Electronic absorption and circular dichroism spectra of Δ-[Os(bipy)2(bipy−)]+, Δ-[Os(bipy)(bipy−)2]0 and Δ-[Os(bipy−)3]−

Abstract

The electronic absorption and circular dichroism spectra of the complexes produced by the one-, two- and three-electron reduction of Δ-[Os(bipy)₃]²⁺ are reported for the first time. The spectra confirm that, as in the cases of the Fe^II and Ru^II analogues, the electrons are localised on the bipyridine ligand and the complexes are correctly formulated [Os(bipy)₂(bipy⁻)]⁺, [Os(bipy)(bipy⁻)₂]⁰ and [Os(bipy⁻)₃]⁻. The absorption spectra of the series of fully reduced complexes [M(bipy⁻)₃]⁻: M  Fe, Ru, Os are compared.