Tuning metalloporphyrin and metallophthalocyanine redox potentials using ligand electrochemical (E-L) and Hammett (sigma(P)) parametrization

A compilation and analysis of literature values for a number of iron and ch romium tetraphenylporphyrins shows that there is a linear correlation betwe en observed M-III II potentials and the total contribution of the axial lig and electrochemical parameters, SigmaE(L)(L). Substituted iron and chromium phthalocyanine adducts in different coordinating solvents indicate that th e potential of the M-II III odor couple is linearly dependent on SigmaE(L)( L) and on the total Hammett para substituent constant, Sigma sigma (p). The application of this electrochemical model to the design of metallomacrocyc les possessing desired values of E,, is discussed, (C) 2001 Elsevier Scienc e B.V. AH rights reserved.