Acta Chimica Sinica ›› 2012, Vol. 70 ›› Issue (06): 699-706.DOI: 10.6023/A1108092 Previous Articles     Next Articles

Special Topic

2-(2′-氨基苯基)苯并咪唑衍生物分子内质子转移理论研究: 取代基效应

易平贵, 周继明, 于贤勇, 汪朝旭, 李筱芳, 刘峥军, 侯博   

  1. 湖南科技大学化学化工学院 理论化学与分子模拟省部共建教育部重点实验室 分子构效关系湖南省普通高等学校重点实验室 湘潭 411201
  • 投稿日期:2011-08-09 修回日期:2011-11-20 发布日期:2011-12-06
  • 通讯作者: 易平贵
  • 基金资助:

    国家自然科学基金(Nos. 21172066, 20772027, 20803020)、湖南省高校创新平台开放基金(No. 09K081)和湖南省自然科学基金(No. 11JJ2007)资助项目.

Theoretical Study on Excited-State Intramolecular Proton Transfer of 2-(2'-Aminophenyl)benzimidazole Derivatives: Substituent Effect

Yi Pinggui, Zhou Jiming, Yu Xianyong, Wang Zhaoxu, Li Xiaofang, Liu Zhengjun, Hou Bo   

  1. Key Laboratory of Theoretical Chemistry and Molecular Simulation of Ministry of Education, Hunan Province College Key Laboratory of QSAR/QSPR, School of Chemistry and Chemical Engineering, Hunan University of Science and Technology, Xiangtan 411201
  • Received:2011-08-09 Revised:2011-11-20 Published:2011-12-06
  • Supported by:

    Project supported by the National Natural Science Foundation of China (Nos. 21172066, 20272077, 20803020), Scientific Research Fund of Hunan Provincial Education Department (No. 09K081), and Hunan Provincial Natural Science Foundation of China (No. 11JJ2007).

The effects of chemical substitution on the ground and excited state intramolecular proton transfer (ESIPT) of 2-(2'-aminophenyl)benzimidazole (APBI) have been theoretically studied when a hydrogen atom of the amino group was replaced by CH3 (E-C), SiH3 (E-OSi), NH2 (E-N), COH (E-CO), NO2 (E-NO2), CF3 (E-F), CN (E-CN3), OMe (E-OMe), COCH3 (E-CC), Ts (E-S), p-CH3C6H4CO (E-C=O) and p-CH3C6H4NHCO (E-NH). The results show that in ground state the most stable configuration is the enolic form E; sub-stable configuration is the rotational isomer R. The keto form K only exists in the ground state when substituents is E-CN3, E-F, E-NO2, E-N or E-OMe. The results of nucleus independent chemical shifts (NICS) show that substituents affect electron delocalization of the APBI ring. Excited state proton transfer potential energy surface studies have shown that intramolecular proton transfer of all the derivatives could occur in excited state. The ESIPT of the APBI is barrierless process in S1 state when introducing the substituents E-CN3, E-N, or E-OMe. There is almost no effect on ESIPT when introducing the substituents E-C,E-C=O or E-OSi. The K* configuration become more stable than E* in S1 state when substitutent is E-CC, E-NH, E-CO, E-F, E-NO2, or E-S.

Key words: 2-(2'-aminophenyl)benzimidazole derivatives, ESIPT, substituent effect, electron delocalization