Assessment of reactivities with explicit and implicit solvent models: QM/MM and gas-phase evaluation of three different Ag-catalysed furan ring formation routes

Péter Pál Fehér,András Stirling

doi:10.1039/c9nj04003j

Abstract

A representative reaction illustrates cases where strong solvent–solute interactions can be sufficiently well captured by continuum solvation model rendering QM/MM unnecessary.

Highlights

Collaboration between experiment and theory to understand and improve catalytic processes has become very efficient and productive over the last few decades.[1,2] An important requirement to achieve accurate theoretical rationalizations and predictions for experiment is to employ an adequate simulation model, i.e. one involving those atoms and interactions which play a decisive role in the mechanism
The reaction steps featured in Scheme 1 are characterized energetically by the activation free energies and the reaction free energies collected in Tables 1 and 2, respectively
There are many examples where explicitly including the solvent into the calculation model has been essential to obtain appropriate chemical insight into reactivity issues.[31]. In these cases the solvent participates directly in the reaction by opening a new route for the reaction steps. Such situations are when the Comparison of calculations with explicit and implicit solvent models on non-catalysed and Ag-catalysed ring-closing reaction steps featuring three different charge states leads to the following conclusions: (i) the effect of the solvent DMF can be adequately described by implicit solvent models; (ii) the simulations have demonstrated that the solvent does not form a stable solvation shell; (iii) site-specific interactions between the solvent molecules and the reactive solute do not play a role in the reaction paths investigated; and (iv) for the present reaction routes inclusion of the solvent effects does not change the reactivity trend obtained even without considering any solvent effect

Summary

Introduction

Collaboration between experiment and theory to understand and improve catalytic processes has become very efficient and productive over the last few decades.[1,2] An important requirement to achieve accurate theoretical rationalizations and predictions for experiment is to employ an adequate simulation model, i.e. one involving those atoms and interactions which play a decisive role in the mechanism. This requirement implies sufficiently accurate methods to calculate forces and sufficiently detailed molecular models. While implicit models speed up calculations enormously, many potentially important effects are

Objectives

Results

Conclusion