Coordination polymers of copper(II) based on mixed N- and O-donor ligands: the crystal structures of [CuL 2(4,4′-bipy)] n (L=lactate or 2-methyllactate)

Abstract

The neutral polymeric complexes of copper(II) [CuL 2(4,4′-bipy)] n , where L is an α-hydroxycarboxylato ligand, lactate in 1, 2-methyllactate in 2, were prepared and characterised structurally. The copper atom is in an elongated tetragonally distorted octahedral environment in both compounds. Both α-hydroxycarboxylato ligands are O, O′-bidentate chelating monoanions and 4,4′-bipyridine acts as an N, N′-bis(monodentate) bridging ligand creating a linear polymeric arrangement. The polymeric chains are interconnected by O hydroxylH⋯O carboxy hydrogen bonds in a way that creates cavities that differ in size between 1 and 2. Spectroscopic data are presented and discussed.