Mesityl or imide acridinium photocatalysts: Accessible versus inaccessible charge-transfer states in photoredox catalysis

Abstract

A study on C9-imide acridinium photocatalysts with enhanced photoredox catalytic activity with respect to the well-established C9-mesityl acridinium salt is presented. The differences observed rely on the diverse accessibility of singlet chargetransfer excited states, which have been proven by CASPT2/CASSCF calculations, fluorescence and quenching studies.