Towards rational synthesis of polar solids. Synthesis and X-ray structuresof cadmium(II) meta-pyridinecarboxylate coordination polymers

Two cadmium(II) coordination polymers, Cd2L41(mu -H2O) 1 and Cd2L42(mu -H2O ) 2 [L-1=(E)-4-(2-thiazolyl)ethenylbenzoate, L-2=(E)-4-(3-pyridyl)ethenylbe nzoate] based on meta-pyridinecarboxylate bridging ligands, were synthesize d by the reactions of cadmium perchlorate and the corresponding benzonitril e precursor ligands under hydro(solvo)thermal conditions. Although both com pounds 1 and 2 are constructed from the Cd2L4n(mu -H2O) building block, X-r ay single crystal structure determinations show that 1 adopts a 2-D polymer ic network structure while 2 exhibits a 3-D framework structure as a result of the slightly different configurations of the bridging pyridinecarboxyla te ligands. Owing to the presence of the bridging water molecules, both 1 a nd 2 crystallize in centrosymmetric space groups.