Computational Mechanochemistry

Abstract

Mechanochemistry is a field with a long history, but only about a decade ago it was transferred from macroscopic milling-type experiments down to the molecular level. The Bochum group headed by Professor Dominik Marx established a general theoretical framework for describing such mechanical manipulation of covalent bonds in terms of force transformed potential energy surfaces. The original static approach has been there recently extended to dynamical simulations of mechanochemical reactions in solution in order to explore both solvation and thermal activation effects what is going to be discussed in this chapter. First of all the isotensional ab initio metadynamics yields force transformed free energy landscapes, which were used successfully to unravel the complex mechanochemistry of force-induced ring-opening of cyclopropanes in the gas phase. After that the step forward from isolated systems into solvated was made and by using a minimal molecular model, which is diethyl disulfide in water, we have most recently published an explanation of the biphasic, Janus-faced behavior of the reaction rate, the so-called “reactivity switch”, as a function of force that has been observed experimentally in stretched proteins. At the end the simulations on protein are shown, where the drastic topological changes of the free energy profiles along the S-S-C-C dihedral angle as the external forces increases are qualitatively similar to those observed for simple molecular model.