Quantum Mechanical Studies on the Mode of Hydrogen Bonding, Stability and Molecular Conformations of Phenol-Water Complexes

Mrinal Jyoti Bezbaruah,Shruti Sharma,Bipul Bezbaruah,Benzir Ahmed

doi:10.4236/cc.2019.73005

Abstract

It is experimentally well established that the phenolic systems such as phenol and diphenols undergo strong hydrogen bonding interaction with water molecule. But, the possible mode hydrogen bonding in phenol-water systems may be of different types. Although, the experimental methods are not always well enough to give the proper hydrogen bonding conformations in the phenol-water complexes. The hydrogen bonding ability in phenol-water systems can directly be influenced by changing the interacting sites in the given molecular systems, which could be investigated by theoretical studies. Generally, in phenol-water system, the hydrogen bonding is taking place through −OH group of phenol with water molecule, and this kind of interactions between phenol-water and diphenol-water complexes have been extensively investigated in electronic ground state by Quantum Mechanical MP4 calculations. It is also very important to study the stability of different phenol-water complexes and to find out the proper phenol-water complexes with minimized interaction energy. This study will also be helpful for understanding the effect of hydrogen bonding interaction in a better way on other aromatic systems.

Highlights

Non-covalent and hydrogen bonding interactions are very important and essential for modern chemistry, material sciences, molecular biology, etc
It is experimentally well established that the phenolic systems such as phenol and diphenols undergo strong hydrogen bonding interaction with water molecule
In phenol-water system, the hydrogen bonding is taking place through −OH group of phenol with water molecule, and this kind of interactions between phenol-water and diphenol-water complexes have been extensively investigated in electronic ground state by Quantum Mechanical MP4 calculations

Summary

Introduction

Non-covalent and hydrogen bonding interactions are very important and essential for modern chemistry, material sciences, molecular biology, etc These interactions are quite common in aromatic-pi systems and these kinds of forces can exist as pi-pi stacking, pi-cations, pi-anions, etc. Computational calculations show that there exists a significant interaction between a hydrogen bond donor and the centre of an aromatic ring, which acts as a hydrogen bond acceptor This interaction is as strong as a normal hydrogen bond, which contributes approximately 3 kcal/mol (1 cal = 4.184 J) of stabilizing energy and it plays a significant role in molecular associations [18]. It has been observed that the hydrogen bonding interaction can affected by infrared spectra at high pressure and temperature, e.g. π-hydrogen bonding interaction between water and aromatic hydrocarbons (like benzene, toluene, ethylbenzene, xylene, and mesitylene) [24]. We try to study more detailed investigation of this mentioned phenomenon where we could investigate on the minute details like different path of interaction, orientation of the molecules by calculating single point energy, Mullikan charge and Gibbs free energy by MPn methods

Methodology

Result and Discussions

Conclusion