Metastable and Collision-activated Decomposition of Protonated Molecules of Isomeric N7- and N9-Substituted Purines in the Gas Phase

✍ Scribed by Bogdan Kralj; Dušan Žigon; Darko Kocjan; Jože Kobe

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 210 KB
• Volume: 11
• Category: Article
• ISSN: 0951-4198
• DOI: 10.1002/(sici)1097-0231(19970215)11:3<273::aid-rcm851>3.0.co;2-r

✦ Synopsis

The structures and reactivities of protonated metastable and collision-activated molecules of isomeric N 7 -and N 9 -substituted purines were investigated using fast atom/ion bombardment ionization and mass analysed ion kinetic energy spectrometry methods. Calculated proton affinities (PAs) of isomeric purine derivatives and the intensities of the observed metastable-ion peaks revealed a direct correlation of PA with the reactivity of protonated molecules. The reactivity of the N 9 -substituted purines possessing N 3 -site specific proton affinities, i.e. N 3 -H + , relates to the strength of hydrogen bonding of N 3 -H + to oxygen atom(s) of the N 9 -substituent, e.g. CH 2 -O -CH 2 CH 2 -O -C(CH 3 ) = O or CH 2 -OCH 2 CH 2 -O -H. Various intramolecular ('intra-ion') hydrogen-bond(s) in the protonated molecules of isomeric purine derivates were revealed using proton affinities and metastable-ion peak intensities.