Syntheses, structural diversity, and photocatalytic-degradation properties for methylene blue of Co() and Ni() MOFs based on terephthalic acid and different imidazole bridging ligands

Six coordination polymers named [Co(TPA)(bimb)(H 2 O) 2 ] n ( 1 ), [Co(TPA)(4,4′-bidpe)] n ( 2 ), [Co(TPA)(4,4′-bibp)] n ( 3 ), [Co 4 (TPA) 3 (tib) 2 (μ 3 -OH) 2 ] n ( 4 ), [Ni(TPA)(4,4′-bidpe)(H 2 O) 2 ] n ( 5 ), and [Ni 2 (TPA) 2 (4,4′-bibp) 3 (H 2 O) 2 ] n ( 6 ) (TPA = terephthalic acid, bimb = 1,4-bis(imidazol)butane, 4,4′-bidpe = 4,4′-bis(imidazolyl)diphenyl ether 4,4′-bibp = 4,4′-bis(imidazolyl)biphenyl, and tib = 1,3,5-tris(1-imidazolyl)benzene) were constructed using a solvothermal method and characterized by X-ray diffraction, elemental analyses, infrared spectroscopy and thermogravimetric analysis. Complex 1 had a 3D supermolecular framework that crystallized in the monoclinic space group P 2 1 / c . Complex 2 crystallized in the tetragonal system I 4 1 / acd space group featuring a 2-fold interpenetrated framework. Complex 3 crystallized in the orthorhombic space group Pnna . Complex 4 exhibited a 3D Co( ii ) metal-organic framework with tetranuclear metal-oxygen clusters, and it crystallized in the monoclinic space group C 2/ c . Complex 5 crystallized in the monoclinic space group P 2 1 / n featuring a 3D supermolecular framework. Complex 6 had a 3D 3-fold interpenetrated fsc topological framework that crystallized in the triclinic space group P 1&cmb.macr;. The photocatalytic-degradation capacity of complex 1-6 for methylene blue (MB) was investigated: complex 1-4 had a better photocatalytic-degradation effect for MB. Six coordination polymers were constructed and characterized by X-ray diffraction, elemental analyses, infrared spectroscopy and thermogravimetric analysis.