Photochemical Processes of Superbase Generation in Xanthone Carboxylic Salts

Autor: Christian Ley, Antoine Siedel, Tony Bertaux, Céline Croutxé‐Barghorn, Xavier Allonas
Rok vydání: 2023
Předmět:
Zdroj: Angewandte Chemie. 135
ISSN: 1521-3757
0044-8249
DOI: 10.1002/ange.202214784
Popis: Photobase generators are species that allow the photocatalysis of various reactions, such as thiol-Michael, thiol-isocyanate, and ring-opening polymerization reactions. However, existing compounds have complex syntheses and low quantum yields. To overcome these problems, photobase generators based on the photodecarboxylation reaction were developed. We synthesized and studied the photochemistry and photophysics of two xanthone photobase, their carboxylic acid precursors, and their photoproducts to understand the photobase generation mechanism. We determined accurate quantum yields of triplet states and photobase generation. We demonstrated the effect of the intermediate radical preceding the base release. We characterized the photophysics of the photobase by femtosecond spectroscopy and showed that the photodecarboxylation process occurred from the second excited triplet state with a rate constant of 2.2 × 109 s-1.
Databáze: OpenAIRE
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