title: Free radicals from X-irradiated single crystals of uridine-5'-phosphate disodium salt.
abstract: X-irradiation of single crystals of uridine-5'-phosphate (disodium salt) between 10 and 300 K as well as storage of irradiated crystals at 300 K produces at least seven different radical species. Between 10 and 77 K, the uracil base anion and a secondary alkoxy radical at the ribose-O3'-site are formed. The latter transforms into a C5'-centred alkylphosphate species between 110 and 130 K which in turn decays between 180 and 220 K under formation of a base 5-yl hydrogen addition radical. Irradiation at 300 K additionally produces the base-located 6-yl radical together with a radical tentatively assigned to the doubly protonated base anion. Storage of crystals for several months results in decay of most of these species leaving a radical possibly located at c5' of the ribose. The spectral parameters of these radicals are given and discussed.
mesh_terms: D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals; D013696:Temperature; D014500:Uracil Nucleotides / Q000528:radiation effects*; D014542:Uridine Monophosphate / Q000528:radiation effects*; D014965:X-Rays
chemical_list: D005609:Free Radicals; D014500:Uracil Nucleotides; D014542:Uridine Monophosphate