Mesitylgold(I) complexes. Crystal structures of NEt4[Au(mes)CI] and [N(PPh3)2][(mes)Au(CN)Au(mes)]

Abstract

Arylation of [AuCl(tht)](tht = tetrahydrothiophene) with [{Ag(mes)}₄](mes = mesityl) gives [{Au(mes)}₅]. Both the silver and gold complex can be used for the syntheses of mono- or bi-nuclear cationic, neutral, or anionic mesitylgold complexes of the form Au(mes) L [L = PPh₃, PPh₂Me, P(OPh)₃, or ½(Ph₂PCH₂PPh₂), [{Au(PPh₃)}₂(µ-mes)]CIO₄, Q[Au(mes)X](Q = NEt₄ or NBu₄; X = C₆F₅ or Cl), or [N(PPh₃)₂][(mes)Au(CN)Au(mes)]. The structures of NEt₄[Au (mes) Cl] and [N(PPh₃)₂][(mes)Au(CN)Au(mes)] have been determined by single-crystal X-ray methods. The complex NEt₄[Au(mes)CI] crystallizes in space group P2₁/n with a= 8.526(1), b= 13.917(2), c= 16.457(2)Å, β= 101. I 4(1)°, and Z= 4; R 0.038 for 2 656 unique observed reflections. The Au–Cl bond is long and the Au–C bond short [2.328(2) and 2.018(7)Å respectively]. The complex [N(PPh₃)₂][(mes)Au(CN)Au(mes)] crystallizes in space group C2/c with a= 27.702(8), b= 12.318(4), c= 20.501(6)Å, β= 135.61(1)°, and Z= 4; R 0.037 for 3 576 unique observed reflections. The anion and the cation both have imposed crystallographic two-fold symmetry, and the bridging CN group must therefore be disordered. The Au–C(mesityl) bond length is 2.035(11)Å.