Factors affecting the strengths of σ-hole electrostatic potentials

• A σ-hole is a region of diminished electronic density on the extension of a covalent bond to an atom.
• A σ-hole often exhibits a positive electrostatic potential and thus can interact with negative sites.
• We have examined the dependence of σ-hole potentials upon the atom having the σ-hole and the remainder of the molecule.
• We demonstrate that both relative electron-attracting powers and relative polarizabilities need to be considered.

A σ-hole is a region of diminished electronic density on the extension of a covalent bond to an atom. This region often exhibits a positive electrostatic potential, which allows attractive noncovalent interactions with negative sites. In this study, we have systematically examined the dependence of σ-hole potentials upon (a) the atom having the σ-hole, and (b) the remainder of the molecule. We demonstrate that not only relative electron-attracting powers need to be considered, but also relative charge capacities (or polarizabilities), and that other factors can also have significant roles.