Resonance Raman, infrared and electronic spectral studies of the µ-Oxo-decahalogenodimetallate species [Ru2OCl10]4–, [Re2OCl10]3–, [Os2OCl10]4–, [Re2OCl10]4–, [W2OCl10]4– and [W2OBr10]4–

Abstract

Studies of the resonance Raman spectra of the series of dimetallate ions [Ru₂OCl₁₀]^4–, [Re₂OCl₁₀]^3–, [Os₂OCl₁₀]^4–, [Re₂OCl₁₀]^4–, [W₂OCl₁₀]^4– and [W₂OBr₁₀]^4– have led, in each case, to the observation of one or more progressions in which the v₁(a_1g) symmetric metal–oxygen–metal stretching mode is the progression-forming mode. Excitation profile measurements on the a_1g Raman bands indicate that the resonant electronic transition is an axially polarised π*â†�π transition of the M—O—M π-system in each case. Force constant calculations show that the metal–oxygen stretching force constant, ƒ_MO, is high in each case (4.53–5.07 mdyn Å^–1), indicative of M—O—M double-bond character.