A Quest for the Origin of Barrier to the Internal Rotation ofHydrogen Peroxide (H2O2) and Fluorine Peroxide (F2O2)

Dulal C Ghosh

doi:10.3390/i7080289

Abstract

In order to understand the structure-property relationship, SPR, an energy-partitioning quest for the origin of the barrier to the internal rotation of two iso-structuralmolecules, hydrogen peroxide, H2O2, and fluorine peroxide, F2O2 is performed. Thehydrogen peroxide is an important bio-oxidative compound generated in the body cells tofight infections and is an essential ingredient of our immune system. The fluorine peroxideis its analogue. We have tried to discern the interactions and energetic effects that entail thenonplanar skew conformation as the equilibrium shape of the molecules. The physicalprocess of the dynamics of internal rotation initiates the isomerization reaction and generatesinfinite number of conformations. The decomposed energy components faithfully display thephysical process of skewing and eclipsing as a function of torsional angles and hence aregood descriptors of the process of isomerization reaction of hydrogen peroxide (H2O2) anddioxygen difluoride (F2O2) associated with the dynamics of internal rotation. It is observedthat the one-center, two-center bonded and nonbonded interaction terms are sharply dividedin two groups. One group of interactions hinders the skewing and favours planar cis/transforms while the other group favours skewing and prefers the gauche conformation of themolecule. The principal energetic effect forcing the molecules into the nonplanar gaucheform is the variation “O–O’ bond energy with torsion in both the molecules. It isdemonstrated that the barrier is not a regional effect rather it is made by the conjoint actionof all one- and two-center bonding and nonbonding interactions comprising the entireframework of the molecule. The present study claims to reveal one amazing feature of non-bonded interactions. Computed results of nonbonding interactions demonstrate that thenature of interaction between two formally positively charged non-bonding H atoms (Hδ+ ----Hδ+ ) is not always repulsive and it is attractive as well; the nature of the non-bondinginteraction between formally negatively charged atom (‘O’) and formally positively charged(‘H’) atom, (Oδ−----Hδ+ ), is not always attractive but repulsive too; it is also demonstrated that the nature of the nonbonding interaction between strongly electronegative atoms, ( Fδ−-- --Fδ−), is not always repulsive and it may be attractive as well.

Highlights

Hydrogen peroxide has been used as an antiseptic and anti-bacterial agent for many years
We propose to make a detailed study of the elucidation of the origin of barrier and justifying the preferred conformations of the hydrogen peroxide and fluorine peroxide molecules in terms of the energy partitioning analysis in the present investigation
Hardness provides with a better picture due to the maximum hardness principle and can be used as a QSAR model for predicting biological activity of any compound [42]

Summary

Introduction

Hydrogen peroxide has been used as an antiseptic and anti-bacterial agent for many years. Bio-oxidative therapies are small amounts of diluted ozone and or hydrogen peroxide for the prevention and treatment of disease. Adherents consider it as one of the greatest healing miracles of all time. Scientists are in search of molecular descriptors as mathematical values that describe the shape and activity and properties of molecules. This efforts generates QSPR and QSAR modules which are integral to the rationale of drug design cycle. Information as to the origin of barrier to internal rotation within a molecule is of interest to theoretical, experimental and biological chemists.

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Conclusion