One-Dimensional Coordination Polymers of Co(II) and Cd(II)-Squarate with 2-Methylimidazole and 4(5)-Methylimidazole Ligands

Abstract

Two new mixed-ligand coordination polymers, {[Co(μ<inf>1,3</inf>-sq)(H<inf>2</inf>O)<inf>2</inf>(2-Meim)<inf>2</inf>]·2(2-Meim)}<inf>n</inf> (1) and [Cd(μ<inf>1,3</inf>-sq)(H<inf>2</inf>O)<inf>2</inf>(4(5)-Meim)<inf>2</inf>]<inf>n</inf> (2), (sq = squarate, 2-Meim = 2-methylimidazole, 4(5)-Meim = 5-methylimidazole) have been synthesized and structurally characterized by X-ray crystallography. The spectral (IR and UV-Vis) and thermal analyses are also reported. The Co(II) and Cd(II) ions are distorted octahedrally coordinated by four oxygen atoms of two O1-O3-bridging squarate ligands and two trans-aqua ligands, and by two nitrogen atoms of the trans-imidazole (2-Meim or 4(5)-Meim) ligands. The structures of 1 and 2 consist of one-dimensional chains of μ-1,3-squarato bridged metal(II) complex units. These chains are held together by hydrogen bonding interactions, forming three-dimensional framework. © 2009 Elsevier Ltd. All rights reserved.