs, which we obtain through photoelectrochemical polymerization (PEP) using 3-alkylthiophen-bearing ruthenium dye, HRS-1, and bis-EDOT, demonstrates the importance of nonbonding interface contact (e.g., pi-pi-stacking) for the successful inclusion of HTMs.

Synthesis and Biological Evaluation of Ru(II) and Pt(II) Complexes Bearing Carboxyl Groups as Potential Anticancer Targeted Drugs.

PubMed

Martínez, Ma Ángeles; Carranza, M Pilar; Massaguer, Anna; Santos, Lucia; Organero, Juan A; Aliende, Cristina; de Llorens, Rafael; Ng-Choi, Iteng; Feliu, Lidia; Planas, Marta; Rodríguez, Ana M; Manzano, Blanca R; Espino, Gustavo; Jalón, Félix A

2017-11-20

The synthesis and characterization of Pt(II) (1 and 2) and Ru(II) arene (3 and 4) or polypyridine (5 and 6) complexes is described. With the aim of having a functional group to form bioconjugates, one uncoordinated carboxyl group has been introduced in all complexes. Some of the complexes were selected for their potential in photodynamic therapy (PDT). The molecular structures of complexes 2 and 5, as well as that of the sodium salt of the 4'-(4-carboxyphenyl)-2,2':6',2″-terpyridine ligand (cptpy), were determined by X-ray diffraction. Different techniques were used to evaluate the binding capacity to model DNA molecules, and MTT cytotoxicity assays were performed against four cell lines. Compounds 3, 4, and 5 showed little tendency to bind to DNA and exhibited poor biological activity. Compound 2 behaves as bonded to DNA probably through a covalent interaction, although its cytotoxicity was very low. Compound 1 and possibly 6, both of which contain a cptpy ligand, were able to intercalate with DNA, but toxicity was not observed for 6. However, compound 1 was active in all cell lines tested. Clonogenic assays and apoptosis induction studies were also performed on the PC-3 line for 1. The photodynamic behavior for complexes 1, 5, and 6 indicated that their nuclease activity was enhanced after irradiation at λ = 447 nm. The cell viability was significantly reduced only in the case of 5. The different behavior in the absence or presence of light makes complex 5 a potential prodrug of interest in PDT. Molecular docking studies followed by molecular dynamics simulations for 1 and the counterpart without the carboxyl group confirmed the experimental data that pointed to an intercalation mechanism. The cytotoxicity of 1 and the potential of 5 in PDT make them good candidates for subsequent conjugation, through the carboxyl group, to "selected peptides" which could facilitate the selective vectorization of the complex toward receptors that are overexpressed in neoplastic cell lines.

An electronic rationale for observed initiation rates in ruthenium-mediated olefin metathesis: charge donation in phosphine and N-heterocyclic carbene ligands.

PubMed

Getty, Kendra; Delgado-Jaime, Mario Ulises; Kennepohl, Pierre

2007-12-26

Ru K-edge XAS data indicate that second generation ruthenium-based olefin metathesis precatalysts (L = N-heterocyclic carbene) possess a more electron-deficient metal center than in the corresponding first generation species (L = tricyclohexylphosphine). This surprising effect is also observed from DFT calculations and provides a simple rationale for the slow phosphine dissociation kinetics previously noted for second-generation metathesis precatalysts.

Plasma-Assisted Synthesis of Monodispersed and Robust Ruthenium Ultrafine Nanocatalysts for Organosilane Oxidation and Oxygen Evolution Reactions.

PubMed

Gnanakumar, Edwin S; Ng, Wesley; Coşkuner Filiz, Bilge; Rothenberg, Gadi; Wang, Sheng; Xu, Hualong; Pastor-Pérez, Laura; Pastor-Blas, M Mercedes; Sepúlveda-Escribano, Antonio; Yan, Ning; Shiju, N Raveendran

2017-11-23

We report a facile and general approach for preparing ultrafine ruthenium nanocatalysts by using a plasma-assisted synthesis at <100 °C. The resulting Ru nanoparticles are monodispersed (typical size 2 nm) and remain that way upon loading onto carbon and TiO 2 supports. This gives robust catalysts with excellent activities in both organosilane oxidation and the oxygen evolution reaction.

Alkyne–Aldehyde Reductive C–C Coupling through Ruthenium-Catalyzed Transfer Hydrogenation: Direct Regio- and Stereoselective Carbonyl Vinylation to Form Trisubstituted Allylic Alcohols in the Absence of Premetallated Reagents

PubMed Central

Leung, Joyce C.; Patman, Ryan L.; Sam, Brannon

2011-01-01

Nonsymmetric 1,2-disubstituted alkynes engage in reductive coupling to a variety of aldehydes under the conditions of ruthenium-catalyzed transfer hydrogenation by employing formic acid as the terminal reductant and delivering the products of carbonyl vinylation with good to excellent levels of regioselectivity and with complete control of olefin stereochemistry. As revealed in an assessment of the ruthenium counterion, iodide plays an essential role in directing the regioselectivity of C–C bond formation. Isotopic labeling studies corroborate reversible catalytic propargyl C–H oxidative addition in advance of the C–C coupling, and demonstrate that the C–C coupling products do not experience reversible dehydrogenation by way of enone intermediates. This transfer hydrogenation protocol enables carbonyl vinylation in the absence of stoichiometric metallic reagents. PMID:21953608

Atomic layer deposition of ruthenium on plasma-treated vertically aligned carbon nanotubes for high-performance ultracapacitors.

PubMed

Kim, Jun Woo; Kim, Byungwoo; Park, Suk Won; Kim, Woong; Shim, Joon Hyung

2014-10-31

It is challenging to realize a conformal metal coating by atomic layer deposition (ALD) because of the high surface energy of metals. In this study, ALD of ruthenium (Ru) on vertically aligned carbon nanotubes (CNTs) was carried out. To activate the surface of CNTs that lack surface functional groups essential for ALD, oxygen plasma was applied ex situ before ALD. X-ray photoelectron spectroscopy and Raman spectroscopy confirmed surface activation of CNTs by the plasma pretreatment. Transmission electron microscopy analysis with energy-dispersive x-ray spectroscopy composition mapping showed that ALD Ru grew conformally along CNTs walls. ALD Ru/CNTs were electrochemically oxidized to ruthenium oxide (RuOx) that can be a potentially useful candidate for use in the electrodes of ultracapacitors. Electrode performance of RuOx/CNTs was evaluated using cyclic voltammetry and galvanostatic charge-discharge measurements.

