碱金属卤化物溶液的表面张力和氢键弛豫的拉曼计量谱学

发布时间：2018-03-08 23:20

本文选题：离子水合层　切入点：氢键　出处：《湘潭大学》2016年硕士论文　论文类型：学位论文

【摘要】：盐离子不仅能够改变蛋白质等大分子溶液的稳定性和溶解度,还能调控水的表面张力、粘度、相变等性质。澄清离子与蛋白质和水的作用机理对于指导盐离子在化学、生物制药、环境等领域中的调控作用具有重要意义。从发现霍夫梅斯特效应以来,人们对离子与蛋白质和水的作用进行了深入的研究。而已有的理论模型只能解释某些性质的霍夫梅斯特序列。因此采用新的思维来探究离子对水的作用机制,是一项充满挑战而富有意义的工作。本论文从氢键(O:H-O)协同弛豫模型和水的四面体中心对称结构出发,采用拉曼声子计量谱学方法和接触角测量等实验方法,研究水中的盐离子与氢键的作用模式与机制,力求从微观角度阐明盐离子与水的作用机理并拓展至霍夫梅斯特序列的物理根源。首先,构建了离子电场协同氢键弛豫和极化的理论模型;然后,测量了不同种类和浓度的YX(X=F、Cl、Br、I;Y=Na、K、Rb、Cs)盐离子溶液的拉曼光谱和接触角,并原创建立了差分声子计量谱方法,以此分析得到了碱金属卤化物水合壳层中氢键弛豫和分子动力学的定量信息。论文的主要研究结果如下:1.溶液中,盐离子形成的点电荷电场或盐离子对形式的偶极子电场,使盐离子与水分子结合形成水合壳层。离子电场会通过静电作用改变水分子的取向,使水分子聚集、极化。2.离子电场使氢键的H-O段键长缩短、键能增强;同时O:H非键伸长变弱。这与水分子低配位和热激发条件下造成的氢键弛豫趋势相同。但是,加盐和加热在影响氢键极化方面效果相反,前者促进极化,后者退极化。3.盐离子电场所致的拉曼频移及接触角变化对离子浓度、种类、分子位置等因素非常敏感。阴、阳两种离子造成的拉曼频移和接触角变化趋势均与离子半径(R)及电负性(η)等离子特性参数有关,且这种变化趋势遵循霍夫梅斯特序列:阴离子X-(R/η)=I-(2.2/2.5)Br-(1.96/2.8)Cl-(1.81/3.0)F-(1.33/4.0)?0,阳离子Y+(R/η)=Na+(0.98/0.9)K+(1.33/0.8)Rb+(1.49/0.8)Cs+(1.65/0.8)。相较而言,阴离子作用效果比阳离子更为明显。4.拉曼光谱和接触角测试结果表明,离子电场不仅能提高溶液中水分子的结构序度和水合壳层的粘度,还能增强溶液的表面张力和热稳定性。本论文从盐离子与氢键作用的微观角度解释了霍夫梅斯特序列中盐溶质和溶剂相互作用的物理机制,同时还建立了一种基于拉曼光谱定量获取盐离子协同氢键弛豫过程中的氢键键长、键能、极化等物理信息的差分声子计量谱学方法。
[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.
【学位授予单位】：湘潭大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O641.3

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