Structures, Photoluminescence, and Photocatalytic Properties of Six New Metal−Organic Frameworks Based on Aromatic Polycarboxylate Acids and Rigid Imidazole-Based Synthons

Abstract

Six metal−organic coordination polymers, [Cu(bdc)(bimb)]n (H2bdc = 1,4-benzenedicarboxylate; bimb = 4,4′-bis(1-imidazolyl)biphenyl) (1), [Cu3(btc)2(bimb)2·(H2O)3]n (H3btc = 1,3,5-benzenetricarboxylate) (2), [M3(btc)2(bimb)2·(H2O)4]n (M = Mn for 3, Co for 4, Cd for 5), and [Cd(btcH)(bimb)]n (6) were obtained under hydrothermal conditions and characterized structurally. The networks exhibit a variety of topologies: compound 1 exhibits a triply interpenetrating three-dimensional (3D) framework with a distorted primitive cubic (α-Po) single net; compounds 2−5 are isomorphic, which possess a trinodal 4-connected 3D framework; compound 6 has a two-dimensional (3,4)-connected framework. In addition, the thermal stabilities for 1−6 and the photoluminescence properties for 5 and 6 were examined. An anionic organic dye X3B was selected as a model pollutant in aqueous media to evaluate the photocatalytic effectiveness of isostructural compounds 3 and 4, and the results indicated compounds 3 and 4 represent rare examples of coordination polymers that exhibit high photocatalytic activity for dye degradation under UV light and show good stability toward photocatalysis. The difference in catalytic activity between 3 and 4 arises from the discrepancy in central metal ions of the two compounds.