Probing C-O bond activation on gas-phase transition metal clusters: Infrared multiple photon dissociation spectroscopy of Fe, Ru, Re, and W cluster CO complexes

NASA Astrophysics Data System (ADS)

Lyon, Jonathan T.; Gruene, Philipp; Fielicke, André; Meijer, Gerard; Rayner, David M.

2009-11-01

The binding of carbon monoxide to iron, ruthenium, rhenium, and tungsten clusters is studied by means of infrared multiple photon dissociation spectroscopy. The CO stretching mode is used to probe the interaction of the CO molecule with the metal clusters and thereby the activation of the C-O bond. CO is found to adsorb molecularly to atop positions on iron clusters. On ruthenium and rhenium clusters it also binds molecularly. In the case of ruthenium, binding is predominantly to atop sites, however higher coordinated CO binding is also observed for both metals and becomes prevalent for rhenium clusters containing more than nine atoms. Tungsten clusters exhibit a clear size dependence for molecular versus dissociative CO binding. This behavior denotes the crossover to the purely dissociative CO binding on the earlier transition metals such as tantalum.

Coordination behavior of ligand based on NNS and NNO donors with ruthenium(III) complexes and their catalytic and DNA interaction studies

NASA Astrophysics Data System (ADS)

Manikandan, R.; Viswnathamurthi, P.

2012-11-01

Reactions of 2-acetylpyridine-thiosemicarbazone HL1, 2-acetylpyridine-4-methyl-thiosemicarbazone HL2, 2-acetylpyridine-4-phenyl-thiosemicarbazone HL3 and 2-acetylpyridine-semicarbazone HL4 with ruthenium(III) precursor complexes were studied and the products were characterized by analytical and spectral (FT-IR, electronic, EPR and EI-MS) methods. The ligands coordinated with the ruthenium(III) ion via pyridine nitrogen, azomethine nitrogen and thiolate sulfur/enolate oxygen. An octahedral geometry has been proposed for all the complexes based on the studies. All the complexes are redox active and display an irreversible and quasireversible metal centered redox processes. Further, the catalytic activity of the new complexes has been investigated for the transfer hydrogenation of ketones in the presence of isopropanol/KOH and the Kumada-Corriu coupling of aryl halides with aryl Grignard reagents. The DNA cleavage efficiency of new complexes has also been tested.

4d Electronic structure analysis of ruthenium in the perovskite oxides by Ru K- and L-edge XAS.

PubMed

Kim, J Y; Hwang, S H; Kim, S J; Demazeau, G; Choy, J H; Shimada, H

2001-03-01

The 4d electronic structure of ruthenium in the perovskite oxides, La2MRuIVO6 (M = Zn, Mg, and Li) and Ba2YRuVO6, has been investigated by the Ru K-and L-edge XANES and EXAFS analyses. Such X-ray absorption spectroscopic results clarify that the RuIV (d4) and RuV (d3) ions are stabilized in nearly regular Oh site. Comparing the Ru L-edge XANES spectra of perovskites containing isovalent ruthenium, it has been found that the t2g state is mainly influenced by A site cation, whereas the eg is mainly affected by neighboring B site cation. The experimental EXAFS spectra in the range of R < or = approximately 4.5 A are well reproduced by ab-initio calculation based on crystallographic data, which supports the long-range structure presented by Rietveld refinement.

Determination of ruthenium in pharmaceutical compounds by graphite furnace atomic absorption spectroscopy.

PubMed

Jia, Xiujuan; Wang, Tiebang; Bu, Xiaodong; Tu, Qiang; Spencer, Sandra

2006-04-11

A graphite furnace atomic absorption (GFAA) spectrometric method for the determination of ruthenium (Rh) in solid and liquid pharmaceutical compounds has been developed. Samples are dissolved or diluted in dimethyl sulfoxide (DMSO) without any other treatment before they were analyzed by GFAA with a carefully designed heating program to avoid pre-atomization signal loss and to achieve suitable sensitivity. Various inorganic and organic solvents were tested and compared and DMSO was found to be the most suitable. In addition, ruthenium was found to be stable in DMSO for at least 5 days. Spike recoveries ranged from 81 to 100% and the limit of quantitation (LOQ) was determined to be 0.5 microg g(-1) for solid samples or 0.005 microg ml(-1) for liquid samples based a 100-fold dilution. The same set of samples was also analyzed by ICP-MS with a different sample preparation method, and excellent agreement was achieved.

From a Decomposition Product to an Efficient and Versatile Catalyst: The [Ru(η5-indenyl)(PPh3)2Cl] Story

PubMed Central

2014-01-01

Conspectus One of the most important challenges in catalyst design is the synthesis of stable promoters without compromising their activity. For this reason, it is important to understand the factors leading to decomposition of such catalysts, especially if side-products negatively affect the activity and selectivity of the starting complex. In this context, the understanding of termination and decomposition processes in olefin metathesis is receiving significant attention from the scientific community. For example, the decomposition of ruthenium olefin metathesis precatalysts in alcohol solutions can occur during either the catalyst synthesis or the metathesis process, and such decomposition has been found to be common for Grubbs-type precatalysts. These decomposition products are usually hydridocarbonyl complexes, which are well-known to be active in several transformations such as hydrogenation, terminal alkene isomerization, and C–H activation chemistry. The reactivity of these side products can be unwanted, and it is therefore important to understand how to avoid them and maybe also important to keep an open mind and think of ways to use these in other catalytic reactions. A showcase of these decomposition studies is reported in this Account. These reports analyze the stability of ruthenium phenylindenylidene complexes, highly active olefin metathesis precatalysts, in basic alcohol solutions. Several different decomposition processes can occur under these conditions depending on the starting complex and the alcohol used. These indenylidene-bearing metathesis complexes display a completely different behavior compared with that of other metathesis precatalysts and show an alternative competitive alcoholysis pathway, where rather than forming the expected hydrido carbonyl complexes, the indenylidene fragment is transformed into a η1-indenyl, which then rearranges to its η5-indenyl form. In particular, [RuCl(η5-(3-phenylindenylidene)(PPh3)2] has been found to be extremely active in numerous transformations (at least 20) as well as compatible with a broad range of reaction conditions, rendering it a versatile catalytic tool. It should be stated that the η5-phenyl indenyl ligand shows enhanced catalytic activity over related half-sandwich ruthenium complexes. The analogous half-sandwich (cyclopentadienyl and indenyl) ruthenium complexes show lower activity in transfer hydrogenation and allylic alcohol isomerization reactions. In addition, this catalyst allows access to new phenylindenyl ruthenium complexes, which can be achieved in a very straightforward manner and have been successfully used in catalysis. This Account provides an overview of how mechanistic insights into decomposition and stability of a well-known family of ruthenium metathesis precatalysts has resulted in a series of novel and versatile ruthenium complexes with unexpected reactivity. PMID:25264626

