The Application of the Hammett Equation with the Constants σ^ph in the Chemistry of Organophosphorus Compounds

The review deals with the application of the Hammett equation to organophosphorus reactions and equilibria using the constants σ^ph. As far as possible a complete list of the constants σ^ph is given. Analysis of the application of the constants σ^ph shows that linear correlations between the rate and equilibrium constants for organophosphorus reactions are usually obtained when the phosphorus atom is not a reaction centre.
For reactions involving phosphorus directly, linear correlations are achieved with the aid of the inductive (σ^ph_I) and resonance (σ^ph_R) constants, namely: Σ(σ^ph_I+ασ^ph_R). A method of calculation of the constants σ^ph_I and σ^ph_R is described and as far as possible a complete list of these constants is given for various groups attached to the phosphorus atom. It has been demonstrated on 124 reaction series as examples the function Σ(σ^ph_I+ασ^ph_R) makes it possible to construct a universal system for the σρ analysis of reactions, equilibria, and certain physical constants in the chemistry of organophosphorus compounds on the basis of the equation lgK = lgK⁰+ρΣ(σ^ph_I+ασ^ph_R) with high correlation coefficients. The relation between the constants α and ρ on the one hand and the type of reaction and its mechanism on the other is discussed.
The bibliography includes 117 references.