Probing Ultrafast Structural Dynamics in Proton Transfer Reactions in Solution with Time-Resolved Infrared and X-Ray Spectroscopies

利用时间分辨红外和 X 射线光谱探测溶液中质子转移反应的超快结构动力学

• 批准号: 208517069
• 负责人: Dr. Erik T.J. Nibbering
• 金额: --
• 依托单位: Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie (MBI)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2012
• 资助国家: 德国
• 起止时间: 2011-12-31 至 2016-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/208517069?language=en
• 关键词: Probing; Ultrafast; Structural; Dynamics; Proton

Photoacids are molecular systems that exhibit a pronounced increase in acidity upon electronic excitation, enabling proton transfer dynamics to be studied in real time using time-resolved spectroscopy. The underlying mechanism for photoacidity is, however, still poorly understood. The goal of the project is to combine the structure resolving potential of time-resolved IR and x-ray spectroscopies to determine hydrogen bond geometries of photoacid-base complexes in liquid solution, and the changes of these hydrogen bond geometries upon electronic excitation of the photoacid chromophores. With femtosecond IR spectroscopy we will investigate the response of OH vibrations of naphthols and NH stretching vibrations of aminonaphthalenes, as well as aminopyrenes. Contributions of the photoacid-base hydrogen bond and of the solvent to the observed frequency shifts in both the electronic ground and excited states will be compared with quantum chemical calculations. Dynamics of hydrogen bonds of the photoacid-base complexes in both electronic states will be studied with transient two-dimensional IR photon echo spectroscopy. Photoacid behaviour has been ascribed to intramolecular charge transfer. The key role played by the intramolecular charge transfer will be studied by investigating a family of naphthol molecules with different substituents, understood to affect the intramolecular charge transfer capability. Time-resolved x-ray spectroscopy will applied to study the N K-edge of a cationic photoacids of the proton donating amino-group, with which we will have direct access to the electronic charge distribution changes of the proton donating group upon UV excitation. The results obtained with time-resolved x-ray absorption will be combined with transient IR absorbance of NH stretching modes of the cationic photoacid, thereby linking the two structurally resolving techniques.

光酸是在电子激发时表现出酸度显著增加的分子系统，使得能够使用时间分辨光谱学在真实的时间中研究质子转移动力学。然而，光酸性的基本机制仍然知之甚少。该项目的目标是结合联合收割机的结构解析潜力的时间分辨红外光谱和X-射线光谱，以确定氢键的几何形状的光酸-碱复合物在液体溶液中，这些氢键的几何形状的变化后，电子激发的光酸发色团。利用飞秒红外光谱，我们将研究萘酚的OH振动和氨基萘以及氨基芘的NH伸缩振动的响应。光酸-碱氢键和溶剂对电子基态和激发态的频移的贡献将与量子化学计算进行比较。利用瞬态二维红外光子回波光谱研究了光酸-碱复合物在两种电子状态下的氢键动力学。光酸行为已被归因于分子内电荷转移。分子内电荷转移所起的关键作用将通过研究一个家庭的萘酚分子与不同的取代基，理解影响分子内电荷转移能力进行研究。利用时间分辨X射线光谱研究了质子供体氨基的阳离子光酸的N-K边，从而可以直接了解质子供体氨基在紫外光激发下的电荷分布变化。时间分辨的X-射线吸收得到的结果将结合瞬态红外吸收的NH伸缩模式的阳离子光酸，从而连接两个结构解析技术。

项目成果

Ultrafast excited-state proton-transfer reaction of 1-naphthol-3,6-disulfonate and several 5-substituted 1-naphthol derivatives.

1-萘酚-3,6-二磺酸酯和几种5-取代1-萘酚衍生物的超快激发态质子转移反应

• DOI: 10.1021/jp308746x
• 发表时间: 2013
• 期刊: The journal of physical chemistry. B
• 作者: M. Prémont-Schwarz;T. Barak;D. Pines;E. T. J. Nibbering;E. Pines
• 通讯作者: E. Pines

Correlating photoacidity to hydrogen-bond structure by using the local O-H stretching probe in hydrogen-bonded complexes of aromatic alcohols.

通过使用芳香醇氢键配合物中的局部 O-H 伸缩探针将光致酸性与氢键结构相关联

• DOI: 10.1021/acs.jpca.5b01530
• 发表时间: 2015
• 期刊: The journal of physical chemistry. A
• 作者: B. T. Psciuk;M. Prémont-Schwarz;B. Koeppe;S. Keinan;D. Xiao;E. T. J. Nibbering;V. S. Batista
• 通讯作者: V. S. Batista