Tumoricidal activity of low-energy 160-KV versus 6-MV X-rays against platinum-sensitized F98 glioma cells

PubMed Central

Lim, Sara N.; Pradhan, Anil K.; Barth, Rolf F.; Nahar, Sultana N.; Nakkula, Robin J.; Yang, Weilian; Palmer, Alycia M.; Turro, Claudia; Weldon, Michael; Bell, Erica Hlavin; Mo, Xiaokui

2015-01-01

The purposes of this study were (i) to investigate the differences in effects between 160-kV low-energy and 6-MV high-energy X-rays, both by computational analysis and in vitro studies; (ii) to determine the effects of each on platinum-sensitized F98 rat glioma and murine B16 melanoma cells; and (iii) to describe the in vitro cytotoxicity and in vivo toxicity of a Pt(II) terpyridine platinum (Typ-Pt) complex. Simulations were performed using the Monte Carlo code Geant4 to determine enhancement in absorption of low- versus high-energy X-rays by Pt and to determine dose enhancement factors (DEFs) for a Pt-sensitized tumor phantom. In vitro studies were carried out using Typ-Pt and again with carboplatin due to the unexpected in vivo toxicity of Typ-Pt. Cell survival was determined using clonogenic assays. In agreement with computations and simulations, in vitro data showed up to one log unit reduction in surviving fractions (SFs) of cells treated with 1–4 µg/ml of Typ-Pt and irradiated with 160-kV versus 6-MV X-rays. DEFs showed radiosensitization in the 50–200 keV range, which fell to approximate unity at higher energies, suggesting marginal interactions at MeV energies. Cells sensitized with 1–5 or 7 µg/ml of carboplatin and then irradiated also showed a significant decrease (P < 0.05) in SFs. However, it was unlikely this was due to increased interactions. Theoretical and in vitro studies presented here demonstrated that the tumoricidal activity of low-energy X-rays was greater than that of high-energy X-rays against Pt-sensitized tumor cells. Determining whether radiosensitization is a function of increased interactions will require additional studies. PMID:25266332

Nitric oxide production by visible light irradiation of aqueous solution of nitrosyl ruthenium complexes.

PubMed

Sauaia, Marília Gama; de Lima, Renata Galvão; Tedesco, Antonio Claudio; da Silva, Roberto Santana

2005-12-26

[Ru(II)L(NH(3))(4)(pz)Ru(II)(bpy)(2)(NO)](PF(6))(5) (L is NH(3), py, or 4-acpy) was prepared with good yields in a straightforward way by mixing an equimolar ratio of cis-[Ru(NO(2))(bpy)(2)(NO)](PF(6))(2), sodium azide (NaN(3)), and trans-[RuL(NH(3))(4)(pz)] (PF(6))(2) in acetone. These binuclear compounds display nu(NO) at ca. 1945 cm(-)(1), indicating that the nitrosyl group exhibits a sufficiently high degree of nitrosonium ion (NO(+)). The electronic spectrum of the [Ru(II)L(NH(3))(4)(pz)Ru(II)(bpy)(2)(NO)](5+) complex in aqueous solution displays the bands in the ultraviolet and visible regions typical of intraligand and metal-to-ligand charge transfers, respectively. Cyclic voltammograms of the binuclear complexes in acetonitrile give evidence of three one-electron redox processes consisting of one oxidation due to the Ru(2+/3+) redox couple and two reductions concerning the nitrosyl ligand. Flash photolysis of the [Ru(II)L(NH(3))(4)(pz)Ru(II)(bpy)(2)(NO)](5+) complex is capable of releasing nitric oxide (NO) upon irradiation at 355 and 532 nm. NO production was detected and quantified by an amperometric technique with a selective electrode (NOmeter). The irradiation at 532 nm leads to NO release as a consequence of a photoinduced electron transfer. All species exhibit similar photochemical behavior, a feature that makes their study extremely important for their future application in the upgrade of photodynamic therapy in living organisms.

X-ray structure determination, Hirshfeld surface analysis, spectroscopic (FT-IR, NMR, UV-Vis, fluorescence), non-linear optical properties, Fukui function and chemical activity of 4‧-(2,4-dimethoxyphenyl)-2,2‧:6‧,2″-terpyridine

NASA Astrophysics Data System (ADS)

Demircioğlu, Zeynep; Yeşil, Ahmet Emin; Altun, Mehmet; Bal-Demirci, Tülay; Özdemir, Namık

2018-06-01

The compound 4‧-(2,4-dimethoxyphenyl)-2,2‧:6‧,2″-terpyridine (Mtpyr) was synthesized and investigated using X-ray single crystal structure determination, combined with Hirshfeld topology analysis of the molecular packing. In addition, Mtpyr was characterized by experimental and theoretical FT-IR, UV-Vis, 1H NMR, 13C NMR and fluorescence emission spectra. The optimized molecular geometry (bond length, bond angle, torsion angle), the complete vibrational frequency and all other theoretical computations were calculated by using density functional theory (DFT) B3LYP method with the help of 6-311++G(d,p) basis set. From the recorded UV-Vis spectrum, the electronic properties such as excitation energies, wavelength and oscillator strength are evaluated by TD-DFT in chloroform solution. The 1H and 13C nuclear magnetic resonance (NMR) chemical shifts of the molecule were calculated by the gauge-independent atomic orbital (GIAO) method and compared with experimental results. The calculated HOMO-LUMO band gap energies confirmed that charge transfer and chemical stability within the molecule. The hyperconjugative interaction energy E(2) and electron densities of donor (i) and acceptor (j) bonds were calculated using natural bond orbital (NBO) analysis. Besides Mulliken and natural population charges (NPA), non-linear optic properties (NLO), Fukui Function analysis, molecular electrostatic potential (MEP) were also computed which helps to identifying the electrophilic/nucleophilic nature.

