Discovery of osmium(III) and osmium(IV) binuclear nonahalide complexes: the synthesis, voltammetry, and spectro-electrochemistry of (Bu4N)3[OsIII2Br9] and (Bu4N)[OsIV2Br9], and their relationship to the corresponding di-osmium decahalides

Abstract

Redox-related [Os^IV₂Br₉]^– and [Os^III₂Br₉]^3– have been isolated and characterised for the first time, initially as tetra(n-butyl)ammonium salts, and compared with face-sharing [Ru₂Br₉]^z–(z= 1, 2, 3) and edge-sharing [Os₂X₁₀]^z–(X = Br, Cl; z= 2, 3, 4), by voltammetry and by spectroscopic studies which include the electrogenerated mixed-valence complexes, [Os₂Br₉]^2– and [Os₂Br₁₀]^3–.