Glycine radicals in the gas phase

2-Glycyl radical (1), 2-glycyl methyl ester (2), and 2-glycyl N-methylamide radicals (3) were generated in the gas phase by collisional neutralization of the corresponding cations and studied by neutralization-reionization (NR) mass spectrometry and ab initio and density functional theory calculations. Stable fractions were found for 1-3 that did not dissociate on the 4 mu s timescale of the experiment. The major unimolecular dissociations observed were cleavages of the CO-X bonds (X = OH, OCH3, and NHCH3) to form aminoketene, and cleavages of the C-CO bond to form aminocarbene, which gave rise to prominent fragments in the NR mass spectra. In addition, hydrogen rearrangements occurred in 1-3:and an unusual methyl migration took place in 3. G2(MP2) bond dissociation energies are reported for 1 and 1(+). Combined B3LYP and PMP2/6-311 + G(2df,p) calculations were used to provide bond dissociation energies;for 2, 2(+), 3 and 3(+).