Negative Condensed-to-Atom Fukui Functions: A Signature of Oxidation-Induced Reduction of Functional Groups

We show that the orbital relaxation contribution to the Fukui function, first derived by Yang, Parr, and Pucci in 1984, is decisive for predicting redox-induced electron transfer. Specifically, we study a dinuclear cobalt complex which has been shown to exhibit redox-induced electron transfer, and show that this effect is associated, computationally, with negative values of the condensed Fukui functions. This establishes that not only can the Fukui function be negative, but negative values of the Fukui function are chemically significant.