Correlation analysis in the chemistry of free radicals

Published data now available on the use of correlation analysis in free-radical chemistry are discussed systematically. The scales of 'radical' σ-constants of substituents proposed previously are analysed. It is shown that none of them is applicable as a general scale because almost in all cases, it is impossible to separate correctly the proper radical and polar contributions to the overall effect of substituents. A new approach to the quantitative estimation of the relationship between the structure and reactivity of molecules in free-radical processes called r^–2-analysis is proposed. The bibliography includes 238 references.