Structural and Spectroscopic Characterization of 2-Mesityl Imidazol-3 Chloride: A Combined Experimental and Theoretical Analysis

Abstract

The title molecular salt, 2-mesityl-1H-benzo[d]imidazol-3-ium chloride (C <inf>16</inf>H <inf>17</inf>N <inf>2</inf> +·Cl), was synthesized unexpectedly from the reaction of N-[(1E)-mesitylmethylene]benzene- 1,2-diamine and CoCl <inf>2</inf>·6H <inf>2</inf>O, and characterized by elemental analysis, 1H NMR and FT-IR spectroscopies, and single-crystal X-ray diffraction technique. In addition, quantum chemical calculations employing density functional theory (DFT) method with the 6-311++G(d,p) basis set were performed to study the molecular, spectroscopic and some electronic structure properties of the title compound, and the results were compared with the experimental findings. The computational result shows that the optimized geometry can well reproduce the crystal structural parameters. The intermolecular proton transfer process between the ionic (C <inf>16</inf>H <inf>17</inf>N <inf>2</inf> +·Cl) and nonionic forms (C <inf>16</inf>H <inf>16</inf>N <inf>2</inf>·HCl) of the title salt is investigated and found to be almost barierless with an energy value of 0.20 kcal mol -1. The NLO properties of the compound are bigger than those of urea. © 2012 Elsevier B.V. All rights reserved.