Electron paramagnetic resonance investigation of di-t-butyl nitroxide in Dianin's compound

Abstract

Dianin's compound, 4-p-hydroxyphenyl-2,2,4-trimethylchroman, forms a crystalline inclusion compound with di-t-butyl nitroxide. Detailed e.p.r. analyses of polycrystalline and single-crystal samples of this clathrate in the temperature range 77–430 K are described. Two magnetically different nitroxide radicals are distinguished, and the orientation of one of these inside the hour-glass shaped cage in the clathrate is determined. Motions of the guest molecules are characterised and the magnitudes of the energy barriers which hinder these motions are deduced. The forms of the e.p.r. spectra obtained from polycrystalline samples when these motions are present are accounted for.