哌啶分子轴向和赤道构象的量子计算

The Quantum Calculation of Axial and Equatorial Conformer of Piperidine

利用Gaussian 03软件对哌啶分子轴向构象和赤道构象进行了量子计算,首先,采用Hartree-Fock(HF)方法,在6-311++G(d,p)高精度基组水平上获得了两种构象分子基态的优化结构、红外光谱和拉曼光谱,这些数据为预测分子结构提供重要的依据;其次,在分子基态稳定构象的基础上,利用Time-Dependent Density Functional Theory(TD-DFT),在HCTH/6-311++G(d,p)高精度基组水平上进一步获得了两种构象的紫外可见光谱,分子激发态能量以及激发态和离子态激发布居信息;最后,由激发态和离子态激发布居信息分析获得了分子激发态电离的相关性.这些结果既可以为实验上区分和标示哌啶分子构象异构体提供依据,也可以为实验上预测哌啶分子的动力学机制提供证据.

The quantum calculations of axial and equatorial conformer of piperidine are carried out by Gaussian 03 software. Firstly,using Hartree-Fock( HF) method with 6-311 ++ G( d,p) level,the optimized ground state molecular structures,IR and Raman spectrums of two conformers are acquired,which provide important basis for predicting molecular structure. Secondly,based on the stable ground state structures,the UV-VIS spectrums,excited state energy of neutral piperidine,and the excitation configurations of neutral and cation piperidine for two conformers are further obtained by Time-Dependent Density Functional Theory( TD-DFT) with HCTH/6-311 + + G( d,p) high-precision basis set level.Finally,the ionization correlations between excited states and cation states are analyzed. These results not only helpful for distinguishing and detecting conformational isomers,but also benefit to predict dynamics mechanism in piperidine.