The activation strain model of chemical reactivity

• Published in: Organic & biomolecular chemistry 2010-07, Vol.8 (14), p.3118-3127
• Main Authors: van Zeist, Willem-Jan, Bickelhaupt, F. Matthias
• Format: Article
• Language: English
• ISSN: 1477-0520; 1477-0539
• DOI: 10.1039/b926828f

Herein, we provide an account of the activation strain model of chemical reactivity and its recent applications. In this model, the potential energy surface Δ E ( ζ ) along the reaction coordinate ζ is decomposed into the strain Δ E strain ( ζ ) of the increasingly deformed reactants plus the interaction Δ E int ( ζ ) between these deformed reactants, i.e. , Δ E ( ζ ) = Δ E strain ( ζ ) + Δ E int ( ζ ). The purpose of this fragment-based approach is to arrive at a qualitative understanding, based on accurate calculations, of the trends in activation barriers and transition-state geometries ( e.g ., early or late along the reaction coordinate) in terms of the reactants' properties. The usage of the activation strain model is illustrated by a number of concrete applications, by us and others, in the fields of catalysis and organic chemistry. We provide an account of the activation strain model and how this model yields insight into the origin of reaction barriers and trends therein, by decomposing the reaction's energy profile (Δ E ) into strain energy in the reactants (Δ E strain ) plus interaction between the reactants (Δ E int ).