Organic guest radical and radical anion trapping in cycloamylose host matrices induced by γ-irradiation at 77 K

Abstract

The e.s.r. spectra of a number of organic radicals and radical anions generated from organic ‘guest’ in cycloamylose matrices by γ-irradiation at 77 K have been investigated. Both hydrogen addition to and hydrogen removal from guest molecules occurs, depending on the nature of the guest. Electron addition is observed only in certain instances, i.e. for highly electron affinic molecules, viz. hexafluorobenzene. The ability of these systems to stabilise organic radicals for the purpose of observing isotropic e.s.r. spectra at well below room temperature compares favourably with the extensively used adamantane systems. Furthermore, since the host void dimensions can be varied to a greater extent enhanced spectral resolution is observed in certain instances and the variations in line width with void size can be studied.