Expression proteomics study to determine metallodrug targets and optimal drug combinations.

PubMed

Lee, Ronald F S; Chernobrovkin, Alexey; Rutishauser, Dorothea; Allardyce, Claire S; Hacker, David; Johnsson, Kai; Zubarev, Roman A; Dyson, Paul J

2017-05-08

The emerging technique termed functional identification of target by expression proteomics (FITExP) has been shown to identify the key protein targets of anti-cancer drugs. Here, we use this approach to elucidate the proteins involved in the mechanism of action of two ruthenium(II)-based anti-cancer compounds, RAPTA-T and RAPTA-EA in breast cancer cells, revealing significant differences in the proteins upregulated. RAPTA-T causes upregulation of multiple proteins suggesting a broad mechanism of action involving suppression of both metastasis and tumorigenicity. RAPTA-EA bearing a GST inhibiting ethacrynic acid moiety, causes upregulation of mainly oxidative stress related proteins. The approach used in this work could be applied to the prediction of effective drug combinations to test in cancer chemotherapy clinical trials.

NITRIC ACID RECPVERY FROM WASTE COLUTIONS

DOEpatents

Wilson, A.S.

1959-04-14

The recovery of nitric acid from aqueous nitrate solutions containing fission products as impurities is described. It is desirable to subject such solutions to concentration by evaporation since nitric acid is regenerated thereby. A difficulty, however, is that the highly radioactive fission product ruthenium is volatilized together with the nitric acid. It has been found that by adding nitrous acids ruthenium volatilization is suppressed and reduced to a negligible degree so that the distillate obtained is practically free of rutheniuim.

Ligand-accelerated activation of strong C-H bonds of alkanes by a (salen)ruthenium(VI)-nitrido complex.

PubMed

Man, Wai-Lun; Lam, William W Y; Kwong, Hoi-Ki; Yiu, Shek-Man; Lau, Tai-Chu

2012-09-03

Kinetic and mechanistic studies on the intermolecular activation of strong C-H bonds of alkanes by a (salen)ruthenium(VI) nitride were performed. The initial, rate-limiting step, the hydrogen atom transfer (HAT) from the alkane to Ru(VI)≡N, generates Ru(V)=NH and RC·HCH(2)R. The following steps involve N-rebound and desaturation. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ruthenium(ii)-polypyridyl zirconium(iv) metal-organic frameworks as a new class of sensitized solar cells.

PubMed

Maza, W A; Haring, A J; Ahrenholtz, S R; Epley, C C; Lin, S Y; Morris, A J

2016-01-01

A series of Ru(ii)L 2 L' (L = 2,2'-bipyridyl, L' = 2,2'-bipyridine-5,5'-dicarboxylic acid), RuDCBPY, -containing zirconium(iv) coordination polymer thin films have been prepared as sensitizing materials for solar cell applications. These metal-organic framework (MOF) sensitized solar cells, MOFSCs, each are shown to generate photocurrent in response to simulated 1 sun illumination. Emission lifetime measurements indicate the excited state quenching of RuDCBPY at the MOF-TiO 2 interface is extremely efficient (>90%), presumably due to electron injection into TiO 2 . A mechanism is proposed in which RuDCBPY-centers photo-excited within the MOF-bulk undergo isotropic energy migration up to 25 nm from the point of origin. This work represents the first example in which a MOFSC is directly compared to the constituent dye adsorbed on TiO 2 (DSC). Importantly, the MOFSCs outperformed their RuDCBPY-TiO 2 DSC counterpart under the conditions used here and, thus, are solidified as promising solar cell platforms.

(η(6)-Benzene)(carbonato-κ(2) O,O')[di-cyclohex-yl(naphthalen-1-ylmeth-yl)phosphane-κP]ruthenium(II) chloro-form tris-olvate.

PubMed

Gowrisankar, Saravanan; Neumann, Helfried; Spannenberg, Anke; Beller, Matthias

2014-07-01

The title compound, [Ru(CO3)(η(6)-C6H6){(C6H11)2P(CH2C10H7)}]·3CHCl3, was synthesized by carbonation of [RuCl2(η(6)-C6H6){(C6H11)2P(CH2C10H7)}] with NaHCO3 in methanol at room temperature. The Ru(II) atom is surrounded by a benzene ligand, a chelating carbonate group and a phosphane ligand in a piano-stool configuration. The crystal packing is consolidated by C-H⋯O and C-H⋯Cl hydrogen-bonding inter-actions between adjacent metal complexes and between the complexes and the solvent mol-ecules. The asymmetric unit contains one metal complex and three chloro-form solvent mol-ecules of which only one was modelled. The estimated diffraction contributions of the other two strongly disordered chloro-form solvent mol-ecules were substracted from the observed diffraction data using the SQUEEZE procedure in PLATON [Spek (2009 ▶). Acta Cryst. D65, 148-155].

In situ formed catalytically active ruthenium nanocatalyst in room temperature dehydrogenation/dehydrocoupling of ammonia-borane from Ru(cod)(cot) precatalyst.

PubMed

Zahmakiran, Mehmet; Ayvalı, Tuğçe; Philippot, Karine

2012-03-20

The development of simply prepared and effective catalytic materials for dehydrocoupling/dehydrogenation of ammonia-borane (AB; NH(3)BH(3)) under mild conditions remains a challenge in the field of hydrogen economy and material science. Reported herein is the discovery of in situ generated ruthenium nanocatalyst as a new catalytic system for this important reaction. They are formed in situ during the dehydrogenation of AB in THF at 25 °C in the absence of any stabilizing agent starting with homogeneous Ru(cod)(cot) precatalyst (cod = 1,5-η(2)-cyclooctadiene; cot = 1,3,5-η(3)-cyclooctatriene). The preliminary characterization of the reaction solutions and the products was done by using ICP-OES, ATR-IR, TEM, XPS, ZC-TEM, GC, EA, and (11)B, (15)N, and (1)H NMR, which reveal that ruthenium nanocatalyst is generated in situ during the dehydrogenation of AB from homogeneous Ru(cod)(cot) precatalyst and B-N polymers formed at the initial stage of the catalytic reaction take part in the stabilization of this ruthenium nanocatalyst. Moreover, following the recently updated approach (Bayram, E.; et al. J. Am. Chem. Soc.2011, 133, 18889) by performing Hg(0), CS(2) poisoning experiments, nanofiltration, time-dependent TEM analyses, and kinetic investigation of active catalyst formation to distinguish single metal or in the present case subnanometer Ru(n) cluster-based catalysis from polymetallic Ru(0)(n) nanoparticle catalysis reveals that in situ formed Ru(n) clusters (not Ru(0)(n) nanoparticles) are kinetically dominant catalytically active species in our catalytic system. The resulting ruthenium catalyst provides 120 total turnovers over 5 h with an initial turnover frequency (TOF) value of 35 h(-1) at room temperature with the generation of more than 1.0 equiv H(2) at the complete conversion of AB to polyaminoborane (PAB; [NH(2)BH(2)](n)) and polyborazylene (PB; [NHBH](n)) units.

