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Competitive benzyl cation transfer and proton transfer: collision‐induced mass spectrometric fragmentation of protonated N,N‐dibenzylaniline

Ma, G., Liu, G., Shen, S., Chai, Y., Yue, L., Zhao, S., Pan, Y.
Journal of mass spectrometry 2017 v.52 no.4 pp. 197-203
aniline, benzene, cations, deuterium, dissociation, nitrogen, tandem mass spectrometry
Collision‐induced dissociation of protonated N,N‐dibenzylaniline was investigated by electrospray tandem mass spectrometry. Various fragmentation pathways were dominated by benzyl cation and proton transfer. Benzyl cation transfers from the initial site (nitrogen) to benzylic phenyl or aniline phenyl ring. The benzyl cations transfer to the two different sites, and both result in the benzene loss combined with 1,3‐H shift. In addition, after the benzyl cation transfers to the benzylic phenyl ring, 1,2‐H shift and 1,4‐H shift proceed competitively to trigger the diphenylmethane loss and aniline loss, respectively. Deuterium labeling experiments, substituent labeling experiments and density functional theory calculations were performed to support the proposed benzyl cation and proton transfer mechanism. Overall, this study enriches the knowledge of fragmentation mechanisms of protonated N‐benzyl compounds. Copyright © 2017 John Wiley & Sons, Ltd.