Journal of the American Chemical Society, Vol.118, No.36, 8566-8574, 1996
Addition Versus Oxygenation of Alkylbenzenes with 10-Methylacridinium Ion via Photoinduced Electron-Transfer
Addition of alkylbenzenes with 10-methylacridinium ion (AcrH(+)) occurs efficiently under visible light irradiation in deaerated acetonitrile containing H2O to yield 9-alkyl-10-methyl-9,10 -dihydroacridine selectively. On the other hand, the photochemical reaction of AcrH(+) with alkylbenzenes in the presence of perchloric acid in deaerated acetonitrile yields 10-methyl-9, 10-dihydroacridine, accompanied by the oxygenation of alkylbenzenes to the corresponding benzyl alcohols. The photooxygenation of alkylbenzenes occurs also in the presence of oxygen, when AcrH(+) acts as an efficient photocatalyst. The studies on the quantum yields and fluorescence quenching of AcrH(+) by alkylbenzenes as well as the laser flash photolysis have revealed that the photochemical reactions of AcrH(+) with alkylbenzenes in both the absence and presence of oxygen proceed via photoinduced electron transfer from alkylbenzenes to the singlet excited state of AcrH(+) to produce alkylbenzene radical cations and 10-methylacridinyl radical (AcrH(.)).
Keywords:CERIUM(IV) AMMONIUM-NITRATE;PROTON-TRANSFER REACTIONS;SUBSTITUTED BENZYL RADICALS;HYDROGEN ATOM ABSTRACTIONS;PHOTOCHEMICAL-REACTION;AROMATIC-COMPOUNDS;CATION RADICALS;IONIZATION-POTENTIALS;THERMODYNAMIC FACTORS;SEMIEMPIRICAL METHODS