Notes. Synthesis and structure of µ-[trans-1,2-bis(diphenylphosphino)ethylene]bis[chlorogold(I)]

Abstract

The 1:2 ligand: Au^I complex [ClAu(µ-trans-Ph₂PCHCHPPh₂)AuCl] was prepared by reduction of Au^III to Au^I with 2,2′-thiodiethanol followed by reaction with an excess of ligand, and thus differs from the product characterized previously from direct reduction of Au^III with the ligand. Infrared band assignments for ν(Au–P) and ν(Au–Cl) of the present complex are 352 and 322 cm^–1, respectively. Assignments for ν(Au–P) and ν(Au–Cl) of 347 and 323 cm^–1, respectively, for the complex of the cis ligand, which are more consistent than present literature values, are reported also. The crystal structure of the complex has been determined from diffractometer data and refined to R= 0.031 based on 2 104 observed reflections [I 3σ(I)]. The molecule sits on an inversion centre in space group C2/c, thus the trans geometry of the ligand and of the complex are rigorously reflected in the crystallographic results. The gold atom is linearly co-ordinated with normal Au–Cl and Au–P bond lengths of 2.291 (2) and 2.235(2)Å, respectively. A short intermolecular Au ⋯ Au contact of 3.043(1)Å is observed.