The Nature and Magnitude of
Specific Halogen Bonds Between
Iodo-perfluorobenzene and
Heterocyclic Systems

ABSTRACT: In this work, first-principle calculations at different levels of theory
have been carried out to investigate a series of complexes formed between iodoperfluorobenzene
and several heteroatomic rings. Such model systems are selected to
mimic halogen bonding interactions experimentally found within supramolecular
architectures. In all cases, the predicted intermolecular distances are significantly
shorter than the sums of van der Waals radii of I and N (O or S) atoms and the
interactions appear to be highly directional. Halogen bonding energies, calculated at the
MP2/lan12dz level, are substantial, ranging from 2.50 to 7.53 kcal/mol. Given the

strength as well as the directionality comparable to hydrogen bonds, these synthons
should be of general use in many fields of chemistry. Finally, to gain more insights into
the nature of such interactions, we have used the natural bond orbital and atoms in
molecules analyses on the studied systems, which show a considerable magnitude of
charge transfer, significant orbital interaction, and distinct bond critical points between
the two interacting atoms. VC 2010 Wiley Periodicals, Inc. Int J Quantum Chem 111:
2352–2358, 2011
Key words: halogen bonds; ab initio; interaction energies; NBO