Ion pairs formed by alkali metals. Part 1.—Complexes of lithium, sodium and potassium with 4-nitropyridine

Abstract
The e.s.r. spectra in dimethoxyethane and tetrahydrofuran of the ion pairs formed by 4-nitropyridine anion radical with lithium, sodium and potassium cations have been studied at various temperatures. The temperature dependence of the alkali metal splitting is interpreted on the basis of the Atherton–Weissman model. To discuss the structure of the ion pair, different quantum mechanical calculations were performed.