Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7605296 | International Journal of Mass Spectrometry | 2013 | 8 Pages |
Abstract
The ESI-formed protonated 2â²-deoxycytidine, cytidine, cytarabine, and gemcitabine have been probed using infrared multiphoton dissociation (IRMPD) spectroscopy performed in the 900-2000Â cmâ1 region at CLIO, the Orsay Free Electron Laser facility, and in the 2800-3800Â cmâ1 region using a YAG-laser coupled to a table-top optical parametric oscillator/amplifier (OPO/OPA). The IRMPD spectra are compared of the protonated nucleosides with the IR spectra of their B3LYP/6-311++G(d,p)-optimized isomeric forms. The stability at room temperature of some conformers has been investigated by means of ab initio molecular dynamics simulations. The IRMPD spectra are consistent with the formation in the ESI source of both the N3- and the O2-protonated nucleosides. The most favoured members of both families are characterized by the pyrimidine base oriented anti to the furanose moiety. Concerning the O2-protonated nucleosides, IRMPD spectra and thermochemical considerations support the predominant formation of the structures with the proton oriented up relative to the furanose moiety.
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Authors
Antonello Filippi, Caterina Fraschetti, Flaminia Rondino, Susanna Piccirillo, Vincent Steinmetz, Leonardo Guidoni, Maurizio Speranza,