Vibrational spectroscopic, structural and quantum chemical studies on N-phenyl-3-pyridinecarboxamide

• Conformational analysis was carried out for N-phenyl-3-pyridinecarboxamide (Nicotinanilide) molecule.
• The observed vibrational frequencies were assigned and compared with the calculated frequencies.
• UV–vis spectrum was simulated and compared with the experimental spectrum.
• The molecular reactivity was investigated by the FMOs analysis.
• The possible electrophilic and nucleophilic reactive sites of the molecule were predicted.

Stable molecular structure of N-phenyl-3-pyridinecarboxmide (Nicotinanilide) was predicted through conformational analysis and the vibrational spectral analysis was carried out using experimental and theoretical methods. The calculated and experimentally observed vibrational frequencies of the molecule were assigned and compared. The observed red shift in CO stretching vibrations confirms the mesomeric effects of the CO functional group. The n→π* and π→π* electronic transitions of the molecule were predicted from the theoretically simulated ultraviolet–visible spectra and were validated experimentally. Natural bond orbital analysis was performed to investigate the intra-molecular stabilization interactions, which are responsible for the bioactivity and the nonlinear optical property of the molecule. Molecular reactivity and the possible reactive sites of the molecule were investigated based on the frontier molecular orbitals analysis and Fukui functions respectively. The total electron density mapped with the molecular electrostatic potential surface was plotted to confirm the possible reactive sites of the molecule. The title molecule is identified to be a potential candidate for pharmaceutical applications.

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