σ-Hole Interactions of Tetrahedral Group IV-VIII Lewis Acid Centers with Lewis Bases: A Comparative Study

In the current study, sigma-hole interactions of group IV-VIII element-containing molecules in tetrahedral geometry with Lewis bases were comparatively scrutinized. The FSiF3, OPF3, NSF3, FClO3, and OArO3 molecules were devoted as Lewis acid centers to interact with NH3 and NCH Lewis bases. According to the results, the most significant sigma-hole interactions were ascribed to the FSiF3 center dot center dot center dot and FClO3 center dot center dot center dot Lewis base complexes with interaction energy up to -29.74 kcal mol(-1) in the case of the FSiF3 center dot center dot center dot NH3 complex. Symmetry-adapted perturbation theory-based energy decomposition analysis (SAPT-EDA) demonstrated that the electrostatic energy (E-elst) was the most prevalent force dominating the explored interactions, while the exchange energies exhibited unfavorable contribution. Quantum theory of atoms in molecules (QTAIM) and noncovalent interaction (NCI) results emphasized the closed-shell nature for all the investigated complexes except FSiF3 center dot center dot center dot NH3 complex that demonstrated a covalent nature. Crucially, the utilization of the positively- and negatively-directed external electric field (EEF) led to amelioration and debilitation of the strength of the studied interactions, respectively. The present findings provide knowledge essential to further expanded applications in the fields pertinent to materials science and crystal engineering.