C. L. Yao

Solvent effects on electrode potentials of metalloporphyrins: Reduction of 5,10,15,20-tetraphenylporphinato complexes in non-aqueous media

Abstract Reduction potentials were collected for 16 different tetraphenylporphyrin complexes which form anion radicals and dianions in non-aqueous media. Data were collected in up to 13 solvents in order to formulate a model of how solvent-metalloporphyrin interactions affect half-wave potentials for stepwise reduction of the different metalloporphyrins. Analysis of the data was by both linear regression and principal vector analysis. The solvent parameters investigated were the Gutmann donor number (DN), the Gutmann acceptor number (ACN), the Dimroth-Reichardt parameter (ET), the solvent dielectric constant (e), and the Taft parameters (α,β,π*). In almost all cases good correlations were found with the solvent acceptor properties ACN and ET. The implications of this correlation in terms of modulating redox potentials is discussed.