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

The diphosphine–disilane iPr2(o-C6H4)­SiMe2SiMe2(o-C6H4)­PiPr2 reacts with AuCl­(SMe2) via coordination
of the two phosphines and oxidative addition of the σ-Si–Si
bond. The ensuing bis­(silyl) gold­(III) complex has been unequivocally
authenticated by NMR spectroscopy at −60 °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 18O labeling experiments, both water and dioxygen
are competent oxygen sources. Oxidative addition of the σ-Si–Si
bond to form a bis­(silyl) gold­(III) complex seems to be a prerequisite
for the disilane → disiloxane conversion to occur.