ESR Study of the Thymine Anion Radical in a Single Crystal of Thymine Monohydrate

Summary

ESR spectroscopy was used to study free radicals in an irradiated single crystal of thymine monohydrate at 77 K. At low microwave power (20 µW), a broad doublet is found to be super-imposed on the well known resonance patterns of the 5-yl and 7-yl radicals. The doublet spectrum has been analysed as a difference spectrum. Its spectroscopic properties and the observed transformation into the 5-yl, H-addition radical on warming the crystal are consistent with its anion nature, T(−).