(Phosphine)gold(I)-silyloxides and -silylthiolates

The gold siloxanes Me(3)PAuOSiMe(3) (1) and Ph(3)PAuOSiPh(3) (2) were prepared from the corresponding (phosphine) gord(I) chlorides and sodium silanolates in dichloromethane as colorless, stable, crystalline solids. The crystal structure of compound 1 (monoclinic, space group C2/c, Z=8) has been determined by X-ray methods. The lattice contains centro-symmetrical dimers with short Au-Au contacts (3.376(2) Angstrom). The Si-O-Au angle is 121.0(4)degrees; the coordination geometry at the gold atom is close to linear. The hexaphenyl compound 2 is assumed to be a monomer like the methylpentaphenyl analog MePh(2)PAuOSiPh(3), owing to steric effects. The thiosiloxane (silylthiolate) Ph(3)PAuSSiPh(3) (3) was obtained from Ph(3)PAu(acac) and Ph(3)SiSH in CH2Cl2. It crystallizes in the monoclinic space group P2(1)/n with Z=4 molecules in the unit cell. The compound is a monomer in the crystal with a narrow angle at the sulfur atom (95.0(1)degrees) and a linear coordination geometry at the gold atom. Association is again prevented by steric effects.