catena-poly[[bis(benzimidazole-N-3)copper(II)]-mu-suberato-O,O ': O '',O '''] and catena-poly[[[bis(benzimidazole-N-3)copper(II)]-mu-sebacato-O,O ': O '',O ''']dihydrate]

Both title compounds, [Cu(C8H12O4)(C7H6N2)(2)], (I), and [Cu(C10H16O4)(C7H6 N2)(2)]. 2H(2)O, (II), display inversion symmetry. The Cu centres are bridg ed by the dicarboxylate ions in a bis-bidentate fashion, forming polymeric chains. In (I) and (II), these chains are differently associated via hydrog en bonds. The Cu Cu intrachain distances are 10.974(1) Angstrom in (I) and 12.417 (5) Angstrom in (II). In both structures, the base of the elongated octahedron of the Cu-II atoms is formed by two short Cu-O and Cu-N bonds [C u-O 1.973(1) and 1.974 (2) Angstrom, and Cu-N 1.974(1) and 1.977(2) Angstro m in (I) and (II), respectively], The carboxylate groups form four-membered unsymmetrical chelate rings and complete the Cu-II coordination to sixfold by long Cu-O bonds of 2.645 (2) Angstrom in (I) and 2.583 (2) Angstrom in (II). The modes of coordination of the Cu-II-dicarboxylic acid ions and ben zimidazole molecules are discussed in terms of the computed bond valences a nd the valences of the Cu and O atoms as the sums of bond valences.