Diverse structures of metal–organic frameworks based on different metal ions: luminescence and gas adsorption properties

Abstract

Four coordination polymers with different metal ions have been synthesized based on a rigid linear pyridine and a flexible V-shaped dicarboxylate ligand (L = 4,4′-(2,5-dimethoxy-1,4-phenylene)dipyridine; H₂OBA = 4,4′-oxydibenzoic acid): {[Co(L)(OBA)]·2H₂O}_n (1), [Zn(L)(OBA)·2H₂O]_n (2), {[Ni(L)(OBA)]·DMF·H₂O}_n (3), [Cd(L)(OBA)]·DMF·H₂O}_n (4). The reaction conditions are similar except for the metal ions for complexes 1–4. Complexes 1 and 2 present a 3D unprecedented hxg-d-4-Cccm net, but 3 and 4 are 4-connected sql nets with a point symbol {4⁴·6²}. These complexes were characterized by single crystal X-ray diffraction, infrared spectroscopy, thermogravimetry, elemental analysis, and powder X-ray diffraction measurements. The UV–visible spectra, fluorescence, and gas adsorption properties of the compounds were also explored.