New routes towards halogeno complexes of gold by halide exchange from [Au2Cl6]. Crystal and molecular structure of triphenylmethylium tetrachloroaurate(III), [CPh3][AuCl4]

Abstract

Anhydrous [Au₂Br₆] and Aul can be obtained by halide exchange from [Au₂Cl₆] with RX (X = Br or I, R = H or alkyl). The addition of [Au₂Cl₆] to CPh₃Cl produces the ionic derivative [CPh₃][AuCl₄] whose crystal and molecular structure has been determined by X-ray diffraction. Crystal data: space group P2₁/c, a= 8.225(3), b= 14.671(6), c= 16.738(8)Å, β= 97.85(2)° and Z= 4. Other organic chlorides RCl (R = Pr, SiMe₃ or Bu^t) react with [Au₂Cl₆] with a partial reduction to the mixed-valence chloride [Au₄Cl₈]. Addition of [Au₂Cl₆] to anhydrous iron(III) chloride produced a mass-spectrometrically active mixed iron–gold species.