Vibrational and spectroscopic investigation on the structure of 5H-dibenzo[b,f]azipine-5-carboxamide

• FTIR, FT-Raman investigations of 5H-dibenzo[b,f]azepine-5-carboxamide were carried out.
• Molecular structure was studied using HF and DFT/B3LYP methods.
• The PED calculation provides a strong support for the frequency assignment.
• NBO analysis used to explain the interaction between electron donors and acceptors.

Fourier transform Raman and Fourier transform infrared spectra of 5H-dibenzo[b,f]azepine-5-carboxamide were recorded in the regions 4000–100 cm−1 and 4000–400 cm−1 respectively in the solid phase. 5H-dibenzo[b,f]azepine-5-carboxamide is typically used for the treatment of seizure disorders and neuropathic pain. The equilibrium geometry harmonic vibrational frequencies, infrared intensities and Raman scattering activities were calculated by density functional B3LYP/6-31G(d,p) method. A detailed interpretation of the vibrational spectra of this compound has been made on the basis of the calculated Potential energy distribution (PED). The thermodynamic functions of the title compound were also performed at the above methods and basis set. A detailed interpretation of the infrared and Raman spectra of 5H-dibenzo[b,f]azepine-5-carboxamide is reported. Stability of the molecule arising from hyper conjugative interactions, charge delocalization has been analyzed using natural bond orbital (NBO) analysis. The linear polarizability (α) and the first order hyperpolarizability (β) values of the investigated molecule have been computed using DFT quantum mechanical calculations. The calculated HOMO and LUMO energies show that charge transfer occurs within the molecule. The observed and calculated wave numbers are found to be in good agreement. The experimental spectra also coincide satisfactorily with those of theoretically constructed spectra.

The Fourier transform infrared and Fourier transform Raman spectra of 5H-dibenzo[b,f]azepine-5-carboxamide are recorded in solid phase, the harmonic vibrational frequencies, infrared intensities, Raman activities, bond length, bond angle are calculated by HF and DFT methods by using 6-31G(d,p)basis set. A detailed vibrational spectral analysis has been carried out and assignments of observed fundamental bands have been proposed on basis of peak positions and relative intensities. The scaled theoretical frequencies showed very good agreement with experimental values. HOMO and LUMO energies are calculated that these energies show charge transfer occurs within the molecule.Figure optionsDownload as PowerPoint slide