Is σ-hole an electronic exchange channel in YX⋯CO interactions?

Abstract

A theoretical study of linear YX⋯CO complexes (in which YX are diatomic interhalogens or hydrogen halide) has been performed to high-level quantum chemical calculations. Calculations show that at the equilibrium geometry, the stabilizing effect that arises from the Pauli exclusion principle is more important than the electrostatic interactions. In addition, the stabilizing terms of the LMOEDA scheme increase with the σ-hole magnitude, being the exchange term the most affected one, followed by electrostatics, polarization and dispersion components. The PAEM function measured on the X⋯C interatomic interaction line gives a measure of the covalence of these interactions.