SYNTHESIS OF THE HEXAKIS[(TRIPHENYLPHOSPHANE)GOLD(I)]METHANIUM(2- CRYSTAL-STRUCTURE DETERMINATION OF THE TETRAFLUOROBORATE SALT() CATION FROM TRIMETHYLSILYLDIAZOMETHANE )

A new synthetic route to the bis(tetrafluoroborate) salt of the hexaki s[(triphenylphosphane)gold(I)]methanium dication has been opened up th rough the reaction of trimethylsilyldiazomethane and tris[ (triphenylp hosphane)gold(I)]oxonium tetrafluoroborate in dichloromethane. Yields are close to 65% if the reaction is carried out in the presence of tri ethylamine as a base. The process is a sequence of desilylation, depro tonation and deazotation reactions at the carbon function of the diazo methane, as shown by the detection of intermediates. The crystal struc ture of the title compound (with three equivalents of crystal dichloro methane) has been determined in a single-crystal X-ray study. The dica tion has no crystallographically imposed symmetry, but the core is a d istorted, carbon-centered octahedron of gold atoms. This result confir ms the data from previous structural studies of salts with ether anion s and interstitial solvents.