Quantum Chemical Studies on Porphyrins

The interesting structures of naturally occurring porphyrins, its isomer, and substituted analogs have been perfected by nature to give functional dyes par excellence.Although there are a good number of literatures discussing the study of the global quantum chemical reactivity parameter of porphyrins, but the study of the local quantum chemical reactivity parameters of porphyrins are limited. The study of the local reactivity parameters for better understanding of the preferred sites for coordination with the metal ion (electron acceptor) of the porphyrins are carried out invoking semi- empirical methods to realize the charge distribution on the different atomic sites of porphyrins to analyze the use of different reactivity descriptors for the prediction of the coordination sites for them.We have tried to establish the fact that the largest and smallest value of the fukui function and local softness do not necessarily correspond to the softness and hardness regions of the molecules like porphyrins.