PARAMAGNETIC MOLECULAR CENTERS IN GAMMA-IRRADIATED ALUMINUM HYDROXIDECOMPLEXED WITH GLYCINE OR SERINE

Paramagnetic molecular centers produced by gamma irradiation at 77 K a nd at 293 K in Al-x(OH)(y), when precipitated with glycine or serine, were studied by ESR spectroscopy, Stable paramagnetic centers characte ristic for the amino acid were observed only in the complexes with DL- alpha-serine, and only in air, In the absence of air, at 293 K, none o f the paramagnetic centers gave ESR spectra characteristic of the amin o acids examined, Irradiation at 77 K produced the glycine radical, (C H2COOH)-C-., only in the complex prepared at pH 6.8 and not in the com plex prepared at pH 9.5, The radical decayed when the sample was warme d. In the serine complexes, at 77 K the radicals characteristic of the amino acid were not observed, Differences in the behavior between gly cine and serine in the complexes prepared under similar conditions are probably due to the serine OH group available for hydrogen bonding in the matrix. (C) 1995 by Radiation Research Society