Hydrogen and deuterium atoms in irradiated single crystals of tris(hydroxymethyl)aminomethane hydrochloride

The loss of electrons, stabilized in polyhydroxy compounds irradiated at low temperatures, leads to the formation of hydroxyalkyl free radicals (FR). In this study hydrogen atoms have been detected by EPR in single crystals of tris(hydroxymethyl)aminomethane hydrochloride (TM-HCl) irradiated at 77 K and the kinetic parameters determined. Single crystals of TM-HCl-(CH2OH)3CNH2·HCl and its partially deuterated analog DTM-DCl-(CH2OD)3CND2·DCl were obtained by slow evaporation from saturated solutions in H2O and D2O. In the EPR spectra of single crystals of TM-HCl and DTM-DCl signals from four types of FR can be distinguished. The width of the lines in the EPR spectra of the hydrogen atoms in TM-HCl and DTM-DCl is the same. Consequently, the hyperfine interaction with the protons of the hydroxy and amino groups do not make a substantial contribution to it. The kinetic parameters of the reactions of deuterium atoms do not differ from those fro hydrogen atoms