Efficient Six-Electron Photoreduction of Nitrobenzene Derivatives by 10-Methyl-9,10-dihydroacridine in the Presence of Perchloric Acid

Abstract

Abstract Photoreduction of nitrobenzene derivatives by 10-methyl-9,10-dihydroacridine (AcrH2) occurs efficiently in the presence of perchloric acid in acetonitrile containing H2O (0.50 mol dm−3) to yield the corresponding six-electron reduced products (aniline derivatives) and 10-methylacridinium ion efficiently. The initial two-electron reduction of PhNO2 to PhNO by AcrH2 in the six-electron reduction of nitrobenzene (PhNO2) is started by electron transfer from AcrH2 to the n,π* triplet state (3PhNO2*), followed by acid-catalyzed thermal reduction of PhNO to PhNHOH by AcrH2 and the subsequent photoreduction of PhNHOH to PhNH2 by AcrH2.