Real time evolution of unprotected protonated galactosamine probed by IRMPD spectroscopy. Issue 13 (14th March 2018)

• Record Type: Journal Article
• Authors: Fraschetti, C.; Guarcini, L.; Zazza, C.; Mannina, L.; Circi, S.; Piccirillo, S.; Chiavarino, B.; Filippi, A.
• Is Part Of: Physical chemistry chemical physics. Volume 20:Issue 13(2018)
• Page Start: 8737
• Page End: 8743
• Publication Date: 2018-03-14
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/c7cp07642h
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : The conformations of unprotected α- and β-galactosamine has been investigated in the gas-phase by ESI-IRMPD-MS measurements and the electrospray ionization effect on the α/β distribution evaluated. Abstract : Conformational characterization of single α- and β-epimers of galactosamine in solution still remains an intriguing task because of their flexibility and ability to interconvert. This difficulty was circumvented by recording several "snapshots" of the epimerization process by means of fast ESI vaporization of a galactosamine·HCl sample solution at different times. Consequently, the so generated gaseous mixtures were spectroscopically investigated and the specific conformational features of both α- and β-epimers were assigned, despite the overlapping of several IR signals. Interestingly, from a comparison with time-resolved 1 H-NMR data obtained for the same solutions, the catalyzing effect of the applied ESI technique in the anomerization process clearly emerges. Finally, the experimental data were supported using both the Density Functional Theory (DFT) and Block-Localized Wavefunction (BLW) approaches: the latter method was applied here for the first time for the investigation of charged species.