SYNTHESIS AND CRYSTAL-STRUCTURES OF 2 POLYMERIC CADMIUM(II) COMPLEXESCONTAINING SKEW-SKEW CARBOXYLATO-BRIDGES

Two polymeric cadmium(II) complexes of betaine (Me3N+CH2CO2 = bet, [Cd -3(bet)(4)(H2O)(2) Cl-4](n)(ClO4)(2n) (1) and [Cd(bet)(2)(NO3)](n)(ClO 4)(n) (2), have been prepared and characterized by X-ray single-crysta l structural analysis. Complex 1 has the metal atoms in two coordinati on geometries. One is coordinated in a distorted octahedral geometry, being surrounded by one aqua ligand, two chloro ligands and three carb oxylate oxygen atoms, while the other is also in a distorted octahedra l geometry, bring surrounded by four chloro ligands and two carboxylat e oxygen atoms. The aqua ligand acts as a terminal ligand [Cd-O = 2.36 8(2) Angstrom], whereas the chloro and carboxylate ligands bridge in t he O,O' bridging modes [Cd-Cl = 2.5828(7), 2.6405(7); Cd-O = 2.251(2), 2.291(2) Angstrom] atom is six-coordinate in a distorted octahedral g eometry. The nitrate anion binds in an isobidentate eta(2)-chelate mod e [Cd-O = 2.405(3) Angstrom], while the carboxylate ligands bridge in the mu(2)-carboxylato-O,O' bridging mode [Cd-O = 2.225(2), 2.315(2) An gstrom]. The bet mu(2)-carboxylato-O,O' groups in complexes 1 and 2 ex hibit unusual skew-skew bridging fashions, with a pair of metal atom l ocated either on the same side or on the opposite side of the carboxyl ate plane. (C) 1997 Elsevier Science Ltd.