Premium
Competitive proton and hydride transfer reactions via ion‐neutral complexes: fragmentation of deprotonated benzyl N ‐phenylcarbamates in mass spectrometry
Author(s) -
Yao Liqing,
Chai Yunfeng,
Sun Cuirong,
Pan Yuanjiang
Publication year - 2015
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/jms.3537
Subject(s) - chemistry , fragmentation (computing) , deprotonation , hydride , mass spectrometry , ion , proton , medicinal chemistry , computational chemistry , organic chemistry , chromatography , hydrogen , physics , quantum mechanics , computer science , operating system
The gas‐phase chemistry of deprotonated benzyl N ‐phenylcarbamates was investigated by electrospray ionization tandem mass spectrometry. Characteristic losses of a substituted phenylcarbinol and a benzaldehyde from the precursor ion were proposed to be derived from an ion‐neutral complex (INC)‐mediated competitive proton and hydride transfer reactions. The intermediacy of the INC consisting of a substituted benzyloxy anion and a phenyl isocyanate was supported by both ortho ‐site‐blocking experiments and density functional theory calculations. Within the INC, the benzyloxy anion played the role of either a proton abstractor or a hydride donor toward its neutral counterpart. Relative abundances of the product ions were influenced by the nature of the substituents. Electron‐withdrawing groups at the N ‐phenyl ring favored the hydrogen transfer process (including proton and hydride transfer), whereas electron‐donating groups favored direct decomposition to generate the benzyloxy anion (or substituted benzyloxy anion). By contrast, electron‐withdrawing and electron‐donating substitutions at the O ‐benzyl ring exhibited opposite effects. Copyright © 2015 John Wiley & Sons, Ltd.