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Exploring the molecular interactions behind light-induced reactions using transition-metal photosensitizers: a cage escape study by Alexia RIPAK -
Mercredi 8 octobre 2025 à 16h00 - Auditoire SOCR-242 - Place Cardinal Mercier - 1348 Louvain-la-Neuve
The cage escape yield, i.e. the ratio of the photoproducts that have escaped the solvent cage over the total amount of excited-state photosensitizers that have reacted, is a key step in photochemical reactions. Indeed, a high quenching combined with a poor cage escape inevitably ends with an overall photoreaction that is unprofitable, and it appears that controlling and knowing which experimental factors governs it, is of prime importance.
This work reports the individual yet intricate studies of several factors influencing the cage escape process i.e. i) the driving force for electron transfer; ii) the counterions, iii) the dielectric constant of the solvent; iv) the spin of the geminate radical pair and v) the nature of the excited state. Taken together, the results obtained in this work helped to create a first scale of impact and a first dichotomous chart to predict the range of cage escape for an unknown quencher with the photosensitizers studied here.
Overall, this work highlights the importance of studying mechanistic steps like cage escape, and that determining crucial factors can help to better understand, design and predict a photo-induced chemical reaction.
Jury members :
Prof. Benjamin Elias (UCLouvain) (Promoteur)
Prof. Yann Garcia (UCLouvain) (Président)
Prof. Olivier Riant (UCLouvain) (Secrétaire)
Prof. Sophie Hermans (UCLouvain)
Prof. Yoann Olivier (UNamur)
Prof. Alejandro Cadranel (Friedrich-Alexander-Universität Erlangen-Nürnberg)
Pay attention : the public defense of Alexia RIPAK will also take place in the form of a videoconference
