含N化合物的相互作用及电荷转移动力学的理论研究

【作者】 孙巧；

【导师】 步宇翔；

【作者基本信息】 曲阜师范大学 ， 物理化学， 2002， 硕士

【摘要】 氨以及一些饱和、不饱和脂肪胺广泛应用于制备农药、药物、染料、离子交换树脂等；一些芳香族含N化合物及其衍生物则广泛存在于自然界和生物体中，因此，用量子化学方法对一系列含N化合物的相互作用及电子转移性的研究是一项有意义的工作。 本文首先介绍了当前电子转移理论的三个主要方面：经典理论、半经典理论和基于含时微扰的黄金规则建立的量子力学理论。尽管这些理论各有不同的表达形式，但他们的共同点是立足于电子转移的关键，即当一个分子或离子得到或失去一个电子时所发生的核平衡构型的变化动力学问题及决定电子转移的电子因子问题，同时实验已验证了理论的可行性，并对理论提出了合理的修正。还介绍了本文工作所用到的有关自交换电子转移活化模型、重组织模型及计算弱耦合体系电子转移速率的理论框架。 分析并比较了目前常用的三种计算方法，它们分别是Hartree-Fock(HF)SCF方法、Moller-Plesset(MP)方法和密度泛函(DFT)方法。就目前的计算条件和计算方法而言，相比之下，DFT方法既有较高的计算精度(与MP相比)，又考虑了电子相关性(与HF相比)，也不太费时，因而成为目前化学及生物研究领域最理想的方法，已经得到广泛的应用。基于DFT方法的诸多优点，本文的大部分工作采用DFT方法。 具体工作为： 1．用DFT(B3P86，B3LYP，B3PW91)和MP2方法，在6-311+G*水平上，对NH3、NH3+、NH2CH3、NH2CH3+、NH(CH3)2、NH(CH3)2+、N(CH3)3、N(CH3)3+和单体及对应的带正电的单体形成的络合物NH3NH3+、CH3NH2NH2CH3+、(CH3)2NHNH(CH3)2+、(CH3)3NN(CH3)3+进行全几何优化(为了表达的方便，分别用1、2、3、4表示NH3、NH2CH3、NH(CH3)2、N(CH3)3；用1+、2+、3+、4+表示NH3+、NH2CH3+、NH(CH3)2+、N(CH3)3+；用11+、22+、33+、44+表示NH3NH3+、CH3NH2NH2CH3+、 lin阜师范大学硕士学位论文 （CH。）ZNHNH（CH。）。十、（CH。）。NN（CH。）。干），得圭各单体及对应的带正 电的单体几它们所形成的络合物的平衡几何构型，探讨了该系列络合 物主要几何参数的变化、净电荷布居变化及络合物稳定性的变化规律。 结果表明形成复合物稳定性的次序为1广＞22＼3＼叩＼ 2．用DFT田3P86，B3LTh，B3PWgl）和n头算方法 （MPZ（FULL＊6上＋G“）优化了 NH3和 NH3”以及电子转移过程中遭 遇复合物则H。…NH力V 几何构型，计算了体系稳定化能。然后用 MPZ（FULL历3＋G”方法扫描势能面找出不同的 N－N接触R巨离活化态 体系的能量、活化能、偶合矩阵元，利用黄金规则计算出不同的N－N 接触距离的电子转移速率。并讨论了活化态体系的能量、活化能、偶 合矩阵元和Franck．Condon因子及电子转移速率与接触距离的依赖关 系。并进一步验证了黄金规则应用于电子转移触的正确性。 3．利用 Dry方法或ah initio方法在6－3iG＊和6－311＋G＊基组水平上，对 吮咯、吮咯阳离子和在吮咯、吮咯阳离子间形成的三种遭遇络合物的凡何构型和 振动频率作了计算，对这三种遭遇络合物的稳定化能作了BSSE．校正，这三种 络合物的稳定性次序是络合物1＞络合物2＞络合物3。讨论了活化能，偶合矩阵 元，电子转移速率随接触距离的变化关系。电子转移反应主要发生在接触距离为 2．5真＜R。－。；；＜6．OA的范围内。还讨论了DFT方法在扫描势能面曲线方面的不适应， 描述了这种非正常行为，即“反对称破坏现贪。 4．为毗哇和吮哇阳离子及其复合物体系结构性质的理论研究。 利用DFT方法或汕initio方法在卜31G＊或6311＋G＊基组水平上，计 算了吮哇、吮吐阳离子和在吮吐、吮吐阳离子间形成的三种复合物的 几何构型。并简单分析了几何构型的差异。计算了三种复合物的稳定 化能并比较了三种复合物的稳定性次序，三种复合物的稳定性是：复 合物 3＞复合物 1＞复合物合 2。更多还原

