A NEW COPPER(II) ALTERNATING-CHAIN STRUCTURE WITH CARBOXYLATO AND CARBOXYLIC-ACID BRIDGES - THE STRUCTURE AND SPECTROSCOPIC PROPERTIES OF CATENA-POLY[BIS(MU-[PENTANE-1,5-BIS(CARBOXYLIC ACID)-MONOATO-O-ALPHA,O-OMEGA])-BIS(BENZIMIDAZOLE)COPPER)-MU-(PENTANE-1,5-BIS(CARBOXYLATO)-O-ALPHA,O-OMEGA)]

Copper (II) bis(carboxylato) benzimidazole complexes of the type Cu(Hbim)(2)(A) and Cu(Hbim)(2)(A)(1/2)(HA) (where Hbim stands for benzimidazole and A and HA for dianion and monoanion of a dicarboxylic acid) have been synthesized and characterized by elemental analyses, and electronic and IR spectroscopic measurements. The X-ray crystal structure of {[Cu-2(Hbim)(4)(Pim)(HPim)(2)]. 8H(2)O}(n) (where Pim and HPim stand for the di- and monodeprotonated forms, respectively, of pimelic acid) has been determined from three-dimensional X-ray diffraction data. Single dianionic and double monoanionic bridges link the metal centres in polymeric chains, where each carboxylate or carboxylic group acts as a monodentate moiety. The Cu-II ions are five-coordinated with a square-pyramidal CuN2O2O chromophore. Short O ... O hydrogen bonds (2.6-2.8 Angstrom) are found between carboxylate and carboxylic groups or water molecules.