Synthesis and structural characterization of novel zinc(II) and cadmium(II) complexes with pyridine-phosphine chalcogenide ligands

New pyridine-phosphine chalcogenide ligands, tris[2-(2-pyridyl)ethyl]phosphine sulfide 1a and tris[2-(2-pyridyl)ethyl]phosphine selenide 1b, react with zinc(II) and cadmium(II) chlorides in EtOH at room temperature to afford complexes of compositions 2ZnCl2·2L (2, L = 1a) and 3CdCl2·2L (3a,b, L = 1a,b) in high yields. The solid-state structure of complexes 2, 3 has been proved by X-ray analysis data. Complex 2 is a centrosymmetric dimer, where two atoms of zinc are bonded by two bridging pyridine-phosphine sulfide ligands through N atoms. Complexes 3a,b exist as polymeric chains with each bridging ligand acting as a chelate N,S- or N,Se-donor to one cadmium(II) center and as a pyridine N-donor to the next cadmium(II) center.

Tris[2-(2-pyridyl)ethyl]phosphine sulfide 1a and tris[2-(2-pyridyl)ethyl]phosphine sulfide and tris [2-(2-pyridyl)ethyl]phosphine selenide 1b react with zinc(II) and cadmium(II) chlorides (r. t., EtOH) to afford complexes of compositions 2ZnCl2·2L (2, L = 1a) and 3CdCl2·2L (3a,b, L = 1a,b). Complex 2 is a centrosymmetric dimer, complexes 3a,b exist as polymeric chains.Figure optionsDownload as PowerPoint slideHighlights
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► Novel Zn(II) and Cd(II) complexes with tris[2-(2-pyridyl)ethyl]phosphine selenide are synthesized.
► Zn is coordinated only by N and its complex is a centrosymmetric dimer.
► Cd is coordinated both by N and S (Se) and its complexes exist as polymeric chains.