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

Abstract

Reaction of (NHC)­Au–X\n(X = halide) complexes with 2- or\n4-mercaptopyridine under basic conditions allows for the preparation\nof a series of (NHC)­Au^I–mercaptopyridine complexes <b>1</b>–<b>4</b> in high yields. All complexes have\nbeen fully characterized by means of ¹H and ¹³C NMR spectroscopy, melting point, and elemental analysis. Single\ncrystals of complexes <b>1</b>–<b>3</b> were obtained,\nand the solid-state structures display a linear Au­(I) center with\ncoordination to the NHC ligand and the sulfur atom of the mercaptopyridine\nmoiety. Interestingly, weak γ-anagostic C–H···Au\ninteractions are found in complexes <b>1</b>–<b>3</b> regardless of the relative N or S position in the mercaptopyridine.\nTaking advantage of the free pyridine nitrogen, reaction of complexes <b>1</b> and <b>2</b> with palladium allyl chloride dimer permits\nthe isolation of heteronuclear Au/Pd complexes <b>5</b> and <b>8</b> featuring a bridging ambidentate mercaptopyridine ligand.\nFurther reactivity of complexes <b>1</b>–<b>3</b> toward B­(C₆F₅)₃ produces complexes <b>6</b>, <b>7</b>, and <b>9</b>, which display frustrated\nLewis pair reactivity with the activation of a H–F bond.