Anokhin Maksim V, Nesterov Evgueni E
Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, Illinois 60115, United States.
J Phys Chem Lett. 2020 Oct 15;11(20):8745-8750. doi: 10.1021/acs.jpclett.0c02473. Epub 2020 Sep 30.
Photochemical reactions are intrinsically difficult to control because they involve high-energy excited-state species. Herein we report a novel approach toward controlling photochemical reactions via using the spatially selective excitation of specific electronic transitions. This can be performed using photochemical irradiation with the plane-polarized light of a photoreactive compound uniformly aligned in a nematic liquid-crystalline (LC) medium. Having chosen cyclopropenone photodecarbonylation as a proof-of-concept reaction, we demonstrated that it could be controlled via changing an angle between the incident light polarization plane and the LC director. We showed that two specific partially forbidden electronic transitions were mostly responsible for this photochemical reaction. We envision that this simple general method can be useful in experimental studies of the fundamental details of various photochemical processes and can help to increase the selectivity of photochemical transformations.
光化学反应本质上难以控制，因为它们涉及高能激发态物种。在此，我们报告一种通过利用特定电子跃迁的空间选择性激发来控制光化学反应的新方法。这可以通过用均匀排列在向列型液晶（LC）介质中的光反应性化合物的平面偏振光进行光化学照射来实现。选择环丙烯酮光脱羰反应作为概念验证反应，我们证明可以通过改变入射光偏振平面与LC指向矢之间的角度来控制该反应。我们表明，两个特定的部分禁阻电子跃迁对该光化学反应起主要作用。我们设想，这种简单通用的方法可用于各种光化学过程基本细节的实验研究，并有助于提高光化学转化的选择性。
