Bifunctional Photocatalysts: Exploiting Proximity for Enhanced Reaction Performance

The bifunctional approach has often been employed in catalysis to obtain more effective and enantioselective transformations. In the sub-area of photocatalysis, bifunctional systems have been designed (i) to introduce chirality in the system and thus gain stereocontrol, and (ii) to more effectively exploit the short-lived catalytic intermediates (e.g., photoexcited species and radicals). In some cases, instead of two distinct catalytic units, a single photoactive group displaying also other types of activity can be employed (“bivalent photocatalysts”). This review aims to cover the most recent examples in this field, establishing—when possible—a comparison with the corresponding dual catalytic systems.