ZnCl2(4,4 '-bpy): a one-dimensional coordination polymer with two isomorphic phases

Two isomorphic phases of one-dimensional coordination polymer ZnCl2(4,4 ' - bpy) were prepared from hydrothermal reactions of ZnCl2 and 4,4 ' -bipyridy l (4,4 ' -bpy). alpha -ZnCl2(4,4 ' -bpy) (I) crystallizes in the monoclinic space group C2/c, with n=15.821(3) Angstrom, b=5.109(1) Angstrom, c=14.612 (3) Angstrom, beta= 110.33(3)degrees. V=1107.5(4) Angstrom (3), Z=4. beta - ZnCl2(4,4 ' -bpy) (II) crystallizes in the orthorhombic space group Pnma, w ith a=17.349(3) Angstrom, b=12.407(2) Angstrom, c=5.114(1) Angstrom, V=1100 .8(3) Angstrom, Z=4. The crystal structures of the two compounds are closel y related to each ether. In both phases, the Zn metal center is tetrahedral ly coordinated to two terminal Cl and two bridging 4,4 ' -bpy. Each 4,4 ' - bpy acts as a bifunctional ligand and is bonded to two Zn to give rise to a Zn(4,4 ' -bpy) zig-zag chain. The extended Huckel (EH) calculations were p erformed on both structures to analyze the bonding. The solubility of the t itle compounds was also tested. (C) 2001 Elsevier Science B.V. All rights r eserved.