Polymeric nickel(II) and copper(II) complexes with btc2− ions as bridging ligands (btc2−=1,2,4,5-benzenetetracarboxylic acid dianion)

Two new complexes of composition {[Ni(L)(btc2−)]·2H2O}n (1) {L=1,4,8,11-tetraazacyclotetradecane} and {[Cu(L)(btc2−)]·H2O}n (2) were obtained by reacting [Ni(L)]·2ClO4 or [Cu(L)]·2ClO4 and btc, and their structures were determined by analytical, spectroscopic, and X-ray diffraction methods. The blue complex 1 and violet complex 2 consist of 1D polymeric chains with nickel(II) or copper(II) macrocycles and bridging btc2− ligands, respectively. In 1 the COO− groups on the 1,4-positions of the btc2− ligand are coordinated to the central nickel(II) atom, but in 2 the COOH groups on the 1,5-positions of the btc2− ligand are involved in interacting with the central copper(II) atom through an unusual carbonyl coordination.