Vibrational Assignment and Structure of Some Derivatives of Chloro-Salysilideneanilin

The purpose of the current study is to investigation the structural and intramolecular hydrogen bonding (IHB) strength of some derivatives of chloro-salysilideneanilin (n-Cl-SaAn) using DFT calculations. The geometries of the ortho-, meta-, and para- of n-Cl-SaAn, which the position of Cl is considered respect to C-C=N group (o-Cl-SaAn, m-Cl-SaAn and p-Cl-SaAn), are fully optimized by density functional theory (DFT) calculation. The molecular structures and vibrational frequencies are calculated at B3LYP/6-311++G**. The geometrical parameters and the vibrational frequencies related to intramolecular hydrogen bonding of these compounds are compared in Table 1. The results are shown the N•••H distance and then the O-H bond length in o-Cl-SaAn respectively are shorter and longer than other derivatives. Also, the νOH and νOD in o-Cl-SaAn in comparison with the corresponding values are shorter than other derivatives. By comparing theoretical result, the trend of strength of hydrogen bond of the above mentioned compounds is as follows: o-Cl-SaAn m-Cl-SaAn p-Cl-SaAn.