Synthesis and characterization of ethylxanthato complexes of zinc(II) with P-donor ligands

Monomeric, five-coordinated bis(ethylxanthato) Zn-II(phosphine) complexes [phosphine = PPh3, P(o-tolyl)(3), P(CH2Ph)(3)] have been synthesized by addition of the phosphine ligand (1: 1 molar ratio) to CH2Cl2 solutions of [Zn(S2COEt)(2)]. Bidentate ligands Ph2PCH2CH2PPh2 (dppe) and Ph2P(CH2)(4)PPh2 (dppb) reacted in a 1: 2 molar ratio to form dinuclear phosphine-bridged complexes. The Zn-P bonds are very labile and are probably broken in solution. The characterization of all the compounds has been carried out by elemental analyses and spectroscopic methods (i.r. and n. m. r.). The structure of binuclear [(S2COEt)(2)Zn(mu-dppb) Zn(S2(C)OEt)(2)], determined by X-ray crystallography, shows a distorted trigonal bipyramidal environment for the Zn atoms, formed by two chelating xanthate and a bridging dppb ligand.