Reaction of a (Salen)ruthenium(VI) nitrido complex with thiols. C-H bond activation by (Salen)ruthenium(IV) sulfilamido species.

PubMed

Man, Wai-Lun; Lam, William W Y; Kwong, Hoi-Ki; Peng, Shie-Ming; Wong, Wing-Tak; Lau, Tai-Chu

2010-01-04

The reaction of [Ru(VI)(N)(L)(MeOH)](PF(6)) [1; L = N,N'-bis(salicylidene)-o-cyclohexyldiamine dianion] with a stoichiometric amount of RSH in CH(3)CN gives the corresponding (salen)ruthenium(IV) sulfilamido species [Ru(IV){N(H)SR}(L)(NCCH(3))](PF(6)) (2a, R = (t)Bu; 2b, R = Ph). Metathesis of 2a with NaN(3) in methanol affords [Ru(IV){N(H)S(t)Bu}(L)(N(3))] (2c). 2a undergoes further reaction with 1 equiv of RSH to afford a (salen)ruthenium(III) sulfilamine species, [Ru(III){N(H)(2)S(t)Bu}(L)(NCCH(3))](PF(6)) (3). On the other hand, 2b reacts with 2 equiv of PhSH to give a (salen)ruthenium(III) ammine species [Ru(III)(NH(3))(L)(NCCH(3))](PF(6)) (4); this species can also be prepared by treatment of 1 with 3 equiv of PhSH. The X-ray structures of 2c and 4 have been determined. Kinetic studies of the reaction of 1 with excess RSH indicate the following schemes: 1 --> 2a --> 3 (R = (t)Bu), 1 --> 2b --> 4 (R = Ph). The conversion of 1 to 2 probably involves nucleophilic attack of RSH at the nitrido ligand, followed by a proton shift. The conversions of 2a to 3 and 2b to 4 are proposed to involve rate-limiting H-atom abstraction from RSH by 2a or 2b. 2a and 2b are also able to abstract H atoms from hydrocarbons with weak C-H bonds. These reactions occur with large deuterium isotope effects; the kinetic isotope effect values for the oxidation of 9,10-dihydroanthracene, 1,4-cyclohexadiene, and fluorene by 2a are 51, 56, and 11, respectively.

Synthesis of phospholyl-bridged heterobimetallic ruthenium hydrides in combination with zirconium and ytterbium and the crystal structure of (THF){sub 2}Yb[{mu}({eta}{sup 5}, {eta}{sup 1})-C{sub 4}Me{sub 4}P]{sub 2 }Ru(H){sub 2}(Ph{sub 3}P){sub 2}

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

Desmurs, P.; Visseaux, M.; Baudry, D.

1996-10-01

Heterobimetallic zirconium-ruthenium and ytterbium-ruthenium dihydrides, having bridging phospholyl ligands, have been obtained for the first time. Reaction of bis({eta}{sup 5}-tetramethylphospholyl)dichlorozirconium [(TMP){sub 2}ZrCl{sub 2}] with RuH{sub 4}(PPh{sub 3}){sub 3} gave the zirconium-ruthenium heterobimetallic Cl{sub 2}Zr[{mu}({eta}{sup 5},{eta}{sup 1})-TMP]{sub 2}Ru(H){sub 2} (PPh{sub 3}){sub 2}. This compound was transformed into the hydridochloride Cl{sub 2}Zr[{mu}({eta}{sup 5},{eta}{sup 1})-TMP]{sub 2}Ru(H)(Cl)( PPh{sub 3}){sub 2} by the action of CCl{sub 4}. Similarly, reaction of [(TMP){sub 2}Yb] with RuH{sub 4}(PPh{sub 3}){sub 3} afforded (THF){sub 2}Yb[{mu}({eta}{sup 5}, meta{sup 1})-TMP]{sub 2}Ru(H){sub 2}(PPh{sub 3}){sub 2}. The structure of this compound, which has been determined by X-ray crystallography, confirms the trans configuration of themore » dihydride deduced previously from NMR data. Attempts to isolate products from the reaction of [(TMP){sub 2}UCl{sub 2}] or [(TMP){sub 2}U(BH{sub 4}){sub 2}] with RuH{sub 4}(PPh{sub 3}){sub 3} were unsuccessful, but NMR data show the formation of both heterobimetallic trans- and cis-ruthenium dihydride-uranium compounds X{sub 2}U[{mu}({eta}{sup 5},{eta}{sup 1})-TMP]{sub 2}Ru(H){sub 2}(P Ph{sub 3}){sub 2} (X = BH{sub 4}, Cl) in solution. 19 refs., 1 fig., 2 tabs.« less

Temperature and oxygen-concentration dependence of singlet oxygen production by RuPhen as induced by quasi-continuous excitation.

PubMed

Varchola, Jaroslav; Huntosova, Veronika; Jancura, Daniel; Wagnières, Georges; Miskovsky, Pavol; Bánó, Gregor

2014-12-01

Assessment of partial pressure of oxygen (pO2) by luminescence lifetime measurements of ruthenium coordination complexes has been studied intensively during the last few decades. RuPhen (dichlorotris(1,10-phenanthroline) ruthenium(ii) hydrate) is a water soluble molecule that has been tested previously for in vivo pO2 detection. In this work we intended to shed light on the production of singlet oxygen by RuPhen. The quantum yield of singlet oxygen production by RuPhen dissolved in 0.9% aqueous NaCl solution (pH = 6) was measured at physiological temperatures (285-310 K) and various concentrations of molecular oxygen. In order to minimize the bleaching of RuPhen, the samples were excited with low power (<2 mW) laser pulses (20 μs long), created by pulsing a cw laser beam with an acousto-optical modulator. We show that, whereas the RuPhen phosphorescence lifetime decreases rapidly with an increase of temperature (keeping the oxygenation level constant), the quantum yield of singlet oxygen production by RuPhen is almost identical in the temperature range of 285-310 K. For air-saturated conditions at 310 K the measured quantum yield is about 0.25. The depopulation rate constants of the RuPhen (3)MLCT (metal-to-ligand charge-transfer) state are determined in the absence and in the presence of oxygen. We determined that the excitation energy for the RuPhen (3)MLCT→d-d transition is 49 kJ mol(-1) in the 0.9% NaCl solution (pH = 6).

