Nonadiabatic Dynamics Mechanism of Chalcone Analogue Sunscreen FPPO-HBr: Excited State Intramolecular Proton Transfer Followed by Conformation Twisting

J Phys Chem B. 2021 Aug 26;125(33):9572-9578. doi: 10.1021/acs.jpcb.1c05809. Epub 2021 Aug 16.

Abstract

Nowadays, traditional sunscreen molecules face many adverse problems: single energy relaxation pathway, lack of adequate UVA light protection, and therefore no longer meeting the growing demand for UVA protection. In this work, we reported a novel sunscreen molecule (E)-3-(5-bromofuran-2-yl)-1-(2-hydroxyphenyl)prop-2-en-1-one (hereinafter referred to as FPPO-HBr) which tackled adverse problems of traditional sunscreen molecules as single energy relaxation pathway, lacking effective UVA light protection. Various nonradiative pathways were proposed and verified by combining the steady-state and femtosecond transient absorption (FTA) spectroscopy and theoretical calculation. Upon UV excitation, the FPPO-HBr mainly decays via excited-state intramolecular proton transfer (ESIPT) followed by conformation twist in ultrafast manner. Importantly, 1H NMR spectra proved that the FPPO-HBr could not undergo trans-cis photoisomerization. Additionally, excellent photostability was also observed for newly synthesized FPPO-HBr. The current work could provide new perspectives for sunscreen molecules synthesis and mechanism.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chalcone*
  • Chalcones*
  • Molecular Conformation
  • Protons
  • Sunscreening Agents

Substances

  • Chalcones
  • Protons
  • Sunscreening Agents
  • Chalcone