發(fā)布時間：2018-04-12 08:09

  本文選題：時間分辨光譜 + DFT�。� 參考：《西北大學(xué)》2017年碩士論文

【摘要】：間位取代的二苯甲酮類化合物能發(fā)生一些“間位效應(yīng)”的光化學(xué)反應(yīng),包括光氧化還原反應(yīng)、甲基脫質(zhì)子反應(yīng)、光取代反應(yīng)。近些年來,單間位取代二苯甲酮衍生物得到了深入研究。時間分辨光譜技術(shù)和密度泛函理論計算相結(jié)合的手段是研究的主要方法。單間位取代基團為吸電子基團或者拉電子基團的光化學(xué)反應(yīng)機理已經(jīng)被研究清楚。然而當(dāng)間位引入兩個取代基團而且一個為吸電子基團一個為供電子基團的情況下,這類二苯甲酮衍生物的光化學(xué)反應(yīng)如何并不清楚?本文選取了 3-氟-3'-羥甲基二苯甲酮(化合物1)和3-氟-3'-甲基二苯甲酮(化合物2)這兩個化合物來研究所提出的問題�；�合物1和化合物2在間位都引入了兩個基團,氟原子為強吸電子基團,羥甲基和甲基都是供電子基團。本文采用時間分辨光譜技術(shù)和密度泛函理論相結(jié)合的手段對化合物1與化合物2的光物理及光化學(xué)過程進行了深入研究。論文的主要內(nèi)容包括:(1)探索了化合物1的光物理及光化學(xué)過程。在乙腈溶液中,化合物1發(fā)生了二苯甲酮類化合物的典型光物理過程。在異丙醇溶液中,化合物1發(fā)生奪氫反應(yīng)。在酸性水溶液中,化合物1發(fā)生了光氧化還原反應(yīng)。明晰了化合物1的光氧化還原反應(yīng)機理,提純了光解產(chǎn)物并得到了產(chǎn)物的核磁共振譜圖。并且發(fā)現(xiàn)酸性越強,光氧化還原反應(yīng)效率越高。通過DFT計算發(fā)現(xiàn),光取代反應(yīng)過渡態(tài)的能壘更高,也就是說相比于光取代反應(yīng)化合物1更容易發(fā)生光氧化還原反應(yīng)。(2)研究了化合物2的光物理及光化學(xué)過程。在乙腈溶液中,化合物2發(fā)生了二苯甲酮類化合物的典型光物理過程。在異丙醇溶液中,化合物1發(fā)生奪氫反應(yīng);在酸性水溶液中,化合物2發(fā)生了側(cè)鏈甲基脫質(zhì)子反應(yīng)。明晰了側(cè)鏈甲基脫質(zhì)子的反應(yīng)機理,提純了光解產(chǎn)物并得到了產(chǎn)物的核磁共振譜圖。通過DFT計算發(fā)現(xiàn),光取代應(yīng)過渡態(tài)的能壘更高,意味著甲基脫質(zhì)子反應(yīng)比光取代應(yīng)更容易發(fā)生。(3)合成了 3-羥甲基-3'-甲氧基二苯甲酮并采用1H-NMR進行表征。配制3-羥甲基-3'-甲氧基二苯甲酮、3-甲基-3'-甲氧基二苯甲酮的pH0乙腈-水溶液(體積比1:1),進行了納秒時間分辨拉曼光譜實驗,然而并沒有發(fā)現(xiàn)有“間位效應(yīng)”的光化學(xué)反應(yīng)發(fā)生。
[Abstract]:The m-substituted benzophenone compounds can undergo some photochemical reactions, including photoredox reaction, methyl deprotonation reaction and photosubstitution reaction.In recent years, monosteric substituted benzophenone derivatives have been deeply studied.The method of combining time-resolved spectroscopy with density functional theory is the main research method.The mechanism of photochemical reaction in which the single substituent group is an electron-absorbing group or an electron-pulling group has been studied.However, when two substituents are introduced and one is an electron acceptor, the photochemical reaction of these benzophenone derivatives is not clear.In this paper, we select 3 fluoro-3-methylol benzophenone (compound 1) and 3-fluoro-3-butadiene-methyl benzophenone (compound 2) to study the problems raised.Compound 1 and compound 2 have introduced two groups, fluorine atom is a strong electron-absorbing group, hydroxymethyl group and methyl group are donor groups.In this paper, the photophysical and photochemical processes of compound 1 and compound 2 are studied by means of time-resolved spectroscopy and density functional theory.The main contents of this paper are as follows: (1) the photophysical and photochemical processes of compound 1 are explored.In acetonitrile solution, compound 1 has a typical photophysical process of benzophenone compounds.Compound 1 reacts with hydrogen in isopropanol solution.The photoredox reaction of compound 1 occurred in acidic aqueous solution.The photoredox reaction mechanism of compound 1 was clarified, the photolysis product was purified and the NMR spectra of the product were obtained.It was found that the higher the acidity, the higher the efficiency of photoredox reaction.It is found by DFT calculation that the energy barrier of the transition state of photosubstitution reaction is higher than that of photosubstituted reaction compound 1. The photo-physical and photochemical processes of compound 2 are studied.In acetonitrile solution, compound 2 has a typical photophysical process of benzophenone compounds.In isopropanol solution compound 1 reacts with hydrogen and compound 2 with side chain methyl deprotonation in acidic aqueous solution.The reaction mechanism of side chain methyl deprotonation was clarified, the photolysis products were purified and the NMR spectra of the products were obtained.By DFT calculation, it was found that the energy barrier of the transition state of photosubstitution was higher, which means that the proton removal reaction of methyl was easier than that of photosubstitution. The 3-hydroxymethyl-3-methoxy benzophenone was synthesized and characterized by 1H-NMR.The pH0 acetonitrile-aqueous solution (volume ratio 1: 1) of 3-methyl-3-methoxybenzophenone was prepared. The nanosecond time-resolved Raman spectroscopy was carried out. However, no "inter site effect" photochemical reaction was found.
【學(xué)位授予單位】：西北大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：O644.19;O625.42

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本文編號：1738899