Effect of solvent and metal on the formation equilibria of naphthalene and diphenyl anion radical

The anion polymerization process is affected by the solvent and the counterion. A study has been made of the quantitative aspects of this effect using as a model reaction the formation of aromatic anion radicals in various ethers. The solvating capacity of the ethers with respect to alkali metal cations has been compared. The stability of the solvate complexes is due more to steric factors than to the electron donor and dielectric properties of the solvent or the polarity of its molecules. The heat of solvation of the cation contributes considerably to the energetics of anion‐radical formation. Therefore the structure of the solvent molecules strongly affects the thermodynamic parameters of the reaction. The solvation mechanism and its role in the ion association are discussed.