Strong orbital interaction in a weak CH-π hydrogen bonding system

Abstract

For the first time, the intermolecular orbital interaction between benzene and methane in the benzene-methane complex, a representative of weak interaction system, has been studied by us using ab initio calculations based on different methods and basis sets. Our results demonstrate obvious intermolecular orbital interaction between benzene and methane involving orbital overlaps including both occupied and unoccupied orbitals. Similar to interatomic orbital interaction, the intermolecular interaction of orbitals forms “bonding” and “antibonding” orbitals. In the interaction between occupied orbitals, the total energy of the complex increases because of the occupation of the antibonding orbital. The existence of the CH-π hydrogen bond between benzene and methane causes a decrease in rest energy level, leading to at least −1.51 kcal/mol intermolecular interaction energy. Our finding extends the concept of orbital interaction from the intramolecular to the intermolecular regime and gives a reliable explanation of the deep orbital reformation in the benzene-methane complex.

Stereoelectronic effects in stabilizing protein–N-glycan interactions revealed by experiment and machine learning

“…Several molecular orbital energy gaps having the capacity to be a significant part of the theoretical model is also consistent with recent reports that the CH-π interaction involves strong interactions among multiple molecular orbitals of the interacting fragments. 39 , 40 This type of multivalent frontier molecular orbital interaction is compatible with the notion that CH-π interactions in the WW domain system may involve overlap between multiple CH antibonding orbitals (σ* CH ) of the sugar and bonding (π) orbitals of the aromatic interactor moieties that are overrepresented in the dataset. 47 Effects similar to this have been previously observed in interaction between methyl CHs and the π system of carbonyl groups in proteins.…”

“…Inclusion of the frontier MO energy gaps in the descriptor set was motivated by the recent reports that CH-π interactions involve strong interactions among MOs of the CH and π system. 39 , 40 The probability of MOs being involved in interfragmentary dispersion and orbital interactions depends on the energy gap between the interacting MOs, among other factors. Accurate descriptions of dispersion interactions have been successfully calculated using models incorporating both occupied and unoccupied orbitals.…”

A High Energy Density Azobenzene/Graphene Oxide Hybrid with Weak Nonbonding Interactions for Solar Thermal Storage

“…Obviously, d trans is much larger than d max , which means the C-H···π interaction cannot occur in trans -isomer while it is possible in cis -isomer. Moreover, the energy difference in Δ E a of AZO-GO before and after t c is about 1.38 Kcal/mol (0.06 eV), matching with the typical energy of C-H···π bonds 38 .…”

“…We would ascribe the origin of the two segments of linear dynamics during the trans -to- cis isomerization as a direct consequence of the existence of C-H···π interaction. When a cis -isomer comes into being, the C-H···π hydrogen bond makes the H atom of the AZO benzene moiety act like an electron donor, while the aromatic ring of the GO substrate beneath acts like an acceptor, which results in local electron-rich region in the GO surface 38 . The perturbations to the electronic structures of GO will enhance the polarizability of GO substrate.…”

Hydrogen-bonding Interactions between Apigenin and Ethanol/Water: A Theoretical Study

“…The investigation of the hydrogen-bonding interactions in mixtures of flavonoids and water/ethanol is particularly important to understand the mechanism of the extraction process and the physical essence of the mixture. Quantum chemical calculations have been widely and effectively used to study the intermolecular interactions theoretically 11 12 13 14 15 16 17 18 19 20 21 . In this work, the hydrogen-bonding interactions between ethanol/water and flavonoids were investigated from a theoretical perspective.…”