The polarographic reduction of conjugated hydrocarbons. I. A theoretical discussion of the polarographic reduction of aromatic hydrocarbons

Abstract

Abstract A theoretical discussion has been given of the linear relation between the half‐wave reduction potential ε1/2 of aromatic hydrocarbons and the root a of the zero order molecular orbital secular equation corresponding to the lowest non‐occupied π‐electronic level of the molecule, which can be represented by the formula: The magnitude of the zero order “exchange” parameter γ = −2.25 ± 0.07 e.v. has been obtained by substituting the reduction potentials of some aromatic compounds in the given formula. The course of the reduction process can be qualitatively predicted by considering the π‐electronic distribution in the intermediate molecule ion and radical ion, the probability for the addition of the proton being largest at the carbon atom with the highest negative charge.