The Role of Linkers in the Excited-State Dynamic Planarization Processes of Macrocyclic Oligothiophene 12-Mers.
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.
Department of Chemistry and Spectroscopy Laboratory for Functional π-Electronic Systems, Yonsei University , Seoul 03722, Korea.
Woojae
W
Kim
Department of Chemistry and Spectroscopy Laboratory for Functional π-Electronic Systems, Yonsei University , Seoul 03722, Korea.
Jooyoung
J
Sung
Department of Chemistry and Spectroscopy Laboratory for Functional π-Electronic Systems, Yonsei University , Seoul 03722, Korea.
Kyu Hyung
KH
Park
Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University , Hachioji, Tokyo 192-0397, Japan.
Hideyuki
H
Shimizu
Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University , Hachioji, Tokyo 192-0397, Japan.
Mika
M
Imamura
Department of Chemistry and Institute of Nano-Bio Molecular Assemblies, Yonsei University , Seoul 03722, Korea.
Minwoo
M
Han
Department of Chemistry and Institute of Nano-Bio Molecular Assemblies, Yonsei University , Seoul 03722, Korea.
Eunji
E
Sim
Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University , Hachioji, Tokyo 192-0397, Japan.
Masahiko
M
Iyoda
Department of Chemistry and Spectroscopy Laboratory for Functional π-Electronic Systems, Yonsei University , Seoul 03722, Korea.
Dongho
D
Kim
broadband fluorescence up-conversion spectroscopy; cyclic oligothiophene; dynamic planarization; linkage pattern; molecular dynamics simulations; vibronic band ratio