| Summary: | 碩士 === 輔仁大學 === 化學學系 === 87 ===
Recently, nonlinear optical(NLO) materials have attracted much attention. They have great potential especially in the field of long-distance communication, information transmittance and photoelectricity technology. There are some commercial products which are available now. Organic NLO materials have advantages as compared to inorganic materials, such as better second-order nonlinear properties, lower costs, greater ease for synthetic design. The major factors in designing these compounds include the strength of donor-acceptor group, the nature of the conjugated system and the π-bridge. It has recently been found that heterocyclic chromophores behave well as NLO materials, and thus we devote ourselves to the synthesis and applications of heterocyclic compounds in NLO. So far there are no reports on pyrrole-containing chromophores as second-order NLO materials.
In this thesis my research focuses on pyrrole-containing chromo-phores as second-order NLO materials. It has been reported that the sulfone group is a good electron-withdrawing group with better transparency. It also provides flexibility in the synthetic process. Hence, a series of sulfone-substituted pyrrole chromophores bearing the π- bridge of C＝N were designed. It is predicted that these compounds would possess good hyperpolarizability(μβ) and transparency, as well as high thermal stability.
From the UV-VIS absorption spectra and solvatochromism of compounds 1-4, the hyperpolarizability can be calculated. The results show that these compounds high μβ values(μβ1064＝90~224×10－48esu, μβ0＝37~83×10－48esu) and good transparency(λmax＝386nm~402nm in 1, 4-dioxane). Compound 2a has good nonlinear optical second harmonic generation(SHG) intensity, which is 2.9 times stronger than quartz. Compound 2b yields single crystals for measuring the X-ray diffraction, but unfortunately it is centrosymmetric with the P21/n space group.
|
|---|
