Substituent Effect on Fluorescence and Photoisomerization of 1-(9-Anthryl)-2-(4-pyridyl)ethenes

Bulletin of the Korean chemical society

Sang Ha Lee¹  Eun Ju Shin¹ 

关键词: Diarylethene;    Substituent effect;    Fluorescence;    Photoisomerization;   

DOI  :  

学科分类：化学（综合）

来源: Korean Chemical Society

【 摘 要 】

The fluorescence and photoisomerization quantum yields of trans-1-(9-anthryl)-2-(4-pyridyl)ethene (t-4-APyE), 1-(10-methyl-9-anthryl)-2-(4-pyridyl)ethene (t-4-MeAPyE), and 1-(10-chloro-9-anthryl)-2-(4- pyridyl)ethene (t-4-ClAPyE) were measured in cyclohexane, acetonitrile, and methanol at room temperature.Polar solvents result in the drastic reduction of fluorescence quantum yield and increase of photoisomerization quantum yield for all three compounds. These results are probably due to the stabilization of intramolecular charge transfer (ICT) excited state in polar solvent. The higher contribution of ICT in the presence of more electron-donating methyl substituent, manifested by largest positive fluorescence solvatochromism, indicates that the pyridine ring acts as an electron acceptor. Protonation or methylation makes pyridine ring stronger electron acceptor and causes long-wavelength ground state charge transfer absorption band and completequenching of fluorescence. The fluorescence from t-4-APyE derivatives can be switched off responding external stimuli viz. medium polarity, protonation, or methylation.

【 授权许可】

Unknown