發(fā)布時(shí)間：2018-06-26 08:11

  本文選題：氫鍵 + 激發(fā)態(tài)質(zhì)子轉(zhuǎn)移(ESPT)��； 參考：《遼寧大學(xué)》2016年碩士論文

【摘要】：激發(fā)態(tài)質(zhì)子轉(zhuǎn)移(ESPT)是極為重要且十分常見(jiàn)的反應(yīng),通常伴隨著其它物理化學(xué)常見(jiàn)反應(yīng)的發(fā)生而進(jìn)行。自然界中多數(shù)物質(zhì)都有氫鍵的形成,它能使物質(zhì)的性質(zhì)發(fā)生一定變化。氫鍵是最早被研究的弱相互作用之一,分子在光激發(fā)作用下到達(dá)激發(fā)態(tài),氫鍵作用會(huì)使分子中的某一質(zhì)子或氫原子通過(guò)氫鍵發(fā)生轉(zhuǎn)移。其中,由于氫鍵作用而發(fā)生的激發(fā)態(tài)質(zhì)子轉(zhuǎn)移應(yīng)用范圍較廣,例如：熒光探針的設(shè)計(jì)與應(yīng)用,激光染料和發(fā)光二極管,紫外線吸收劑和分子開(kāi)關(guān)等等。激發(fā)態(tài)質(zhì)子轉(zhuǎn)移的研究對(duì)于研究新型發(fā)光材料、研發(fā)新藥物及探索生命體征都發(fā)揮著十分重要的作用。本文主要對(duì)7AI-2H_2O體系和BBPC體系在激發(fā)態(tài)發(fā)生的的質(zhì)子轉(zhuǎn)移機(jī)制進(jìn)行了深入的研究和詳細(xì)的探討。兩個(gè)體系的所有計(jì)算都是在高斯09軟件下展開(kāi)的,主要采用的方法是密度泛函(DFT)理論和含時(shí)密度泛函(TDDFT)理論。我們通過(guò)對(duì)7AI-2H_2O體系理論計(jì)算結(jié)果及掃取的勢(shì)能曲線進(jìn)行分析,發(fā)現(xiàn)7AI-2H_2O體系沿著氫鍵鏈進(jìn)行激發(fā)態(tài)鏈?zhǔn)蕉噘|(zhì)子轉(zhuǎn)移反應(yīng),這個(gè)過(guò)程是比較特別的。另外,我們發(fā)現(xiàn)前人均僅采用節(jié)面模型方法來(lái)研究激發(fā)態(tài)質(zhì)子轉(zhuǎn)移的機(jī)理,雖然節(jié)面模型提出了勢(shì)壘阻礙的問(wèn)題,但并不能給出勢(shì)壘大小情況,其結(jié)論的可靠性是值得我們懷疑的。借助我們構(gòu)建的勢(shì)能面,對(duì)BBPC體系激發(fā)態(tài)上的分子內(nèi)單質(zhì)子轉(zhuǎn)移與雙質(zhì)子轉(zhuǎn)移相互競(jìng)爭(zhēng)機(jī)制進(jìn)行探討,根據(jù)對(duì)計(jì)算結(jié)果的分析,我們提出BBPC體系在激發(fā)態(tài)能夠產(chǎn)生兩個(gè)等價(jià)的單質(zhì)子轉(zhuǎn)移反應(yīng)。這些研究成果不僅說(shuō)明了量化計(jì)算方法的合理性與高效性,更進(jìn)一步提出了通過(guò)構(gòu)建大分子勢(shì)能面的方法解釋激發(fā)態(tài)質(zhì)子轉(zhuǎn)移機(jī)理。
[Abstract]:Excited state proton transfer (ESPT) is a very important and common reaction, which is usually accompanied by other physical and chemical reactions. Most substances in nature have hydrogen bonds, which can change the nature of matter. Hydrogen bond is one of the first weak interactions studied. The molecule reaches the excited state under the action of light. The hydrogen bond will make a proton or hydrogen atom in the molecule transfer through the hydrogen bond. Among them, the excited proton transfer due to hydrogen bonding has a wide range of applications, such as the design and application of fluorescent probes, laser dyes and light-emitting diodes, ultraviolet absorbers and molecular switches, and so on. The study of excited proton transfer plays an important role in studying new luminescent materials, developing new drugs and exploring vital signs. In this paper, the proton transfer mechanism in excited states of 7AI-2H2O and BBPC systems is studied and discussed in detail. All the calculations of the two systems are carried out under the software of Gao Si 09. The main methods are density functional theory and time-dependent density functional theory. By analyzing the theoretical calculation results of 7AI-2H2O system and the potential energy curve, we find that 7AI-2H2O system performs excited chain multi-proton transfer reaction along the hydrogen bond chain, which is a special process. In addition, we find that the nodal model method is only used to study the mechanism of excited proton transfer. Although the nodal model raises the problem of barrier hindrance, it can not give the size of potential barrier. The reliability of the conclusion is doubtful. With the help of the potential energy surface constructed by us, the competitive mechanism of intramolecular single proton transfer and double proton transfer on the excited state of BBPC system is discussed. We propose that the BBPC system can produce two equivalent single proton transfer reactions in the excited state. These results not only explain the rationality and efficiency of the quantitative calculation method, but also explain the mechanism of excited proton transfer by constructing the potential energy surface of large molecules.
【學(xué)位授予單位】：遼寧大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2016
【分類號(hào)】：O641

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本文編號(hào)：2069775