A mechanistic study of the prominent loss of H2O from ionized 2-hydroxyaminoethanol

作者：Jobst Karl J; Jogee Shaheda; Bowen Richard D; Terlouw Johan K^*

来源：International Journal of Mass Spectrometry, 2011, 306(2-3): 138-149.

DOI：10.1016/j.ijms.2010.10.004

• Tandem mass spectrometry
• CBS-QB3 model chemistry
• 1,2-Oxazetidine
• Hydrogen-bridged radical cations

Tandem mass spectrometry experiments on the HCl salt of 2-hydroxyaminoethanol reveal that low-energy ions HOCH2CH2NHOH center dot+ dissociate by loss of H2O with remarkable efficiency (c. 10%). Analysis of its high energy collision-induced dissociation (CID) mass spectrum leaves little doubt that the resulting m/z 59 ion is the cyclic 1,2-oxazetidine ion, whose elusive neutral counterpart has not yet been identified by experiment.
A mechanistic analysis using the CBS-QB3 model chemistry indicates that the dissociation chemistry of HOCH2CH2NHOH center dot+ is entirely different from that of the structurally related ions HOCH2CH2ONH2 center dot+ and HOCH2CH2OH center dot+. It involves a 1,5-H transfer in one of its stable conformers that leads to a hydrogen-bridged radical cation of the 1,2-oxazetidine ion and a water molecule. In support of this proposal the isotopologues DOCH2CH2NDOD center dot DCl and HOCH2CD2NHOH center dot HCl, upon ionization (almost) exclusively lose D2O and H2O, respectively.

• 出版日期2011-9-15