| Summary: | 碩士 === 國立嘉義大學 === 應用化學系研究所 === 97 === 2-(2’-naphthyl)-1-Substituentethylene (2-stN-X) and 2-(2’-quinolyl)-1-Substituentethylene (2-stQ-X) derivatives was used to study the influence of substituent effects on photophysics. The influence were evidenced by solvent effects, Stokes shift, the difference of basicity between ground state and excited state, and the appearance of a photoinduced proton transfer reaction.
For the 2-stQ-X derivatives, the fluorescence yields increase with the content of ICT in a neutral condition, but the fluorescence yields reduced obviously after acid was added. For compound do not display any ICT character, such as 2-stQ-cyclohexane, the fluorescence was hardly detected in a neutral condition, but the fluorescence increased sharply in an acidic condition. For 2-stN-X derivatives, the fluorescence yields increase 2-5 times when the medium was acidic by trifluoroacetic acid. For 2-stN-X and 2-stQ-X derivatives, the fluorescence yields reduced when the protonation position was located on the acceptor site, but the fluorescence yields increased if the protonation position was located on the donor site. The influences of metal ion were similar with proton.
Because 2-stQ-cyclohexane displays strong fluorescence after protonation or complex with metal ion, we can use it to detect the acidity change of the medium, or detect the existence of metal ion. Another possible candidate for chemosensor was 2-stN-NMe2, which the emission display different figure after complex with various metal ion.
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