ORGN 554 |
| Tadao Takada, Kiyohiko Kawai, Sachiko Tojo, and Tetsuro Majima. The Institute of Scientific and Industrial Research, Osaka University, Mihogaoka 8-1, Ibaraki, Osaka, 567-0047, Japan |
| Photo-regulation of hole transfer in DNA conjugated with two molecules, phenothiazine (Ptz) and 8-oxoguanine (oxG), was investigated using pulse radiolysis-laser flash photolysis combined method. A hole generated in DNA during pulse radiolysis can migrate to Ptz with the lowest oxidation potential among molecules in the DNA, and therefore Ptz radical cation with an absorption peak at 520 nm was observed. When Ptz radical cation was selectively excited with a 532-nm laser pulse at 50 ms after the electron pulse, bleaching of absorption of Ptz radical cation was observed, indicating that the hole transfer occurred from Ptz radical cation in the excited state to oxG. Effects of distance between Ptz and oxG on the efficiency of forward hole transfer and the rate constant of back hole transfer were examined by monitoring the transient absorption of Ptz radical cation. Photo-regulation and mechanism of the hole transfers were discussed. |
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Heterocycles, Aromatics, Metal-Mediated Reactions, Physical Organic, Materials
9:00 AM-11:00 AM, Wednesday, March 26, 2003 Convention Center -- Hall I-1, Poster
Division of Organic Chemistry |