title: A class of nonplanar conjugated compounds with aggregation-induced emission: structural and optical properties of 2,5-diphenyl-1,4-distyrylbenzene derivatives with all cis double bonds.
abstract: We have studied the structural and optical properties of four 2,5-diphenyl-1,4-distyrylbenzene derivatives with all cis double bonds. These compounds belong to a class of nonplanar conjugated compounds possessing a typical Aggregation-Induced Emission (AIE) property that has no emission in solution but intense emission in crystal. The four molecules are packed in different stacking modes with different intermolecular interactions, resulting in different crystalline state photoluminescence (PL) efficiency. The torsional molecular configuration increases the intermolecular distances effectively in the crystalline state, which decreases the difference of the optical properties from the frozen isolated molecules to the crystalline state. The Stokes shifts of these compounds are very large and the PL spectra have only one broad emission band with poor structure, due to the relatively large configuration difference between the ground state and the first singlet excited state, and the abundant vibration energy levels of the torsional molecule with changeable conformation.
authors.affiliation: Key Laboratory for Supramolecular Structure and Materials of Ministry of Education, Jilin University, Changchun, 130012, PR China.
authors.forename: Zengqi
authors.initials: Z
authors.lastname: Xie
authors.forename: Bing
authors.initials: B
authors.lastname: Yang
authors.forename: Weijie
authors.initials: W
authors.lastname: Xie
authors.forename: Linlin
authors.initials: L
authors.lastname: Liu
authors.forename: Fangzhong
authors.initials: F
authors.lastname: Shen
authors.forename: Huan
authors.initials: H
authors.lastname: Wang
authors.forename: Xuyan
authors.initials: X
authors.lastname: Yang
authors.forename: Zhiming
authors.initials: Z
authors.lastname: Wang
authors.forename: Yupeng
authors.initials: Y
authors.lastname: Li
authors.forename: Muddasir
authors.initials: M
authors.lastname: Hanif
authors.forename: Guangdi
authors.initials: G
authors.lastname: Yang
authors.forename: Ling
authors.initials: L
authors.lastname: Ye
authors.forename: Yuguang
authors.initials: Y
authors.lastname: Ma