Alcoholysis/hydrolysis of 1,1′-carbonyldiimidazole as a means of preparing unprecedented, imidazole-containing one-dimensional coordination polymers of copper(II)

Abstract

The use of 1,1′-carbonyldiimidazole, (im)2CO, for the synthesis of imidazolate (im-) and/or imidazole (Him)-containing copper(II) coordination polymers is described. The [Cu2(O 2CMe)4(H2O)2]/(im)2CO reaction system in EtOH yields the new polymeric species [Cu(O 2CMe)(im)(Him)(EtOH)]n (1) and the known compound [Cu(im)2]n (2), depending on the reaction conditions. A mechanism for the alcoholysis/hydrolysis of (im)2CO is proposed. Complex 1 comprises neutral, zigzag chains with the η1: η1:μ im- ligand bridging two neighbouring Cu II atoms. Each square pyramidal metal centre is coordinated to two imidazolate nitrogen atoms, the pyridine-type nitrogen atom of the terminal imidazole ligand, one acetate oxygen atom and the ethanol oxygen atom. The dc magnetic susceptibility data for 1 have been analysed according to the Bonner-Fisher model for an equally spaced S = 1/2 chain, revealing moderate antiferromagnetic CuII⋯CuII exchange interactions (J = -33.5 cm-1 using the H = - 2J∑ŜiŜi+1 spin Hamiltonian). The reaction system Cu(NO3)2·3H2O/(im)2CO in EtOH leading to the preparation of known trans-[Cu(NO3) 2(Him)4] (3) is also described. With terephthalate(-2) (tp2-), instead of MeCO2 -, in MeOH/H 2O the product is the new, 1D linear coordination polymer [Cu(tp)(Him)2(H2O)]n·2nH2O (4·2nH2O). Adjacent square pyramidal CuII atoms are singly bridged by the bis-monodentate tp2- ligand, while two monodentate Him groups and one H2O molecule complete five-coordination at each metal centre. The chains of 1 and 4·2nH 2O form interesting, hydrogen-bonded 3D networks. The combined work demonstrates the usefulness of (im)2CO in the preparation of interesting CuII coordination polymers which can not be obtained by the use of Him. © 2009 The Royal Society of Chemistry.