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  

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

作　　者：易平贵[1] 周继明[1] 于贤勇[1] 汪朝旭[1] 李筱芳[1] 刘峥军[1] 侯博[1] 

机构地区：[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

出　　处：《化学学报》2012年第6期699-706,共8页Acta Chimica Sinica

基　　金：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);湖南省自然科学基金(No.11JJ2007)资助项目~~

摘　　要：研究了2-(2′-氨基苯基)苯并咪唑(APBI)氨基中一个H被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)和p-CH3C6H4NHCO(E-NH)取代后,其基态及激发态分子内质子转移(ESIPT)性质的变化规律.结果表明各衍生物基态最稳定构型为烯醇式构型E,次稳定构型旋转异构体R,酮式构型K只有当取代基为E-CN3,E-F,E-NO2,E-N,E-OMe和E-S时才存在.基态各环的核独立化学位移(NICS)研究表明取代基的引入会影响APBI环电子离域性.所有APBI衍生物都能发生激发态分子内质子转移,当引入取代基为E-CN3,E-N或E-OMe时,所得的APBI衍生物S1态分子内质子转移是无能垒过程;引入取代基为E-C,E-C=O或E-OSi时,对APBI的ESIPT势能面基本无影响,而当取代基为E-CC,E-NH,E-CO,E-F,E-NO2和E-S时,使得S1态APBI的K*构型能量低于E*.The effects of chemical substitution on the ground and excited state intramolecular proton trans- fer （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）, Sill3 （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-CH3C6HaCO （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 sub stituents 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 S~ state when substitutent is E-CC, E-NH, E-CO, E-F, E-NO2, or E-S.

关 键 词：2-(2’-氨基苯基)苯并咪唑衍生物 ESIPT 取代基效应 电子离域性 

分 类 号：O626.23[理学—有机化学]