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Laser Flash Photolysis Studies on the Model System for Photo-Oxidation-Induced Polycondensation Polyimides with Fullerene C 60

Laser flash photolysis studies were carried out to elucidate the quenching mechanism of the triplet state of fullerene C 60 ( 3 C 60 * ) by furan-substituted diimides, which are the model compounds for photosensitive polyimides based on the photo-oxidation-induced polycondensation (POP) reaction. Th...

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Bibliographic Details
Published in:Japanese Journal of Applied Physics 2004-03, Vol.43 (3R), p.1172
Main Authors: Shigemitsu, Yasuo, Tajima, Yusuke, Hoshino, Mikio, Tezuka, Yoshihiko, Takeuchi, Kazuo
Format: Article
Language:English
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Summary:Laser flash photolysis studies were carried out to elucidate the quenching mechanism of the triplet state of fullerene C 60 ( 3 C 60 * ) by furan-substituted diimides, which are the model compounds for photosensitive polyimides based on the photo-oxidation-induced polycondensation (POP) reaction. The decay kinetics of transient 3 C 60 * triplet-triplet absorption at 740 nm revealed that the model diimides quenched 3 C 60 * in γ-butyrolactone, with the quenching rate constants, k q (obsd), being determined to be on the order of 10 5 to 10 6 M -1 ·s -1 . The free-energy changes for electron transfer from the model diimides to 3 C 60 * , Δ G et , and the calculated electron transfer rate constants, k q (calcd), were also evaluated from the Rehm-Weller equation using the oxidation potentials for the model diimides. The k q (obsd) values were found to be, on the whole, correlated with Δ G et and to be in fair agreement with the k q (calcd) values. These results indicate that the quenching reaction occurs primarily by electron transfer from the diimide to 3 C 60 * . Furthermore, the k q (obsd) value for benzyl 2-furoate, which constitutes a part of the model diimide molecule was found to be small compared with those for the model diimides. We therefore drew the conclusions that the electron transfer occurs predominantly from the benzimido moiety to 3 C 60 * , not from the furoate moiety and, consequently, the furoate moiety may not take part in electron transfer.
ISSN:0021-4922
1347-4065
DOI:10.1143/JJAP.43.1172