文献类型：期刊文献

英文题名：Tuning the Conformation and Color of Conjugated Polyheterocyclic Skeletons by Installing ortho-Methyl Groups

作者：Zhang, Zhiyun[1];Chen, Chi-Lin[1];Chen, Yi-An[1];Wei, Yu-Chen[1];Su, Jianhua[2,3];Tian, He[2,3];Chou, Pi-Tai[1]

机构：[1]Natl Taiwan Univ, Dept Chem, Taipei 10617, Taiwan;[2]East China Univ Sci & Technol, Key Lab Adv Mat, Shanghai 200237, Peoples R China;[3]East China Univ Sci & Technol, Inst Fine Chem, Shanghai 200237, Peoples R China

年份：2018

卷号：57

期号：31

起止页码：9880

外文期刊名：ANGEWANDTE CHEMIE-INTERNATIONAL EDITION

收录：;EI(收录号：20183005614827);WOS:【SCI-EXPANDED(收录号:WOS:000439741900053)】；

基金：P.-T. Chou thanks the Ministry of Science and Technology, Taiwan, for financial support. H. Tian gratefully acknowledges the financial support from NSFC/China (21788102).

语种：英文

外文关键词：conformation analysis; conjugation; heterocycles; methylation; steric hindrance

摘要：ortho-Methyl effects are exploited to tune steric hindrance between side-chain N,N-diaryls and polycyclic dihydrodibenzo[a,c]phenazine, and in turn control the conformations of N,N-diphenyl-dihydrodibenzo[a,c]phenazine (DPAC) and its ortho-methyl derivatives Mx-My (x=0, 1 or 2, y=1 or 2, x and y correlate with the number of methyl groups in the ortho-positiond of N,N-diphenyl). The magnitude of steric hindrance increases as x and y increase, and the V-shaped dihydrodibenzo[a,c]phenazine skeleton is gradually tuned from a bent (DPAC) to planar (M2-M2) structure in the ground state. As a result, the relaxation of the excited-state structure of DPAC and its numerous analogues could be mimicked by model structures Mx-My, demonstrating for the first time the the conformation change from bent-to-planar and hence a large range of energy-gap tuning of polycyclic conjugated structures controlled by the steric hindrance.