Study On Proton Transfer Of Substituted Imidazole And Oxazole In Nano-limited Mediumby Spectroscopic Methodology

Proton transfer is one of the focus topicsin chemistry field, as a basic reaction existing in a variety of chemical and biochemical processes, such as communication between the cells and in the cell, base mutation in nucleic acid. Therefore, the studieson proton transfer in organisms have drew a large number of researchers’attention. In this paper, the method of host-guest interaction has been used to study the proton transfer reaction taking place in macocycle host such as cucurbiturilorcyclodextrin.1,The spectroscopic properties of2-(2’-Hydroxyphenyl)imidazo[1,2-a]pyridine(HPIP)have been study useing UV absorption and fluorescence emission spectrum in different solvents. The result shows that the fluorescence emission spectrum of HPIP is solvent dependent, the UV emission band is dominant in polar solvent and the low power emission band is dominant in nonpolar solvent. The interaction of HPIP with Cucurbit[7]urils(CB7) has been studied by UV absorption, fluorescence emission spectrum and Transient fluorescence spectroscopy, the proton transfer efficiency was reduced followed by the increasing of CB7in dioxane, and the proton transfer efficiency was increased in hexane, the stoichiometry of HPIP-CB7complex is1:1both in dioxane and hexane. Furthermore, the fluorescence lifetime of HPIP is decreased and the quantum yield is increased followed by the form of HPIP-CB7complex in dioxane.2, The photophysical properties of2-(2-hydroxyphenyl)benzoxazole (HPBO) in different solvents have been detected by UV absorption and fluorescence emission spectrum, it is solvent dependent.The result was confirmed by the fluorescence emission spectrum of HPBO in different polar solvents. The proton transfer efficiency of HPBO was increased both in methanol and dimethylsulfoxide when CB7added dropwise into solution, but the fluorescence lifetime of HPBO was decreased, Benesi-Hildebrand plots of HPBO binding with CB7shows that the stoichiometry of HPBO-CB7complex is1:1.3,2-(3-hydroxyl-2-pyridyl)benzoxazole(3H2PyBO) was synthesized and characterized, the spectroscopic properties of3H2PyBO in different solvents was monitored by using UV absorption and fluorescence emission spectrum, the fluorescence emission spectrum was solvent dependent, the proton transfer efficiency in polar solvents was lower than in nonpolar solvents. The fluorescence emission spectrum of3H2PyBO binding with β-CD shows that3H2PyBO-β-CDcomplexes was come into being and the stoichiometry of the complexes is1:1, the proton transfer efficiency was increased. The fluorescence emission spectrum of3H2PyBO binding with CB8shows that3H2PyBO-CB8complexes was formed and the stoichiometry of the complexes is1:2,the proton transfer efficiency was increased, the influence of CB8is higher compare to β-CD when binding with3H2PyBO.