Investigation of Excited-State Proton Transfer of 2-(3-Acetamido-2-pyridyl)benzimidazole in the Confined Nanocavity of Cucurbit[7]uril

Pinggui Yi, Xichun Yang, Jin Liu, Bo Hou, Xianyong Yu, Xiaofang Li, Zhaoxu Wang, Baishu Zheng
2013 Youji huaxue  
The interaction of 2-(3-acetamido-2-pyridyl)-benzimidazole (2-3Am2PyBI) with cucurbit[7]uril (CB7) macrocycle and the effect of inclusion on the proton transfer of 2-3Am2PyBI were studied by using emission fluorescence, 1 H NMR spectra and quantum chemical calculation. By the way, the proton transfer of the dye with and without acetyl (2-3A2PyBI) was also studied. The results indicate that the acetyl promoted the process of proton transfer of the benzimidazole and the cationic form binds with
more » ... c form binds with CB7 easier than the other forms of the dye. The fluorescence studying at selected pHs suggest that the proton transfer process of the dye was retarded by interacting with CB7 nanocavity and the molar rate is host∶guest=1∶1 analyzed by the Benesi-Hildebrand method. The dye entered into the CB7 cavity with its benzene ring was proved by the 1 H NMR titration experiment and the protonated forms were verified by the quantum calculation with fluorescence spectra.
doi:10.6023/cjoc201212044 fatcat:pepubcsgbncqddatpwy3qb7vli