An ESR study of 77 K alkoxy and hydroxyalkyl radicals in x-ray irradiated trehalose single crystals

Abstract

Four different alkoxy radicals were identified by ESR studies in x-ray irradiated single crystals of trehalose. The radical sites are O′2(I), O2(II), O′3(III), and the probable ring oxygen O5(IV). All alkoxy radicals exhibit one or two β-proton couplings. An additional coupling to a γ proton for radical II is observed. The difference in the gmax value for the alkoxy radicals is discussed in terms of the type of hydrogen bonding involved. Two hydroxyalkyl radicals VI and VII were also produced at 77 K. Storage of crystals for one week results in decay of radicals I and II. Alkoxy radical II transform into a C6-centered hydroxyalkyl radical V.