Gas-phase interactions between lead(II) ions and thiouracil nucleobases: A combined experimental and theoretical study


DOI: 10.1016/j.jasms.2008.10.015

Cite this article as:
Salpin, JY., Guillaumont, S., Tortajada, J. et al. J Am Soc Mass Spectrom (2009) 20: 359. doi:10.1016/j.jasms.2008.10.015


The gas-phase interactions between lead(II) ions and 2-thiouracil, 4-thiouracil, and 2,4-dithiouracil have been investigated by combining mass spectrometry and theoretical calculations. The most abundant complexes observed, namely [Pb(thiouracil) − H]+, have been studied by MS/MS experiments. Cationization by the metal allows an unambiguous characterization of the sulfur position, several fragment ions being specific of each isomer. Moreover, compared with the uracil fragmentation, new fragmentation channels are observed: elimination of PbS or total reduction of the metal. Calculations performed on the different structures, including tautomers, show that sulfur is the preferred complexation site, suggesting the greater affinity of lead for sulfur. The most stable structures are always preferentially bidentate. Natural population analysis indicates a charge transfer from the base to the metal with a more pronounced covalent character for sulfur compared to oxygen. Energetic profiles associated with the main fragmentations have been described.

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© American Society for Mass Spectrometry 2009

Authors and Affiliations

  1. 1.Bâtiment Maupertuis, Boulevard François MitterrandUniversité d’Evry Val d’Essonne, Laboratoire Analyse et Modélisation pour la Biologie et l’Environnement (LAMBE)EvryFrance
  2. 2.Departemento de Química C-9, Facultad de CienciasUniversidad Autónoma de MadridCantoblancoSpain

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