The quest for complexes with a coordinative gold-bismuth bond

In attempts to prepare gold(I) bismuthine compounds of the type R3Bi-AuX with a coordinative Au-Bi bond, the complexes (C4H8S)AuCl, (Me2S)AuCl, (C4H8S)AuC6F5, (Ph3P)AuCl, and [(Ph3P)Au]BF4 were reacted with the tertiary bismuthines Me3Bi, MePh2Bi, Ph3Bi, (2-MeO-C6H4)(3)Bi, and (2-Me2NCH2-C6H4)(3)Bi in different molar ratios in dichloromethane at low temperatures. In all reactions the bismuthines acted as alkylating or arylating agents for gold to give organogold complexes. The products with the sulfur ligands were generally unstable and decomposed above -50 degreesC. With phosphine ligands, the organogold(I) complexes can be traced in the reaction mixtures by NMR spectroscopy. The primary product (Ph3P)AuPh is aurated further by [(Ph3P)Au]BF4 to give C6H5[Au(PPh3)](2)BF4. A stable dinuclear arylgold complex was obtained in the reactions of the thioether complexes with tris(2((dimethylamino)methyl)phenyl)bismuthine, and the structure of this 10-membered metallacyclic compound has been determined: [-Au-C6H4CH2NMe2-](2). The molecules feature strong transannular aurophilic interactions. The crystal structure of tris(2-methoxyphenyl)bismuthine has also been determined.