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A series of aurocyanide and auricyanide complexes of phosphines, phosphine sulfides, and phosphine selenides were synthesized. These new complexes have the general formula [L n Au(CN) m ], where L could be Cy3P, (2-CN-Et)3P, Me3PS, Et3PS, Ph3PS, Me3PSe, or Ph3PSe. Auricyanide was reacted with L at 1 : 2 ratio. Products were characterized using elemental analysis, melting point, UV, IR, far-IR solution, and solid-state NMR spectroscopy. Phosphine ligands cause gold(III) reduction to gold(I); less redox tendency was found for phosphine sulfides and phosphine selenides. Tri-coordinate complexes [L2AuCN] were produced from phosphine ligands with gold-tetracyanide. IR and UV spectroscopic methods were used to identify gold oxidation state in the synthesized complexes.

The preparation and characterization of zinc complexes of formula ZnL2X2 (X = Cl and Br), with L = 1,3-diazinane-2-thione (Diaz), 1,3-diazipane-2-thione (Diap), imidazolidine-2-thione (Imt) and its methyl and n-propyl substituted derivatives, are described. The complexes dichlorobis(1-methylimidazolidine-2-thione-S)-zinc(II) (1) and dichlorobis(1-propylimidazolidine-2-thione-S)-zinc(II) (2) have been characterized by single-crystal X-ray methods. Both complexes adopt distorted tetrahedral geometry. Only intramolecular hydrogen bonding interactions are observed in 1 and 2. Solution and solid state 13C NMR show a significant shift of the C=S carbon resonance of the ligands, while other resonances are relatively unaffected, indicating that most likely the solid state structure is maintained in solution. Antimicrobial activity studies of the free ligands and their complexes show that ligands exhibit substantial antibacterial activities compared to the complexes.