A redefinition of global conceptual density functional theory reactivity indexes by means of the cubic expansions of the energy

In the present work, a new definition of the conceptual density functional theory reactivity indexes is proposed, based on a cubic interpolation of the energy as function of number of electrons as well as a generalization of the net electrophilicity index. This new proposal takes into account both the influence of hyperhardness on the reactivity and a weighted average of the electrodonating and electroacepting powers. Thus, the presented redefinition incorporates corrections and additional degrees of freedom to the prior CDFT indexes. Numerical support for global descriptors is presented for 30 benzhydrylium ions (i.e., charged electrophiles) and 15 alkyl and aryl nucleophiles taken as reference cases from the Mayr Database of Reactivity Parameters. In the best-case scenario, the descriptors correlated better with the electrophilicity parameter (r² = 0.981) than with the nucleophilicity parameter (r² = 0.827).