Ruthenium porphyrin-induced photodamage in bladder cancer cells.

PubMed

Bogoeva, Vanya; Siksjø, Monica; Sæterbø, Kristin G; Melø, Thor Bernt; Bjørkøy, Astrid; Lindgren, Mikael; Gederaas, Odrun A

2016-06-01

Photodynamic therapy (PDT) is a noninvasive treatment for solid malignant and flat tumors. Light activated sensitizers catalyze photochemical reactions that produce reactive oxygen species which can cause cancer cell death. In this work we investigated the photophysical properties of the photosensitizer ruthenium(II) porphyrin (RuP), along with its PDT efficiency onto rat bladder cancer cells (AY27). Optical spectroscopy verified that RuP is capable to activate singlet oxygen via blue and red absorption bands and inter system crossing (ISC) to the triplet state. In vitro experiments on AY27 indicated increased photo-toxicity of RuP (20μM, 18h incubation) after cell illumination (at 435nm), as a function of blue light exposure. Cell survival fraction was significantly reduced to 14% after illumination of 20μM RuP with 15.6J/cm(2), whereas the "dark toxicity" of 20μM RuP was 17%. Structural and morphological changes of cells were observed, due to RuP accumulation, as well as light-dependent cell death was recorded by confocal microscopy. Flow cytometry verified that PDT-RuP (50μM) triggered significant photo-induced cellular destruction with a photoxicity of (93%±0.9%). Interestingly, the present investigation of RuP-PDT showed that the dominating mode of cell death is necrosis. RuP "dark toxicity" compared to the conventional chemotherapeutic drug cisplatin was higher, both evaluated by the MTT assay (24h). In conclusion, the present investigation shows that RuP with or without photoactivation induces cell death of bladder cancer cells. Copyright © 2016 Elsevier B.V. All rights reserved.

New superhindered polydentate polyphosphine ligands P(CH2CH2P(t)Bu2)3, PhP(CH2CH2P(t)Bu2)2, P(CH2CH2CH2P(t)Bu2)3, and their ruthenium(II) chloride complexes.

PubMed

Gilbert-Wilson, Ryan; Field, Leslie D; Bhadbhade, Mohan M

2012-03-05

The synthesis and characterization of the extremely hindered phosphine ligands, P(CH(2)CH(2)P(t)Bu(2))(3) (P(2)P(3)(tBu), 1), PhP(CH(2)CH(2)P(t)Bu(2))(2) (PhP(2)P(2)(tBu), 2), and P(CH(2)CH(2)CH(2)P(t)Bu(2))(3) (P(3)P(3)(tBu), 3) are reported, along with the synthesis and characterization of ruthenium chloro complexes RuCl(2)(P(2)P(3)(tBu)) (4), RuCl(2)(PhP(2)P(2)(tBu)) (5), and RuCl(2)(P(3)P(3)(tBu)) (6). The bulky P(2)P(3)(tBu) (1) and P(3)P(3)(tBu) (3) ligands are the most sterically encumbered PP(3)-type ligands so far synthesized, and in all cases, only three phosphorus donors are able to bind to the metal center. Complexes RuCl(2)(PhP(2)P(2)(tBu)) (5) and RuCl(2)(P(3)P(3)(tBu)) (6) were characterized by crystallography. Low temperature solution and solid state (31)P{(1)H} NMR were used to demonstrate that the structure of RuCl(2)(P(2)P(3)(tBu)) (4) is probably analogous to that of RuCl(2)(PhP(2)P(2)(tBu)) (5) which had been structurally characterized.

Targeting Photoinduced DNA Destruction by Ru(II) Tetraazaphenanthrene in Live Cells by Signal Peptide.

PubMed

Burke, Christopher S; Byrne, Aisling; Keyes, Tia E

2018-06-06

Exploiting NF-κB transcription factor peptide conjugation, a Ru(II)-bis-tap complex (tap = 1,4,5,8-tetraazaphenanthrene) was targeted specifically to the nuclei of live HeLa and CHO cells for the first time. DNA binding of the complex  within the nucleus of live cells was evident from gradual extinction of the metal complex luminescence after it had crossed the nuclear envelope, attributed to guanine quenching of the ruthenium emission via photoinduced electron transfer. Resonance Raman imaging confirmed that the complex remained in the nucleus after emission is extinguished. In the dark and under imaging conditions the cells remain viable, but efficient cellular destruction was induced with precise spatiotemporal control by applying higher irradiation intensities to selected cells. Solution studies indicate that the peptide conjugated complex associates strongly with calf thymus DNA ex-cellulo and gel electrophoresis confirmed that the peptide conjugate is capable of singlet oxygen independent photodamage to plasmid DNA. This indicates that the observed efficient cellular destruction likely operates via direct DNA oxidation by photoinduced electron transfer between guanine and the precision targeted Ru(II)-tap probe. The discrete targeting of polyazaaromatic complexes to the cell nucleus and confirmation that they are photocytotoxic after nuclear delivery is an important step toward their application in cellular phototherapy.

Regioselective Formation of α-Vinylpyrroles from the Ruthenium-Catalyzed Coupling Reaction of Pyrroles and Terminal Alkynes Involving C–H Bond Activation

PubMed Central

Gao, Ruili; Yi, Chae S.

2010-01-01

The cationic ruthenium catalyst, Ru3(CO)12/NH4PF6, was found to be highly effective for the intermolecular coupling reaction of pyrroles and terminal alkynes to give gem-selective α-vinylpyrroles. The carbon isotope effect on the α-pyrrole carbon and the Hammett correlation from a series of para-substituted N-arylpyrroles (ρ = −0.90) indicate a rate-limiting C–C bond formation step of the coupling reaction. PMID:20384382

Synergistic Interaction within Bifunctional Ruthenium Nanoparticle/SILP Catalysts for the Selective Hydrodeoxygenation of Phenols.

