Binuclear copper complexes of bis(1,4,7-triazacyclonon-1-yl) ligands incorporating acetate pendant arms

Two new bis(pentadentate) compounds, 1,2-bis[4,7-bis(carboxymethyl)-1,4,7-triazacyclonon-1-yl]ethane(L(1)) and 1,4-bis[4,7-bis(carboxymethyl)-1,4,7-triazacyclonon-1-yl]butane (L(2)), have been prepared by functionalisation of the corresponding alkyl-bridged bis(macrocycles) with acetate pendant arms. Their binuclear copper(II) complexes have been prepared and characterised by X-ray crystallography. Both [Cu(2)L(1)]. 5H(2)O and [Cu(2)L(2)]. 2H(2)O are centrosymmetric about the alkyl bridge with the pentadentate compartments hosting the copper(Ii) centres oriented away from one another. Each Cu-II exhibits distorted square-pyramidal geometry with an N2O2 basal plane and an apical N atom.