Pyrene-sensitized photolysis of N-(1-naphthylsulfonyl)-N-phenyl-O-(p- toluoyl)hydroxylamine

Article abstract of DOI:10.1246/bcsj.66.3707

The title hydroxylamine (SO₂NT) underwent singlet-sensitized photolysis in the presence of pyrene to give rearrangement and fragmentation products. SO₂NT was found to quench both pyrene-monomer and -excimer fluorescences. The presence of a sulfonyl group with a semipolar-bond character in SO₂NT was suggested to be responsible for a pronounced termolecular interaction between the pyrene excimer and SO₂NT to result in a quenching of the excimer emission. An energetic consideration of the pyrene monomer and excimer as well as the N-O bond cleavage of SO₂NT allows us to propose that not the excimer, but the monomer, activates SO₂NT to induce its sensitized decomposition. An analysis of the solvent polarity effects on both limiting the quantum yields for the appearance of the products and the quenching of pyrene fluorescence by SO₂NT demonstrated that the sensitized reaction proceeds by a singlet-exciplex mechanism in benzene, whereas an electron- transfer mechanism predominates in acetonitrile.