title: Topological characterization of electron density, electrostatic potential and intermolecular interactions of 2-nitroimidazole: an experimental and theoretical study.
abstract: An experimental charge density distribution of 2-nitroimidazole was determined from high-resolution X-ray diffraction and the Hansen-Coppens multipole model. The 2-nitroimidazole compound was crystallized and a high-angle X-ray diffraction intensity data set has been collected at low temperature (110 K). The structure was solved and further, an aspherical multipole model refinement was performed up to octapole level; the results were used to determine the structure, bond topological and electrostatic properties of the molecule. In the crystal, the molecule exhibits a planar structure and forms weak and strong intermolecular hydrogen-bonding interactions with the neighbouring molecules. The Hirshfeld surface of the molecule was plotted, which explores different types of intermolecular interactions and their strength. The topological analysis of electron density at the bond critical points (b.c.p.) of the molecule was performed, from that the electron density ρbcp(r) and the Laplacian of electron density ∇2ρbcp(r) at the b.c.p.s of the molecule have been determined; these parameters show the charge concentration/depletion of the nitroimidazole bonds in the crystal. The electrostatic parameters like atomic charges and the dipole moment of the molecule were calculated. The electrostatic potential surface of the molecule has been plotted, and it displays a large electronegative region around the nitro group. All the experimental results were compared with the corresponding theoretical calculations performed using CRYSTAL09.
authors.affiliation: Laboratory of Biocrystallography and Computational Molecular Biology, Department of Physics, Periyar University, Salem 636 011, India.
authors.forename: Chinnasamy
authors.initials: C
authors.lastname: Kalaiarasi
authors.affiliation: Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560 012, India.
authors.forename: Mysore S
authors.initials: MS
authors.lastname: Pavan
authors.affiliation: Laboratory of Biocrystallography and Computational Molecular Biology, Department of Physics, Periyar University, Salem 636 011, India.
authors.forename: Poomani
authors.initials: P
authors.lastname: Kumaradhas
keywords: 2-nitroimidazole; Hirshfeld surface; charge-density distribution; electrostatic potential; radiosensitizer