The Liquid Crystal Materials of Luminescent Tri-Aromatic Conjugated Rings Molecules and Their H-Bond Derivatives
|摘要:||本實驗主要是以Heck reaction、Wittig reaction與Sonogashira reaction合成出一系列含吡啶之三芳香共軛環的螢光材料，所有化合物經由H1-NMR、Mass和元素分析加以鑑定其結構與純度，再與不同的質子予體酸製備成氫鍵錯合物。在熱性質方面，以熱重分析儀(TGA)得知熱裂解溫度(Td)為310℃~382℃，由熱微差掃瞄分析儀(DSC)與偏光顯微鏡(POM)測得化合物的相變化溫度與液晶相，而化合物的光學性質則由紫外光可見光光譜儀（UV/Vis)和螢光分光光譜儀測得，化合物在極稀的二氯甲烷溶劑中所得到的最大吸收波長範圍為334~382nm;最大螢光（PL）放射波長為424~461nm，化合物PBBOC8 ()、PFBOC8 ()、PMBOC8 ()與PDMBOC8 ()為發藍綠光材料，PMB1OC8 ()與PDMB1OC8 ()發藍光材料，量子效率為40.8~73.2%，再由循環伏安法(CV)量測，引入不同雜環分子可改變HOMO與LUMO的能階。最後在形成氫鍵錯合物時可觀察到較未配氫鍵前有明顯的紅位移，以THDA紅位移最為明顯。|
A series of novel photoluminescent materials with three conjugated aromatic segment including an end-capping pyridine were synthesized successfully via Heck ,Wittig and Sonogashira reaction. H-bonded complexes were obtained from the reaction of these compounds with different proton donors containing carboxylic acids groups. The thermal properties of these materials were measured by TGA、DSC and POM. The onset decomposition temperatures (Td) of all compounds range from 310℃to382 ℃. The optical properties of these materials were measured by UV/VIS and PL (photoluminescent) spectroscopic studies. All of these compounds exhibit the maxaimum absorption in the range of 334~382 nm in diluted dichloromathane. They emit blue to blue-green fluorescence around 424~461nm in dichloromathane. The energy gap of these compounds can be modifided by variation of the end groups and conjugation length as evidenced from CV and UV studies. The experimental results suggest that the H-bonded interaction of the complexes results in a red-shift of the UV and PL spectra.THDA has the most red-shifted emission due to its lowest pH value. Moreover, the emission color of the compounds can be easily tuned by H-bond.