Synthesis, spectroscopic, magnetic and electrochemical properties of diruthenium-(<scp>II</scp>,<scp>III</scp>) and -(<scp>III</scp>,<scp>III</scp>) complexes containing the mixed-carboxylato ligand systems CH₃CO₂^––CF₃CO₂^–and C₆H₅CO₂^––CF₃CO₂^–

Abstract

The interaction of the Ru25+ tetra-µ-carboxylates [Ru2(O2CR)4Cl](R = CH3 or C6H5) with alcoholic solutions of Ag(O2CCF3) yields the Ru25+ mixed-carboxylato, monotrifluoroacetato derivatives [Ru2(O2CR)4(O2CCF3)L2](L = H2O or MeOH). The omission of alcohol and inclusion of trifluoroacetic acid in the reaction medium directs the synthesis to the Ru25+ mixed-carboxylato, tris(trifluoroacetato) complexes, [Ru2(O2CR)2(O2CCF3)3(H2O)0.5]. Under aerobic conditions the oxidized, paramagnetic Ru26+ tetrakis(trifluoroacetato) complex [Ru2(O2CCH3)2(O2CCF3)4(H2O)2] is obtained. Conductivity measurements, electronic and i.r. absorption spectra, and magnetic susceptibility data are given. Cyclic voltammetry measuements show that increased numbers of CF3CO2– ligands in the complexes are responsible for an anodic shift in the potential of the Ru25+⇌ Ru24+ couple. Structures are proposed for the tris- and tetrakis-(trifluoroacetato) complexes.