1. Tuning the Conformation and Color of Conjugated Polyheterocyclic Skeletons by Installing ortho‐Methyl Groups.
- Author
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Zhang, Zhiyun, Chen, Chi‐Lin, Chen, Yi‐An, Wei, Yu‐Chen, Su, Jianhua, Tian, He, and Chou, Pi‐Tai
- Subjects
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METHYL groups , *CONJUGATED polymers , *CONFORMATIONAL analysis , *STERIC hindrance , *SUBSTITUENTS (Chemistry) , *PHENAZINE - Abstract
Abstract: 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. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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