Ruthenium complexes tetranuclear

Nagashima reported the hydrogenation of di-, tri- and tetranuclear ruthenium complexes bearing azulenes below 100 °C revealed that only the triruthenium compounds reacted with H2 via triruthenium dihydride intermediates.398 This indicates that there exists a reaction pathway to achieve facile activation of dihydrogen on the face of a triruthenium carbonyl moiety.399... 

Electrochemical studies of the tetranuclear ruthenium complex of ligand (62) indicate two reversible two-electron redox waves in the anodic region attributed to oxidation of the Ru11 metal centers. This complex is said to act as two binuclear subunits with little or no electronic interaction between subunits. The first two-electron oxidation process results in a mixed valence complex with each subunit having a Ru11 and Ru111 metal center. 

Luminescent and redox-reactive building blocks for the design of photochemical molecular devices mono-, di-,tri-, and tetranuclear ruthenium(n) polypyridine complexes. [G. Denti, S. Campagna, L. Sabatino, S. Serroni, M. Ciano, V. Balzani, Inorg. Chem. 1990, 29(23), 4750-4758] [ 830]. 

The tetranuclear complex [(Ru(NH3)5)4TCNE]8+ shows four, one electron oxidations and a one electron reduction.527 The 10+ is more stable than the 9+ and 11 + species, with a strong coupling between metal centres being proposed.527 A heteronuclear ferrocene-ruthenium complex [(Ru(NH3)5)2Fc(CN)2]4+ (Fc(CN)2 = l,l -dicyanoferrocene) has been prepared. No evidence was observed for an end to end interaction in the corresponding 5 + ion.547... 

Haga and coworkers examined the electrochemical response from a tetranuclear ruthenium polypyridine compound with a dendritic morphology, and using cyclic voltammetry, they were able to observe the central metal of the complex being oxidized at a potential about 150 mV less positive than that for the oxidation... 

Yi CS, Zeczycld TN, Lindeman SV (2008) Kinetic, spectroscopic, and X-ray crystallographic evidence for the cooperative mechanism of the hydration of nitriles catalyzed by a tetranuclear ruthenium-p-oxo-p-hydroxo complex. Organometallics 27 2030... 

More recently, tetranuclear complexes, related to those previously obtained for both ruthenium and osmium, have been obtained for iron, and their structures have been established by X-ray analysis 118). The reported adducts are [Fe4(CO)11(RC2R1)2] (R = H, R1 = Me, Et, n-Pr R = R1 = Me), and are obtained in very low yield (<1%). For R = H, R1 = C2H5, the structure is shown in Fig. 16. This involves a distorted tetrahedral metal system with the two alkyne groups bonding in a manner similar to that observed for the "butterfly molecule [Co4(CO)10(EtC2Et)] 119). 

The mixed-metal tetranuclear derivatives that have been prepared are H2Re2Ru2(CO)i6, CReRu3(CO)16] , HMnOs3(CO)16, and HReOs3(CO)18 (238). All the complexes result from the reaction of the carbonyl, M3(CO)i2, with the related anion, [Mn(CO)5]- or [Re(CO)s]. The ruthenium anion [ReRu3(CO)16] was isolated as its tetramethylammo-nium salt. The infrared spectrum was complex, but consistent with... 

TRI- AND TETRANUCLEAR CARBONYL-RUTHENIUM CLUSTER COMPLEXES CONTAINING ISOCYANIDE, TERTIARY PHOSPHINE, AND PHOSPHITE LIGANDS. RADICAL ION-INITIATED SUBSTITUTION OF METAL CLUSTER CARBONYL COMPLEXES UNDER MILD CONDITIONS... 

Linares F, Galindo MA, Galli S, Angustias Romero M, Navarro JAR, Barea E (2009) Tetranuclear coordination assemblies based on half-sandwich ruthenium(II) complexes noncovalent binding to DNA and cytotoxicity. Inorg Chem 48 7413-7420... 

In addition to described heterogeneous systems a homogeneous photocatalytic C02 reduction was tested using heteroleptic rhenium complexes [99, 100] and supramolecular ruthenium and rhenium bi- and tetranuclear complexes their excited states were quenched by 1-benzyl-1,4-dihydronicotinamide (BNAH) and C02 was reduced by the electron donor intermediate species [101]. 

Gholamkhass B, Mametsuka H, Koike K, Tanabe T, Furue M, Ishitani O. Architecture of supramolecular metal complexes for photocatalytic C02 reduction ruthenium-rhenium bi- and tetranuclear complexes. Inorg Chem 2005 44 2326-36. 

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