A robust dimethylgold(III) complex stabilized by a 2-pyridyl-2-pyrrolide ligand

Reaction of isopropyl[(2-pyridyl)alkyl]amines such as N-isopropyl-N-2-methylpyridine or N-isopropyl-N-2-ethylpyridine with aqueous solutions of NaAuCl4 led to the formation of [LAuCl2][AuCl4] in low yields, where L = pyridyl amine bound to gold in a bidentate fashion. Reaction of 2-(3,5-diphenyl-1H-pyrrol-2-yl)pyridine with aqueous NaAuCl4, however, proceeded with formal loss of HCl and direct formation of the gold(III) amido complex L′AuCl2, where L′ = deprotonated pyrrolyl ligand. Optimization of the reaction conditions to make the new amido complex identified MeCN:H2O (1:2) as the best choice of solvent, affording product in 92% yield. This dichloro amido complex is a convenient precursor to L′AuMe2, which was found to be air-stable and thermally robust.

The bidentate ligand 2-(3,5-diphenyl-1H-pyrrol-2-yl)pyridine (8) reacts with aqueous solutions of NaAuCl4 with a formal loss of HCl to yield the ligated dichlorogold(III) complex (11) in high yields. Complex 11 is a convenient precursor to the corresponding dimethylgold(III) complex (12).Figure optionsDownload as PowerPoint slide