(β-Diketiminato)dimethylgold(III): Synthesis, Structure, and Reactivity

The reaction between [Me,AuCl], and the lithium salt of a beta-diketimine, [HC{C(Me)N(C6H3-2, 6-Me-2)}(2)Li], yields the neutral Au(III) compound [HC{C(Me)N(C6H3-2,6-Me-2)}(2)AuMe2] (1). Compound 1 reacts with I equiv of triflic acid (HOTf) at 78 C to provide the cationic Au(III) compound [H2C{C(Me)N(C6H3-2,6-Me-2)}(2)AuMe2][OTf] (2). Treatment of I with 2 equiv of HOTf results in the displacement of Me2AuOTf and formation of the beta-diketiminato triflate salt [HC{C(MONH(C6H3-2,6-Me)}(2)][OTf] (3). Compound I reacts with I-2 to yield the cation [HC(I)-{C(Me)N(C6H3-2,6-Me-2)}(2)AuMe2](+), which is isolated as the triflate salt [HC(I){C(Me)N(C6H3-2,6-Me-2)}(2)AuMe2][OTf] (4). The reaction of 1 with (PPh3)AuCl in the presence of AgOTf provides [HC(AuPPh3){C(Me)N(C6H3-2,6-Me-2)}(2)AuMe2][OTf] (5). Molecular structures of 1, 4, and 5 were elucidated by single-crystal ti-ray diffraction experiments; that of 4 was additionally confirmed by quantum-chemical calculations. The reactivity experiments indicate that the methine carbon in the beta-diketiminato unit of I is the exclusive site of electrophilic attack, while the Au C bonds are not perturbed.