π-hole interactions of group III–VI elements with π-systems and Lewis bases: a comparative study

Herein, a thorough comparative investigation for the potentiality of triel, tetrel, pnicogen, and chalcogen to engage in π-hole interactions with π-systems and Lewis bases was conducted. π-hole donors, namely, AlF3, SiF2O, PFO2, and SO3, were subjected to interact with benzene (BZN)/hexafluorobenzene (HFB) as electron-rich/electron-deficient π-systems and NH3, NCH, FH, and CO2 as Lewis bases. Using a wide range of quantum mechanical calculations, it was manifested that the investigated π-hole···π-system/Lewis base interactions exhibited preferential negative interaction energies with values up to −30.38 kcal/mol for AlF3···NH3 complex. π-hole···Lewis base complexes participated in a stronger π-hole bond than the π-hole···π-system analogs. In comparison, the reversed pattern was noticed for the π-hole···electron-deficient π-system. Quantum theory of atoms in molecules (QTAIM) analysis announced the closed-shell nature of all complexes under study except π-hole···NH3 interactions that recognized with a salient covalent nature. Symmetry-adapted perturbation theory-based energy decomposition analysis (SAPT-EDA) announced that the π-hole···π-system interactions were governed by the dispersion forces, whereas the π-hole···Lewis base interactions were dominated by the electrostatic terms. The emerging findings from the current work will establish a fruitful linchpin for the future progress of π-hole and π-system based interactions, which in turn lead to the amelioration of research in materials science, crystal engineering, and drug design.