An electron spin resonance study of the vanadyl ion separation in dimeric vanadyl 1-hydroxycyclohexanecarboxylate

Abstract

The theory of the e.s.r. spectra of dipolar coupled paramagnetic ion pairs of spin =½ has been extended to vanadyl ions. Computational procedures have been evolved to determine the vanadyl–vanadyl ion separation in dimeric species. The existence of such species in dimethylformamide solutions of the vanadyl chelates of 1-hydroxycyclohexanecarboxylic acid and mandelic acid has been established. The low-field component of the spectra of the vanadyl complex with 1-hydroxycyclohexanecarboxylic acid attributed to ΔM= 2 transitions, lends itself to quantitative treatment; the parameters of chief interest being the internuclear distance of the vanadium ions in the dimeric species. This distance has been determined to be 3·6 Å, which is comparable with that obtained for similar chelates of copper(II).