Electrophilicity index inverse

Hence, it is clear that fundamentally and operationally the physico-chemical process of protonatirMi can be linked to the above akin descriptors — the ionization process, the hardness, softness, electronegativity and electrophilicity. Recently, we (Islam et al. 2010, 2011a, b Ghosh et al. 2011a) have published good number of papers where we have discussed that the three descriptors, the electronegativity, the hardness and the electrophilicity index of atoms and molecules are fundamentally qualitative per se and operationally the same. All three represent the attraction of screened nuclei towards the electron pair/bond. Thus, we can safely and reasonably conclude that the proton affinity and the three descriptors have inverse relationship. 

A modification of the Hammett approach, suggested by Brown, called the selectivity relationship is based on the principle that reactivity of a species varies inversely with selectivity. Table 11.3 " shows how electrophiles can be arranged in order of selectivity as measured by two indexes (1) their selectivity in attacking toluene rather than benzene, and (2) their selectivity between the meta and para positions in toluene. As the table shows, an electrophile more selective in one respect is also more selective in the other. In many cases, electrophiles known to be more... 

The nucleophilicity N index/ the inverse of the electrophilicity ( / >), and the inverse of the electrodonating power ( / > ) have been checked towards the following reactions (i) 5-substituted indoles for which rate constants were available (ii) para-substituted phenols and (iii) 2,5-disubstituted bicyclic[2.2.1]hepta-2,5-dienes. The nucleophilicity N index was found to work well, especially for more complex molecules, which was not always the case for l/ > and Hco ... 

The nucleophilicity of 32 amine, amide, carbamate, amidine, and pyridine nucleophiles was calculated at the B3LYP/6-31G(d,p) level of theory using the gas-phase ionization potential based on the nucleophilicity index The correlation coefficient for the calculated pyridine nucleophilicity against Mayr s values was 0.947, and it was 0.987 against the inverse of the electrophilicity scale Mm. The site selectivity predicted for the nucleophiles with more than one nucleophilic centre correlates well with that predicted by the local nucleophilicity index and the philicity index m. ... 

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