title: Selective oxygenation of 4,4'-dimethylbiphenyl with molecular oxygen, catalyzed by 9-phenyl-10-methylacridinium ion via photoinduced electron transfer.
abstract: Photooxygenation of 4,4'-dimethybiphenyl with oxygen occurs efficiently in the presence of 9-phenyl-10-methylacridinium perchlorate (AcrPh(+)ClO(4)(-)) under visible light irradiation in O(2)-saturated chloroform (CHCl(3)) to yield 4-(4'-methylphenyl)benzaldehyde as a main oxygenated product. Prolonged photoirradiation afforded the further oxygenated product, 4,4'-diformylbiphenyl. The reactive radical intermediates involved in the photocatalytic cycle have successfully been detected by laser flash photolysis and electron spin resonance (ESR) measurements. The photocatalytic mechanism for the oxygenation of 4,4'-dimethybiphenyl via photoinduced electron transfer from 4,4'-dimethybiphenyl to the singlet excited state of AcrPh(+) is clarified based on the dependence of quantum yields on concentrations of substrates and the detected radical intermediates.
authors.affiliation: Department of Material and Life Science, Graduate School of Engineering, Osaka University, SORST, Japan Science and Technology Agency (JST), Suita, Osaka 565-0871, Japan.
authors.forename: Kyou
authors.initials: K
authors.lastname: Suga
authors.forename: Kei
authors.initials: K
authors.lastname: Ohkubo
authors.forename: Shunichi
authors.initials: S
authors.lastname: Fukuzumi
mesh_terms: D000166:Acridines / Q000737:chemistry*; D001547:Benzaldehydes / Q000737:chemistry*; D001713:Biphenyl Compounds / Q000737:chemistry* / Q000528:radiation effects; D002384:Catalysis; D002725:Chloroform / Q000737:chemistry / Q000528:radiation effects; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods; D004583:Electrons; D005609:Free Radicals / Q000737:chemistry / Q000528:radiation effects; D008027:Light; D015394:Molecular Structure; D010100:Oxygen / Q000737:chemistry* / Q000528:radiation effects; D010472:Perchlorates / Q000737:chemistry*; D010777:Photochemistry; D011789:Quantum Theory; D012680:Sensitivity and Specificity; D013997:Time Factors
chemical_list: C521007:4-(4'-methylphenyl)benzaldehyde; C521006:9-phenyl-10-methylacridinium perchlorate; D000166:Acridines; D001547:Benzaldehydes; D001713:Biphenyl Compounds; D005609:Free Radicals; D010472:Perchlorates; C106616:4,4'-dimethylbiphenyl; D002725:Chloroform; D010100:Oxygen