New organogold(I) complexes: Synthesis, structure, and dynamic behavior of the polynuclear organogold diphenylmethane and diphenylethane derivatives

Two organogold derivatives of diphenylmethane and diphenylethane, Ph3PAu(o-C6H4)CH2(C6H4-o)AuPPh3 (1) and Ph3PAu(o-C6H4)(CH2)2(C6H4-o)AuPPh3 (2), have been synthesized by the reaction of ClAuPPh3 with Li(o-C6H4)CH2(C6H4-o)Li and Li(o-C6H4)(CH2)2(C6H4-o)Li respectively. The interaction of 1 with dppe results in the replacement of the two PPh3 groups to give a macrocyclic compound Au(o-C6H4)CH2(C6H4-o)Au(μ-PPh2CH2CH2P︹Ph2) (3) that includes an Au ⋯ Au bond. Compounds 1 and 2 react with one or two equivalents of [Ph3PAu]BF4 to form new types of cationic complex [CH2(C6H4-o)2(AuPPh3)3]BF4 (4), [CH2(C6H4-o)2(AuPPh3)4](BF4)2 (5), and [(CH2)2(C6H4-o)2(AuPPh3)4](BF4)2 (6). Complexes 1–6 have been characterized by X-ray diffraction studies, FAB MS, and IR as well as by 1H and 31P NMR spectroscopy. A complicated system of Au ⋯ H-C agostic interactions, involving the bridging alkyl groups (—CH2— and CH2-CH2—) of diphenylmethane and diphenylethane ligands, has been found to occur in complexes 1–3 and 6.