有机化学 ›› 2013, Vol. 33 ›› Issue (07): 1451-1456.DOI: 10.6023/cjoc201212044 上一篇    下一篇

研究论文

七元瓜环纳米腔限制环境下2-(3-乙酰胺基-2-吡啶基)苯并咪唑的激发态质子转移

易平贵, 阳习春, 刘金, 侯博, 于贤勇, 李筱芳, 汪朝旭, 郑柏树   

  1. 湖南科技大学化学化工学院 湘潭 411201
  • 收稿日期:2012-12-25 修回日期:2013-03-02 出版日期:2013-07-25 发布日期:2013-03-15
  • 通讯作者: 易平贵 E-mail:pgyi@hnust.cn
  • 基金资助:

    国家自然科学基金(Nos. 21172066, 20971041);湖南省自然科学基金(Nos. 10JJ4011, 11JJ2007)和湖南省高校科技创新团队支持计划(No,[2012]318-17))资助项目.

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

Yi Pinggui, Yang Xichun, Liu Jin, Hou Bo, Yu Xianyong, Li Xiaofang, Wang Zhaoxu, Zheng Baishu   

  1. School of Chemistry and Chemical Engineering, Hunan University of Science and Technology, Xiangtan 411201
  • Received:2012-12-25 Revised:2013-03-02 Online:2013-07-25 Published:2013-03-15
  • Supported by:

    Project supported by the National Natural Science Foundation of China (Nos. 21172066, 20971041), the Hunan Provincial Natural Science Foundation of China (No. 11JJ2007), the Science and Technology Innovative Research Team in Higher Educational Instituions of Hunan Province (No.[2012]318-17).

以荧光发射光谱, 1H NMR 谱及量子化学计算研究了2-(3-乙酰胺基-2-吡啶基)苯并咪唑(2-3Am2PyBI)质子转移过程及其与七元瓜环超分子(CB7)的包合作用, 考察了乙酰基取代基效应及CB7的包合作用对2-3Am2PyBI质子转移过程的影响. 结果表明: 乙酰基取代促进了质子转移过程; 2-3Am2PyBI 阳离子构型更易与CB7 发生包合作用; 在特定溶液pH 值条件下, 摩尔比法荧光光谱实验表明超分子包合作用抑制了2-3Am2PyBI 的激发态质子转移过程; Benesi-Hildebrand 方程拟合得到, 超分子体系的包合比为1:1; 1H NMR 测试进一步表明2-3Am2PyBI 以苯环部分进入CB7 的空腔, 同时, 以量化计算与荧光实验结合, 从理论与实验方面共同验证了2-3Am2PyBI 的质子转移异构体.

关键词: 质子转移, 七元瓜环, 荧光发射光谱, 1H NMR 谱, 量化计算

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, 1H 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 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 1H NMR titration experiment and the protonated forms were verified by the quantum calculation with fluorescence spectra.

Key words: proton transfer, cucurbit[7]uril, emission fluorescence, 1H NMR spectra, quantum calculation