Construction of Co/Ni-tcbpe Crystalline Framework Structures and the Inspiration for Fluorescence “Turn-On” Behavior toward Asp

Abstract

Two three-dimensional porous network structures of Co/Ni-tcbpe were constructed with 4′,4‴,4⁗′,4″′′′′′-(ethene-1,1,2,2-tetrayl)tetrakis([1,1′-biphenyl]-4-carboxylic acid) (H 4 tcbpe) as a linker via solvothermal conditions. The structure−activity relationship between the structures and solidstate fluorescence spectra are studied. Moreover, based on their weak fluorescence characteristic, it is first found that Co/Ni-tcbpe has a selective and sensitive fluorescence "turn-on" ability for aspartic acid in aqueous solution, with limitations of detection of 6.27 and 7.49 μmol/L. For studying comprehensive fluorescence response of Co/Ni-tcbpe toward aspartic acid, 10 aliphatic dicarboxylic acids with a similar structure to aspartic acid were selected, and their fluorescence sensing behavior was tested with Co/Ni-tcbpe. The results indicate that the detection mechanism of aspartic acid and aliphatic dicarboxylic acids is the synergistic effect of energy and electron transfer, while the detection of aliphatic dicarboxylic acids mainly involves energy transfer. This research achievement is the first example of using Co/Ni-tcbpe MOFs to detect aspartic acid and lays a solid foundation for further study of practical detection of amino acids in complex environments.