Kim Woojae, Sung Jooyoung, Park Kyu Hyung, Shimizu Hideyuki, Imamura Mika, Han Minwoo, Sim Eunji, Iyoda Masahiko, Kim Dongho
Department of Chemistry and Spectroscopy Laboratory for Functional π-Electronic Systems, Yonsei University , Seoul 03722, Korea.
Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University , Hachioji, Tokyo 192-0397, Japan.
J Phys Chem Lett. 2015 Nov 5;6(21):4444-50. doi: 10.1021/acs.jpclett.5b02189. Epub 2015 Oct 28.
Linkers adjoining chromophores play an important role in modulating the structure of conjugated systems, which is bound up with their photophysical properties. However, to date, the focus of works dealing with linker effects was limited only to linear π-conjugated materials, and there have been no detailed studies on cyclic counterparts. Herein we report the linker effects on the dynamic planarization processes of π-conjugated macrocyclic oligothiophene 12-mers, where the different ratio between ethynylene and vinylene linkers was chosen to control the backbone rigidity. By analyzing transient fluorescence spectra, we demonstrate that the connecting linkers play a crucial role in the excited-state dynamics of cyclic conjugated systems. Faster dynamic planarization, longer exciton delocalization length, and higher degree of planarity were observed in vinylene inserted cyclic oligothiophenes. Molecular dynamics simulations and density functional theory calculations also stress the importance of the role of linkers in modulating the structure of cyclic oligothiophenes.
连接发色团的连接体在调节共轭体系的结构中起着重要作用，这与其光物理性质密切相关。然而，迄今为止，处理连接体效应的研究重点仅局限于线性π共轭材料，对于环状共轭材料尚未有详细研究。在此，我们报道了连接体对π共轭大环低聚噻吩12聚体动态平面化过程的影响，其中选择乙炔基和乙烯基连接体的不同比例来控制主链刚性。通过分析瞬态荧光光谱，我们证明连接体在环状共轭体系的激发态动力学中起着关键作用。在插入乙烯基的环状低聚噻吩中观察到更快的动态平面化、更长的激子离域长度和更高的平面度。分子动力学模拟和密度泛函理论计算也强调了连接体在调节环状低聚噻吩结构中所起作用的重要性。
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