TY - JOUR
T1 - Unimolecular reactivity upon collision of uracil-Ca2+ complexes in the gas phase
T2 - Comparison with uracil-M+ (M = H, alkali metals) and uracil-M2+ (M = Cu, Pb) systems
AU - Trujillo, Cristina
AU - Lamsabhi, Al Mokhtar
AU - Mó, Otilia
AU - Yáñez, Manuel
AU - Salpin, Jean Yves
N1 - Funding Information:
This work has been partially supported by the DGI Project No. CTQ2009-13129-C02, by the Project MADRISOLAR2, Ref.: S2009PPQ/1533 of the Comunidad Autónoma de Madrid, by Consolider on Molecular Nanoscience CSD2007-00010, and by the COST Action COST CM0702. A generous allocation of computing time at the CCC of the UAM is also acknowledged. JYS would like to thank Denis Brasseur (Sanofi-Aventis) for kindly providing few milligrams of uracil-3- 15 N.
PY - 2011/9/1
Y1 - 2011/9/1
N2 - The stability against collisional dissociation of [uracil-Ca]2+ complexes has been investigated by combining nanoelectrospray ionization/mass spectrometry techniques and B3LYP/6-311++G(3df,2p)//B3LYP/6-31+G(d,p) density functional theory (DFT) calculations. The reactivity upon collision seems to be dominated by Coulomb explosion processes, since the most intense peaks in the MS/MS spectra correspond to singly-charged species (CaOH+ and [C 4,H3,N2,O]+). Nevertheless, additional peaks corresponding to the loss of neutral species, namely [H,N,C,O] and H2O have been also detected. A systematic study of the CID spectra obtained with different labeled species, namely, 2-13C- uracil, 3-15N-uracil and 2-13C-1,3-15N 2-uracil, concludes unambiguously that the loss of [H,N,C,O] involves exclusively atoms C2 and N3. Suitable mechanisms for these fragmentation processes are proposed through a theoretical survey of the corresponding potential energy surface. A comparison between these results and those reported for two other metal dications, namely Cu2+ and Pb2+, as well as for protonated uracil and uracil-M+ (M = Li, Na, K) complexes denotes the existence of significant differences and interesting similarities, among the various systems.
AB - The stability against collisional dissociation of [uracil-Ca]2+ complexes has been investigated by combining nanoelectrospray ionization/mass spectrometry techniques and B3LYP/6-311++G(3df,2p)//B3LYP/6-31+G(d,p) density functional theory (DFT) calculations. The reactivity upon collision seems to be dominated by Coulomb explosion processes, since the most intense peaks in the MS/MS spectra correspond to singly-charged species (CaOH+ and [C 4,H3,N2,O]+). Nevertheless, additional peaks corresponding to the loss of neutral species, namely [H,N,C,O] and H2O have been also detected. A systematic study of the CID spectra obtained with different labeled species, namely, 2-13C- uracil, 3-15N-uracil and 2-13C-1,3-15N 2-uracil, concludes unambiguously that the loss of [H,N,C,O] involves exclusively atoms C2 and N3. Suitable mechanisms for these fragmentation processes are proposed through a theoretical survey of the corresponding potential energy surface. A comparison between these results and those reported for two other metal dications, namely Cu2+ and Pb2+, as well as for protonated uracil and uracil-M+ (M = Li, Na, K) complexes denotes the existence of significant differences and interesting similarities, among the various systems.
KW - calcium
KW - DFT calculations
KW - nanoelectrospray/mass spectrometry
KW - potential energy surfaces
KW - unimolecular reactivity upon collision
KW - Uracil
UR - http://www.scopus.com/inward/record.url?scp=80051777164&partnerID=8YFLogxK
U2 - 10.1016/j.ijms.2011.05.018
DO - 10.1016/j.ijms.2011.05.018
M3 - Article
AN - SCOPUS:80051777164
SN - 1387-3806
VL - 306
SP - 27
EP - 36
JO - International Journal of Mass Spectrometry
JF - International Journal of Mass Spectrometry
IS - 1
ER -