Tribenzo[ b , d , f ]azepines as Minimalistic Purely Organic Photocatalysts

Few examples of organic photocatalysts (PCs) can be used in singlet electron transfer (SET) and energy transfer (EnT) processes and generally include relatively complex scaffolds based on transition-metal complexes or IPN-based TADF emitters. In this work, we introduce a family of minimalist bifunctional organic photocatalysts based on tribenzo[b,d,f]azepine that can promote both activation types. The study shows that, for SET, the stability of radical-ion PC intermediates is crucial. In contrast, a slow intersystem crossing increases the level of triplet formation, thereby enhancing EnT reactivity.