Protonated carbamic acid. Collisional activation and unimolecular dissociation of CH4NO +2

Abstract

Protonated carbamic acid is generated by elimination of a vinyl radical from the radical cation of ethyl carbamate. Double hydrogen transfer leads to an excited state of the stable Y-configuration in addition to other isomers. The properties of gaseous CH₄NO⁺₂ have been disclosed on the basis of collisional activation mass spectrometry as well as unimolecular dissociation (MIKE) in combination with an extensive use of ¹⁵N and deuterium labelling. Thermochemical aspects of the protonated carbamic acid are discussed based on semiempirical MNDO calculations, supplementary to appearance energy measurements.