Ionic Liquidized-modifled Sensor And Recognition Property For Anions

Fluorescent low melting salt (FLMSs) is compared with the traditional molecularfluorescent material, it has high temperature and long term stability, electrical property andwater solublility, solution and liquid fluorescent controlled, good environmental compatibility,and low toxicity, so that it has potential application prospect for selective detection inbiological imaging, small biological molecules and inorganic anions. Ionic liquid becomes anew way to develop FLMSs. So far, the research of ionic liquidized-modified material morefocused on imidazolium salt derivatives. Therefore, a new structure of ionicliquidized-modified sensor is synthesized in this article,which is designed by the hydrazidegroups connecting coumarin fluorophore and imidazolium salt, to research the recognitionproperty for anions.By changing the length of alkyl chain of imidazolium salt, constructingfluorescent-colorimetric dual channel sensors LC2-10,1HNMR and GC/MS have identifiedtheir structures. LC2-10display specific identification on CN-among the anions (F-, Cl-, Br-,I-, HSO4-, H2PO4-, AcO-, CN-) in acetonitrile. After adding CN-, LC2-10led to98-103nmblue-shift in absorbance maximum, the solution color change from yellow-green to colorlesswith "naked eye" observed, fluorescence quenching94%-96%, fluorescence color changefrom bright green to colorless,other anions have no obvious interference for LC2-10detectingCN-.Mechanism research shows that LC and CN-formed a non-traditional hydrogen bond[(C2-H）…CN-],to generate1:1coordination compound,and occurred the reaction of carbonylnucleophilic addition. In addition, the surfactant CTAB existting in the aqueous system(1%ethanol), only LC10recognized CN-with fluorescence quenching obviously among the seriesof sensors, and other sensors have no obvious response, it shows that surfactant micellemicroenvironment has a effect on the different alkyl chain length of sensors for recognizingCN-.