ABSTRACT
The search for relationships among the equilibrium and kinetic properties of compounds has been a paradigm in chemistry for many years. It reflects three major goals of chemists: categorize information on the behavior of chemicals, explain their behavior in terms of fundamental physical-chemical principles, and predict unmeasured properties from measured properties of a chemical or from the behavior of related compounds. Prediction of a compound's chemical reactivity strictly from its molecular structure is a much more ambitious task. The physical-chemical properties used in property-activity relationships fall into two general categories: those related to a compound's availability or transportability, and those related to its chemical/biological reactivity. No global relationship exists between the thermodynamics of reactions and the rates at which they approach equilibrium. Reactions favored by high electron density at the reaction site are accelerated by substituents like methyl groups that produce such an increase.
