FT-IR and FT-Raman spectra, vibrational assignments, NBO analysis and DFT calculations of 2-amino-4-chlorobenzonitrile

In this work, we report a combined experimental and theoretical study on molecular structure, vibrational spectra and NBO analysis of 2-amino-4-chlorobenzonitrile (2A4CBN). The FT-IR (400–4000 cm−1) and FT-Raman spectra (50–3500 cm−1) of 2A4CBN were recorded. The molecular geometry, harmonic vibrational frequencies and bonding features of 2A4CBN in the ground state have been calculated by using the density functional B3LYP method with 6-311++G (d,p) as higher basis set. The energy and oscillator strength calculated by Time-Dependent Density Functional Theory (TD-DFT) result complements with the experimental findings. The calculated HOMO and LUMO energies show that charge transfer occurs within the molecule. Finally the calculation results were applied to simulate infrared and Raman spectra of the title compound which show good agreement with observed spectra.