AIE ligands-based new cobalt metal-organic framework as bifunctional sensor for Fe3+ ion and TNP in aqueous solution

Abstract A novel MOF, namely, {Co(TCPP)0.5(Tipa)}n (1) based on the mixed ligands 2, 3, 5, 6-tetrakis(4-carboxyphenyl)pyrazine (H4TCPP) and tri(4-imidazolylphenyl)amine (Tipa) has been successfully constructed by assembling two aggregation-induced emission (AIE) ligands with cobalt nitrate under hydrothermal condition. Crystal structure analysis indicates 1 displays a (3,4,5)-connected 3D framework, with a new Schlafli symbol of {42·6}2{42·84}{43·6·86}2. Fluorescence measurement shows 1 exhibits more bright fluorescent emission in water compared with that in other solvents. Meanwhile, it shows fluorescence stability in water with different pH values ranging from 3.0 to 11.0. More significantly, compound 1 could be employed as bifunctional sensor for ferric ion (Fe3+) and picric acid (TNP) in aqueous solution with high selectivity, high sensitivity and well cyclic utilization, and the detection limits for Fe3+ and TNP are estimated to be 0.098 ​μM and 0.326 ​μM, respectively.