The Increase of the Reactivity of Molecular Hydrogen with Hydroxyl Radical from the Gas Phase versus an Aqueous Environment: Quantum Chemistry and Transition State-Theory Calculations

Abstract

One of the simplest elementary reactions, that between H2 and OH, is of great theoretical interest in chemical kinetics. Surprisingly it turned out recently to be of importance in medical and biological environments, in search of role of hydrogen as radical scavenger participating in the human body: water is supposed to be of possible influence in this reaction. However, there are no theoretical studies considering solvent effects in the title reaction which in the gas phase is slow. Here, we aim to analyze the H2 + OH reaction with a blend of electronic structure calculations and the deformed Transition-State Theory (TST) approach. Inclusion of the continuum solvation model density (SMD) was applied for mimicking the role of the aqueous phase. Preliminary results demonstrate an enormous increase in the reactivity between H2 and OH molecules in water environment, approximately 150- and 138-fold at 25 ℃ and 36.5 ℃, respectively. We expect that these results can help to shed new light on the understanding of the H2 + OH reaction in aqueous phase, paving the way to research for medical and technological applications.