Department of Chemistry, Kanchi Mamunivar Centre for Post-Graduate Studies, Puducherry 605008, India.
Spectrochim Acta A Mol Biomol Spectrosc. 2009 Oct 15;74(3):642-9. doi: 10.1016/j.saa.2009.07.012. Epub 2009 Jul 18.
The Fourier transform infrared (FTIR) and FT-Raman spectra of 2-chloro-1H-isoindole-1,3(2H)-dione and 2-methyl-1H-isoindole-1,3(2H)-dione have been measured in the range of 4000-400 and 4000-100 cm(-1), respectively. Complete vibrational assignment and analysis of the fundamental modes of the compounds were performed using the observed FTIR and FT-Raman data. The geometry was optimised without any symmetry constraints using the DFT/B3LYP method with 6-31G(d,p) and 6-311++G(d,p) basis sets. The vibrational frequencies determined experimentally are compared with those obtained theoretically from DFT gradient calculations employing the B3LYP/6-31G(d,p) and B3LYP/6-311++G(d,p) methods for the optimised geometry of the compounds. The structural parameters and normal modes of vibration obtained from DFT method are in good agreement with the experimental data. The force fields obtained from DFT method were utilised and the potential energy distributions of all the fundamental vibrations of the compounds were calculated.
已测量了 2-氯-1H-异吲哚-1,3(2H)-二酮和 2-甲基-1H-异吲哚-1,3(2H)-二酮的傅立叶变换红外（FTIR）和 FT-Raman 光谱，范围分别为 4000-400 和 4000-100 cm(-1)。使用观察到的 FTIR 和 FT-Raman 数据，对化合物的基本模式进行了完整的振动分配和分析。使用 DFT/B3LYP 方法和 6-31G(d,p)和 6-311++G(d,p)基组，在没有任何对称约束的情况下对几何形状进行了优化。实验确定的振动频率与从 DFT 梯度计算获得的理论值进行了比较，这些计算使用了 B3LYP/6-31G(d,p)和 B3LYP/6-311++G(d,p)方法对化合物的优化几何形状进行了优化。从 DFT 方法获得的结构参数和振动模式与实验数据非常吻合。利用从 DFT 方法获得的力场，计算了化合物所有基本振动的势能分布。
