Preparation and structure of poly(gold)telluronium salts

Tris[(triphenylphosphine)gold(I)]telluronium teratrafluoroborate (1) was prepared from the corresponding oxonium salt and bis(t-butyldimethylsilyl)tellurium in dichloromethane at -78 degrees C. The product forms yellow crystals, thermally stable to 125 degrees C. It was identified by standard analytical and spectroscopic techniques, including a single crystal X-ray diffraction study In the crystal lattice, the cations form tellurium-capped triangles of gold, which are associated into dimers through short intermolecular Au-Au contacts, resembling those in the corresponding sulfur and selenium compounds. - The reaction of (t-BuMe(2)Si)(2)Te with four equivalents of {[(Ph(3)P)Au]Te-4}(2+) 2 BF4- in tetrahydrofuran at -78 degrees C gives a tetranuclear compound, {[(Ph(3)P)Au]Te-4}(2+) 2 BF4- (2) which differs from 1 in its analytical and spectroscopic data. Its structure could not be determined, but it is assumed that the dications have a square pyramidal geometry.