Mono- and bi-dentate carboxylato complexes of ruthenium(IV)

Abstract

Treatment of the ruthenium(IV) chloro-bridged dimer [{Ru(η³:η³-C₁₀H₁₆)Cl(µ-Cl)}₂]1 with sodium acetate or silver acetate at room temperature in acetone gives the chelate complex [Ru(η³:η³-C₁₀H₁₆)-Cl(O₂CMe)]2. Refluxing 1 in trifluoroacetic acid, or reaction of 1 at room temperature with Ag[CF₃CO₂] gives the monodentate, dicarboxylate species [Ru(η³:η³-C₁₀H₁₆)(O₂CCF₃)₂(OH₂)]3, which contains a tightly bound water ligand. A range of chloro and fluoro substituted carboxylato complexes has been prepared (5–9) and the ‘cross-over’ point between mono- and bi-dentate co-ordination determined. The hexafluoro β-diketonate complex [Ru(η³:η³-C₁₀H₁₆)Cl{F₃CC(O)CHC(O)-CF₃}]10, exhibits the expected bidentate mode of co-ordination. Reaction of 1 with thioacetic acid over short reaction times yields the adduct [Ru(η³:η³-C₁₀H₁₆)Cl₂{SC(OH)Me}]11. The corresponding chelate species [Ru(η³:η³-C₁₀H₁₆)Cl(SOCMe)]12, is formed over longer reaction times. Analogous reacions with thiopivalic and thiobenzoic acids result only in the isolation of the chelate products [Ru(η³:η³-C₁₀H₁₆)Cl(SOCR)](R = Bu^t13 or Ph 14). The structures of complexes 2 and 3 have been verified by X-ray crystallography.