Palladium(II) Complexes of Tridentate Ligands. The Crystal Structure of Chloro[2,6-di(2-imidazolin-2-yl)pyridine]palladium(II) Chloride

Abstract

Mono(ligand) palladium(II) complexes of 2,6-di-(thiazol-2-yl)pyridine (1a), 2,6-di(4-methylthia-zol-2-yl)pyridine (1b), 2,6-di(thiazol-4-yl)pyridine (2a), 2,6-di(imidazolin-2-yl]pyridine (3) and 2,6-di(benzimidazol-2-yl)pyridine (4a) of the general formula [ PdLCl ] Cl have been prepared. Stoichiometries have been confirmed by C, H, N and Pd analyses; the presence of solvate molecules has been confirmed by thermogravimetry . The crystal structure of [ PdLCl ]Cl.H₂O, L = (3), has been determined by single-crystal X-ray diffractometry. The compound crystallizes in an orthorhombic space group, Pna2₁, a 7.427(2), b 21.932(3), c 8.935(1)Ǻ. The geometry of the complex cation is approximately square planar. The imidazolinyl rings closely approach planarity which is imposed by the delocalization of π-density in the NCN moiety. A hydrogen-bonding scheme involving the imino hydrogens of the ligand, chloride ions and the water molecule is present. The structure was refined by least-squares methods to a residual of 0.018 for 1273 reflections.