Gas-phase protonation of arylalkylamines. A metastable ion study

✍ Scribed by Ana M. Cardoso; Sílvia M. G. Alexandre; Cristina M. F. Barros; A. J. Ferrer-Correia; Nico M. M. Nibbering

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 135 KB
• Volume: 12
• Category: Article
• ISSN: 0951-4198
• DOI: 10.1002/(sici)1097-0231(19980715)12:13<825::aid-rcm243>3.0.co;2-k

✦ Synopsis

3 ; and n = 1-3, generated by chemical ionization with water and ammonia as ionizing reagents, have been examined via the analysis of the mass-analysed ion kinetic energy spectra of the protonated molecules. The mechanisms proposed have been probed by chemical ionization of the deuterated analogues of the amines with D 2 O and ND 3 . The results show that protonation occurs preferentially on the amino group leading to abundant ions due to ammonia (or amine) loss, although ions resulting from transfer of the proton from the amino group to the aromatic ring, to the hydroxy group para to the aliphatic chain and to the benzylic OH, are also observed. Experimental evidence for H/D exchange between the deuteronated amino group and the aromatic ring is presented, and discussed in terms of the internal energy content of the deuterated ions and structural features of the amines, such as aliphatic chain length and the presence of a second hydroxy group on the aromatic ring.