STRUCTURE OF A COORDINATION POLYMER REMINISCENT OF THE PLEATED SHEETSOBSERVED IN POLYPEPTIDES - UA-(2,2'-BIPYRIDINE-3,3'-DICARBOXYLATO)-COPPER(II)

The preparation and crystal structure of [Cu(BPDC)-(H2O)(2)] (BPDC = C 12H6N2O42-, the dianion of 2,2-bipyridine-3,3'-dicarboxylic acid) are described, The Cu atom is pentacoordinate; the BPDC ligands and water molecules form a distorted square-pyramidal geometry about the metal a tom, BPDC residues linking Cu atoms to give a coordination polymer wit h head-to-tail alignment {i.e. -mu-(2,2'-bipyridine-3,3'-dicarboxylato -N,N':O)]}. Adjacent antiparallel chains are cross-linked by hydrogen bonds in a sheet-like structure reminiscent of the pleated sheets obse rved in polypeptides, The non-metallated O atoms of the carboxylate gr oups participate in hydrogen-bonding interactions with water molecules .