For the first time, unconventional lone‐pair (lp) hole interactions were uncovered in chalcogen⋅⋅⋅, halogen⋅⋅⋅, and aerogen⋅⋅⋅Lewis base complexes. An lp‐W‐XYZ⋅⋅⋅B nomenclature was proposed to describe the lp‐hole interaction, where W is the Group V‐VIII element, XYZ are three atoms on the same side of the lp‐hole and B is a Lewis base. Point‐of‐Charge (PoC) approach was adopted to investigate the characteristics of lp‐hole interactions from an electrostatic perspective. Results showed: (i) the occurrence of lp‐holes in the pnicogen‐, chalcogen‐, halogen‐, and aerogen‐containing molecules, (ii) that strength of the lp‐hole interaction increases with increasing negativity of the Lewis basicity, and (iii) the more electronegative XYZ atoms are the lower the favorable interaction energy. The key role of Lewis basicity in orienting the geometrical structure of molecules containing Group V‐VIII elements was reported for the first time.

The potentiality of sp 3 -hybridized chalcogen-containing molecules to participate in lone-pair (lp) hole interactions was reported for the first time. lp hole interactions were characterized and compared to σ-hole ones for OF 2 and SF 2 molecules as a case study . Various quantum mechanical calculations, including molecular electrostatic potential (MEP), maximum positive electrostatic potential ( V s,max ), point of charge (PoC), symmetry-adapted perturbation theory (SAPT), quantum theory of atoms in molecule (QTAIM), and reduced density gradient–noncovalent interaction (RDG-NCI) calculations, were carried out. The more significant findings to emerge from this study are the following: (i) the V s,max calculation was proved to be an unreliable method to determine the precise σ-hole and lp hole locations. (ii) The maximum positive electrostatic potential of the σ hole and lp hole was found to be at the F–Chal···PoC angle (θ) of 180° and at the centroid of XYlp plane, respectively. (iii) Lewis basicity has a significant effect on the strength of σ-hole and lp hole interactions. (iv) The studied molecules more favorably interact with Lewis bases via the σ hole compared to the lp hole, and (v) stabilization of the σ-hole and lp hole interactions stems from the electrostatic and dispersion forces, respectively.

The characteristics and nature of ±R˙-hole interactions were uncovered for the first time and compared to their ±σ-hole analogs in ˙TF3⋯ and W–T–F3⋯B/R˙/A complexes.

A comparative investigation for the versatility of sp 2-hybridized trivalent triel-containing molecules to engage in � π-hole interactions with Lewis base, Lewis acid, σ-hole-containing molecules, and lp-hole-containing molecules was dwelled using quantum mechanical calculations. According to the results, it was found that the À π-hole interactions were more favorable than the + π-hole ones, with larger negative interaction energies and shorter intermolecular distance. + π-hole interactions with lp-hole-containing molecules were observed with larger substantial interaction energies than Lewis acids, and σ-hole-containing molecules varied from-0.65 to-5.18 kcal/mol. Quantum theory of atoms in molecules and noncovalent interaction index analyses revealed the noncovalent nature for � π-hole interactions. As well, symmetry-adapted perturbation theory-based energy decomposition analysis affirmed that electrostatic and dispersion forces controlled the À π-hole interactions, whereas the + π-hole analogs were dominated by dispersion forces only. These findings will be of advantage to the forthcoming studies in the materials and supramolecular chemistry.