Figueira Nunes Joao Pedro, Ibele Lea Maria, Pathak Shashank, Attar Andrew R, Bhattacharyya Surjendu, Boll Rebecca, Borne Kurtis, Centurion Martin, Erk Benjamin, Lin Ming-Fu, Forbes Ruaridh J G, Goff Nathan, Hansen Christopher S, Hoffmann Matthias, Holland David M P, Ingle Rebecca A, Luo Duan, Muvva Sri Bhavya, Reid Alexander H, Rouzée Arnaud, Rudenko Artem, Saha Sajib Kumar, Shen Xiaozhe, Venkatachalam Anbu Selvam, Wang Xijie, Ware Matt R, Weathersby Stephen P, Wilkin Kyle, Wolf Thomas J A, Xiong Yanwei, Yang Jie, Ashfold Michael N R, Rolles Daniel, Curchod Basile F E
University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States.
CNRS, Institut de Chimie Physique UMR8000, Université Paris-Saclay, Orsay, 9140, France.
J Am Chem Soc. 2024 Feb 14;146(6):4134-4143. doi: 10.1021/jacs.3c13046. Epub 2024 Feb 5.
Identifying multiple rival reaction products and transient species formed during ultrafast photochemical reactions and determining their time-evolving relative populations are key steps toward understanding and predicting photochemical outcomes. Yet, most contemporary ultrafast studies struggle with clearly identifying and quantifying competing molecular structures/species among the emerging reaction products. Here, we show that mega-electronvolt ultrafast electron diffraction in combination with molecular dynamics calculations offer a powerful route to determining populations of the various isomeric products formed after UV (266 nm) excitation of the five-membered heterocyclic molecule 2(5)-thiophenone. This strategy provides experimental validation of the predicted high (∼50%) yield of an episulfide isomer containing a strained three-membered ring within ∼1 ps of photoexcitation and highlights the rapidity of interconversion between the rival highly vibrationally excited photoproducts in their ground electronic state.
识别超快光化学反应过程中形成的多种竞争反应产物和瞬态物种，并确定它们随时间演变的相对丰度，是理解和预测光化学结果的关键步骤。然而，大多数当代超快研究在清晰识别和量化新兴反应产物中相互竞争的分子结构/物种方面存在困难。在这里，我们表明，兆电子伏特超快电子衍射与分子动力学计算相结合，为确定五元杂环分子2(5)-噻吩酮在紫外光（266 nm）激发后形成的各种异构体产物的丰度提供了一条有力途径。该策略为光激发后约1皮秒内预测的含应变三元环的环硫醚异构体的高产率（约50%）提供了实验验证，并突出了相互竞争的高振动激发光产物在其基态电子态之间相互转化的快速性。
