Synthesis and Reactivity of (NHC)Au^I–Mercaptopyridine Complexes

Abstract

Reaction of (NHC)Au–X (X = halide) complexes with 2- or 4-mercaptopyridine under basic conditions allows for the preparation of a series of (NHC)AuI–mercaptopyridine complexes 1–4 in high yields. All complexes have been fully characterized by means of 1H and 13C NMR spectroscopy, melting point, and elemental analysis. Single crystals of complexes 1–3 were obtained, and the solid-state structures display a linear Au(I) center with coordination to the NHC ligand and the sulfur atom of the mercaptopyridine moiety. Interestingly, weak γ-anagostic C–H···Au interactions are found in complexes 1–3 regardless of the relative N or S position in the mercaptopyridine. Taking advantage of the free pyridine nitrogen, reaction of complexes 1 and 2 with palladium allyl chloride dimer permits the isolation of heteronuclear Au/Pd complexes 5 and 8 featuring a bridging ambidentate mercaptopyridine ligand. Further reactivity of complexes 1–3 toward B(C6F5)3 produces complexes 6, 7, and 9, which display frustrated Lewis pair reactivity with the activation of a H–F bond.