Molecular docking and structural analysis of non-opioid analgesic drug acemetacin with halogen substitution: A DFT approach

• The bioactive conformer of ACM was recognized through PES scan study.
• The spectral features are described in both solid and gaseous state.
• Effect of the halogen substituent on the geometrical parameters was described.
• NBO results reveal the hyperconjugative and ICT interactions.
• Halogen substituent effects of ACM were investigated aided by molecular docking.

Acemetacin is a non-opioid analgesic which belongs to the class, the non-steroidal anti-inflammatory drug. The bioactive conformer was identified through potential energy surface scan studies. Spectral features of acemetacin have been probed by the techniques of Fourier transform infrared, Raman and Nuclear magnetic resonance combined with density functional theory calculations at the B3LYP level with 6-311 + G(d,p) basis set. The detailed interpretation of vibrational spectral assignments has been carried out on the basis of potential energy distribution method. Geometrical parameters reveal that the carbonyl substitution in between chlorophenyl and indole ring leads to a significant loss of planarity. The red-shifted CO stretching wavenumber describe the conjugation between N and O atoms. The shifted CH stretching wavenumbers of OCH3 and OCH2 groups depict the back-donation and induction effects. The substitution of halogen atoms on the title molecule influences the charge distribution and the geometrical parameters. Drug activity and binding affinity of halogen substitution in title molecule with target protein were undertaken by molecular docking study. This study enlightens the effects of bioefficiency due to the halogen substitution in the molecule.

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