A Relation between Different Scales of Electrophilicity: Are the Scales Consistent Along a Chemical Reaction?

In this paper, a relationship is established between three electrophilicity scales, namely, the electrophilicity index defined by Parr, Liu, and von Szentpaly; the electron affinity; and the energy of the lowest unoccupied molecular orbital (LUMO). Profiles of electrophilicity index and LUMO energies for different kinds of chemical reactions are compared to verify if they remain consistent during a whole chemical process. It appears that the electrophilicity index and the LUMO energies are linearly correlated in almost all the cases. Besides electrophilicity scales, profiles provide valuable information about the charge-transfer stage of a chemical process.