PubMed

Luska, Kylie L; Migowski, Pedro; El Sayed, Sami; Leitner, Walter

2015-12-21

Ruthenium nanoparticles immobilized on acid-functionalized supported ionic liquid phases (Ru NPs@SILPs) act as efficient bifunctional catalysts in the hydrodeoxygenation of phenolic substrates under batch and continuous flow conditions. A synergistic interaction between the metal sites and acid groups within the bifunctional catalyst leads to enhanced catalytic activities for the overall transformation as compared to the individual steps catalyzed by the separate catalytic functionalities. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Process of forming catalytic surfaces for wet oxidation reactions

NASA Technical Reports Server (NTRS)

Jagow, R. B. (Inventor)

1977-01-01

A wet oxidation process was developed for oxidizing waste materials, comprising dissolved ruthenium salt in a reactant feed stream containing the waste materials. The feed stream is introduced into a reactor, and the reactor contents are then raised to an elevated temperature to effect deposition of a catalytic surface of ruthenium black on the interior walls of the reactor. The feed stream is then maintained in the reactor for a period of time sufficient to effect at least partial oxidation of the waste materials.

Selective Hydrogen Generation from Formic Acid with Well-Defined Complexes of Ruthenium and Phosphorus-Nitrogen PN(3) -Pincer Ligand.

PubMed

Pan, Yupeng; Pan, Cheng-Ling; Zhang, Yufan; Li, Huaifeng; Min, Shixiong; Guo, Xunmun; Zheng, Bin; Chen, Hailong; Anders, Addison; Lai, Zhiping; Zheng, Junrong; Huang, Kuo-Wei

2016-05-06

An unsymmetrically protonated PN(3) -pincer complex in which ruthenium is coordinated by one nitrogen and two phosphorus atoms was employed for the selective generation of hydrogen from formic acid. Mechanistic studies suggest that the imine arm participates in the formic acid activation/deprotonation step. A long life time of 150 h with a turnover number over 1 million was achieved. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis of m-Alkylphenols via a Ruthenium-Catalyzed C-H Bond Functionalization of Phenol Derivatives.

PubMed

Li, Gang; Gao, Panpan; Lv, Xulu; Qu, Chen; Yan, Qingkai; Wang, Ya; Yang, Suling; Wang, Junjie

2017-05-19

The first example of the synthesis of m-alkylphenols via a ruthenium-catalyzed C Ar -H bond functionalization of phenol derivatives with sec/tert-alkyl bromides is reported. Mechanistic studies indicated that the m-C Ar -H bond alkylation may involve a radical process and that a six-membered ruthenacycle complex was the active catalyst. Moreover, this approach can provide an expedited strategy for the atom-/step-economical synthesis of many noteworthy pharmaceuticals and other functional molecules.

Density functionalized [RuII(NO)(Salen)(Cl)] complex: Computational photodynamics and in vitro anticancer facets.

PubMed

Mir, Jan Mohammad; Jain, N; Jaget, P S; Maurya, R C

2017-09-01

Photodynamic therapy (PDT) is a treatment that uses photosensitizing agents to kill cancer cells. Scientific community has been eager for decades to design an efficient PDT drug. Under such purview, the current report deals with the computational photodynamic behavior of ruthenium(II) nitrosyl complex containing N, N'-salicyldehyde-ethylenediimine (SalenH 2 ), the synthesis and X-ray crystallography of which is already known [Ref. 38,39]. Gaussian 09W software package was employed to carry out the density functional (DFT) studies. DFT calculations with Becke-3-Lee-Yang-Parr (B3LYP)/Los Alamos National Laboratory 2 Double Z (LanL2DZ) specified for Ru atom and B3LYP/6-31G(d,p) combination for all other atoms were used using effective core potential method. Both, the ground and excited states of the complex were evolved. Some known photosensitizers were compared with the target complex. Pthalocyanine and porphyrin derivatives were the compounds selected for the respective comparative study. It is suggested that effective photoactivity was found due to the presence of ruthenium core in the model complex. In addition to the evaluation of theoretical aspects in vitro anticancer aspects against COLO-205 human cancer cells have also been carried out with regard to the complex. More emphasis was laid to extrapolate DFT to depict the chemical power of the target compound to release nitric oxide. A promising visible light triggered nitric oxide releasing power of the compound has been inferred. In vitro antiproliferative studies of [RuCl 3 (PPh 3 ) 3 ] and [Ru(NO)(Salen)(Cl)] have revealed the model complex as an excellent anticancer agent. From IC 50 values of 40.031mg/mL in former and of 9.74mg/mL in latter, it is established that latter bears more anticancer potentiality. From overall study the DFT based structural elucidation and the efficiency of NO, Ru and Salen co-ligands has shown promising drug delivery property and a good candidacy for both chemotherapy as well as light therapy. Copyright © 2017 Elsevier B.V. All rights reserved.

Simulating Ru L 3 -Edge X-ray Absorption Spectroscopy with Time-Dependent Density Functional Theory: Model Complexes and Electron Localization in Mixed-Valence Metal Dimers

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

Van Kuiken, Benjamin E.; Valiev, Marat; Daifuku, Stephanie L.

2013-05-30

Ruthenium L3-edge X-ray absorption (XA) spectroscopy probes unoccupied 4d orbitals of the metal atom and is increasingly being used to investigate the local electronic structure in ground and excited electronic states of Ru complexes. The simultaneous development of computational tools for simulating Ru L3-edge spectra is crucial for interpreting the spectral features at a molecular level. This study demonstrates that time-dependent density functional theory (TDDFT) is a viable and predictive tool for simulating ruthenium L3-edge XA spectroscopy. We systematically investigate the effects of exchange correlation functional and implicit and explicit solvent interactions on a series of RuII and RuIII complexesmore » in their ground and electronic excited states. The TDDFT simulations reproduce all of the experimentally observed features in Ru L3-edge XA spectra within the experimental resolution (0.4 eV). Our simulations identify ligand-specific charge transfer features in complicated Ru L3-edge spectra of [Ru(CN)6]4- and RuII polypyridyl complexes illustrating the advantage of using TDDFT in complex systems. We conclude that the B3LYP functional most accurately predicts the transition energies of charge transfer features in these systems. We use our TDDFT approach to simulate experimental Ru L3-edge XA spectra of transition metal mixed-valence dimers of the form [(NC)5MII-CN-RuIII(NH3)5] (where M = Fe or Ru) dissolved in water. Our study determines the spectral signatures of electron delocalization in Ru L3-edge XA spectra. We find that the inclusion of explicit solvent molecules is necessary for reproducing the spectral features and the experimentally determined valencies in these mixed-valence complexes. This study validates the use of TDDFT for simulating Ru 2p excitations using popular quantum chemistry codes and providing a powerful interpretive tool for equilibrium and ultrafast Ru L3-edge XA spectroscopy.« less

Oxidation of Bromide to Bromine by Ruthenium(II) Bipyridine-Type Complexes Using the Flash-Quench Technique.

