Mechanistic Aspects of the Photophysics of UVA Filters Based on Meldrum Derivatives - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of Physical Chemistry A Année : 2021

Mechanistic Aspects of the Photophysics of UVA Filters Based on Meldrum Derivatives

Résumé

Skin photoprotection against UVA radiation is crucial, but it is hindered by the sparsity of approved commercial UVA filters. Sinapoyl malate (SM) derivatives are promising candidates for a new class of UVA filters. They have been previously identified as an efficient photoprotective sunscreen in plants due to their fast nonradiative energy dissipation. Combining experimental and computational results, in our previous letter (J. Phys. Chem. Lett. 2021, 12, 337−344) we showed that coumaryl Meldrum (CMe) and sinapoyl Meldrum (SMe) are outstanding candidates for UVA filters in sunscreen formulations. Here, we deliver a comprehensive computational characterization of the excitedstate dynamics of these molecules. Using reaction pathways and excited-state dynamics simulations, we could elucidate the photodeactivation mechanism of these molecules. Upon photoexcitation, they follow a two-step logistic decay. First, an ultrafast and efficient relaxation stabilizes the excited state alongside a 90°twisting around the allylic double bond, giving rise to a minimum with a twisted intramolecular excitedstate (TICT) character. From this minimum, internal conversion to the ground state occurs after overcoming a 0.2 eV barrier. Minor differences in the nonradiative decay and fluorescence of CMe and SMe are associated with an additional minimum present only in the latter.
Fichier principal
Vignette du fichier
p159_toldo_meldrum_jpca_2021.pdf (2.87 Mo) Télécharger le fichier
Origine : Publication financée par une institution

Dates et versions

hal-03276126 , version 1 (01-07-2021)

Identifiants

Citer

Josene M Toldo, Mariana T Do Casal, Mario Barbatti. Mechanistic Aspects of the Photophysics of UVA Filters Based on Meldrum Derivatives. Journal of Physical Chemistry A, 2021, 125 (25), pp.5499-5508. ⟨10.1021/acs.jpca.1c03315⟩. ⟨hal-03276126⟩
46 Consultations
47 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More