Gold complexes with heterocyclic thiones as ligands. X-Ray structure determination of [Au(C₅H₅NS)₂]ClO₄

Displacement of the weakly co-ordinating tetrahydrothiophene (tht) ligand in [AuX(tht)], [Au(tht)2]ClO4, or [Au(PPh3)(tht)]ClO4(X = Cl or C6F5) by heterocyclic thiones HL (HL = C3H5NS2, C4H4N2S, C5H5NS, C7H5NS2, or C7H6N2S), leads to the formation of neutral or cationic complexes of the types [AuX(HL)], [Au(HL)2]ClO4, or [Au(PPh3)(HL)]ClO4. For gold(III) complexes the tht ligand cannot be displaced but [Au(C6F5)3(OEt2)] reacts with HL to give neutral complexes [AuR3(HL)]. Deprotonation of the NH unit in the cationic complexes leads to neutral monomeric complexes and since the deprotonated N atom is now a donor, binuclear complexes can be prepared by displacement of a weakly co-ordinating ligand from other suitable complexes. The structure of [Au(HL)2]ClO4(HL = C5H5NS) has been established by X-ray crystallography [space group P, a= 9.609(3), b= 15.024(6), c= 16.712(7)Å, α= 97.52(4), β= 104.17(2), γ= 104.76(2)°, and R′= 0.045 for 5 499 unique observed reflections]. The cations are arranged in a way that is unprecedented for gold(I) compounds. Five of the six cations in the cell are linked by short Au ⋯ Au contacts (3.3 Å) and the sixth cation is monomeric.