Experimental and theoretical charge density, intermolecular interactions and electrostatic properties of metronidazole. Issue 6 (6th November 2019)

• Record Type: Journal Article
• Authors: Kalaiarasi, Chinnasamy; George, Christy; Gonnade, Rajesh G.; Hathwar, Venkatesha R.; Poomani, Kumaradhas
• Is Part Of: Acta crystallographica. Volume 75:Issue 6(2019:Dec.)
• Page Start: 942
• Page End: 953
• Publication Date: 2019-11-06
• Subjects: metronidazole -- radiosensitizer -- intermolecular interactions -- electron density -- atomic valence index -- electrostatic potential
• DOI: 10.1107/S2052520619011272
• Languages: English
• ISSNs: 2052-5206

Abstract

Abstract : A detailed investigation is presented of the experimental and theoretical charge density and electrostatic properties of the metronidazole molecule. The topological properties of electron density reveal the charge‐density distribution of the molecule and non‐bonding regions. Abstract : Metronidazole is a radiosensitizer; it crystallizes in the monoclinic system with space group P 21 / c . The crystal structure of metronidazole has been determined from high‐resolution X‐ray diffraction measurements at 90 K with a resolution of (sin gθ/λ)max = 1.12 Å −1 . To understand the charge‐density distribution and the electrostatic properties of metronidazole, a multipole model refinement was carried out using the Hansen–Coppens multipole formalism. The topological analysis of the electron density of metronidazole was performed using Bader's quantum theory of atoms in molecules to determine the electron density and the Laplacian of the electron density at the bond critical point of the molecule. The experimental results have been compared with the corresponding periodic theoretical calculation performed at the B3LYP/6‐31G** level using CRYSTAL09 . The topological analysis reveals that the N—O and C—NO2 exhibit less electron density as well as negative Laplacian of electron density. The molecular packing of crystal is stabilized by weak and strong inter‐ and intramolecular hydrogen bonding and H…H interactions. The topological analysis of O—H…N, C—H…O and H…H intra‐ and intermolecular interactions was also carried out. The electrostatic potential of metronidazole, calculated from the experiment, predicts the possible electrophilic and nucleophilic sites of the molecule; notably, the hydroxyl and the nitro groups exhibit large electronegative regions. The results have been compared with the corresponding theoretical results.