Two- and three-dimensional photoluminescent Cd(II)-carboxylate coordination frameworks bridged by benzenepentacarboxylate and N-donor ligands

Abstract

Reactions of Cd(OAc)2·H2O, benzenepentacarboxylic acid (H5bpc), 2,2′-bpy/4,4′-bpy, and Et3N yield two new coordination polymers [Cd5(bpc)2(2,2′-bpy)4(H2O)4] (1) and [Cd5(bpc)2(4,4′-bpy)2(H2O)4]·3H2O (2). Complex 1 is a 2-D structure based on six-connected Cd-carboxylate layers. Adjacent layers are linked by π–π interactions and hydrogen bonds to generate a layered supramolecular network. Complex 2 is a 3-D coordination framework. The bpc ligands adopting μ 7-bridging mode connect Cd(II) ions to form a 3-D open framework with elliptic channels, in which the coordinated 4,4′-bpy ligands fill to support the whole framework. Complex 2 exhibits strong photoluminescence at room temperature.