The Synthesis And Properties Of Fluoride Fluorescent Chemsensors

The synthesis of fluorescent chemsensors for selectivity sensing certain chemical species is one of the main content of supramolecular chemistry. In recent years, the recognition and sensing of the biologically and environmentally important anions has emerged as a significant goal in the field of chemical sensors in recent years. Among all the anions, fluoride ion is the smallest anion and widely exists in nature. The recognition of fluoride ions is attracting a great deal of interest because of its potential applications, such as dental caries prevention, the clinical diagnosis of osteoporosis, and even more, nerve gas and nuclear weapons uranium refining. Therefore, considerable efforts have been devoted to fluoride ion sensing via UV and fluorescence. In this thesis, a series of small chemosensors with coumarin and naphthalimide as fluorophore were designed and synthesized and there sensing abilities to fluoride ion were studied using UV-Vis and fluorescence. The dissertation consist three parts as following:In the first part, the progress of the anion chemosensor and their sensing mechanism were briefly described, then the progress of chemosensor selectively sensing to fluoride ion in recent five years were emphasized.In the second part, the two traditional fluoride chemosensors L1and L2which based on coumarin as the chromophore and urea as sensing group were designed and synthesized. The sensing abilities were studied using Uv-vis, fluorescence spectrum and NMR titration analysis. The results showed that these two kinds of moleculars can selectively recognize fluoride ion, and the ester group on the coumarin of chemosensor L1was used for the further synthesis of the water-soluble chemosensors.In the third part, a serial chemosensors L3to L6derivated from coumarin and naphthlide containing Schiff base and-OH group as sensing sites were designed and synthesized. The sensing abilities were studied by Uv-vis and fluorescence spectrum. The results showed that these chemosensors can selectively recognize fluoride ion and CN-. The Job’s plots indicated that four chemosensors combined F with1:1stoichiometry and the binding constant towards F" was determined and found to be1.358×104、1.087×104、9.317×103、5.45×103M-1, respectively, and they can also effctively sense CN-via cyclization.