Exploring the bond topological and electrostatic properties of benzimidazole molecule via experimental and theoretical charge density study

The experimental electron density distribution of benzimidazole has been determined from multipole refinement model using accurate high resolution X-ray diffraction intensity data collected at 100 K. The theoretical charge density distribution was calculated from high level Density functional theory calculations, using B3LYP method with the basis set 6-311G**. The bond topological analysis of the experimental electron density shows the difference of charge density distribution between homo and hetero-atomic bonds in the molecule. Further, the difference of molecular charge density between theory and experiment explicitly reveals the influence of crystal field effect in the experimental electron density distribution. The isosurface of molecular electrostatic potential shows the electro positive and negative regions of the molecule. A large negative potential found at the vicinity of nitrogen atom. The bond topological parameters of NH⋯N intermolecular hydrogen bonding interaction confirm the strength of this interaction.