The reaction of the hydrogen-bridged radical cation [NH2COHOCH2]•+ with dioxygen

The title ion (HBRC-1) has recently been shown to be a stable hydrogen-bridged radical cation that is easily accessible by the decarbonylation of ionized methyl oxamate, NH2COCOOCH3.In this study, we report on the intriguing reactivity of HBRC-1 and its deuterium isotopologue [NH2CODOCD2]•+ towards dioxygen in the ion-molecule reaction chamber of the Mons Autospec 6F mass spectrometer.Theory and experiment agree that the encounter complex [NH2C(O2)OHOCH2]•+ is the key starting configuration for the three product ions observed. These are: NH2C(OOH)OH+, the hydrogen-bridged ion [CH2OHN(H)CO]+ and NH2C(O2)OH•+, generated by loss of HCO•, O2H• and CH2O respectively. The peroxide-type ion NH2C(O2)OH•+ generated in this experiment is not observed in the reaction of solitary ions NH2COH•+ with O2, which is ascribed to the stabilizing effect of the CH2O dipole in the terbody encounter complex.