Excited-State Proton Transfer Dynamics of Fisetin in Acetonitrile and Methanol  

漆黄素在乙腈和甲醇中的激发态质子转移动力学

作　　者：Long Yu Yongchun Tan Jie Zhao Jian Luo 余龙;谭永春;赵洁;罗健(长江大学物理与光电工程学院,荆州434023)

机构地区：[1]School of Physics and Optoelectronic Engineering,Yangtze University,Jingzhou 434023,China

出　　处：《Chinese Journal of Chemical Physics》2025年第2期181-188,I0007-I0012,I0040,共15页化学物理学报(英文)

基　　金：supported by the National Natural Science Foundation of China(No.22003066)。

摘　　要：Fisetin attracts intense attention not only due to its antioxidant and anticancer properties but also be-cause of wide applications in fluo-rescence probes and sensors,which are based on the dual fluorescence induced by excited-state proton transfer(ESPT).However,to date,its ESPT dynamics remains unknown yet.In this study,we give a comprehensive investiga-tion on ESPT dynamics of fisetin in both protic methanol and aprot-ic acetonitrile by using femtosecond transient absorption spectroscopy combined with time-dependent density functional theory calculations.In acetonitrile,the ESPT time constant of fisetin is 1.2 ps.In methanol,two distinct intermolecular hydrogen bonding configurations contribute to a fast(<90 fs)and slow ESPT(11.1 ps),respectively.The slow ESPT in methanol explains the higher emission intensity of normal species than in acetonitrile.The ex-cited-state relaxation of fisetin involves two main vibrational modes:rotation between B and C rings and butterfly-like motion of C ring.Our results give insight into the effect of solvent-solute hydrogen bonding interaction on the dual fluorescence,providing a fundamental guide-line for the development of fluorescent probes and sensors based on ESPT.漆黄素是一种天然的类黄酮,具有抗氧化和防癌的特性.不仅如此,漆黄素能够发生光致激发态质子转移,发出双荧光,在荧光探针和传感领域也有着广泛应用.然而,到目前为止,漆黄素的激发态质子转移动力学仍不清楚.本文利用飞秒瞬态吸收光谱和含时密度泛函理论计算相结合,系统地研究了漆黄素在质子性甲醇溶液和非质子性乙腈溶液中的激发态质子转移动力学.漆黄素在乙腈中的激发态质子转移的时间常数是1.2 ps,而在甲醇中,存在两种不同的分子间氢键网络,分别导致了超快的(时间常数小于90 fs)和较慢的(时间常数为11.1ps)激发态质子转移过程.甲醇中存在较慢的激发态质子转移,解释了漆黄素在甲醇中质子转移前的荧光强度高于乙腈溶液中的荧光强度的实验事实.另外,漆黄素的激发态弛豫主要包含2种振动模式:B环和C环的相对扭转,C环的类似蝴蝶振动.综上所述,本文深入研究了溶剂-溶质氢键作用对双荧光的影响,对设计基于激发态质子转移的荧光探针和传感器也能提供基础的指导.

关 键 词：Excited-state proton transfer Ultrafast spectroscopy Nonradiative relaxation Excited-state dynamics FLAVONOIDS 

分 类 号：O641[理学—物理化学]