聚集誘導(dǎo)發(fā)光的基本科學(xué)問題年度報告（2013）

李嫕 李沙瑜 彭謙 黃旭輝

摘要：建立和完善AIE模型和理論可以為分子設(shè)計、材料制備、聚集體結(jié)構(gòu)調(diào)控及器件實際應(yīng)用等方面提供了理論指導(dǎo)。 2013年度本研究重要進展如下： （1）. 基于第一性原理計算，定量考察了位阻、溫度、聚集等因素對分子體系發(fā)光性質(zhì)的影響。從微觀角度給出了分子聚集誘導(dǎo)發(fā)光機理：分子激發(fā)態(tài)的無輻射能量衰減通道主要是對應(yīng)于低頻模式的芳香環(huán)扭轉(zhuǎn)和高頻模式的碳碳伸縮振動。當(dāng)位阻增加、溫度降低或者分子聚集時，芳香環(huán)的轉(zhuǎn)動受限，無輻射能量衰減通道被抑制，從而提高分子的熒光量子產(chǎn)率，熒光增強；為了更深層次地理解藍色磷光分子結(jié)構(gòu)與發(fā)光效率之間的關(guān)系，結(jié)合密度泛函理論，運用我們最近發(fā)展的系間竄越速率的振動關(guān)聯(lián)函數(shù)計算方法，定量研究了新型藍光發(fā)射分子fac-tris（2-（4，6-difluorophenyl）pyridyl iridium （fac-Ir（F2ppy）3）的磷光光譜、輻射躍遷和無輻射躍遷速率及其與溫度的依賴關(guān)系，計算結(jié)果很好地解釋了實驗測量結(jié)果。理論研究表明可以通過分子設(shè)計來抑制這些振動來進一步提高這類材料的發(fā)光效率。 （2）. 研究了AIE分子作為生物探針和生物體系的相互作用。BSPOTPE分子和蛋白質(zhì)可以通過BSPOTPE的芳香環(huán)和蛋白質(zhì)疏水性氨基酸之間的疏水相互作用結(jié)合，研究表明，BSPOTPE可以同時作為胰島素分子錯誤折疊纖維化的過程的探針和抑制劑。運用Markov態(tài)模型對導(dǎo)致II型糖尿病的hIAPP蛋白質(zhì)誤折疊聚集進行了理論研究，找到了一些可能導(dǎo)致其聚集的重要的構(gòu)象態(tài)，初步實驗中也證實了AIE分子有可能作為hIAPP蛋白質(zhì)聚集的分子探針和抑制劑。 （3）. 發(fā)展了一種利用不水溶的熒光探針和水凝膠體系定量檢測純水中F？的新方法。合成了一個新的熒光探針N-（3-（benzo[d]thiazol-2-yl）-4- （tertbutyldiphenylsilyloxy） phenyl） acetamide （BTBPA），其與F？作用后熒光顏色由藍色變?yōu)榫G色。這種方法可以在15 s內(nèi)定量檢測濃度低至飲用水標(biāo)準(zhǔn)級別的F？，具有檢測速度快，靈敏度高，選擇性好等特點。而且該方法可使用非水溶性熒光探針，大大擴展了可用于離子檢測的熒光分子應(yīng)用范圍。

關(guān)鍵詞：聚集誘導(dǎo)發(fā)光；熱振動關(guān)聯(lián)函數(shù)；系間竄越速率理論；磷光量子效率；氟離子檢測；蛋白質(zhì)錯誤折疊；聚集體

Scientific problems of aggregation-induced emission--establishment and improvement of the AIE models and the theories

Abstract：The establishment and improvement of the AIE models and the theories has shown importance in molecular design， material preparation， structure control of aggregates， and device application. The project is in proper progress and some achievements have been made， which meets the annual objectives. Eleven SCI papers have been published this year （the impact factor is higher than 10 for two papers， and higher than 5 for another two papers）. One patent is authorized and four patents have been notified for the acceptance of application. Three and two students have obtained their PhD degree and Master degree， respectively. The fund in place of this year is 1.13 million yuan， and the outlay on the scientific research has been 0.498 million yuan. The important achievements of the project are as follows. （1）. Based on the first principles， we quantitatively investigated the effect of steric hindrance， temperature and aggregation for the molecular luminescence properties. It is found that （i） the low frequency normal modes associated with the phenyl ring rotational motions and the high frequency normal modes belonging to C–C stretching vibration are the main channels to dissipate excited-state energy nonradiatively； （ii） the aggregate restricted rotation of the phenyl rings is the main factor for blocking the nonradiative decay process and thus enhancing the fluorescence quantum efficiency. （2）. We found that BSPOTPE can indeed affect the insulin fibrillogenesis under low pH at high temperature. Theoretical modeling using molecular dynamics simulations and docking reveals that BSPOTPE is prone to binding to partially unfolded insulin through hydrophobic interaction of the phenyl rings of BSPOTPE with the exposed hydrophobic residues of insulin. Our model reveals a number of metastable states with populations of only a few percent or less rather than a single dominant free energy minimum. （3）. We invented a new method for F？ detection by adopting the hydrogel as the supporter of reaction between a water insoluble fluorescent probe and F？ in the water environment. This method is highly rapid， selective， and sensitive， which can determine F？ levels in 15 s at the drinking water standard. Additionally， this method does not require the probe substances to be water-soluble， which greatly expands the range of the specific fluorescent molecules used in ion detection.

Keywords：aggregation induced emission （AIE）； thermal vibration correlation formalisms； theory of intersystem crossing； phosphorescence quantum efficiency； F- detection； protein misfolding； aggregation

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