A C5'-centred deoxyribose radical in single crystals of 5-chloro-and 5-bromodeoxyuridine X-irradiated at low...

X-irradiation at 77 K and subsequent warming to 150 K of single crystals of 5-chloro-and 5-bromodeoxyuridine produces a radical located at position C5' of the deoxyribose moiety. The radical exhibits identical spectral properties in both crystal systems. It is characterized by interaction of the unpaired electron with an alpha-proton(-17-0, -8-7, -33-7G), a beta-proton (18-6, 21-3, 17-5 G) as well as an OH-proton (4-8, 7-9, 12-8 G). The principal values of the g-tensor are 2-0034, 2-0049 and 2-0042. The spectral parameters are discussed in relation to those of the same or similar radicals in other nucleosides (-tides).