Synthesis and characterization of [H2NC(S)NP(S)(OiPr)2]- complexes of Co(II), Ni(II), Zn(II) and Cd(II)

Reaction of the potassium salt of the N-thiophosphorylthiourea H2NC(S)NHP(S)(OiPr)(2) (HL) with Co(II), Ni(II), Zn(II) and Cd(II) cations in aqueous EtOH leads to the chelate complexes [ML2] all showing a 1,5-S,S'-coordination formed by the C=S and P=S sulfur atoms of two deprotonated ligands L . The structures of the resulting compounds were studied by IR, UV-Vis, H-1, P-31{H-1} NMR spectroscopy and micro-analysis. The metal center is found in a tetrahedral environment in [CoL2], [ZnL2] and [CdL2]. According to NMR and UV-Vis spectroscopy the metal cation of [NiL2] exhibits square planar coordination geometry in CH2Cl2, CHCl3 and C6H6, while tetrahedral geometry is observed in acetone, DMSO and DMF. Regardless of the solvent used for the crystallization of [NiL2], the molecular structure in the solid is always square planar as was confirmed by XRD of single crystals and magnetic measurements of the polycrystalline material. The magnetic and photoluminescent properties of all complexes are also reported. (C) 2010 Elsevier B.V. All rights reserved.