本文選題：活性位點 + 分子結(jié)構(gòu)　； 參考：《北京科技大學(xué)》2017年博士論文

【摘要】：通過量子化學(xué)計算方法可以方便且容易地得到分子各種參數(shù),利用理論分析方法能夠描述、解釋、預(yù)測或確定分子的物理、化學(xué)性質(zhì)。近年來,反應(yīng)活性位點的預(yù)測以及分子結(jié)構(gòu)等影響因素已成為研究的熱點。在分子反應(yīng)活性位點的研究中,目前已有許多方法被提出,但它們的可靠性都缺乏系統(tǒng)的檢驗和對比,關(guān)于理論方法的預(yù)測值與化學(xué)反應(yīng)速率的相關(guān)性方面也缺乏系統(tǒng)的研究。在分子結(jié)構(gòu)性質(zhì)的研究中,傳統(tǒng)分子結(jié)構(gòu)理論模型往往基于參與成鍵原子的電負性差異,沒有考慮不同化學(xué)體系以及不同電子態(tài)所形成的化學(xué)環(huán)境差異,不具有普適性。因此,分子反應(yīng)活性位點和分子結(jié)構(gòu)性質(zhì)的理論研究仍需要不斷的完善和發(fā)展。本文主要研究內(nèi)容如下：首先,本文將碳基化合物、芳香族化合物、吡啶及其衍生物和雜環(huán)化合物共4類分子作為測試體系,對14種預(yù)測反應(yīng)活性位點方法的可靠性進行了詳細的比較分析。我們發(fā)現(xiàn),體現(xiàn)局部電子軟度的方法可以很好地預(yù)測反應(yīng)活性位點,例如簡縮雙描述符方法,但是表現(xiàn)靜電效應(yīng)的預(yù)測方法整體表現(xiàn)很差,例如靜電勢分析方法。對于本文中所用的測試體系來說,其分子反應(yīng)活性位點預(yù)測最準(zhǔn)確的方法是簡縮雙描述符和Hirshfeld電荷分析方法。其次,在前面工作的基礎(chǔ)上,選擇7種能夠準(zhǔn)確預(yù)測親核和親電反應(yīng)活性位點方法來分析實驗反應(yīng)速率和理論預(yù)測結(jié)果之間的相關(guān)性。結(jié)果表明,對于芳香族化合物而言,不論是親電反應(yīng),還是親核反應(yīng),體系局部電子硬度的方法,例如分子范德華表面1.6A處的靜電勢以及Hirshfeld電荷方法,’其預(yù)測結(jié)果能較好地反應(yīng)實驗反應(yīng)速率的相對大小,但體現(xiàn)局部電子軟度的方法,例如簡縮福井函數(shù)和簡縮雙描述符,其預(yù)測結(jié)果和實驗反應(yīng)速率的相關(guān)性較小。再次,研究了基態(tài)極性分子的鍵角和鍵偶極矩之間的關(guān)系。我們采用ADCH電荷來計算分子的鍵偶極矩,電子局域函數(shù)和鍵臨界點處的局域函數(shù)值來分析鍵的電子結(jié)構(gòu),通過對IVA族(IVA=C, Si, Ge), VA族(VA=N, P, As), VIA族(VIA=O, S, Se)和ⅦA族(VIIA=F, Cl, Br)元素形成的系列共價型基態(tài)分子,以及環(huán)狀基態(tài)分子的鍵角和鍵偶極矩數(shù)據(jù)進行分析,發(fā)現(xiàn)在鍵的電子結(jié)構(gòu)類似的情況下,由于鍵偶極矩的排斥作用,這些分子的鍵角隨鍵偶極矩的增加而增大。這一發(fā)現(xiàn)有助于加深我們對分子幾何結(jié)構(gòu)的認(rèn)識。最后,提出了一種新的能量外推方法。完全活性空間組態(tài)相互作用計算與完全活性空間中的活性電子數(shù)和活性軌道數(shù)有關(guān),但完全活性空間組態(tài)相互作用的能量不是活性電子數(shù)和活性軌道數(shù)的單調(diào)遞減函數(shù),因此活性軌道數(shù)和活性電子數(shù)不能用來外推完全活性空間組態(tài)相互作用的能量。為此,我們定義了一個新的變量：活性空間中的最大未占滿軌道數(shù)。我們對一系列單重態(tài)、雙重態(tài)和三重態(tài)分子進行了完全活性空間組態(tài)相互作用的計算,并利用活性空間中的活性電子數(shù)和最大未占滿軌道數(shù)這兩個變量,對這些基態(tài)能量進行了擬合和外推,擬合的均方根誤差都在10-6數(shù)量級。外推能量的精度優(yōu)于MP4,對小分子體系,其精度高于CCSD。外推的FCI能量值和實際計算的FCI值也很接近。另外,我們還利用外推能量來優(yōu)化雙原子分子的平衡鍵長,并計算諧振平率,其精度優(yōu)于CASSCF。
[Abstract]:The molecular parameters can be easily and easily obtained by quantum chemical calculation. The physical and chemical properties of the molecules can be described, explained, predicted or determined by theoretical analysis. In recent years, the prediction of the reactive sites and the molecular structure have become a hot spot in the study. At present, many methods have been proposed, but their reliability is lack of systematic examination and comparison. There is no systematic study on the correlation between the predictive value of theoretical methods and the rate of chemical reactions. In the study of the molecular structure, the traditional molecular structure theory model is often based on the electronegativity difference involved in the bond forming atoms. It does not consider the chemical environment differences between different chemical systems and different electronic states, and it is not universally suitable. Therefore, the theoretical study of the molecular reaction active sites and molecular structure properties needs to be perfected and developed. The main contents of this paper are as follows: first, the carbon based compounds, aromatic compounds, pyridine and their properties are studied. A total of 4 groups of derivatives and heterocyclic compounds are used as test systems, and the reliability of the 14 methods for predicting reactive sites is compared in detail. We find that the method of local electronic softness can predict the reactive sites, such as the