Carboxylate-bridged helical-chain Cu(II) complex and zig-zag chain Ni(II) and Co(II) complexes from 8-quinolinyloxyacetate

Abstract

Tridentate carboxylate-containing ligand L (L=8-quinolinyloxyacetate) reacts with M(II) chloride (M=Cu, Ni and Co) to give rise to three coordination polymers [CuLCl] n ( 1), {[NiL(H 2O) 2]Cl·H 2O} n ( 2), and {[CoL(H 2O) 2]Cl·H 2O} n ( 3), respectively. Complex 1 is a helix chain polymer while 2 and 3 are two zig-zag chain polymers. The bridging carboxylate groups are in anti– anti bridging mode in complex 1 while they are within syn– anti conformation in 2 and 3. In 1, carboxylate groups link two basal positions in basal–apical, while in complexes 2 and 3, they are basal–basal positions. The structures of these complexes have been determined by X-ray crystallography. Interestingly, three chain complexes are also linked to form 3D networks through hydrogen bonds.