Impact of Fluorine Substitution on the Ultrafast Dynamic Processes of
Coumarin Molecules
GE Jing1, 2, LI Zhi-biao1, 2, XUE Bing-qian1, 2, BAI Xi-lin1, 2*
1. School of Physics and Information Engineering, Shanxi Normal University, Taiyuan 030031, China
2. Key Laboratory of Spectral Measurement and Analysis of Shanxi Province, Taiyuan 030031, China
Abstract：The development of highly efficient, photostable, and eco-friendly fluorescent dyes is currently a prominent focus in scientific research, attracting significant attention. Recent studies have emphasized Twisted Intramolecular Charge Transfer (TICT) 's crucial role in determining fluorescent dyes' luminescence efficiency. Consequently, effectively suppressing the TICT process is imperative for progressing fluorescent markers and probes. Among the various fluorescent dyes, coumarin and its derivatives, particularly 7-amino coumarin dyes, have gained significant recognition as extensively utilized constituents in diverse systems owing to their robust fluorescence and prolonged fluorescence lifetimes. Nevertheless, previous examinations have predominantly concentrated on the effect of different solvents on the excited-state behavior of coumarin dye molecules, overlooking the significant influence of dye molecule structure on the TICT process. This study utilized a combination of femtosecond time-resolved transient absorption (TA) spectroscopy and density functional theory (DFT) calculations to gain deeper insights into the excited-state dynamics of coumarin dyes C460 and C481 in various solvents. The results revealed that C481 predominantly undergoes the TICT process in highly polar methanol solvents with strong hydrogen-bonding capabilities. Furthermore, quantum chemical calculations indicated that introducing fluorine substitutions reduces the molecules' internal torsional barriers, leading to enhanced non-radiative deactivation processes and, consequently, more pronounced fluorescence quenching phenomena. This investigation provides insights into the selection of suitable solvents for optimizing the performance of fluorescent dyes and offers valuable guidance for their design.
Key words：Transient absorption spectroscopy; Twisted intramolecular charge transfer;Density functional theory
葛 晶，李智彪，薛丙乾，白西林. 氟取代对香豆素分子超快动力学过程的影响[J]. 光谱学与光谱分析, 2024, 44(11): 3128-3135.
GE Jing, LI Zhi-biao, XUE Bing-qian, BAI Xi-lin. Impact of Fluorine Substitution on the Ultrafast Dynamic Processes of
Coumarin Molecules. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2024, 44(11): 3128-3135.
[1] Rotkiewicz K, Grellmann K H, Grabowski Z R. Chemical Physics Letters, 1973, 19(3): 315.
[2] Wang Chao, Chi Weijie, Qiao Qinglong, et al. Chemical Society Reviews, 2021, 50(22): 12656.
[3] Kuimova M K, Yahioglu G, Levitt J A, et al. Journal of the American Chemical Society, 2008, 130(21): 6672.
[4] Zhao Guangjiu, Han Keli. Physical Chemistry Chemical Physics, 2010, 12(31): 8914.
[5] Gao Shuai, Wei Guoguang, Zhang Sihang, et al. Nature Communications, 2019, 10(1): 2206.
[6] Ge Jing, Zhang Qun, Jiang Jun, et al. Physical Chemistry Chemical Physics, 2015, 17(19): 13129.
[7] QIN Chao-chao, LIU Hua, ZHOU Zhong-po（秦朝朝，刘 华，周忠坡）. Spectroscopy and Spectral Analysis(光谱学与光谱分析), 2021, 41(6): 1695.
[8] Ge Jing, Zhang Xuedong, Li Zhibiao, et al. RSC Advances, 2023, 13(31): 21746.
[9] Yang Songqiu, Han Keli. The Journal of Physical Chemistry A, 2016, 120(27): 4961.
[10] Ghosh Rajib, Manna Biswajit. Physical Chemistry Chemical Physics, 2017, 19(34): 23078.
[11] Barik Atanu, Kumbhakar Manoj, Nath Sukhendu, et al. Chemical Physics, 2005, 315(3): 277.
[12] Li You, Sun Chaofan, Han Jianhui, et al. Journal of Luminescence, 2020, 221: 117110.
[13] Sayed Mhejabeen, Maity Dilip Kumar, Pal Haridas. Journal of Photochemistry and Photobiology A: Chemistry, 2023, 434: 114265.
[14] Frisch M J, Trucks G W, Schlegel H B, et al. Gaussian 09, Revision D.01, Gaussian, Inc., Wallingford CT，2009.
[15] Ge Jing, Zhang Xuedong, Peng Yue, et al. RSC Advances, 2023, 13(8): 4924.
[16] Wang Chao, Qiao Qinglong, Chi Weijie, et al. Angewandte Chemie, 2020, 59(25): 10160.
[17] Jadhav Manoj, Vaghasiya Jayraj V, Patil Dinesh, et al. New Journal of Chemistry, 2019, 43(23): 8970.
[18] Porobic Slavica J, Bozic Bojan D, Dramicanin Miroslav D, et al. Dyes and Pigments, 2020, 175: 108139.
[19] Liu Jiawei, Chen Cheng, Fang Chong. Chemosensors, 2022, 10(10): 411.
