An investigation of structural motifs in gold complexes

A series of gold(I) phosphine halides complexes of the type [AuX(PAr3)] have been synthesized. All of the complexes have been investigated and structurally characterised by means of NMR spectroscopy and single crystal X-ray crystallography. In the solid state all of the complexes adopt an approximately linear geometry at gold with the bond angles ranging from 170.50(12)° to 179.19(6)° for Cl-Au-P, 169.32(6)° to 179.10(6)° for Br-Au-P and 165.35(7)° to 178.62(7)° for I-Au-P. The Au-X bond lengths ranged from 2.277(2) Å to 2.319(3) Å (X = Cl), 2.3470(4) Å to 2.4248(10) Å (X = Br) and 2.5513(6) Å to 2.5787(7) Å (X = I), while the Au-P distances were between 2.219(2) Å and 2.261(2) Å. The presence, or otherwise, of short Au···Au interactions as a function of halide and phosphine steric and electronic parameters has been investigated. The Au···Au distances range from 3.1273(8) Å in [AuCl{P(3,4,5-C6H2F3)3}] to 9.0059(6) Å in [AuCl(3,5-(CF3)2C6H3)3]. For all complexes the Au···Au distances increase as the halide changes from Cl, Br, I, except for [AuX{P(3,5-(CF3)2C6H3)3}], X = Cl, Br, I, where the reverse trend is observed. The secondary C-H···X, C-H···F and F···F interactions are also investigated.