Hi

In general, when you use a theoretical principle to explain chemical reactivity, you can always find examples that do not follow the principle for a wide variety of reasons. The principles of conceptual DFT are obviously not an exception, so it is unsurprising that they are not always obeyed. Some of these parameters are usually approximated using Koopman's theorem to the difference in energy between the HOMO and the LUMO. Despite the fact that the HOMO-LUMO gap can be informative about the reactivity of a species, it is easy to imagine that it is not enough to fully explain how a molecule reacts.

There are several articles that discuss these topics, and you will probably find this one useful: J. Phys. Chem. A 2013, 117, 8, 1843-1852.

Hope this helps. Best wishes,

Martí

Thank you Martí Garçon . If I am not wrong, these parameters are basis set and functional dependent (HOMO-LUMO energies) and so the partial atomic charge used for this purpose. Could you share some more articles regarding this? especially electro-nucleophilicity index?

Thanks again.