Efficient formation of H-addition radical and secondary alkyl radical in pentylthymines γ-irradiated at 77 K

Abstract

EPR detection of three pentylthymines γ-irradiated at 77 K showed the production of a 5,6-dihydro-5-thymyl radical (5-thymyl radical) as an H-addition radical and a secondary alkyl radical formed by C–H bond fission at the second carbon from the end of the pentyl group. The introduction of the pentyl group into thymine increased total radical yields at 77 K up to about twice that of thymine and considerably enhanced 5-thymyl radical yields. Several discussions on the radical formation suggest that the efficient production of 5-thymyl radical is related to the concomitant formation of the secondary radical.