Microsolvation effect on chlorination reaction of simple alcohols

Abstract

The microsolvation effect was investigated on bimolecular nucleophilic substitution (SN2$S_N2$) mechanism for chlorination of methanol, ethanol, and propanol using water as explicit solvent. Based on theoretical calculations, within Density Functional Theory (DFT) combined with polarizable continuum model (PCM) and explicit solvent molecules, it was possible to compare the effect of hydration on the nucleophile and on the leaving group, for the main extremal points of potential surfaces, that is, pre‐complex, transition state (TS), and post‐complex. The possible disposition of water molecules was also investigated raging from one to four explicit molecules. This study was carefully and systematically done for methanol and the main conclusions were used to guide the corresponding study for ethanol and propanol. The results point out to an increase of activation energy with the number of explicit water molecules, showing the importance of hydrogen bond on the stabilization of structures, effect not captured by PCM alone.

Role of Explicit Solvation in Computational Modeling of Chemical Reactions: Mechanism of Cu(I) Transfer Between Thiolate-Based Chelators in Water

“…6,7,18 Recent studies on microsolvation have been carried out for organic substitution and rearrangement reactions. 6,7 There are also some comparative studies by varying number of explicit solvent molecules in an implicitexplicit hybrid setup. 8 Solvent effects in inorganic reactions are well acknowledged, especially in the field of bioinorganic chemistry, where solvent is water.…”

“…Due to the computational burden of dealing with explicit solvents, attempts to model beyond the regular continuum treatments are relatively scarce. In recent years, because of steady increase in affordable computational resources, renewed interest in better treatment of solvation by including more explicit water, termed as “effect of microsolvation”, has resulted in several studies. ,, Recent studies on microsolvation have been carried out for organic substitution and rearrangement reactions. , There are also some comparative studies by varying number of explicit solvent molecules in an implicit-explicit hybrid setup . Solvent effects in inorganic reactions are well acknowledged, especially in the field of bioinorganic chemistry, where solvent is water.…”

“…In recent years, because of steady increase in affordable computational resources, renewed interest in better treatment of solvation by including more explicit water, termed as "effect of microsolvation", has resulted in several studies. 6,7,18 Recent studies on microsolvation have been carried out for organic substitution and rearrangement reactions. 6,7 There are also some comparative studies by varying number of explicit solvent molecules in an implicitexplicit hybrid setup.…”

“…Despite the advances, it is generally acknowledged that treatment of solvent effects in complicated environment is still an outstanding problem as discussed in a recent review. , Under strong solute–solvent interactions, e.g., hydrogen bonding, the continuum treatment is likely to run into problems. Those situations are generally handled by inclusion of few explicit solvent molecules. − This hybrid approach is often used to study reaction mechanisms in aqueous medium or when a water molecule is expected to participate in the chemical reaction, either directly or in some other significant way. ,− …”

Solvate Suite: A Command-Line Interface for Molecular Simulations and Multiscale Microsolvation Modeling

“…19 For instance, the presence of only a few solvent molecules can induce alterations in the geometric and electronic structures of a solute molecule, subsequently impacting its properties and reactivity. 20,21 It is investigated through various experimental and theoretical methods, including spectroscopy, molecular dynamics simulations, and quantum chemical calculations. 22,23 From theoretical and computational standpoints, a crucial aspect of the microsolvation treatment lies in the arrangement of solvent molecules around the solute.…”