Gold-Mediated Insertion of Oxygen into Silicon-Silicon Bond: An Original Au(I)/Au(III) Redox Sequence

The diphosphine-disilane iPr(2)(o-C6H4)SiMe2SiMe2(o-C6H4)PiPr(2) reacts with AuCl(SMe2) via coordination of the two phosphines and oxidative addition of the sigma-Si-Si bond. The ensuing bis(silyl) gold(III) complex has been unequivocally authenticated by NMR spectroscopy at -60 degrees C. Upon heating, it evolves cleanly to give a disiloxane gold(I) complex that has been fully characterized, including by X-ray diffraction analysis. Oxidation of the disilane proceeds via an original Au(I)/Au(III) redox sequence. According to O-18 labeling experiments, both water and dioxygen are competent oxygen sources. Oxidative addition of the sigma-Si-Si bond to form a bis(silyl) gold(III) complex seems to be a prerequisite for the disilane -> disiloxane conversion to occur.