One-dimensional and two-dimensional coordination polymers constructed from Cd2+ ions and flexible bipyridyl bridging ligands

Abstract

The syntheses and structures of the coordination polymers [Cd(ppeb)2(H2O)2]n·(NO3)2n (1), [Cd(ppeb)2(ClO4)2]n (2), [Cd(opeb)2(NO3)2]n (3), and [Cd(opeb)2(H2O)2]n·(ClO4)2n (4), where ppeb and opeb represent the 1,4- and 1,2-isomers of bis[2-(3-pyridyl)ethyl]-benzene, C20H20N2, respectively, are described. Each structure contains trans-CdO2N4 octahedra. In 1 and 2, they are bridged by pairs of ligands to generate looped chains, whereas in 3 and 4 the ligands link the metal nodes into squashed 44 polymeric sheets. In 1 and 4, O–H…O hydrogen bonds from the coordinated water molecules to the uncoordinated anions help to consolidate the structures.