Unconventional Type III Halogen···Halogen Interactions: A Quantum Mechanical Elucidation of σ-Hole···σ-Hole and Di-σ-Hole Interactions

Mahmoud A A Ibrahim; Nayra A M Moussa

doi:10.1021/acsomega.0c02887

Unconventional Type III Halogen···Halogen Interactions: A Quantum Mechanical Elucidation of σ-Hole···σ-Hole and Di-σ-Hole Interactions

ACS Omega. 2020 Aug 19;5(34):21824-21835. doi: 10.1021/acsomega.0c02887. eCollection 2020 Sep 1.

Authors

Mahmoud A A Ibrahim¹, Nayra A M Moussa¹

Affiliation

¹ Computational Chemistry Laboratory, Chemistry Department, Faculty of Science, Minia University, Minia 61519, Egypt.

Abstract

Herein, two unconventional type III halogen···halogen interactions, namely, σ-hole···σ-hole and di-σ-hole interactions, were reported in a series of halogenated complexes. In type III, the A-halogen···halogen angles are typically equal to 180°, and the occurrence of σ-hole on halogen atoms is mandatory. Using diverse quantum mechanical calculations, it was demonstrated that the occurrence of such interactions with binding energies varied from -0.35 to -1.30 kcal/mol. Symmetry-adapted perturbation theory-based energy decomposition analysis (SAPT-EDA) revealed that type III interactions are dominated by dispersion forces, while electrostatic forces are unfavorable. Cambridge Structure Database (CSD) survey unveiled the experimental evidence for the manifestation of σ-hole···σ-hole interactions in crystal structures. This work might be deemed as a foundation for a vast number of forthcoming crystal engineering and materials science studies.