Synthesis and characterization of neutral and cationic diamino carbene complexes of gold(I)

Abstract Bis(1-methylimidazolyl)aurate compounds were prepared by reacting 1-methylimidazol-2-yllithium and 1-methylbenzimidazol-2-yllithium with [AuCl(THT)] (THT = tetrahydrothiophene). Protonation or alkylation of the aurates yielded bis(carbene) complexes of the type [Au{ CNR 1 CR 2 CR 3 N (Me)} 2 ] + (R 1 = H or Me; R 2 = H or R 2 R 3 = C 4 H 4 ). The reaction of 1-methylimidazol-2-yllithium with [AuCl(PPh 3 )] afforded the same bis(carbene) cation after protonation or alkylation. Mono(diamino)gold(I)carbene complexes resulted from the sequential reactions of 1-methylimidazol-2-yllithium with [Au(C 6 F 5 )(THT)] or AuCN and CF 3 SO 3 Me or CF 3 SO 3 H. Complicating side-reactions such as homoleptic rearrangement and protonation on carbon rather than nitrogen were observed.