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

Abstract

Two cadmium(II) coordination polymers, Cd₂L¹₄(μ-H₂O) 1 and Cd₂L²₄(μ-H₂O) 2 [L¹ = (E)-4-(2-thiazolyl)ethenylbenzoate, L² = (E)-4-(3-pyridyl)ethenylbenzoate] based on meta-pyridinecarboxylate bridging ligands, were synthesized by the reactions of cadmium perchlorate and the corresponding benzonitrile precursor ligands under hydro(solvo)thermal conditions. Although both compounds 1 and 2 are constructed from the Cd₂Lⁿ₄(μ-H₂O) building block, X-ray single crystal structure determinations show that 1 adopts a 2-D polymeric network structure while 2 exhibits a 3-D framework structure as a result of the slightly different configurations of the bridging pyridinecarboxylate ligands. Owing to the presence of the bridging water molecules, both 1 and 2 crystallize in centrosymmetric space groups.