科研之友
微信
新浪微博
Facebook
分享链接
摘要
The complex conformational profile and the vibrational spectra of carbohydrazide (1,3-diaminourea) and thiocarbohydrazide were investigated by the DFT-B3LYP and ab initio MP2 and MP4(SDQ) levels of theory using the 6-311G** basis set. The planar syn-cis-anti-trans structure of the two molecules with C-s symmetry was predicted to have an imaginary frequency. The corresponding non-planar structure (C-1 symmetry) was predicted to be the lowest energy structure and to have a positive real frequency as the real minima of the molecules. The stability of the non-planar structure agrees with the X-ray study of carbohydrazide where significant molecular distortions from planarity were reported for the lowest energy form as a result of strong intermolecular hydrogen bonding in the crystal. The vibrational wavenumbers of the lowest energy non-planar conformer of carbohydrazide and thiocarbohydrazide were computed at the B3LYP level and complete vibrational assignments were provided on the basis of the combined DFT-B3LYP results, normal coordinate calculations and experimental infrared and Raman data.
- 出版日期2013-4-10
- 单位中国石油大学（北京）
