Renuga S, Karthikesan M, Muthu S
Department of Physics, Indira Institute of Engineering and Technology, Thiruvallur, Tamil Nadu, India.
National Institute for Research in Tuberculosis, Chennai 600031, Tamil Nadu, India.
Spectrochim Acta A Mol Biomol Spectrosc. 2014 Jun 5;127:439-53. doi: 10.1016/j.saa.2014.02.068. Epub 2014 Mar 3.
The Fourier transform infrared (FT-IR) and FT-Raman spectra of N,N-dimethyl-3-phenyl-3-pyridin-2-yl-propan-1-amine have been recorded in the range 4000-500cm(-1) and 4000-50cm(-1) respectively. The complete vibrational assignment and analysis of the fundamental modes of the compound were carried out using the observed FT-IR and FT Raman data. The vibrational frequencies experimentally determined, was compared with the theoretical frequencies computed by DFT gradient calculations (B3LYP method) employing the 6-31+G(d,p) basis set for the optimized geometry of the compound. The geometry and normal modes of vibration obtained from the DFT method are in good agreement with the experimental data. The assignments of the vibrational spectra have been carried out with the help of Normal Coordinate Analysis (NCA) following the Scaled Quantum Mechanical Force Field Methodology (SQMFF). The calculated infrared and Raman spectra of the title compounds were also stimulated utilizing the scaled force fields and the computed dipole derivatives for IR intensities and polarizability derivatives for Raman intensities. The change in electron density (ED) in the σ() and π() antibonding orbitals and stabilization energies E(2) have been calculated by Natural Bond Orbital (NBO) analysis to give clear evidence of stabilization originating in the hyper conjugation of hydrogen-bonded interaction. The electronic spectrum determined by TD-DFT method is compared with the observed electronic spectrum.
已分别在4000 - 500cm⁻¹和4000 - 50cm⁻¹范围内记录了N,N - 二甲基 - 3 - 苯基 - 3 - 吡啶 - 2 - 基 - 丙 - 1 - 胺的傅里叶变换红外（FT - IR）光谱和傅里叶变换拉曼光谱。利用观测到的FT - IR和FT拉曼数据，对该化合物的基本振动模式进行了完整的振动归属和分析。将实验测定的振动频率与采用6 - 31 + G(d,p)基组对化合物优化几何结构进行DFT梯度计算（B3LYP方法）所计算的理论频率进行了比较。从DFT方法获得的几何结构和正常振动模式与实验数据吻合良好。振动光谱的归属是借助于遵循标度量子力学力场方法（SQMFF）的简正坐标分析（NCA）进行的。还利用标度力场以及计算得到的用于红外强度的偶极导数和用于拉曼强度的极化率导数模拟了标题化合物的计算红外光谱和拉曼光谱。通过自然键轨道（NBO）分析计算了σ()和π()反键轨道中的电子密度（ED）变化以及稳定化能E(2)，以明确证明氢键相互作用的超共轭作用所产生的稳定化作用。将通过TD - DFT方法测定的电子光谱与观测到的电子光谱进行了比较。
