Dynamical Analysis of Chemical Activity of Sterically Encumbered Lewis acid/base Pairs

Abstract: This licentiate thesis is about the dynamics analysis of chemical reactions involving a stoichiometric mixture of sterically hindered Lewis base (LB) and Lewis acid (LA) – the so-called frustrated Lewis pairs (FLPs). The tool for dynamical description of chemical reactions is the ab initio molecular dynamics (AIMD) simulations together with the calculation of minimum energy paths (MEPs) on the potential energy surfaces (PESs). The aim is to take into account both the interatomic forces, computed with the dispersion-corrected density functional theory, and the motion of the atoms at finite (non-zero) temperature. With extensive AIMD/PES simulations, we have exposed and explained transition state theory (TST)/MEP paradigm failures for such important chemical reactions as binding (sequestration) of CO2 and the heterolytic cleavage of H2 by a Lewis base, tBu3P, and a Lewis acid, B(C6F5)3. The insight into dynamical aspects of FLP activity, obtained from a synergistic combination of AIMD and PES calculations, is the basis for qualitative and quantitative predictions which could be useful for future experiments