【Abstract】 Ammonia and some saturated and unsaturated acyclic ammonia have been widely used in many ways, such as, making pesticide, medicine, coloring matters, ion exchange colophony and etc. Some aroma nitric compounds and their ramifications are widelyexisting in nature and biological organisms. Thus, studying the interaction and electron transfer of the nitric compounds is a significant work.At first, the basic theories of electron transfer reaction are decipited. There are three successful theories of electron transfer reaction, which are the classical model, the semi-classical model and the quantum mechanics model (which is base on perturbative theory and Gold role). Although these theories have different expressions, they are based on the same sticking point, which are the difference of the equilibrium structurewhen a molecule or a cation receive or lose a electron and the electronic factor of electron transfer. The experimental methods are helpful to not only validate the feasibilities of the theories but also do many reasonable revisions to ihe theories. In addition, the activation model, reorganization model and the theroretical expression of the electron-transfer rate have also been introduced.The three calculational methods that are used at the present time have also been discussed in this article. The three calculational methods are Hartree-Fock(HF) SCF, Moller-Plesset (MP) and Density function theory. The other subject is the meanings of basic level and the rules of the choice of ab initio function. As to the condition and calculated methoeds at present, DFT is a relectively accurate method (whichis compared with the MP method). DFT has the character of electronic correlation and with moderate computational time, and has also relative accuration. As a result, DFT have become successful methods and are widly used to study the action of molecules.As to the systems of the thesis, there are four parts.1. Density function theory (B3P86, B3LYP, B3PW91) w&abinitio calculation (MP2) at 6-311+G* basis set level were used to optimize the molecular structures of NH3, NH3\ NH2CH3, NH2CH3\ NH(CH3)2, NH(CH3)2,(CH3)3, N (CH3), and the complexes formed between molecules and their cations. NH3NH3\ CH3NH2NH2CH3\ (CH3) jNHNH (CH3) , . (CH3) M (CH3) the four complexes can be expresses as 11, 22, 33 44*. The stability order of the four complexes is ir>22*>33*>442. Density function theory (B3P86, B3LYP) at 6-31G* and 6-311+G* basis set level and ab initio calculation (MP2(FULL)) at 6-311+G* basis set level were used to optimize the molecular structures of NH3, NH/ and the encounter complex (NH3...NH?) * in the process of electron transfer, and the stabilization energy of this system was calculated. Then at 6-311+G* basis set level MP2(FULL) method was used to scan the potential energy surface of different N-N contact distance in order to obtain the energies, activation energies, coupling matrix elements and Franck-Condon factors of this system. At last, the contact distance dependence of the activation energies, coupling matrix elements and the electron-transfer rates were discussed. The rationality of Golden-rule has been justified for the application to electron transfer system once again.3. The geometries and vibrational frequencies of pyrrole,pyrrole cation and three encounter complexes formed between pyrrole and pyrrole cation have been calculated using DFT and/or ab initio methods at 6-31G* and/or 6-311+G* basis set levels. Then the stability energies of the three encounter complexes are calculated with the correction for BSSE. The stability order of the three complexes is Complex l>Complex 2>Complex 3. The contact distance dependence of the activation energy, coupling matrix element and the electron-transfer rate has also been discussed using MP2/ 6-31G* level. Electron transfer can occur over a range of encounter distance. For the CAN/CiHslT coupling system, electron transfer occurs chiefly over a range of contact distance where 2. 5A<R?b<6. OA. This paper has also discussed the更多还原