Mixed valence gold chemistry: Stepwise oxidation of a cyclic trigold(I) complex

Oxidation of the cyclic complex Au₃(CH₃OCNCH₃)₃ by iodine or bromine produces three distinct complexes Au₃(CH₃OCNCH₃)₃X_n (_n = 2,4 or 6, X = Br or I) in which the gold atoms undergo stepwise oxidative halogen addition. The products have been characterized by elemental analysis, molecular weight determinations, proton magnetic resonance spectra and IR spectra. The complexes with n = 4 or 2 undergo spontaneous autodecomposition. In the case of Au₃(CH₃OCNCH₃)₃Br₄ this decomposition produces gold metal, Au₃(CH₃OC NCH₃)₃Br₆, methyl bromide, and methyl isocyanate in an extremely clean reaction.