Infrared, Raman spectra and DFT calculations of chlorine substituted anilines

The infrared and Raman spectra of chlorine substituted anilines (2,5-dichloroaniline, 2,4-dichloroaniline and 3,5-dichloroaniline) have been measured in the region of 4000–600 cm−1. FAR infrared spectrum of 2,5-dichloroaniline has been also presented. Vibrational frequencies, rotational constants and energies of these molecules have also been calculated by means of quantum chemical calculations using density functional theory and Restricted Hartree–Fock method with 6-31+G* and 6-311++G** basis sets. An assignment of normal modes of vibration to the observed frequencies has been based on these calculations. Non-co-planarity of amino group with respect to the phenyl ring has been investigated. To test the reliability of the computational methods, a series of calculations has been done for aniline to substituted anilines using different basis sets.