Phenol vs Water Molecule Interacting with Various Molecules: σ-type, π-type, and χ-type Hydrogen Bonds, Interaction Energies, and Their Energy Components

TLDR: In this article, the authors investigated the nature of interactions of phenol with various molecules (Y = HF, HCl, H2O, H 2S, NH3, PH3, MeOH, MeSH) using ab initio calculations.

Abstract: The nature of interactions of phenol with various molecules (Y = HF, HCl, H2O, H2S, NH3, PH3, MeOH, MeSH) is investigated using ab initio calculations. The optimized geometrical parameters and spectra for the global energy minima of the complexes match the available experimental data. The contribution of attractive (electrostatic, inductive, dispersive) and repulsive (exchange) components to the binding energy is analyzed. HF favors σO-type H-bonding, while H2O, NH3, and MeOH favor σH-type H-bonding, where σO-/σH-type is the case when a H-bond forms between the phenolic O/H atom and its interacting molecule. On the other hand, HCl, H2S, and PH3 favor π-type H-bonding, which are slightly favored over σO-, σH-, σH-type bonding, respectively. MeSH favors χH-type bonding, which has characteristics of both π and σH. The origin of these conformational preferences depending on the type of molecules is elucidated. Finally, phenol−Y complexes are compared with water−Y complexes. In the water−Y complexes where σO/σ...