Practical Applications of Conceptual DFT Descriptors

The defrnition of fugality indices entails the need for simple mathematical expressions to assess the group electrophilicity and group nucleophilicity. These defrnitions are based on the additivity rule for global softness S  

Using these properties, the definition of nucleofiigality Vg and electrofugahty Vg of a group or molecirlar fragment G, say, may simply be expressed as [34,37] 

The direct approach for the scrutiny of reaction mechanisms is the full exploration of the PES. Within this approach, relative stability of ground states, TS, and intermediate structures can be assessed and the activation and reaction energies be quantitatively established. In the present approach, the PES is used as input information for the evaluation of reactivity indices to assess reactivity and site activation along a reaction coordinate. 

In the addition-elimination mechanism, the nucleophile transfers some of its electronic charge to a vacant jc orbital in the substrate. This interaction permits the addition of the nucleophile forming metastable species—the MC intermediate. If the attack occurs at a position of the aromatic ring 

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