几种类型氢键结构的电子密度拓扑研究

【作者】 王海燕；

【导师】 郑世钧； 孟令鹏；

【作者基本信息】 河北师范大学 ， 物理化学， 2005， 硕士

【摘要】 本论文的研究目的在于利用量子化学方法和电子密度拓扑分析方法研究氢键体系的结构及性质,从而对分子间氢键形成的特性做出正确的描述和分析,为弱相互作用的深入研究提供理论基础。本论文主要针对经典的氢键、π型氢键、双氢键及蓝移型氢键这四种类型的氢键进行了详细的研究和讨论。 氢键是分子内或分子间的一种弱相互作用,但对物质的性质有很大的影响,在生物、化学、材料及生命科学等领域起着重要的作用,是目前人们研究的热门领域之一。氢键涉及分子间和分子内基团的相互作用、涉及超分子、各种分子组合体和聚集体的结构和性质、涉及生命物质内部的作用等等,内涵十分丰富。可见,氢键是21世纪化学键研究的主要课题。近年来从实验和量子化学的角度对氢键体系的研究已有大量的报道。但是,关于氢键体系的拓扑研究还比较少见。 本论文的第二章对量子化学基本原理与量子拓扑学理论的发展历史和研究现状进行了简单的回顾和介绍。量子化学的应用研究范围正在不断扩大,化学键和分子的电子结构仍然是量子化学研究的主要内容之一。近几年来,国际上应用量子拓扑学对化学键及化学反应机制的研究取得了很大的成就 本论文的第三章对H₂O,H₂S与ClO自由基形成的氢键进行了详细的研究,研究发现H₂O或H₂S与ClO分子间相互作用均存在2种稳定的构型,并用Bader的AIM理论进行了详细的拓扑分析。 本论文第四章对吡咯与HX（X=F,Cl,Br）形成的经典的氢键和π型氢键,从其几何参数、拓扑性质和电子积分等方面进行了研究,并对π型氢键运用我们自行编写的GTA2000程序将π电子与σ电子分离,可以得到π型氢键体系的,π电子的密度等值线和拉普拉斯量等值线图,还可以与AIM2000程序接轨得到各原子的π电子积分,形象的说明了,π型氢键的作用本质。 本论文第五章对以吡咯为质子供体的一系列双氢键体系,从其几何参数、拓扑性质和双氢键强度之间的相互关系,并根据Bader的AIM理论对双氢键体系进行了电子密度拓扑分析,讨论了质子供体的H原子的积分净电荷、偶极矩、体积和能量的变化情况以及双氢键形成过程中这些性质的变化情况。 本论文第六章对吡咯与CH₃X,CHF₃分子间蓝移型氢键体系,从其几何参数、拓扑性质和电子积分等方面进行了研究,发现蓝移型氢键与经典的氢键有很多相似之处。关于其形成的本质还有待进行更深入的研究。更多还原

【Abstract】 The purpose of this paper is to study the geometry configurations, bonding nature by Quantum Chemistry and topological analysis of the electronic density methods. The rules of formation of intermolecular hydrogen bonds were discussed in order to help the further research in this field. In this thesis, the four types of hydrogen bonds such as conventional hydrogen bond, π-type hydrogen bond, dihydrogen bond and blue- shifting hydrogen bond were studied.Hydrogen bond is a kind of weak interaction between intramolecular or intermolecular, but it impacts on the natures of substances. It is also of importance in chemistry, biology, materials and life sciences and now this weak interaction has deeped into supermolecular systems and iner-life systems, and so on. So, the studies about hydrogen bonds have become one of the main subjects in 21th century. In recent years, hydrogen bond is being pay more attention to the experimental and theoretical investigations. But it is very seldom about hydrogen bond by topological analysis methods.At the second part of the work, the wide application of Quantum Chemistry and Quantum Chemical Topology was summarized. Bonding characters and electronic structures are still the main area of quantum chemical research. Because the topological analysis of the electronic density method is a new method, many studies are need to be done by the theory.In chapter three, the hydrogen bonds between H2O or H2S and ClO were studied particularly. Two stable geometry structures were found in every hydrogen bond systems and made the topological analysis of the electronic density by the AIM theory.In chapter four, the conventional hydrogen bond or π-type hydrogen bond of pyrrole with halogen hydride(HX) studied by topological analysis of the electronic density, and the π-electron could be seprated from π-type hydrogen bond complexes by our program of GTA2000, it could describe the contours of π-electronic density and laplacian and could link to program of AIM2000 calculate the π-electron integral. The results proved clearly the nature of π-type hydrogen bond.In chapter five, a series of dihydrogen-bonded complexes with pyrrole as a proton-donating molecule were studied. According to the calculated results, the relationships of the topological property and characteristic with the strength of更多还原