| Abstract
| - The excited-state intramolecular proton transfer(ESIPT) of 2-(2‘-hydroxyphenyl)benzimidazole (HBI)hasbeen studied using absorbance, steady-state, and time-resolved emissionspectroscopies in cyclodextrins (β-,γ-, and 2,6-di-O-methyl-β-cyclodextrins) and in binaryaqueous solvent mixtures. The spectralcharacteristicsof HBI in cyclodextrins and binary solvent mixtures (dioxane:water,MeOH:water, and solutions of cyclohexanecontaining MeOH and trifluoroethanol) are compared to further study theeffects of various microenvironmentson the ground and excited-state properties of the molecule. Theintermolecular interactions of HBI withcyclodextrins and various solvents appear to weaken intramolecularhydrogen bonding in HBI and facilitatethe formation of strong intermolecular hydrogen bonds with the variouscyclodextrins and solvent molecules.The acquired data are used to suggest the formation of azwitterionic structure of HBI in cyclodextrins.
|
