| Summary: | 碩士 === 國立交通大學 === 應用化學系所 === 93 === The major part of this thesis is about the syntheses and EPR studies of a series of radical pair precursors (55, 56 and 57) which contain 1-toluene sulphonyl benzimidazoles as the key components. The photolysis (230-325 nm) of 55 at 77 K in a MTHF matrix gave EPR signals characteristic of a randomly oriented triplet radical pair and its zero-field splitting parameters are determined to be |D/hc| = 0.0144 cm-1 and |E/hc| = 0.0020 cm-1, respectively. Furthermore, the photolysis of 55 in the presence of MNP in CDCl3 at room temperature gave not only the Photo-Fries rearrangement products 72 and 73, but also the radical trapping product, Ts-MNP. The results support that 55 is a good precursor for radical pair under photochemical conditions, and the overall photochemical quantum yield for radical pair formation is determined to be 0.24 �b 0.07. The photolysis of 56, a precursor for two triplet radical pairs linked by a meta-xylene unit, gave EPR signals which are consistent with a triplet species rather than a quintet species and the D´ value of 85 and 86 is smaller than 84 taken at 77 K. Finally, the photolysis of 57 at 77 K in MTHF glassy matrix did not show EPR signals of the predicted three triplet states plus a quartet state. Compound 57 was found to be inert under low temperature glassy matrixes which was confirmed by a low temperature UV/vis study at the same matrixes (carried out by Dr. Itoh in Japan).
In part Ⅱ, the preparation of dye sensitized TiO2 solar cells was carried out. Cis-di(thiocynato)bis(2,2´-bipyridyl-4,4´-dicarboxylate) ruthenium (Ⅱ), the N3 dye, which has the record high quantum efficiency (10-12%) for light to energy transfer was out first target compound. A similar analogue, 92, was also synthesized. Further work is needed before we can find a substitute for the N3 dye in Dye Sensitized Solar Cells.
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