Characterisation of two-, three-, and four-co-ordinate gold(I) complexes by 197Au Mössbauer and 31P-{1H} nuclear magnetic resonance spectroscopy

Abstract

The isolation of some new three- and four-co-ordinate gold(I) complexes is reported. ¹⁹⁷Au Mössbauer data are given for two-, three-, and four-co-ordinate complexes, and the technique is shown to be well suited to the determination of co-ordination numbers. For the two- and three-co-ordinate systems the point-charge (partial quadrupole splitting) approach works well, provided that the structures are regular. ³¹P-{¹H} n.m.r. data for the Au⁺–P(C₆H₁₁)Ph₂ system show that a maximum of three ligands can be bound to the cation. Data for this and other ligands are correlated with the ligand cone angles. Inconsistencies between the species present in solution and those obtained by crystallisation are discussed.