Electron spin resonance of di-t-butyl-ketyl alkali metal ion pairs

Abstract

Alkali metal radical ion pairs were prepared by reacting di-t-butyl ketone with the whole series of the alkali metals. Two different types of spectra were recorded, one showing hyperfine splitting by one alkali nucleus and one with splitting produced by two counter ions. The latter, though attributed in the literature to a biradical species, is shown to be due to ionic aggregates formed by a ketyl radical, two alkali cations and possibly a diamagnetic anion. Linewidth alternation effects in the alkali multiplets indicate that the alkali nuclei do not occupy equivalent positions and that they are subjected to an intramolecular motion which interchange the two positions. The carbonyl ¹³C hyperfine splitting constants are shown to be strongly dependent on the counter ion.