| MOFs have developed rapidly as an emerging material.It can be applied to many aspects such as sensing,drug packaging,adsorption,gas storage,catalysis,electrochemistry and other fields.In particular,fluorescent metal-organic frameworks（LMOFs）have achieved remarkable results in sensing.In this paper,three ligands have been synthesized,tetra（4-imidazoylphenyl）ethylene（L1）and 3,6-bis（3-carboxyphenyl）-9-（4-carboxyphenyl）carbazole（H3L2）,both contain aromaticπsystems;2-sulfo-4,4’-biphenyldicarboxylic acid（H2L3）contain a sulfonic acid functional group.Five LMOFs were successfully synthesized by solvothermal method and stirring method:[Cd3（L1）2（H2O）2（SO4）3]·2DMF（LJ1）;[Cd3（L1）2（COO）2（OH）2]·4DMF（LJ2）;[Cd3（L1）2（H2O）2（NO3）5]·2DMF（LJ3）;[Mg2（H3L2）2（H2O）8]·DMF·2H2O（LJ4）;UiO-67-SO3H（LJ5）.The results of X-ray diffraction data show that LJ1,LJ2 and LJ3 have three-dimensional topological structure and LJ4 has one-dimensional chain structure.IR and PXRD show that LJ5 is a three-dimensional sulfonic acid functionalized UiO-67-SO3H.PXRD and TG characterization prove that the five complexes have high phase purity and good thermal stability,LJ1,LJ2 and LJ4 have good water stability.The results of fluorescence recognition experiments show that:LJ1 can recognize ReO4-by fluorescence quenching and detection limit is 335 nM.Currently,there are few reports of LMOF that can recognize ReO4-;LJ2 can recognize lysine（Lys）through fluorescence enhancement.To our knowledge,this is the first LMOF to recognize Lys through fluorescence enhancement,detection limit is 200 nM;In DMF solution,LJ3 can recognize dimetridazole（DTZ）by fluorescence quenching,detection limit is 143 nM;LJ4 can recognize Cr2O72-by fluorescence quenching,detection limit is 264 nM.By comparison,the recognition effect of LJ1,LJ3 and LJ4 is better than most reported LMOFs.It is proved that they have excellent selectivity through anti-interference experiments.The possible causes of fluorescence changes were discussed. |
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