Infrared multiphoton and collision-induced dissociation studies of some gaseous alkylamine ions

✍ Scribed by C.H. Watson; G. Baykut; M.A. Battiste; J.R. Eyler

• Book ID: 104100532
• Publisher: Elsevier Science
• Year: 1985
• Tongue: English
• Weight: 779 KB
• Volume: 178
• Category: Article
• ISSN: 0003-2670
• DOI: 10.1016/s0003-2670(00)86263-7

✦ Synopsis

Collision-induced dissociation and infrared multiphoton dissociation of ions formed in di-and tri-ethylamine, di-and tri-n-propylamine, and di-isopropylamine were investigated by Fourier-transform ion-cyclotron resonance mass spectrometry. Molecular ions of all amines except di-n-propylamine produced similar fragment ions when subjected to either dissociation technique. The initial fragmentation involved Cc-$ bond cleavage, loss of an alkyl radical, and formation of an immonium ion. Subsequent fragmentations of the immonium ions produced by both dissociation mechanisms involved McLaffertytype rearrangements and loss of alkenes. The molecular ion of di-n-propylamine fragmented by a different mechanism when subjected to infrared irradiation. Protonated molecules of di-and tri-n-propylamine yielded C,H, and an ammonium ion upon infrared multiphoton dissociation, while protonated molecules of the other amines did not dissociate when this technique was applied. In contrast, collision-induced dissociation produced fragmentation for all protonated molecules. Explanation of the different fragmentations observed for the two dissociation techniques is given in terms of a mechanism involving a tight transition state for protonated di-and tri-n-propylamine dissociation.