On the Ability of Pnicogen Atoms to Engage in Both σ and π-hole Complexes. Heterodimers of ZF₂C₆H₅ (Z = P, As, Sb, Bi) and NH₃

Authors

Wiktor Zierkiewicz, Wrocław University of Science and Technology
Mariusz Michalczyk, Wrocław University of Science and Technology
Rafał Wysokiński, Wrocław University of Science and Technology
Steve Scheiner, Utah State UniversityFollow

Document Type

Article

Journal/Book Title

Journal of Molecular Modeling

Publication Date

5-8-2019

Publisher

Springer

Volume

25

Issue

152

First Page

1

Last Page

13

Abstract

When bound to a pair of F atoms and a phenyl ring, a pyramidal pnicogen (Z) atom can form a pnicogen bond wherein an NH₃ base lies opposite one F atom. In addition to this σ-hole complex, the ZF₂C₆H₅ molecule can distort in such a way that the NH₃ approaches on the opposite side to the lone pair on Z, where there is a so-called π-hole. The interaction energies of these π-hole dimers are roughly 30 kcal/mol, much larger than the equivalent quantities for the σ-hole complexes, which are only 4–13 kcal/mol. On the other hand, this large interaction energy is countered by the considerable deformation energy required for the Lewis acid to adopt the geometry necessary to form the π-hole complex. The overall energetics of the complexation reaction are thus more exothermic for the σ-hole dimers than for the π-hole dimers.

Recommended Citation

Zierkiewicz, W., Michalczyk, M., Wysokiński, R. et al. J Mol Model (2019) 25: 152. https://doi.org/10.1007/s00894-019-4031-6