ESR Study of an Acetylenic Radical in Two Host Crystals. X-Irradiated Methyl-2-Nonynoate Trapped in Urea and Perhydrotriphenylene Inclusion Crystals

Abstract
Single crystals of methyl‐2‐nonynoate–urea and methyl‐2‐nonynoate–perhydrotriphenylene inclusion compounds were x irradiated at 77°K and investigated by ESR at room temperature. The stable radical observed in both inclusion crystals is CH3(CH2)4CH–C≡C–CO2CH3. This radical exists in quite different conformations in the two host crystals. All spectra are well resolved and agree with computer‐simulated spectra. A table of proton coupling constants and g values is given.