E.s.r. study of ion pairs involving the perylene anion

Abstract

The formation of ion pairs between the perylene ion and alkali metal ions in a variety of ethereal solvents has been investigated by e.s.r. Loose ion pairs or free ions were found to be formed in dimethoxyethane (DME) and tetrahydrofuran (THF) when lithium, sodium or potassium were used as the counter ion. Thermodynamic data were obtained on the equilibria between tight ion pairs and free ions in tetrahydrofuran using cesium and in 2-methyl-tetrahydrofuran (MTHF) using sodium, potassium or cesium. A dynamic equilibrium between tight and loose ion pairs was observed in diethylether (DEE) with lithium as the counter ion. A speculative model of the structure of the ion pairs is presented which is consistent with the experimental data.