Crystal structures, selective fluorescent sensing and photocatalytic properties of cobalt(II) and copper(II) coordination architectures with 2,4,5-tri(4-pyridyl)-imidazole

Solvothermal reaction of MII (M = Co, Cu) ions with 2,4,5-tri(4-pyridyl)-imidazole (Htpim) gave two MOFs, [Co1.5(tpim)(FA)2(H2O)]n (1) and [Cu2(Htpim)(tpim)(FA)(NO3)2(DMF)]n (2) (HFA = formic acid, DMF = N,N-dimethylformamide). Single-crystal X-ray diffraction analyses indicated that 1 exhibits a 3D {43.412} topology framework assembled by hexanuclear [Co6(FA)8(H2O)4] units and tpim ligands, while 2 presents a 2-D double layer {4.62}2{42.64.82.102}{62.8} network. Hereinto, an inorganic acid was not only used to adjust the pH value of reaction system but also to act as an oxidizing agent to participate in in situ organic reactions. Moreover, 1 displays high sensitivity in the detection of nitrobenzene as a fluorescent sensor and exhibits a relatively good photocatalytic activity toward the degradation of rhodamine B in aqueous solution under UV irradiation.