Dalton Jack, Sanders Hans, Buma Wybren Jan, Stavros Vasilios G
Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, U.K.
Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands.
J Phys Chem Lett. 2025 Feb 27;16(8):2016-2022. doi: 10.1021/acs.jpclett.5c00137. Epub 2025 Feb 18.
-Urocanic acid (UA) was once thought to be an ideal natural UV sunscreen filter because of its strong UV absorption and efficient nonradiative decay, in addition to its natural presence in human skin. However, its commercial use was abandoned following the discovery of the immunosuppressive properties of the isomer formed following photoexcitation. From the extensive literature accumulated over the past decades, UA serves as a perfect scaffold for developing next-generation nature-inspired UV filters by eliminating the immunosuppressive characteristics and retaining the favorable photophysics. Here, gas-phase time-resolved ion-yield and time-resolved photoelectron spectroscopy are combined to uncover the fundamental ultrafast photodynamics of three UA derivatives. We find that minor molecular adjustments between derivatives have considerable influence on the overall excited state behavior, leading to different relaxation mechanisms and lifetimes. These findings establish foundations for further molecular design and aid in the interpretation of these derivatives under complex environmental conditions.
尿刊酸（UA）曾被认为是一种理想的天然紫外线防晒滤光剂，这是由于其具有强烈的紫外线吸收能力和高效的非辐射衰变，此外它还天然存在于人体皮肤中。然而，在发现光激发后形成的异构体具有免疫抑制特性后，其商业用途被放弃。从过去几十年积累的大量文献来看，通过消除免疫抑制特性并保留有利的光物理性质，尿刊酸可作为开发下一代受自然启发的紫外线滤光剂的理想框架。在这里，气相时间分辨离子产率和时间分辨光电子能谱相结合，以揭示三种尿刊酸衍生物的基本超快光动力学。我们发现，衍生物之间微小的分子调整对整体激发态行为有相当大的影响，导致不同的弛豫机制和寿命。这些发现为进一步的分子设计奠定了基础，并有助于解释这些衍生物在复杂环境条件下的情况。
