The Grand Canonical General-Purpose Reactivity Indicator: A Conceptual DFT Approach to Predict Molecular Reactivity and Experimental Electrophilicity and Nucleophilicity Scales

The Grand Canonical General-Purpose Reactivity Indicator (GC-GPRI) is introduced as a tool for predicting reactivity and for discerning the relative electrophilicity and nucleophilicity of electrophiles and nucleophiles, respectively. The GC-GPRI is derived within the zero-temperature grand canonical ensemble conceptual density-functional theory (CDFT) framework using a perturbative approach. In this model, the electrophile-nucleophile interaction energy is modeled by perturbations in the chemical and external potentials of the isolated species. The GC-GPRI accurately identifies the most reactive hard and soft atoms in complex molecules with multiple reactive sites. This model also reproduces experimental electrophilicity and nucleophilicity scales for 21 electrophiles and 20 nucleophiles, with R² correlations of 0.98 and 0.94, respectively.