Gold(I) complexes derived from secondary phosphines: [{Au(µ-PR2)}n],[(AuBr)2(µ-PPh2)]–, [AuX(PHR2)], and [{Au(PHR2)n}]+. Crystal structure of [AuBr(PHPh2)]

Abstract

The interaction of secondary phosphines with a variety of gold(I) compounds has been studied. In the presence of bases or polar solvents, polymeric gold(I) phosphides [{Au(µ-PR₂)}_n] are formed. When these are obtained in the absence of additional ligands they are soluble, presumably with ring structures. More usually, insoluble forms are found, presumably with chain structures. The probable formation of these materials from complexes of the type [AuX(PH R₂)] is discussed, and the isolation of the latter complexes (X = Cl or Br, R = Ph or p-tolyl) and of the novel monomeric phosphido-bridged anion [(AuBr)₂(µ-PPh₂)]^– is described. In non-polar solvents a series of secondary phosphine complexes is formed, [Au(PHPh₂)_n]⁺(n= 2–4), but that with n= 3 appears to be unstable to disproportionation. The compounds are characterised by ³¹P n.m.r. and ¹⁹⁷Au Mössbauer spectroscopy, and X-ray crystallography in the case of [AuBr(PH Ph₂)].