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 H C=NC(CH3)=C(H)S, CH3S C=NC(CH3)=C(H)S, (I) or piperidine yields the neutral mononuclear imine complexes [Au(C6F5){ N=C(H)SC(H)=C CH3}](2) and [Au(C6F5){ N=C(SCH3)SC(H)=C CH3}](3), or the amine complex [Au(C6F5){ N(H)CH2(CH2)3C H2}](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 CH2Cl2via 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)°]. N-coordination of the imine complexes has been confirmed by 15N NMR and the crystal structure determination of 2 which exhibits the expected linear Ncoordination 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.