Density functional based reactivity parameters: Thermodynamic or kinetic concepts?

The Density Functional Theory of chemical reactivity has provided and effective way to develop a mathematical framework for many empirical chemical concepts. In this work, the relation of some of the proposed indexes with the thermodynamic and kinetic effects on a chemical reaction will be discussed. In order to give a numerical support to the discussion, families of S(N)2 reactions and Diels-Alder reactions have been studied. It is concluded that the theoretical proposed indexes represent neither thermodynamic nor kinetic effects but a combination of both depending on the type of reaction. (C) 2009 Elsevier B.V. All rights reserved.