HARDNESS AND BOND INDEX PROFILES OF HYDROGEN-BONDED COMPLEXES WITH SINGLE-MINIMUM AND DOUBLE-MINIMUM POTENTIALS

The dissociation reaction, H3N ... HF --> H3N + HF and the proton-tran sfer reaction (F-H ... Cl)- --> (F ... H-Cl)-have been studied at the HF//6-31G* level in order to understand the progress of these reactio ns in terms of global and local reactivity parameters. Both the reacti ons are found to obey the maximum hardness principle. The potential en ergy curve for the proton transfer reaction passes through a transitio n state wherein the hardness is at a minimum. In this reaction bond in dex profiles of the bonds being broken and formed intersect at the poi nt corresponding to the maximum in the potential energy curve. Condens ed Fukui functions have been calculated at different stages of dissoci ation of H3N ... HF. Variation of reactivity of a particular site towa rds electrophilic, nucleophilic or radical attack is properly reflecte d in these values.