Ruthenium and Osmium Complexes Containing Multiple Bonds to Heteroatoms

Ruthenium and Osmium Complexes Containing Multiple Bonds to Heteroatoms 

In general, as we go through the various oxidation states in this review, we will come to see that corresponding oxidation states are less stable in ruthenium than in osmium. This has partially been attributed to the lower ioinization potentials for the corresponding oxidation states of a 5d element compared to a 4d element. 

Selected Metal-Oxo Bond Distances and Stretching Frequencies for Ruthenium and Osmium Oxo Complexes 

A ruthenium(IV) oxo complex containing pyridyl-type ligands, [RuIV (N40)(0)]+, has been generated by electrochemical oxidation of [Ru111 (N40)(0H2)]2+ in aqueous solution (pH 3.5). No isolation has been reported and this Ru(IV) oxo species was found to disproportionate to Ru(III) and Ru(V) in acidic solution (45). 

An oxoaquaruthenium(IV) complex of a macrocyclic mixed N,0-donor ligand, [RuIV(N202)(0)(H20)]2+ (N202 = l,12-dimethyl-3,4 9,10-dibenzo-l,12-diaza-5,8-dioxacyclopentadecane), has been prepared by electrochemical oxidation of rRuin(N202)(0H)(0H2)]2+ and characterized by X-ray crystallography (Fig. 2) (46). Isolation of this complex from aqueous solution has been taken as an indication of a very small equilibrium constant for the reaction 

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