| Summary: | 碩士 === 國立交通大學 === 應用化學系 === 89 === A laser Photolysis system has been used to study the absorption spectra and kinetics with quenchers of the transient intermediates of thiophenesultines. The intermediates, produced by photolyzing 5,7-diphenylthiophenesultine and 4,6-diphenylthiophenesulfolene with Nd:YAG laser output at 266 nm, both absorb strongly at 340 nm. From the temperature effect studies of the decay of intermediates, we obtained the activation energy 21.3 kJ / mol for sultine, and 12.1 kJ / mol for sulfolene. Both intermediates decay biexpontentially. We obtained the quenching rate of about 109 M-1 s-1 by oxygen, 106 M-1 s-1 by fumaronitrile , and 107 M-1 s-1 by N-phenylmalemide, The photochemistry of both compounds were also studied. Cycloadducts were obtained when 5,7-diphenylthiophenesultine, but not 4,6-diphenylthiophenesulfolene, was irradiated by 254 nm in the presence of trapping agents. The ESR spectra of thiophenesultine and thiophenesulfolene were recorded after being irradiated with 254 nm light. The spectra showed the characters of triplet species, implying the triplet state of intermediates for thiophenesultine and thiophenesulfolene photolysis at 266 nm. The intermediate of thiophenesultine photoolysis would proceed further the carbon-sulfur bond breaking, but not the intermediate of thiophenesulfolene. We also observed that the intermediate of thiophenesultine procceed self-quenching reaction at a constant of about 108 M-1 s-1. Polarization induced by the two phenyl groups may be attributed to this phenomenon.
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