含胺基之二苯乙烯衍生物的分子內光誘導電子轉移之C-N斷鍵反應及激態錯合體之研究

Intramolecular Electron Transfer Induced C-N Bond Cleavage and Exciplex Formation of the double bond Constrained Aminostilbenes Derivatives

林彥多(Yan-Duo Lin)

指導教授 ： 楊吉水 ； 侯敦仁

國立中央大學/理學院/化學系/博士(2008年)

摘要

本論文主要是探討對位胺甲基、胺乙基和胺丙基之二苯乙烯衍生物的光化學行為在激發態衰退路徑中C-N斷鍵與分子內電子轉移間之關係，以及分子內激態錯合體之行為。化合物DPhI、MPhI和DEtI在中高極性溶劑中有雙螢光產生，一為定域化激發態（LE）螢光，另ㄧ則是分子內電荷轉移（ICT）螢光。DPyCI僅於CH3CN中有雙螢光，DCEtI及DPyI則無論在任何溶劑中皆僅有單一放射峰。DPhI和MPhI在n-hexane、CH2Cl2和CH3CN溶劑中與化合物DPyI和DPyCI於CH3CN中持續照光後，其LE螢光會逐漸增強，然而DEtI在此三溶劑中皆無類似行為。此乃前述化合物進行C-N斷鍵產生具有高螢光量子產率之化合物HI或CI所致。透過螢光及斷鍵反應之量子產率（ΦICT及Φfra）數值分析，化合物DPyI和DPyCI之Φfra隨溶劑極性增加而增加，但化合物DPhI和MPhI之Φfra卻呈現相反之趨勢。因電荷轉移和電子重返分別坐落於Marcus-Hush理論中的正常區及反轉區模型中，且ΦBET增快較ΦICT多，故Φfra隨溶劑極性增加而減少。
化合物DPyI2和DPyI3於極性或非極性之溶劑下僅有單一放射峰，但隨溶劑極性增加其螢光量子產率減低且螢光生命期逐漸增加，顯示電子予體與受體間仍有交互作用。而DPhI2和DPhI3隨著溶劑極性增加則逐漸顯現雙螢光，較長波長放射峰來自分子內激態錯合體。另外，相較於僅隔一亞甲基之化合物，化合物DPyI2、DPyI3、DPhI2和DPhI3不論在何種溶劑中皆不進行C-N斷鍵反應。

關鍵字

激態錯合體 ； 碳-氮斷鍵反應 ； 光誘導電子轉移 ； 二苯乙烯

並列摘要

This thesis is aimed to study the relationship between the photoinduced intramolecular electron transfer processes and the excited-state C-N bond cleavage reaction as well as intramolecular exciplex formation of a series of amine-bridge-stilbene derivatives. The fluorescence spectra of DPhI, MPhI and DEtI show dual fluorescence in polar solvents, but DCEtI and DPyI display only the locally-excited (LE) fluorescence in both nonpolar and polar solvents. Compounds DPhI and MPhI in nonpolar and polar solvents and DPyI and DPyCI in CH3CN undergo the C-N bond cleavage, leading to the formation of HI and CI of higher fluorescence quantum yields (Φf). However, such a C-N bond fragmentation reaction was not observed for DEtI in either nonpolar or polar solvents. The Φf and the quantum yields of the C-N bond cleavage reaction (Φfra) for DPyI and DPyCI increase as increasing the solvent polarity. In contrast, an opposite solvent dependence of Φfra was observed for DPhI and MPhI because the intramolecular electron transfer and back electron transfer processes locate in the Marcus normal and inverted region, respectively, and the value of ΦBET increases more than that of ΦICT with increasing the solvent polarity.
Compounds DPyI2 and DPyI3 display only the LE fluorescence in both nonpolar and polar solvents, but the fluorescence quantum yields decrease and the fluorescence life times increase with increasing the solvent polarity. This indicates the presence of electron donor and acceptor interactions. Compounds DPhI2 and DPhI3 show dual fluorescence in moderate and highly polar solvents, and the long-wavelength emission band results from intramolecular exciplexes. When compared with the one-mothylene-bridged compounds, compounds DPyI2, DPyI3, DPhI2 and DPhI3 do not undergo the cleavage of C-N bond in both nonpolar and polar solvents.

並列關鍵字

photoinduced electron transfer ； C-N bond cleavage ； intramolucular exciplexes ； stilbene derivatives

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