Synthesis and characterisation of N-coordinated pentafluorophenyl gold(I) thiazole-derived complexes and an unusual self-assembly to form a tetrameric gold(I) complex

Treatment of [Au(C6F5)(SC4H8)] (1) (SC4H8 = tetrahydrothiophene or tht) with HC=NC(CH3)=C(H) S, CH3SC=NC(CH3)=C(H) S, (I) or piperidine yields the neutral mononuclear imine complexes [Au(C6F5){ N=C(H) SC(H)=CCH3}] (2) and [Au(C6F5){N=C(SCH3) SC(H)=CCH3}] (3), or the amine complex [Au(C6F5){N(H) CH2(CH2)(3)CH2}] ( 4). The reaction of 1 with S=CN(H) C(CH3) =C(H) S, (II) affords the thione complex [Au(C6F5){S=CN(H)C(CH3)=C(H) S}] (5), which, in CH2Cl2 via spontaneous intermolecular deprotonation of the thione ligand, self-assembles to an unique tetramer of Au(I), [Au{S=CNC(CH3)=C(H)S}](4) (6) containing a folded rectangle of Au-atoms with aurophlilic interactions [av. Au ... Au distance, 3.02(4) Angstrom and av. Au - Au - Au angle, 87(2) degrees]. N-coordination of the imine complexes has been confirmed by N-15 NMR and the crystal structure determination of 2 which exhibits the expected linear N-coordination and intermolecular Au...Au [3.345(1) Angstrom] contacts. The crystal structure of 5 shows thione S-coordination of II to the central Au atom.