二卤代乙腈和异二卤代乙腈分子结构、振动光谱和电子光谱的密度泛函研究

Geomtery Structures,Vibrational Spectra and Electronic Transition Energies for Dihaloacetonitrile and Iso-Dihaloacetonitrile—an Density Functional Theory Study

采用密度泛函量子化学计算方法获得了在RPA/ /B3LYP/ 6 - 311G (d ,p)的理论水平上的二卤代乙腈和异二卤代乙腈的平衡几何构型、振动光谱和电子跃迁能。与已报道的异二碘甲烷和异二溴甲烷的结果比较后得出 ,异二碘甲烷和异二溴甲烷中的氢原子被吸电子的CN基取代后 ,形成的异二卤代乙腈分子变得相对稳定 ,它们的电子吸收光谱比异二卤代甲烷的进一步红移。表明从能量角度上二卤代乙腈比二卤代甲烷更易发生光异构化。

Density functional theory(DFT)calculations at the RPA∥B3LYP/6 311G(d,p)level of theory are done to predict the geometry structures,vibrational spectra and electronic transition energies for dihaloacetonitriles and iso dihaloacetonitriles.Comparison with the results previously reported for iso diiodomethane and iso dibromomethane indicates that the substitution of one hydrogen atom for iso dihalomethane by C≡N,an electron attractive group,stabilizes dihaloacetonitriles and makes their UV Visible absorption spectra red shift further.This suggests that dihaloacetonitriles are energetically more subject to photoisomerization to form iso dihaloacetonitriles than dihalomethanes.