本文選題：銅系催化劑 + 醇氧化�。� 參考：《內(nèi)蒙古工業(yè)大學(xué)》2017年碩士論文

【摘要】：醇的選擇性氧化在有機(jī)合成中是非常重要的反應(yīng)之一,其產(chǎn)品在精細(xì)化學(xué)品和有機(jī)中間體的合成中都有廣泛的應(yīng)用。為了滿足環(huán)境和經(jīng)濟(jì)的需求,人們都在積極的尋找綠色、有效的氧化方法來代替?zhèn)鹘y(tǒng)的化學(xué)計(jì)量氧化。模擬天然酶催化的高效性和高選擇性的性質(zhì)來合成小分子化合物是當(dāng)今化學(xué)與仿生學(xué)前沿的課題之一。目前,已經(jīng)提出的以銅為中心的催化劑有很多,它們對醇的催化氧化是非常有效的。因此,了解以Cu為中心的催化劑的微觀的反應(yīng)機(jī)制不僅對均相銅體系提供有益的見解,還為設(shè)計(jì)新型的高效催化劑提供理論基礎(chǔ)。本論文主要使用密度泛函方法,從量子化學(xué)角度出發(fā),研究了以Cu為中心的催化劑的微觀反應(yīng)機(jī)理,計(jì)算了反應(yīng)勢能面上的反應(yīng)物、中間體、過渡態(tài)和產(chǎn)物的幾何結(jié)構(gòu)。具體的研究工作如下:1.采用B3LYP密度泛函方法計(jì)算(bipy)Cu II-TEMPO/DBU(NMI)催化體系催化氧化一級醇的反應(yīng)機(jī)理。我們研究了兩條可能的反應(yīng)路徑(路徑A和路徑B),計(jì)算結(jié)果顯示,底物氧化過程中的氫原子轉(zhuǎn)移步驟為速控步驟,其中,DBU為堿時,Cu-OH奪取Cα-H上的氫原子;NMI為堿時,TEMPO奪取Cα-H上的氫原子,這與動力學(xué)實(shí)驗(yàn)結(jié)果一致。計(jì)算得到在(bipy)Cu II-TEMPO催化系統(tǒng)中,DBU為堿時的反應(yīng)勢壘比NMI為堿時的反應(yīng)勢壘低,這與實(shí)驗(yàn)上DBU堿的活性比NMI堿的活性高的結(jié)論一致。同時,文章中證明了-OTf陰離子的重要性,即-OTf陰離子能幫助堿奪氫。2.采用M06L密度泛函方法計(jì)算了二叔丁基二氮雜環(huán)丙酮(L)/CuBr催化體系催化氧化一級醇,二級醇成為相應(yīng)的羰基化合物的反應(yīng)機(jī)理。在該體系中活性物質(zhì)為[CuL]Br,對于該活性物質(zhì),提出了兩種可能的結(jié)構(gòu):二價銅配合物[Cu(II)-·L~-]Br~-或者三價銅配合物[Cu(III)-L~(2-)]Br~-。計(jì)算結(jié)果顯示,活性物質(zhì)[CuL]Br是以二價銅配合物形式存在的。在該體系中,醇的氧化過程分為兩個步驟,質(zhì)子轉(zhuǎn)移和氫原子轉(zhuǎn)移。根據(jù)氫原子轉(zhuǎn)移的不同,提出了兩條可能的反應(yīng)路徑(路徑A和路徑B),計(jì)算結(jié)果顯示,路徑A是優(yōu)勢路徑。此外,對于一級醇和二級醇來說,質(zhì)子轉(zhuǎn)移過程為速控步驟,能量勢壘分別為16 kcal/mol和16.1 kcal/mol,在室溫下能進(jìn)行反應(yīng)。對于該反應(yīng)機(jī)理,配體L和反應(yīng)底物的比例為1:1,與實(shí)驗(yàn)結(jié)果近似。
[Abstract]:Selective oxidation of alcohols is one of the most important reactions in organic synthesis, and its products are widely used in the synthesis of fine chemicals and organic intermediates. In order to meet the environmental and economic needs, people are actively looking for green, effective oxidation methods to replace the traditional stoichiometric oxidation. The synthesis of small molecular compounds by mimicking the high efficiency and selectivity of natural enzyme catalysis is one of the frontier topics in chemistry and bionics. At present, there are many copper-centered catalysts, which are very effective for the catalytic oxidation of alcohols. Therefore, understanding the microcosmic reaction mechanism of Cu-centered catalyst not only provides useful insights for homogeneous copper system, but also provides a theoretical basis for the design of novel high-efficient catalysts. In this paper, we mainly use density functional method to study the micro reaction mechanism of Cu catalyst from the angle of quantum chemistry, and calculate the geometric structure of reactants, intermediates, transition states and products on the potential energy surface of the reaction. The specific research work is as follows: 1: 1. The B3LYP density functional method was used to calculate the reaction mechanism of the catalytic oxidation of primary alcohols in the catalytic system of CuII-TEMPO / DBU NMIs. We have studied two possible reaction paths (path A and path BN). The calculation results show that the hydrogen atom transfer step in the substrate oxidation process is a rate-controlled step. The hydrogen atom on C 偽 -H is captured by Cu-OH when DBU is base, and the hydrogen atom on C 偽 -H is captured by TEMPO when NMI is base. This is in agreement with the kinetic experimental results. The results show that the reaction barrier of DBU base is lower than that of NMI base in II-TEMPO catalytic system, which is consistent with the experimental conclusion that the activity of DBU base is higher than that of NMI base. At the same time, the importance of the -OTF anion is proved, that is, the -OTF anion can help the alkali hydrogen capture. 2. M06L density functional method was used to calculate the reaction mechanism of the catalytic oxidation of primary alcohols and secondary alcohols into corresponding carbonyl compounds in the catalyst system of second tert Ding Ji diazocyclic acetone L / Cubr. In this system, the active material is [CuL] Br.The two possible structures of the active compound are [CuOIII-Ln-] Brn-, or the trivalent copper complex, [CuCIIII-LUXIAN2-2] Br-ON-, for which two possible structures have been proposed. The results show that the active compound [CuL] Br exists in the form of divalent copper complex. In this system, the oxidation of alcohols is divided into two steps: proton transfer and hydrogen atom transfer. According to the difference of hydrogen atom transfer, two possible reaction paths (path A and path B) are proposed. The calculated results show that path A is the dominant path. In addition, for primary alcohols and secondary alcohols, the proton transfer process is a rate-control step, and the energy barrier is 16 kcal/mol and 16.1 kcal / mol, respectively, and can react at room temperature. For the reaction mechanism, the ratio of the ligand L to the substrate is 1: 1, which is similar to the experimental results.
【學(xué)位授予單位】：內(nèi)蒙古工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：O621.251

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