EPR studies of ion pairing in nematic butyl p-(p-ethoxyphenoxy carbonyl)—phenyl carbonate

Abstract

The potassium salt of tetracyanoethylene (KTCNE) has been dissolved in nematic butyl p-(p-ethoxyphenoxy carbonyl)—phenyl carbonate by itself and in the presence of the ionophores 18-crown-6, dibenzo-18-crown-6, cryptand 222, nonactin, and valinomycin. The EPR spectra obtained from the ionophore containing solutions indicate the following equilibrium IK+ + TCNE− ⇌ (IK+ — TCNE−). Here I represents the ionophore and (IK+ — TCNE−) represents an ionophore complexed loose ion pair. A similar equilibrium occurs in the absence of the ionophore. In general for the (IK+— TCNE−) ion pair, the degree of orientational ordering and the magnitude of its temperature dependence decrease as the molecular weight of I increases.