Triindolo-Truxene Derivatives: Design,Synthesis, and Fine-Tuning of Electronic Properties and Molecular Assembly through Molecular Engineering |
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Authors: | Jun-Bo Chen Dr Cen Zhou Ru-Qiang Lu Dr Xin-Chang Wang Hang Qu Dr Mithu Saha Hao-Liang Liu Prof Hui Zhang Prof Xiao-Yu Cao |
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Institution: | State Key Laboratory of Physical Chemistry of Solid Surfaces, Key Laboratory of Chemical Biology of Fujian Province, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005 P. R. China |
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Abstract: | Triindolo-truxene, a C3-symmetric molecule with a large π-conjugated plane, has six methylene carbon atoms and three aromatic carbon atoms that can be facilely functionalized. Herein, butyl, carbonyl, cyano, and/or malononitrile groups were introduced at six methylene carbon atoms (6-, 14-, 22- or 8-, 16-, 24-positions) and/or three aromatic carbon atoms (2-, 10-, and 18-positions) of triindolo-truxene to produce eight derivatives. Their photophysical properties, electrochemical properties, and molecular assembly can be effectively modulated by substituents and substitution patterns. Incorporation of electron-deficient groups led to redshifts in both the absorption and emission of these derivatives and also lowered their HOMO and LUMO levels. Different substitution patterns resulted in the different intramolecular donor–acceptor interactions. Electron-deficient substituents at the methylene carbon atoms in the 6-, 14-, and 22-positions led to intramolecular charge transfer from the fluorene arms to the truxene core, whereas the corresponding substitutions at the methylene carbon atoms in the 8-, 16-, and 24-positions resulted in intramolecular charge transfer from the truxene core to the fluorene arms. The molecular packing in single crystals and molecular aggregation in solution are also influenced by the substituents and substitution patterns. This work provides a straightforward strategy to alter the properties of triindolo-truxene. |
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Keywords: | aggregation donor–acceptor systems substituent effects synthetic methods triindolo-truxenes |
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