Ab initio investigation for π-hole interactions of tetrel- and aerogen-bearing molecules with multiple CO Lewis bases

Unconventional π-hole interactions of tetrel-bearing molecules (TO2 where T = Ge and Sn) with multiple CO Lewis bases were investigated and comparatively addressed with the aerogen analogs (ZF2 where Z = Kr and Xe) using ab initio calculations. Toward elucidating the occurrence of π-hole interactions, the TO2∙∙∙ and ZF2∙∙∙(CO)n complexes (n = 1–5) were examined. From the point-of-charge (PoC) calculations, stabilization energies were noticed for all TO2∙∙∙ and ZF2∙∙∙PoC systems, ensuring the potential of TO2 and ZF2 molecules to participate in π-hole interactions from the electrostatic perspective. From energy calculations, negative interaction energy (Eint) values were observed for all optimized TO2∙∙∙ and ZF2∙∙∙(CO)n complexes with values up to −15.19 kcal/mol. Additionally, negative Eint values were observed to enhance in the order of TO2/ZF2∙∙∙(CO)1 < (CO)2 < (CO)3 < (CO)4 < (CO)5 complexes. Notably, more negative Eint values were observed for tetrel-bearing complexes than aerogen analogs, outlining the higher favorability of TO2 molecules to engage in π-hole interactions. From the quantum theory of atoms in molecules and noncovalent interaction index analyses, the favorable nature of the investigated interactions was elucidated. Based on FMOs results, changes in molecular orbital distributions were observed after the interaction with multiple CO LBs, demonstrating the favorability of π-hole interactions within TO2∙∙∙ and ZF2∙∙∙(CO)n complexes. Subsequently, alterations in the calculated electronic parameters were observed following the interaction with CO LBs, outlining the occurrence of π-hole interactions within TO2∙∙∙ and ZF2∙∙∙(CO)n complexes. Such π-hole interactions would be underpinning for the forthcoming studies relevant to supramolecular chemistry and crystal engineering fields.