Caught in the act: real-time observation of the solvent response that promotes excited-state proton transfer in pyranine.
Caught in the act: real-time observation of the solvent response that promotes excited-state proton transfer in pyranine.
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DOI：
10.1039/d2sc07126f
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发表时间：
2023-04-12
期刊：
影响因子：
8.4
通讯作者：
中科院分区：
文献类型：
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光诱导激发态质子转移（ESPT）反应在许多生物和化学过程中具有重要意义。然而，对于目前的实验和理论方法来说，确定溶剂重组促进质子转移的机理细节是具有挑战性的。利用光泵太赫兹探针（OPTP）光谱和分子动力学模拟，我们能够阐明三种吡嗪衍生物：光酸HPTS、甲氧基衍生物MPTS和光碱衍生物OPTS在溶剂化环境中的超快变化。在实验中，我们发现太赫兹信号在短时间内存在阻尼振荡，我们的模拟使它们能够分配到光激发发色团和附近溶剂分子之间的振动能量转移跳动。HPTS的模拟揭示了亚ps能量向特定溶剂模式的高效转移，该模式在4太赫兹附近活跃，可以为溶剂重组提供促进质子转移所需的能量。对于所有三种导数，太赫兹信号中都存在类似的振荡，但是对于HPTS （0.4 ps以内），信号衰减迅速，对于MPTS （1.4 ps以内）和OPTS （2.0 ps以内），信号衰减较慢。对于HPTS，我们还描述了质子在体中的额外声子样传播，周期为140 ps，阻尼时间为83 ps。溶剂的热化发生在超过120ps的时间尺度上。光诱导激发质子转移（ESPT）反应的观察：从质子转移开始到热化。
Photo-induced excited-state proton transfer (ESPT) reactions are of central importance in many biological and chemical processes. Identifying mechanistic details of the solvent reorganizations that facilitate proton transfer however, is challenging for current experimental and theoretical approaches. Using optical pump THz probe (OPTP) spectroscopy and molecular dynamics simulations, we were able to elucidate the ultrafast changes in the solvation environment for three derivatives of pyranine: the photoacid HPTS, the methoxy derivative MPTS, and the photobase OPTS. Experimentally, we find damped oscillations in the THz signal at short times and our simulations enable their assignment to vibrational energy transfer beatings between the photoexcited chromophore and nearby solvent molecules. The simulations of HPTS reveal strikingly efficient sub-ps energy transfer into a particular solvent mode, that is active near 4 THz, and which can provide the requisite energy required for solvent reorganization promoting proton transfer. Similar oscillations are present in the THz signal for all three derivatives, however the signal is damped rapidly for HPTS (within 0.4 ps) and more slowly for MPTS (within 1.4 ps) and OPTS (within 2.0 ps). For HPTS, we also characterize an additional phonon-like propagation of the proton into the bulk with a 140 ps period and an 83 ps damping time. Thermalization of the solvent occurs on a time scale exceeding 120 ps. Observation of photoinduced excited proton transfer (ESPT) reactions: from the onset of proton transfer up to thermalization.
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DOI：
10.1002/anie.202014133
发表时间：
2021-02-15
期刊：
Angewandte Chemie (International ed. in English)
影响因子：
--
作者：
Sebastiani F;Ma CY;Funke S;Bäumer A;Decka D;Hoberg C;Esser A;Forbert H;Schwaab G;Marx D;Havenith M
通讯作者：
Havenith M
影响因子：
8.4
作者：
Liu W;Wang Y;Tang L;Oscar BG;Zhu L;Fang C
通讯作者：
Fang C
影响因子：
15
作者：
Day, TJF;Schmitt, UW;Voth, GA
通讯作者：
Voth, GA
影响因子：
2.9
作者：
Herr, Jonathan D.;Talbot, Justin;Steele, Ryan P.
通讯作者：
Steele, Ryan P.
影响因子：
1.6
作者：
Hoberg, C.;Balzerowski, P.;Havenith, M.
通讯作者：
Havenith, M.