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Tuning the Conformation and Color of Conjugated Polyheterocyclic Skeletons by Installing ortho ‐Methyl Groups
Author(s) -
Zhang Zhiyun,
Chen ChiLin,
Chen YiAn,
Wei YuChen,
Su Jianhua,
Tian He,
Chou PiTai
Publication year - 2018
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201806385
Subject(s) - steric effects , phenazine , bent molecular geometry , conjugated system , chemistry , excited state , crystallography , stereochemistry , relaxation (psychology) , ground state , organic chemistry , physics , psychology , social psychology , quantum mechanics , nuclear physics , polymer
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 M x ‐M y ( 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 M x ‐M y , 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.