Fukui function nomenclature

Figure 4. Fukui functions/ y for attack by a nucleophile, calculated for the model system of Cpd I sketched on the left-hand side. Panel a) shows the multiplicity lowering function f2 arising from doublet coupling, b) shows the respective multiplicity raising function fl J. c) and d) show the same functions evaluated for quartet coupling, and f respectively. Nomenclature follows Equation 11, contour levels as in Figures 2-3.

The above equations provide a correspondence between this local parameter and the frontier orbital theory of chemical reactions [79] and thus justifies the nomenclature of Fukui (frontier) function. A large value off, f+, or f° at a particular site denotes the high probability of electrophilic, nucleophilic, or radical attack to take place at that site. 

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