simplified double descriptor method, but the prediction method of the electrostatic effect is complete. The body performance is very poor, such as the method of electrostatic potential analysis. For the test system used in this paper, the most accurate method for the prediction of the molecular reactive sites is the simplified double descriptor and the Hirshfeld charge analysis method. Secondly, on the basis of the previous work, 7 methods can be used to accurately predict the active sites of nucleophilic and electrophilic reactions. The correlation between the experimental reaction rate and the theoretical prediction results is analyzed. The results show that, for aromatic compounds, whether it is an electrophilic reaction or a nucleophilic reaction, a method of local electron hardness, such as the electrostatic potential at the 1.6A surface at the molecular Fan Dehua surface and the Hirshfeld charge method, 'is a good reaction to the experimental reaction. The relative size of the rate, but the method of reflecting the local electronic softness, such as the contraction Fukui function and the contraction double descriptor, has a little correlation with the experimental reaction rate. Again, the relationship between the bond angle and the dipole moment of the ground state polarity molecule is studied. We use the ADCH charge to calculate the molecular bond dipole moment, the electronic Bureau. The domain function and the local function value at the critical point of the key are used to analyze the electronic structure of the key. By analyzing the IVA group (IVA=C, Si, Ge), the VA group (VA=N, P, As), the VIA group (VIA=O, S, Se) and VII, the bond angle and the bond dipole moment data of the ring ground state are analyzed, and the key is found in the key. In the case of similar substructure, the bond angles of these molecules increase with the increase of bond dipole moments due to the repulsion of the bond dipole moments. This discovery helps to deepen our understanding of the molecular geometry. Finally, a new energy extrapolation method is proposed. The calculation of fully active space group state interaction and the full active space. The number of active electrons is related to the number of active orbits, but the energy of the fully active space configuration interaction is not a monotone decreasing function of the number of active electrons and the number of active orbits. Therefore, the number of active orbits and the number of active electrons can not be used to extrapolate the energy of the interaction of the fully active space configuration. The maximum unoccupied orbit in a sexual space. We calculate the interaction of a series of singlet, double and three states, and use the two variables of the active electrons in the active space and the maximum number of unoccupied orbit, to fit and extrapolate the energy of these basic states, and to fit the root mean square. The error is in the order of 10-6. The precision of extrapolation energy is better than MP4. For small molecular system, its precision is higher than that of CCSD. extrapolated FCI energy and the FCI value of actual calculation. In addition, we also use extrapolation energy to optimize the equilibrium bond length of diatomic molecules and calculate the Xie Zhenping rate, which is better than CASSCF..
【學(xué)位授予單位】：北京科技大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2017
【分類號】：O641

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本文編號：1966254