Computational study of non-covalent interactions in oxirane^…XF complexes (X = H, F, Cl, Br, Li) and their F-/Li-substituted analogues

Abstract

A computational study found oxirane^…XF (X = H, Cl, Br, F, Li) dimers to be energetically stable, with their interaction energies increasing with the magnitude of the XF dipole moment in the order XF = LiF > BrF ∼ HF > ClF > F₂. Their relative stabilities roughly correlate with the amount of charge transferred from the lone pairs on the O atom of oxirane to the antibonding σ* orbital of XF. However, the most strongly bound dimer, oxirane^…LiF, is stabilised by the largest dipole but involves the smallest charge transfer. The variation in the strength of the oxirane^…XF interaction was subsequently investigated by the sequential substitution of the protons on oxirane by either electron-donating Li or electron-withdrawing F atoms.

Keywords:

• non-covalent interactions
• hydrogen bonding
• halogen bonding
• lithium bonding
• oxirane
• σ-hole

Disclosure statement

No potential conflict of interest was reported by the authors.