Next Article in Journal
A New Series of Cytotoxic Pyrazoline Derivatives as Potential Anticancer Agents that Induce Cell Cycle Arrest and Apoptosis
Next Article in Special Issue
Nucleophilicities of Lewis Bases B and Electrophilicities of Lewis Acids A Determined from the Dissociation Energies of Complexes B⋯A Involving Hydrogen Bonds, Tetrel Bonds, Pnictogen Bonds, Chalcogen Bonds and Halogen Bonds
Previous Article in Journal
Special Issue: Sulfonamides
Previous Article in Special Issue
Looking Back, Looking Forward at Halogen Bonding in Drug Discovery
Article Menu
Issue 10 (October) cover image

Export Article

Open AccessFeature PaperArticle
Molecules 2017, 22(10), 1634;

Halogen Bonds Formed between Substituted Imidazoliums and N Bases of Varying N-Hybridization

Department of Chemistry and Biochemistry, Utah State University, Logan, UT 84322-0300, USA
Received: 28 August 2017 / Revised: 26 September 2017 / Accepted: 27 September 2017 / Published: 29 September 2017
(This article belongs to the Special Issue Halogen Bonds and Beyond)
Full-Text   |   PDF [789 KB, uploaded 29 September 2017]   |  


Heterodimers are constructed containing imidazolium and its halogen-substituted derivatives as Lewis acid. N in its sp3, sp2 and sp hybridizations is taken as the electron-donating base. The halogen bond is strengthened in the Cl < Br < I order, with the H-bond generally similar in magnitude to the Br-bond. Methyl substitution on the N electron donor enhances the binding energy. Very little perturbation arises if the imidazolium is attached to a phenyl ring. The energetics are not sensitive to the hybridization of the N atom. More regular patterns appear in the individual phenomena. Charge transfer diminishes uniformly on going from amine to imine to nitrile, a pattern that is echoed by the elongation of the C-Z (Z=H, Cl, Br, I) bond in the Lewis acid. These trends are also evident in the Atoms in Molecules topography of the electron density. Molecular electrostatic potentials are not entirely consistent with energetics. Although I of the Lewis acid engages in a stronger bond than does H, it is the potential of the latter which is much more positive. The minimum on the potential of the base is most negative for the nitrile even though acetonitrile does not form the strongest bonds. Placing the systems in dichloromethane solvent reduces the binding energies but leaves intact most of the trends observed in vacuo; the same can be said of ∆G in solution. View Full-Text
Keywords: NBO; molecular electrostatic potential; AIM; trimethylamine; imine; nitrile NBO; molecular electrostatic potential; AIM; trimethylamine; imine; nitrile

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

Share & Cite This Article

MDPI and ACS Style

Scheiner, S. Halogen Bonds Formed between Substituted Imidazoliums and N Bases of Varying N-Hybridization. Molecules 2017, 22, 1634.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics



[Return to top]
Molecules EISSN 1420-3049 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top