Studies on the Synthesis and Photophysical and Electrochemiluminescent Properties of Donor-Acceptor Substituted Phenylene Ethynylene Vinylene Conjugated Systems
Date Issued
2006
Date
2006
Author(s)
Huang, Han-Yao
DOI
zh-TW
Abstract
In this thesis, we report the synthesis, photophysical, and electrochemiluminescent properties of a series of push-pull quinoline derivatives. The target compounds are 2- and 4-substituted quinolines （2PEPVQs and 4PEPVQs）, where the substituents are arylene-ethynylene-phenylene-vinylene conjugated systems. They were prepared trough aldol condensation reaction and Sonogashira coupling reaction. Their photophysical behavior was investigated in acetonitrile solutions. The absorption spectra of all the compounds are structureless. Except for 2PEPVQ-DMA and 4PEPVQ-DMA that have absorption maxima at ca. 380 nm due to more significant intramolecular charge transfer （ICT）, the absorption maxima of the other compounds are all at ca 350 nm, indicating that the spectra are insensitive to the position and nature of the quinoline substitutents. Both 2PEPVQ-DMA and 4PEPVQ-DMA are nonfluorescent, and the fluorescence quantum yields for the other compounds are between 0.02 and 0.55. As manifested by the large Stokes shift in the fluorescence spectra, the ICT behavior is more significant for these compounds in the excited sates.
The electrochemical properties of 2PEPVQs and 4PEPVQs were investigated by cyclic voltammetry. Whereas the oxidation potential decreases as the electron-donating ability of the substituent is increased, their reduction potentials are nearly independent of the nature of the substituents（E = -1.9 eV for 2PEPVQs and -1.75 for 4PEPVQs）. ECL properties of these compounds were investigated under N2-outgassed acetonitrile solutions. Except for 2PEPVQ-DMA and 4PEPVQ-DMA, ECL can be detected for all the other compounds.
Subjects
電致化學放光
分子內電荷轉移
密度泛函理論
ECL
ICT
DFT
Type
thesis
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