The First Metal Complexes Derived from 3,5-Diethynylpyridine. X-ray Crystal Structure of [(AuPTo3)2{μ-(C⋮C)2Py}] (Py = Pyridine-3,5-diyl; To = p-Tolyl)

The reactions of 3,5-diethynylpyridine (Py(C⋮CH)2) with PPN[Au(acac)2] (2.5:1; PPN = Ph3PNPPh3) or with [AuCl(SMe2)] and NEt3 (1:2:2) give respectively PPN[Au{C⋮C(Py)C⋮CH}2] (1) and [Au2{μ-(C⋮C)2Py}] n (2). Complex 2 reacts with monodentate ligands (1:2) or with 1,6-bis(diphenylphosphino)hexane (dpph, 1:1) to give neutral dinuclear complexes of the general formula [(AuL)2{μ-(C⋮C)2Py}] (L = CN t Bu (3), PMe3 (4), PPh3 (5), PTo3 (To = C6H4Me-4) (6); Au2L2 = Au2(μ-dpph) (7)). The reactions of 6 with the complexes [MCl] and TlTfO (1:1:1) (TfO = CF3SO3) give the cationic trinuclear complexes [M{Py(C⋮CAuPTo3)2}]TfO (M = AuPTo3 (8), cis-PtCl(PPh3)2 (9)). The crystal structure of complex 6 has been determined.