Heavier pnictinidene gold(i) complexes

Abstract

N,C,N-Chelated pnictinidenes ArE [where E = As, Sb or Bi; Ar = 2,6-(tBuNCH)₂C₆H₃] were used as ligands for the coordination of various gold(I) complexes. Thus, the reaction of ArE with [AuCl(Me₂S)] gave complexes [AuCl(ArE)] [where E = As (1) or Sb (2)] that exhibited only limited stability in solution. By contrast, the reaction of ArBi with [AuCl(Me₂S)] led to the immediate deposition of gold metal and the oxidation of the bismuth atom giving ArBiCl₂. The treatment of a tetrameric gold alkynyl complex [Au(CCPh)]₄ with ArAs and ArSb gave ionic compounds [Au(ArAs)₂]⁺[Au₂(CCPh)₃]⁻ [denoted as 3⁺[Au₂(CCPh)₃]⁻] and [Au(ArSb)₂]⁺[Au(CCPh)₂]⁻ [denoted as 4⁺[Au(CCPh)₂]⁻], respectively. Finally, the reaction of ArE with the carbene gold(I) complex [Au(IPr)(MeCN)]⁺[BF₄]⁻ [where IPr = 1,3-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene, MeCN = acetonitrile] produced ionic complexes [Au(IPr)(ArE)]⁺[BF₄]⁻ [for cations: E = As (5⁺), Sb (6⁺) or Bi (7⁺)]. All complexes were characterized using ¹H and ¹³C NMR, high mass accuracy electrospray ionization mass spectrometry (ESI-MS), IR and Raman spectroscopy and (except for 1) by single-crystal X-ray diffraction analysis. Furthermore, the structure and bonding of both neutral and ionic complexes with different coordination patterns have also been investigated in detail using a Density Functional Theory (DFT) computational approach.