title: Influence of Aggregation on the Structure and Fluorescent Properties of a Tetraphenylethylene Derivative: a Theoretical Study.
abstract: The case that aggregation has a large influence on the structure and fluorescent properties of 5-(4-(1,2,2-triphenylvinyl)phenyl)thiophene-2-carbaldehyde (P4TA) is investigated in detail herein by employing quantum mechanics and molecular mechanics. Besides the isolated molecule, the aggregated molecule in water and in the crystalline state was studied by focusing on the comparison of photoelectronic properties, including the geometrical and electronic structures at ground and excited states, emission and internal conversation properties. For the aggregation state, the intermolecular interaction was used to explain the difference in structure, emission color and intensity of different polymorphs. The noticeable contribution from low-frequency region, corresponding to the four phenyl rings twisting vibration, to the Huang-Rhys factor and reorganization energy, as well as the possible potential energy surface crossing between S0and S1states for isolated molecules was considered as the reason of its aggregation-induced emission (AIE) performance. Importantly, the aggregation process in water simulated at the same time helps us to have a deeper understanding of the AIE behavior of P4TA, which also provides another perspective to explore the AIE phenomenon in theory.
authors.affiliation: Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun, 130024, P.R. China.
authors.forename: Ying-Chen
authors.initials: YC
authors.lastname: Duan
authors.affiliation: School of Pharmaceutical Sciences, Changchun University of Chinese Medicine, 1035 Boshuo Road, Changchun, 130117, P.R. China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Faculty of Chemistry and Chemical Engineering, Hunan University of Arts and Science, Changde, 415000, P.R. China.
authors.forename: Jun-Ling
authors.initials: JL
authors.lastname: Jin
authors.affiliation: Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun, 130024, P.R. China.
authors.forename: Dong-Mei
authors.initials: DM
authors.lastname: Gu
authors.affiliation: Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun, 130024, P.R. China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Geng
authors.affiliation: Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun, 130024, P.R. China.
authors.forename: Min
authors.initials: M
authors.lastname: Zhang
authors.affiliation: Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun, 130024, P.R. China.
authors.forename: Zhong-Min
authors.initials: ZM
authors.lastname: Su
keywords: ab initio calculations; aggregation; fluorescence; huang-rhys factor; tetraphenylethylene derivative