Triruthenium

Summarized are a series of investigations using both thermal and photochemical techniques to probe the reaction dynamics of intermediates formed in various reactions of triruthenium cluster complexes. 

In this article we have summarized the use of both photochemical and more classical thermal kinetics techniques to deduce the nature of intermediates in the ambient temperature, fluid solution chemistry of several triruthenium clusters. In some cases the photochemically generated intermediates appear to be the same as those proposed to be formed along thermal reaction coordinates, while in other cases unique pathways are the results of electronic excitation. The use of pulse photolysis methodology allows direct observation, and the measurement of the reaction dynamics of such transients and provides quantitative evaluation of the absolute reactivities of these species. In some cases, detailed complementary information regarding... 

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... 

The triruthenium pentahydride cluster [ (775-C5Me5)Ru 3(/x-H)3(//3-H)2] reacted with exactly 1 equiv. of diethylzinc, Scheme 102, with the elimination of ethane and the formation of [ (775-C5Me5)Ru 3(/x-FI)3(/X3-ZnEt)(/X5-FI)] 168 in... 

Oxo-Centered Triruthenium-Acetate Cluster Complexes Derived from Axial or Bridging Ligand Substitution... 

Keywords Acetate Cluster Electronic interaction Ligand substitution Redox Triruthenium... 

Triruthenium Complexes from Axial Ligand Substitution... 

Triruthenium Complexes with Ortho-Metallated Ligands... 

It has been several decades since oxo-centered triruthenium-carboxylate complexes with triangular cluster frameworks of Ru3(p3-0)(p-00CR)6 (R = alkyl or aryl) were first isolated [1,2]. In the early 1970s, the first oxo-centered triruthenium complex was structurally characterized by Cotton through X-ray crystal structural determination [3]. Since then, oxo-centered trinuclear ruthenium-carboxylate cluster complexes with general formula [Ru30(00CR)6(L)2L ]n+ (R = aryl or alkyl, L and... 

L = axial ligands, n = 0, 1, 2) have been extensively investigated regarding their specific electronic, chemical, and physical properties [4], Particularly, oxo-centered triruthenium cluster complexes with bridging acetates attracted the most attention owing to their synthetic accessibility, multiple redox behavior, intriguing mixed-valence chemistry, and versatile catalytic properties [5-7]. 

N-heterocycles are a class of neutral ligands with strong coordination affinity to many metal ions. Since a number of neutral N-donors ligands are available, a wide range of oxo-centered triruthenium complexes with various N-heterocyclic ligands have been prepared through axial ligand substitution. By judicious selection of the N-heterocyclic type and modification of the substituents with different electronic and steric effects, the electronic, redox, and spectroscopic properties in these oxo-centered triruthenium derivatives are controllable. 

Using solvent-containing triruthenium species 1 as a synthetic precursor, a series of pyridyl-substituted triruthenium derivatives [Ru30(0Ac)6(py)2(L)]+ (L = 4,4 -bpy 5, BPE 6, BPA 7) were prepared by Meyer et al. [9]. Electrochemical studies showed that these triruthenium complexes exhibit four to five reversible one-electron redox waves in the potential range of +2.0 to —2.0 V, suggesting that these complexes can... 

By introducing redox-active N-methyl-4,4/-bipyridinium ion (mbpy+) to the oxo-centered triruthenium cores, a series of triruthenium derivatives bearing two or three axially coordinated mbpy+ were prepared by Abe et al. [12, 13]. Electrochemical studies indicated that these mbpy+-containing triruthenium complexes afforded a total of seven to nine reversible or quasi-reversible redox waves in acetonitrile solutions at ambient temperature. Of these redox waves, four or five one-electron redox processes arise from RU3 -based oxidations or reductions involving five or six formal oxidation states, including... 

Layer-by-layer Ru3 cluster-based multilayers were fabricated onto preorganized self-assembled monolayer gold electrode surfaces by Abe et al. [15], in which [Ru3(q3-0)( i-0Ac)6(4,4/-bpy)2(C0)] was utilized as the synthetic precursor. The stepwise connection of oxo-centered triruthenium cluster units onto the gold electrode surface is a feasible approach for construction of Ru3 cluster-based oligomers on a solid surface, in which the bridging ligand 4,4 -bipyridine appears to mediate weak cluster-cluster electronic interaction between the Ru3 cluster centers. 

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