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Dinuclear Ruthenium Complexes (dinuclear + ruthenium_complex)
Selected AbstractsInfluence of pH on the Photochemical and Electrochemical Reduction of the Dinuclear Ruthenium Complex, [(phen)2Ru(tatpp)Ru(phen)2]Cl4, in Water: Proton-Coupled Sequential and Concerted Multi-Electron ReductionCHEMISTRY - A EUROPEAN JOURNAL, Issue 15 2005Norma R. de Tacconi Prof. Abstract The dinuclear ruthenium complex [(phen)2Ru(tatpp)Ru(phen)2]4+ (P; in which phen is 1,10-phenanthroline and tatpp is 9,11,20,22-tetraaza tetrapyrido[3,2-a:2,3,-c:3,,,2,,-l:2,,,,3,,,]-pentacene) undergoes a photodriven two-electron reduction in aqueous solution, thus storing light energy as chemical potential within its structure. The mechanism of this reduction is strongly influenced by the pH, in that basic conditions favor a sequential process involving two one-electron reductions and neutral or slightly acidic conditions favor a proton-coupled, bielectronic process. In this complex, the central tatpp ligand is the site of electron storage and protonation of the central aza nitrogen atoms in the reduced products is observed as a function of the solution pH. The reduction mechanism and characterization of the rich array of products were determined by using a combination of cyclic and AC voltammetry along with UV-visible reflectance spectroelectrochemistry experiments. Both the reduction and protonation state of P could be followed as a function of pH and potential. From these data, estimates of the various reduced species' pKa values were obtained and the mechanism to form the doubly reduced, doubly protonated complex, [(phen)2Ru(H2tatpp)Ru(phen)2]4+ (H2P) at low pH (,7) could be shown to be a two-proton, two-electron process. Importantly, H2P is also formed in the photochemical reaction with sacrificial reducing agents, albeit at reduced yields relative to those at higher pH. [source] Hydrolysis of Dinuclear Ruthenium Complexes [{CpRu(PPh3)2}2(,,,1:1 -L)][CF3SO3]2 (L=P4, P4S3): Simple Access to Metal Complexes of P2H4 and PH2SHCHEMISTRY - A EUROPEAN JOURNAL, Issue 23 2007Pierluigi Barbaro Dr. Abstract The reaction of [CpRu(PPh3)2Cl] (1) with half an equivalent of P4 or P4S3 in the presence of AgCF3SO3 as chloride scavenger affords the stable dimetal complexes [{CpRu(PPh3)2}2(,,,1:1 -P4)][CF3SO3]2, 3,CH2Cl2 (2) and [{CpRu(PPh3)2}2(,,,1:1 -Papical -Pbasal -P4S3)][CF3SO3]2, 0.5,C7H8 (3), in which the tetrahedral P4 and mixed-cage P4S3 molecules are respectively bound to two CpRu(PPh3)2 fragments through two phosphorus atoms. The coordinated cage molecules, at variance with the free ligands, readily react with an excess of water in THF under mild conditions. Among the hydrolysis products, the new, remarkably stable complexes [{CpRu(PPh3)2}2(,,,1:1 -P2H4)][CF3SO3]2 (4) and [CpRu(PPh3)2(,1 -PH2SH)]CF3SO3 (8) were isolated. In the former, diphosphane, P2H4, is coordinated to two CpRu(PPh3)2 fragments, and in the latter thiophosphinous acid, H2PSH, is coordinated to the metal centre through the phosphorus atom. All compounds were characterised by elemental analyses and IR and NMR spectroscopy. The crystal structures of 2, 3, 4 and 8 were determined by X-ray diffraction. [source] Synthesis and Structure of a Novel Cluster with Trigonal-bipyramidal Ge2Ru3 CoreCHINESE JOURNAL OF CHEMISTRY, Issue 11 2002Yong-Qiang Zhang Abstract When t -BuC5H4Me2GeGeMe2C5E4Bu- t and Ru3 (CO)12 were refluxed in nonane, a novel germanium-ruthenium duster with a trigonal-bipyramidal Ge2Ru3 core {(,3 -Ge) [Ru(CO)2 (,5 -C5H4Bu- t)]}2Ru3 (CO)9 (1) and a dinuclear ruthenium complex [(Me2Ge)(,5 -C5H3Bu- t)Ru2(CO)6] (2) were obtained. The structures of 1 and 2 were fully characterized by 1H NMR, 13C NMR, IR spectra and elemental analysis, and 1 has also been determined by X-ray diffraction analysis. [source] Modifying the structure of dinuclear ruthenium complexes with antitumor activityAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 6 2008Maria G. Mendoza-Ferri Abstract In order to modulate the structure of a recently developed series of antitumor-active, dinuclear Ru(II),arene compounds, complexes 1c,4c were synthesized. The complexes were modified with respect to their pyridinone moieties and the spacer linking the two metal centers. More particularly, the series of dinuclear ruthenium(II) complexes was extended to compounds with longer spacers, i.e. tetradecane and 3,7,10-trioxotridecane, and the pyridinone ring was modified by replacing the methyl group by an ethyl group and by shifting the position of the methyl group. The organometallic ruthenium compounds were obtained from the reaction between [RuCl2(,6 - p -isopropyltoluene)]2 and ligands 1b,4b with yields ranging from 41 to 67%. All compounds were characterized by standard methods: MS, 1H and 13C NMR spectroscopy and elemental analysis. Copyright Š 2008 John Wiley & Sons, Ltd. [source] Highly Selective Hydrogenation of Carbon,Carbon Multiple Bonds Catalyzed by the Cation [(C6Me6)2Ru2(PPh2)H2]+: Molecular Structure of [(C6Me6)2Ru2(PPh2)(CHCHPh)H]+, a Possible Intermediate in the Case of Phenylacetylene HydrogenationCHEMISTRY - A EUROPEAN JOURNAL, Issue 1 2007Mathieu J.-L. Abstract The dinuclear cation [(C6Me6)2Ru2(PPh2)H2]+ (1) has been studied as the catalyst for the hydrogenation of carbon,carbon double and triple bonds. In particular, [1][BF4] turned out to be a highly selective hydrogenation catalyst for olefin functions in molecules also containing reducible carbonyl functions, such as acrolein, carvone, and methyljasmonate. The hypothesis of molecular catalysis by dinuclear ruthenium complexes is supported by catalyst-poisoning experiments, the absence of an induction period in the kinetics of cyclohexene hydrogenation, and the isolation and single-crystal X-ray structure analysis of the tetrafluoroborate salt of the cation [(C6Me6)2Ru2(PPh2)(CHCHPh)H]+ (2), which can be considered as an intermediate in the case of phenylacetylene hydrogenation. On the basis of these findings, a catalytic cycle is proposed which implies that substrate hydrogenation takes place at the intact diruthenium backbone, with the two ruthenium atoms acting cooperatively in the hydrogen-transfer process. [source] A Ru-Hbpp-Based Water-Oxidation Catalyst Anchored on Rutile TiO2,CHEMSUSCHEM CHEMISTRY AND SUSTAINABILITY, ENERGY & MATERIALS, Issue 4 2009Laia Francās Abstract In support of a split: A water oxidation catalyst based on ruthenium bis-(2-pyridyl)pyrazole anchored on rutile TiO2 was prepared. The performance of this new material with regard to its capacity to catalytically oxidize water to molecular oxygen in a heterogeneous phase was evaluated. Two organic ligands based on bis-(2-pyridyl)pyrazole (Hbpp) functionalized with a para -methylenebenzoic acid (Hbpp-Ra) or its ester derivative (Hbpp-Re) were prepared and characterized. The ester-functionalized ligand was then used to prepare a series of related dinuclear ruthenium complexes of general formula [RuII2(L- L)(bpp-Rn)(trpy)2]m+ (L-L=,-Cl, ,-acetato, or (H2O)2; n=e or a; trpy=2,2,:6,,2,,-terpyridine; m=2 or 3). The complexes were characterized in solution by 1D and 2D,NMR spectroscopy, UV/Vis spectroscopy, and electrochemical techniques. The [RuII2(,-Cl)(bpp-Re)(trpy)2](PF6)2 complex was further characterized in the solid state by X-ray diffraction. The complexes containing the free carboxylic acid ligand were anchored onto rutile TiO2 and treated with 0.1,M triflic acid solution to generate the homologous water-oxidation catalysts TiO2 -[RuII2(H2O)2(bpp-Ra)(trpy)2]2+. This new hybrid material catalytically oxidizes water to molecular oxygen in a heterogeneous manner using CeIV as chemical oxidant. The generation of molecular oxygen is accompanied by the formation of carbon dioxide as well as some leaching of the Ru catalyst. [source] | ||||||||||