The crystal structure and photocatalytic properties of a three-dimensional cadmium(II) metal-organic framework: poly[bis(μ3-benzene-1,2-dicarboxylato)[μ2-1,4-bis(pyridin-3-ylmethoxy)benzene]dicadmium(II)].

Photocatalysis is a green technology for the treatment of all kinds of contaminants and has advantages over other treatment methods. Recently, much effort has been devoted to developing new photocatalytic materials based on metal-organic frameworks for use in the degradation of many kinds of organic contaminants. With the aim of searching for more effective photocatalysts, the title three-dimensional coordination polymer, [Cd2(C8H4O4)2(C18H16N2O2)]n, was prepared. The asymmetric unit contains one Cd(II) cation, one benzene-1,2-dicarboxylate anion (denoted L(2-)) and half of a centrosymmetric 1,4-bis(pyridin-3-ylmethoxy)benzene ligand (denoted bpmb). Each Cd(II) centre is five-coordinated by four carboxylate O atoms from two L(2-) ligands and by one N atom from a bpmb ligand, forming a disordered pentagonal pyramidal coordination geometry. The Cd(II) centres are interlinked by L(2-) ligands to form a one-dimensional [Cd2L2]n chain. Adjacent chains are further connected by bpmb linkers, giving rise to a two-dimensional network, and these networks are pillared by bpmb to afford a three-dimensional framework with a 3(3).4(2).6(3).7(1).8(1) topology. Each grid in the framework has large channels which are filled mainly by the two other equivalent frameworks to form a threefold interpenetrating net. The compound exhibits relatively good photocatalytic activity towards the degradation of methylene blue in aqueous solution under UV irradiation.