Design,Synthesis And Binding Ability Of Chemodosimeter For Fluoride Ions Based On F~--triggered Si-O Bond Cleavage

Anion plays an important role in chemistry, medicine, biology and environment field. The design and development of artificial fluorescent sensor with the specific sensing performances have attracted great attention in supramolecular chemistry. Fluoride ion, an anion with the smallest volume, was widely existing in the nature. Being a necessary trace element for the human body, fluoride ion with a proper amount plays a profitable role in caries prevention and clinical treatment of osteoporosis, but it will cause damage to the human body with excess or too little amount. Therefore, the development of specific probes for sensing fluoride ion is extremely important in medicine, food science and environmental science.In this paper, based on the literature, we designed two types of fluorescent probes based on F--triggered Si-O bond cleavage, and the sensing mechanism was investigated in detail. So the specific research includes the following two parts:The first part:with 7-hydroxy-4-trifluoromethyl coumarin as the fluorophore, TBDPS as a hydroxy protecting group, a luminescence acceptor A6 was designed and synthesized based on F--triggered cascade reaction. Detailed spectroscopy experiments indicated that the receptor has highly specific selectivity for fluoride ion, and the UV-visible and fluorescence detection limit of dosimeter A6 was determined to be 18.6 uM and 0.13 μM, respectively. In addition, receptor A6 can also be applied in an aqueous solvent and the test paper for sensitive detection of fluoride ion.In the second part, a chemodosimeter (B5) based on 1,8-naphthalimide was constructed by Si-O group and -CHCN group, the reference receptors (B6, B7, B8) were also synthesized. After 2.0 equiv. of F-was added into B5 in acetonitrile,275 nm red-shifts was observed in UV-visible with naked-eye detection color change from colorless to blue. The sensing mechanism was demonstrated to the cooperation of F- -triggered Si-O bond cleavage followed by the deprotonation/autoxidation of secondary nitrile C-H group by the experiments of the UV-visible, fluorescence and 1H-NMR titrations. The fluorescence detection limit was determined to be 0.105 μM.Further, chemodosimeter B5 can also be used in an aqueous solvent.