An efficient fluorescence sensor for superoxide with an acridinium ion-linked porphyrin triad

Abstract

Addition of potassium superoxide with 18-crown-6 ether (KO 2 •- - 18-crown-6) to a toluene solution of an acridinium ion-linked porphyrin triad (Acr + - H 2P - Acr +) resulted in a remarkable enhancement of the fluorescence intensity. Thus, Acr + - H 2P - Acr + acts as an efficient fluorescence sensor for superoxide. Electron transfer from KO 2 • - - 18-crown-6 to the Acr + moiety to produce the two-electron-reduced species (Acr • - H 2P - Acr •) results in inhibition of the fluorescence quenching via photoinduced electron transfer, as revealed by laser flash photolysis measurements. © 2011 American Chemical Society.