Crystal structure, DFT calculation, Hirshfeld surface analysis and energy framework study of 6-bromo-2-(4-bromo-phen-yl)imidazo[1,2- a]pyridine

Hussien Ahmed Khamees; Kumara Chaluvaiah; Nasseem Ahmed El-Khatatneh; Ananda Swamynayaka; Kwong Huey Chong; Jagadeesh Prasad Dasappa; Mahendra Madegowda

doi:10.1107/S2056989019013410

Crystal structure, DFT calculation, Hirshfeld surface analysis and energy framework study of 6-bromo-2-(4-bromo-phen-yl)imidazo[1,2- a]pyridine

Acta Crystallogr E Crystallogr Commun. 2019 Oct 3;75(Pt 11):1620-1626. doi: 10.1107/S2056989019013410. eCollection 2019 Nov 1.

Authors

Hussien Ahmed Khamees¹, Kumara Chaluvaiah², Nasseem Ahmed El-Khatatneh¹, Ananda Swamynayaka¹, Kwong Huey Chong³, Jagadeesh Prasad Dasappa², Mahendra Madegowda¹

Affiliations

¹ Department of Studies in Physics, Manasagangotri, University of Mysore, Mysuru 570 006, Karnataka, India.
² Department of Chemistry, Mangalore University, Mangalagangothri, Mangaluru 574 199, Karnataka, India.
³ Department of Chemistry, Faculty of Science, Universiti Putra Malaysia 43400, UPM Serdang, Selangor Darul Ehsan, Malaysia.

Abstract

The title imidazo[1,2-a] pyridine derivative, C₁₃H₈Br₂N₂, was synthesized via a single-step reaction method. The title mol-ecule is planar, showing a dihedral angle of 0.62 (17)° between the phenyl and the imidazo[1,2-a] pyridine rings. An intra-molecular C-H⋯N hydrogen bond with an S(5) ring motif is present. In the crystal, a short H⋯H contact links adjacent mol-ecules into inversion-related dimers. The dimers are linked in turn by weak C-H⋯π and slipped π-π stacking inter-actions, forming layers parallel to (110). The layers are connected into a three-dimensional network by short Br⋯H contacts. Two-dimensional fingerprint plots and three-dimensional Hirshfeld surface analysis of the inter-molecular contacts reveal that the most important contributions for the crystal packing are from H⋯Br/Br⋯H (26.1%), H⋯H (21.7%), H⋯C/C⋯H (21.3%) and C⋯C (6.5%) inter-actions. Energy framework calculations suggest that the contacts formed between mol-ecules are largely dispersive in nature. Analysis of HOMO-LUMO energies from a DFT calculation reveals the pure π character of the aromatic rings with the highest electron density on the phenyl ring, and σ character of the electron density on the Br atoms. The HOMO-LUMO gap was found to be 4.343 eV.

Keywords: DFT calculation; Hirshfeld surface analysis; crystal structure; energy framework; frontier molecular orbitals; imidazole-pyridine derivative; π–π interactions.