Diruthenium(II,III) Carboxylate Compounds: Existence of both Polymeric and Ionic Forms in Solution and Solid State.

The reaction of Ru2Cl(μ-O2CMe)4 and ethoxyacetic acid in methanol/water affords a compound of formula Ru2Cl(μ-O2CCH2OEt)4·H2O (1). The crystal structure determination of this complex shows that in the solid state [Ru2(μ-O2CCH2OEt)4] exist, linked by chlorine atoms, together with cationic−anionic complexes of the type [Ru2(μ-O2CCH2OEt)4(H2O)2]+[Ru2Cl2(μ-O2CCH2OEt)4]-. The reaction of 1 with OPPh3 in acetone leads to a compound with the stoichiometry Ru2Cl(μ-O2CCH2OEt)4(OPPh3) (2), which spectroscopic data suggest has a similar structure with cationic−anionic species together with discrete molecular units. These are the first diruthenium compounds containing three different diruthenium units with an anionic−cationic complex.