σ-Hole, lone-pair-hole, and π-hole site-based interactions in aerogen-comprising complexes: a comparative study

Area of Science:

• Computational Chemistry
• Supramolecular Chemistry
• Materials Science

Background:

• Non-covalent interactions are crucial in molecular assembly and material properties.
• Hole-site interactions (sigma, lp, pi) in electron-deficient regions are key interaction sites.
• Aerogen-comprising molecules offer tunable electronic properties for studying these interactions.

Purpose of the Study:

• To comparatively investigate sigma-, lp-, and pi-hole site-based interactions in aerogen-based molecules (ZO3, ZF2 where Z=Ar, Kr, Xe).
• To elucidate the influence of external electric fields (EEF) on the strength of these interactions.
• To explore the correlation between interaction strength, aerogen atomic size, and EEF magnitude.

Main Methods:

• Utilized various ab initio computational methods to study interaction energies.
• Employed oriented external electric fields (EEF) of varying magnitudes.
• Analyzed interaction energies for ZO3/ZF2 complexes with NH3 and NCH.

Main Results:

• Sigma-hole interactions exhibited the most significant preference, with negative interaction energies (e.g., -11.65 kcal mol-1 for XeO3⋯NH3).
• Interaction strength for sigma- and lp-holes correlated directly with aerogen atomic size and EEF magnitude.
• An irregular correlation was observed for pi-hole interactions, with Kr-complexes showing stronger interactions than Ar and Xe counterparts, except under strong positive EEF.

Conclusions:

• Sigma-hole interactions are energetically favored in these aerogen systems.
• External electric fields play a critical role in modulating the strength and behavior of hole-site interactions.
• Findings provide a basis for future research in aerogen-based complexes for materials science and crystal engineering.