Ruthenium complexes trinuclear

Nazeeruddin, M. K. Liska, P. Moser, J. Vlachopoulos, N. Graetzel, M. Conversion of light into electricity with trinuclear ruthenium complexes adsorbed on textured Ti02 films, Helv. Chinu Acta 1990, 73, 1788. 

II,III,III) state of the oxo-centered trinuclear ruthenium complex 9 and the (III,IV) state of the oxo-bridged diosmium complex 4 is noted. 

It is noted that the linearly oxo-bridged trinuclear ruthenium complex [NH3)5Ru-0-Ru(NH3)4-0-Ru(NH3)5] + (Ru "-Ru Ru", called Ru-red) is a better catalyst for water oxidation than the dimer ruthenium complexes in homogeneous solution The Ru" -Ru -Ru " is oxidized electrochemically... 

Water Oxidation Center Model Using Trinuclear Ruthenium Complexes... 

Polynuclear metal complexes are more suited for water oxidation catalyst because of their nature to act as multielectron transfer reagents in addition to the fact that charge delocalization can lead to stabilization of the catalyst rather than decomposition during the process. The trinuclear ruthenium complexes Ru-red and Ru-brown, [(NH3)sRu-0-Ru(NH3)4-0-Ru(NH3)j] - (Ru "-Ru" -Ru" ) and [(NH3)sRu-0-Ru(NH3)4-0-Ru(NH3)5] + (Ru -Ru" -Ru ), respectively, have been shown to be efficient water oxidation catalysts for oxygen evolution with high turnover numbers When Ru-red was dissolved in an acidic aqueous solution, it underwent one-electron oxidation with the formation of Ru-brown. When Ru-brown was dissolved in a basic solution, the complex underwent reduction to produce Ru-red. The one-electron oxidation and reduction of the Ru-red and Ru-brown has already been well established (Eq. 11) 6 65-6 )... 

The cyclic voltammetric studies of Ru-red in aqueous solution showed that the trinuclear ruthenium complex undergoes various redox processes to produce Ru -Ru -Ru. The stability of the trinuclear ruthenium complex in the various oxidation states can be interpreted on the basis of intramolecular charge delocalization among the ruthenium centers. 

The water oxidation experiment to evolve dioxygen was reported using trinuclear ruthenium complexes with higher turnover numbers. The higher... 

Trinuclear complexes. 26 243 Triphenyl phosphite, ruthenium complex. 26 178... 

Treatment of (80) and (81) with Ru3(CO)12 gave the >/4-silatrimethylenemethane-ruthenium complexes in 9% and 22% yield, respectively. The major product of the Z-alkylidenesilacyclopropane reaction was trinuclear ruthenium carbonyl cluster (82), whose structure was established by x-ray diffraction (Equation (37)). This appears to be the first example of a main group metal-bound carbonyl inserting into a silacyclopropane <9lJA279i, 94OM4606). 

Note that the kinetic model assumes that immobilization will stabilize the structures toward reactions with the sol-gel matrix, or with its components. Structural stabilization afforded by covalent attachment has not been studied extensively, but experiments with mononuclear Fe complexes (162, 172, 181), mononuclear copper complexes (40, 161), and mono- (162), di-, and trinuclear ruthenium complexes (186) suggest that the immobilization reactions do tend to have this stabilizing effect. 

Keene and coworkers made the chiral trinuclear ruthenium complex [(Ru(Phen)3(62)] (5.102) by treatment of the hexadentate bridging ligand HAT (62) (HAT = 1,4,5,8,9,12-Hexaazatriphenylene) with three equivalents of the A-/A-[Ru(Phen)2(CO)2] building block (Figure 5.44). Keene and coworkers investigated this approach thoroughly and... 

Self-assembly of the trinuclear ruthenium complex AAARU3 (5.102) with HAT bridging ligand 62 (from reference ... 

Because it is affected by the interaction of a redox molecule and a matrix, charge transfer can involve both physical diffusion and charge hopping. A typical example is an oxo-bridged trinuclear ammine ruthenium complex called Ru-red 6. 

The mechanisms of the oxidation of phosphines and arsines by chromium(VI) have been examined both in solution and on a diatomite support. Kinetic parameters are presented for both supported and solution reactions. A ruthenium complex of 1,4,8,1 l-tetramethyl-l,4,8,ll-tetraazacyclotetradecane has been utilized to oxidize triphenylphosphine in acetonitrile. Although a limited temperature range was utilized, a AH value of 8.7 0.8 kcal mor and a A5 value of -20 2 cal K mor were calculated. The secondary phosphine oxides, HP(0)R (R = n-butyl, isobutyl, cyclohexyl) and 9H-9-phosphabicyclononane-9-oxide, react with cobaltocene to yield dihydrogen and cobalt(I) compounds. With the less bulky phosphorus ligands at elevated temperatures trinuclear cobalt(III, II) complexes may be obtained. Arsenious acid may be utilized to catalyze the oxygen atom... 

Rg. 3 Trinuclear ruthenium complex able to photocatalyse the selective oxidation of alcohols to the corresponding aldehydes or ketones. Adapted from ref. 103 with permission from The Royal Society of Chemistry. 

Figure 2. Structure of a trinuclear ruthenium complex (Adapted from ref. 11)...

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