Comparison of σ/π-hole aerogen-bonding interactions based on C2H4•••NgOX2 (Ng = Kr, Xe; X= F, Cl, Br) complexes

The geometric structure, energy properties, and electronic properties of the aerogen-bonding interaction formed by C2H4 and NgOX(2) (Ng = Kr, Xe; X =F, Cl, Br) have been studied at the B2PLYP-D3(BJ)/ aug-cc-pVTZ (PP) level. Two kinds of aerogen-bonding interactions were observed among the title systems: the sigma-hole and the pi-hole complexes. The sigma-hole aerogen-bonding complex has a binding energy in the range of -6.29 similar to -8.17 kcal/mol, which is the most stable. The binding energies of C2H4 center dot center dot center dot NgOX(2) increased as X =F < Cl < Br and Ng = KrOX2 < XeOX2 for the sigma/pi-hole aerogen-bonding complexes. The atoms in molecules (AIM), the non-covalent interaction (NCI) index, and the LMO-EDA energy decomposition analysis were adopted to study the nature of the sigma/pi-hole aerogen-bonding interaction. The results show that the electrostatic term contributes the most to the total interaction energy for the sigma/pi-hole aerogen-bonding complexes.