PubMed

Tsai, Kelvin Yun-Da; Chang, I-Jy

2017-07-17

Six ruthenium complexes, [Ru(bpy) 3 ] 2+ (1), [Ru(bpy) 2 (deeb)] 2+ (2), [Ru(deeb) 2 (dmbpy)] 2+ (3), [Ru(deeb) 2 (bpy)] 2+ (4), [Ru(deeb) 3 ] 2+ (5), and [Ru(deeb) 2 (bpz)] 2+ (6) (bpy: 2,2'-bipyridine; deeb: 4,4'-diethylester-2,2'-bipyridine; dmbpy: 4,4'-dimethyl-2,2'-bipyridine, bpz: 2,2'-bipyrazine), have been employed to sensitize photochemical oxidation of bromide to bromine. The oxidation potential for complexes 1-6 are 1.26, 1.36, 1.42, 1.46, 1.56, and 1.66 V vs SCE, respectively. The bimolecular rate constants for the quenching of complexes 1-6 by ArN 2 + (bromobenzenediazonium) are determined as 1.1 × 10 9 , 1.6 × 10 8 , 1.4 × 10 8 , 1.2 × 10 8 , 6.4 × 10 7 , and 8.9 × 10 6 M -1 s -1 , respectively. Transient kinetics indicated that Br - reacted with photogenerated Ru(III) species at different rates. Bimolecular rate constants for the oxidation of Br - by the Ru(III) species derived from complexes 1-5 are observed as 1.2 × 10 8 , 1.3 × 10 9 , 4.0 × 10 9 , 4.8 × 10 9 , and 1.1 × 10 10 , M -1 s -1 , respectively. The last reaction kinetics observed in the three-component system consisting of a Ru sensitizer, quencher, and bromide is shown to be independent of the Ru sensitizer. The final product was identified as bromine by its reaction with hexene. The last reaction kinetics is assigned to the disproportionation reaction of Br 2 -• ions, for which the rate constant is determined as 5 × 10 9 M -1 s -1 . Though complex 6 has the highest oxidation potential in the Ru(II)/Ru(III) couple, its excited state fails to react with ArN 2 + sufficiently for subsequent reactions. The Ru(III) species derived from complex 1 reacts with Br - at the slowest rate. Complexes 2-5 are excellent photosensitizers to drive photooxidation of bromide to bromine.

Radiosensitization of high-Z compounds by medium-energy 160 kV vs. high-energy 6 MV X-rays for radiation therapy: Theoretical, in vitro and in vivo studies of platinum compounds activating glioma F98 cancer cells

NASA Astrophysics Data System (ADS)

Lim, S.; Pradhan, A.; Nahar, S.; Montenegro, M.; Barth, R.; Nakkula, R.; Turro, C.

2013-03-01

Energy dependence of X-ray irradiation of high-Z compounds for enhanced radiosensitization is explored thoeretically and via in vitro and in vivo experiments. The cell killing ability of medium-energy X-rays from 160 kV source are found to be more effective than 6 MV X-rays in activating high-Z contrast agents. Results are presented for a newly synthesized Pt compound, Pyridine Terpyridine Pt(II) Nitrate ([Pt(typ)(py)]) and carboplatin in treating F98 rat glioma. In-vitro results show considerable reduction in cell viability for radiosensitized cells irradiated with a 160 kV irradiator. Cells treated with 6 MV LINAC radiation find little variation with radiation dose. Maximum dose enhancement factors (DEFs) and minimum cancer cell survival fractions correspond to 50-200 keV range, and fall rapidly at higher energies. Theoretical calculations of photoelectric absorption vis-a-vis total scattering demonstrates this energy dependence. However, in vivo studies of rats treated with [Pt(tpy)(py)] had a severe negative neurotoxic response, confirmed by histopathological analysis. But subsequent in vivo studies using carboplatin showed very positive results in the treatment of F98 glioma bearing rats and potential clinical radiation therapy.

Construction and optical properties of infinite Cd and finite Cu molecules stairs

NASA Astrophysics Data System (ADS)

Zhao, Qiang; Mao, Wutao; Shen, Zhi; Wang, Qinghong; Zhou, Qian

2017-02-01

Two coordination complexes, namely [(hpdq)(pta)Cd]n (1) and [(pptp)(pta)Cu2Cl] (2) have been synthesized by solvothermal method based on two polypyridyl ligands, 2,3,6,7,10,11-hexakis- (2-pyridyl)dipyrazino[2,3-f:2‧,3‧-h]quinoxaline) (hpdq), 4‧-(4- (3H-pyrrol-3-yl)phenyl)- 2,2‧:6‧,2″- terpyridine (pptp) and auxiliary ligand p-phthalic acid (pta), respectively. Single crystal x-ray diffraction analyses reveal that complexes 1 and 2 assembled based on distinct asymmetric unit comprising one and two respective polypyridyl ligands but one Cd(II) and two Cu(I)ions, respectively. Among them, The asymmetric units in 1 was extended to one dimensional chain via the link of auxiliary ligand pta, just like infinite layers of stairs that connected by cadmium ions as the node. While that in 2 to Zero dimensional tetranuclear structure via the link of auxiliary ligand pta, just like finite four layers of stairs that Copper ion as the node connection. Furthermore, solid fluorescence spectra properties of two complexes were also investigated, and the result shows the fluorescence intensity of complex 1 is stronger than that of the hpdq ligand, but the fluorescence intensity of complex 2 is weaker than that of the pptp ligand. CCDC number of 1and 2 are 1483301 and 1483302.