本文選題：離子水合層　切入點：氫鍵　出處：《湘潭大學》2016年碩士論文　論文類型：學位論文

【摘要】：鹽離子不僅能夠改變蛋白質等大分子溶液的穩(wěn)定性和溶解度,還能調控水的表面張力、粘度、相變等性質。澄清離子與蛋白質和水的作用機理對于指導鹽離子在化學、生物制藥、環(huán)境等領域中的調控作用具有重要意義。從發(fā)現(xiàn)霍夫梅斯特效應以來,人們對離子與蛋白質和水的作用進行了深入的研究。而已有的理論模型只能解釋某些性質的霍夫梅斯特序列。因此采用新的思維來探究離子對水的作用機制,是一項充滿挑戰(zhàn)而富有意義的工作。本論文從氫鍵(O:H-O)協(xié)同弛豫模型和水的四面體中心對稱結構出發(fā),采用拉曼聲子計量譜學方法和接觸角測量等實驗方法,研究水中的鹽離子與氫鍵的作用模式與機制,力求從微觀角度闡明鹽離子與水的作用機理并拓展至霍夫梅斯特序列的物理根源。首先,構建了離子電場協(xié)同氫鍵弛豫和極化的理論模型;然后,測量了不同種類和濃度的YX(X=F、Cl、Br、I;Y=Na、K、Rb、Cs)鹽離子溶液的拉曼光譜和接觸角,并原創(chuàng)建立了差分聲子計量譜方法,以此分析得到了堿金屬鹵化物水合殼層中氫鍵弛豫和分子動力學的定量信息。論文的主要研究結果如下:1.溶液中,鹽離子形成的點電荷電場或鹽離子對形式的偶極子電場,使鹽離子與水分子結合形成水合殼層。離子電場會通過靜電作用改變水分子的取向,使水分子聚集、極化。2.離子電場使氫鍵的H-O段鍵長縮短、鍵能增強;同時O:H非鍵伸長變弱。這與水分子低配位和熱激發(fā)條件下造成的氫鍵弛豫趨勢相同。但是,加鹽和加熱在影響氫鍵極化方面效果相反,前者促進極化,后者退極化。3.鹽離子電場所致的拉曼頻移及接觸角變化對離子濃度、種類、分子位置等因素非常敏感。陰、陽兩種離子造成的拉曼頻移和接觸角變化趨勢均與離子半徑(R)及電負性(η)等離子特性參數(shù)有關,且這種變化趨勢遵循霍夫梅斯特序列:陰離子X-(R/η)=I-(2.2/2.5)Br-(1.96/2.8)Cl-(1.81/3.0)F-(1.33/4.0)?0,陽離子Y+(R/η)=Na+(0.98/0.9)K+(1.33/0.8)Rb+(1.49/0.8)Cs+(1.65/0.8)。相較而言,陰離子作用效果比陽離子更為明顯。4.拉曼光譜和接觸角測試結果表明,離子電場不僅能提高溶液中水分子的結構序度和水合殼層的粘度,還能增強溶液的表面張力和熱穩(wěn)定性。本論文從鹽離子與氫鍵作用的微觀角度解釋了霍夫梅斯特序列中鹽溶質和溶劑相互作用的物理機制,同時還建立了一種基于拉曼光譜定量獲取鹽離子協(xié)同氫鍵弛豫過程中的氫鍵鍵長、鍵能、極化等物理信息的差分聲子計量譜學方法。
[Abstract]:Salt ions can not only change the stability and solubility of macromolecular solution such as protein, but also regulate the surface tension, viscosity and phase transition of water. Regulation in biopharmaceutical, environmental and other fields is of great significance. Since the discovery of the Hoff Mestre effect, The interaction of ions with proteins and water has been deeply studied. However, the existing theoretical models can only explain some properties of the Hoff Mestre sequence. Therefore, new thinking is used to explore the mechanism of ion action on water. It is a challenging and meaningful work. Based on the hydrogen bond O: H-O co-relaxation model and the tetrahedron centrosymmetric structure of water, Raman phonon spectroscopy and contact angle measurement are used in this paper. The mode and mechanism of the interaction between salt ions and hydrogen bonds in water are studied in order to clarify the mechanism of salt ions and water from a microscopic point of view and extend to the physical roots of the Hoff Mestre sequence. A theoretical model of ionic electric field synergistic hydrogen bond relaxation and polarization was established, and then the Raman spectra and contact angle of different kinds and concentrations of YXHX FU FU Con Bran (Igna) Knai RbCs) salt solution were measured, and the differential phonon metrology method was established, and the results were as follows: (1) the theoretical model of ionic electric field synergistic hydrogen bond relaxation and polarization, and then, the Raman spectrum and contact angle of the salt solution were measured. The quantitative information of hydrogen bond relaxation and molecular dynamics in the hydrated shell of alkali metal halide is obtained. The main results of this paper are as follows: 1. In solution, the point charge electric field formed by salt ions or the dipole electric field in the form of salt ion pair are obtained. The ionic electric field will change the orientation of the water molecule by electrostatic action and make the water molecule gather. 2. The ionic electric field will shorten the H-O bond length of the hydrogen bond and enhance the bond energy. At the same time, the non-bond elongation of O: h becomes weaker. This is the same trend of hydrogen bond relaxation caused by low coordination and thermal excitation of water molecules. However, the effect of salt addition and heating on hydrogen bond polarization is opposite, the former promotes the polarization, The latter depolarization .3.The Raman frequency shift and contact angle changes caused by salt ion electric site are very sensitive to ion concentration, species, molecular position and other factors. The Raman frequency shift and contact angle change caused by two kinds of cationic ions are both related to the ion radius R) and the characteristic parameters of electronegativity (畏), and this trend follows the Hoff Mestre sequence: Anion X-R / 畏 ~ (2. 2 / 2. 2 / 2. 2 / Br-1.96 / 2. 8) Cl-1.81 / 3.0F-1.33 / 4.0??? 0, cationic Y, Y, R / 畏, R / N, 0.98 / 0.9, K ~ (+), 1.33 / 0.8R ~ (49 / 0.8) Cs ~ (1.65) / 0.8). Compared with cationic ions, the effect of anions is more obvious than that of cationic ions .4. Raman spectra and contact angle measurements show that ionic electric field can not only increase the structural order of water molecules in solution and the viscosity of aqueous shell, but also increase the structure order of water molecules and the viscosity of aqueous shell. It can also enhance the surface tension and thermal stability of the solution. In this paper, the physical mechanism of the interaction between the salt solute and the solvent in the Hof#internal_person0# sequence is explained from the microscopic point of view of the interaction between the salt ions and the hydrogen bond. At the same time, a differential phonon metrology method based on Raman spectroscopy is established to quantitatively obtain the physical information of hydrogen bond length, bond energy and polarization in the process of salt ion synergistic hydrogen bond relaxation.
【學位授予單位】：湘潭大學
【學位級別】：碩士
【學位授予年份】：2016
【分類號】：O641.3

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本文編號：1586002