Synthesis, crystal structures and dye removal properties of a series of metal-organic frameworks based on N-heterocyclic carboxylic acid ligands

Abstract

Abstract Six functional metal-organic frameworks build by 4,4'-(1H-1,2,4-triazol-1-yl)methylenebis (benzonic acid) (H2tmlb), namely: [Zn4(tmlb)4(H2O)]n (1), [Ni4(tmlb)4(H2O)]n (2), [Cu(tmlb)]n (3), [Co(tmlb)]n (4), [Pb(tmlb)(H2O)]n (5), {[Zn(tmlb)(H2tmlb)]H2O}n (6), have been successfully synthesized. The X-ray diffraction analysis show that the complexes 1 and 2 exhibited a two interpenetrating (3, 6, 6)-connected framework with a Schlafli symbol of (4·62)2 (42·610·83) topology. The complexes 3 and 4 show a two interpenetrating (3, 6)-connected net with (611·84) (63)2 topology. The complex 5 shows a (3, 8)-connected network with a point symbol of (4·62)2 (42·615·78·8·92) topology. The complex 6 exists a 2-fold interpenetrating topology framework and the point symbol is (6·6·6). Moreover, the photocatalytic studies show that complexes 1–5 have highly photocatalytic ability to degrade methylene blue (MB). In addition, the complex 6 can efficiently adsorb Congo red through H-bonds and the adsorption kinetic have been discussed.