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Photochemical and photophysical properties of cinnamate derivatives |
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| รหัสดีโอไอ | |
| Title | Photochemical and photophysical properties of cinnamate derivatives |
| Creator | Thitinun Monhaphol |
| Contributor | Supason Wanichwecharungruang, Bo Albinsson |
| Publisher | Chulalongkorn University |
| Publication Year | 2549 |
| Keyword | Cinnamates -- Properties, Cinnamates -- Analysis, Photochemistry, ซินนาเมต -- คุณสมบัติ, ซินนาเมต -- การวิเคราะห์, โฟโตเคมี, ปริญญาดุษฎีบัณฑิต |
| Abstract | The syntheses and photochemical properties of ten methoxy substituted cinnamates were carried out and the photophysical properties of five selected methoxy substituted 2-ethylhexyl-cinnamates were studied. Both experimental and theoretical methods indicated that the fluorescence quantum yields varied strongly with the substituted position on the phenyl ring. A methoxy substitution at meta position gave strong fluorescence whereas tha para substituted compounds were strongly quenched. This observation could be correlated to the corresponding changes in the UV absorption spectra; the two lowest [pipi *] states were spited for the meta-substituted cinnamates but almost degenerate for the para compounds. Semin-empirical quantum calculation confirmed the observed state ordering and supported the difference in the experimentally determined activation energies for non-radiative decay. This “meta-effect” could be applied for the trimethoxy substituted compounds: strong fluorescence with relatively high barrier for non-radiative decay in 2,4,5- and weak fluorescence with relatively low barrier for non-radiative decay in 2,4,6- trimethoxycinnamate. |
| URL Website | cuir.car.chula.ac.th |
