Molecular Structure, Hydrogen Bonding Interactions and Docking Simulations of Nicotinamide (Monomeric and Trimeric Models) by Using Spectroscopy and Theoretical Approach

Abstract

The present work focuses on the structural properties, spectroscopic signatures, intermolecular hydrogen bonding interactions, chemical and biological activity of nicotinamide (NIC) based on its monomeric and trimeric models using density functional theory and vibrational spectroscopy. FT-IR and FT-Raman spectra were obtained using the double-side forward-backward acquisition mode under vacuum. UV-Vis absorption spectra were recorded in methanol and compared with the calculated values. Geometry optimization and vibrational wavenumbers were obtained with the aid of Gaussian 09 program packages. The structural analysis of NIC revealed that the trimeric model was in better agreement with the experimental values than the monomer due to the incorporation of nearest hydrogen bond interactions. Spectroscopic results showed that NH₂ and C = O groups of NIC were involved in intermolecular interactions in the trimeric model. The natural bond orbital (NBO) and quantum theory of atoms in molecules (QTAIM) analyses determined the presence, strength as well as nature of the hydrogen bonds were partially covalent. The lesser value of the HOMO-LUMO energy gap for the trimeric model indicated higher reactivity than monomer. Moreover, chemical reactivity was calculated using molecular electrostatic potential surface (MESP) and reactivity descriptors. The docking studies for NIC with several targets explored its biological activity.

Keywords:

• Nicotinamide
• spectroscopy
• hydrogen bonding
• chemical reactivity
• molecular docking

Acknowledgments

The financial support to PP under Centre of Excellence, Govt. of Uttar Pradesh (360/70-4-2019-1035/2018), is gratefully acknowledged. Financial support to PT from the DST-SERB project [Grant No. CRG/2019/006671] is gratefully acknowledged. Authors are thankful to the Central Facility for Computational Research (CFCR), University of Lucknow, Lucknow, India. MR.S. thanks the Knut and Alice Wallenberg Foundation (funding No. 2019.0124) for financial support.

Disclosure statement

No potential conflict of interest was reported by the author(s). The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Ethics approval

Not applicable

CRediT author statement

Priya Verma: Writing- Original draft preparation, Methodology and Software. Anubha Srivastava: Quality check and correction. Preeti Prajapati: Performed UV-Vis spectral Investigation and correction. Poonam Tandon: Conceptualization, Supervision and Validation. Manishkumar R. Shimpi: Experimental data and interpretation.