A new visible light triggered Arrhenius photobase and its photo-induced reactions

Abstract

Arrhenius photobases are of potential use for excited state hydroxide ion dissociation (ESHID), photo-induced pOH jump experiments, and base-catalyzed reactions. However, previously studied Arrhenius photobases have to be excited by UV light and undergo ESHID reactions only in protic solvents. These characteristics have become a disadvantage to their application in many fields of research. In this work, we have designed and synthesized a new Arrhenius photobase (NO₂-Acr-OH), the ESHID reaction of which is readily triggered by visible light excitation. In contrast to previously studied Arrhenius photobases, NO₂-Acr-OH undergoes ESHID reactions in protic solvents as well as in polar aprotic solvents. Solvent-dependent photo-induced reactions of NO₂-Acr-OH are comprehensively studied by time-resolved fluorescence spectroscopy. Molecular designs for visible light triggered acridinol-based Arrhenius photobases with a large ΔpK_b value are proposed.