Gold(I)-Komplexe sekundärer Phosphine / Gold(I) Complexes of Secondary Phosphines

Abstract

Gold(I) complexes with secondary phosphines R2PH (la—d) of the type R2PH · AuCl (2a—d) have been obtained in good yield from reactions of (carbonyl)chlorogold(I) and the corresponding ligand in diethylether. Both compounds 2a, b bearing aromatic substituents with R = 2,4,6-trimethylphenyl (mesityl) and 2-methylphenyl (o-tolyl), and compounds 2c, d with the bulky alkyl substituents R = t-butyl and R = cyclohexyl, resp., are air-stable crystalline solids. — The coordination compounds have been characterized by NMR and IR data, and — in the cases of 2b and 2c — by single crystal X-ray diffraction studies. Crystals of these two compounds are both monoclinic, space group P21/c with four formula units (Z = 4). The analysis shows independent monomers for compound 2c with no intermolecular Au···Au contacts. Molecules of 2b are arranged in centrosymmetrical dimers (head to tail) with an Au···Au distance of 3.56 Å and a dihedral angle P—Au—Au′—P′ of 180°. (This structural study is as yet incomplete and suffers from an unsatisfactory data set for 2b.) It appears that intermolecular contacts are largely controlled by steric effects.