The metal vapor synthesis and reactions of bis(trifluoromethyl)gold-mu-halide dimers

Abstract

The metal vapor synthesis of two novel bis(trifluoromethyl)gold-$\mu$-halide dimers was accomplished by the codeposition of gold atoms with freons (CF$\sb3$X; X = Br, I) at $-$196$\sp\circ$C. The reactor, the reaction procedures and conditions, and the isolation and purification techniques are described here. Solution IR, $\sp{19}$F NMR, mass spectrometry, and x-ray crystallography were used to characterize the two compounds. Both compounds showed moderate vapor pressures and were treated with thallium hexafluoroacetylacetonate, phosphorus trifluoride, and tris(trifluoromethyl)phosphine in an attempt to synthesize monomeric compounds with higher vapor pressures. The dimers were decomposed by PF$\sb3$ and did not react with P(CF$\sb3)\sb3$; neither reaction yielded soluble gold compounds detectable by mass spectrometry. Reaction with Tl(hfacac) resulted in an unstable oily product which gave a mass spectrum characteristic of bis(trifluoromethyl)gold hexafluoroacetylacetonate. This compound decomposed readily and resisted isolation. All of the isolated gold compounds were light sensitive. The bis(trifluoromethyl)gold-$\mu$-halide dimers were resistant to air oxidation.