Gas-phase interactions of organotins compounds with cysteine

Latifa Latrous (1) , Jean-Yves Salpin (2) , Violette Haldys (2) , Emmanuelle Léon (2) , Catarina Correia (2) , Al Mokhtar Lamsabhi (3)

1 UTM - Université de Tunis El Manar
2 LAMBE - Laboratoire Analyse et Modélisation pour la Biologie et l'Environnement
3 Departemento de Química

The gas-phase interactions of cysteine with di-organotin and tri-organotin compounds have been studied by mass spectrometry experiments and quantum calculations. Positive-ion electrospray spectra show that the interaction of di- and tri-organotins with cysteine results in the formation of [(R)₂Sn(Cys-H)]⁺ and [(R)₃Sn(Cys)]⁺ ions, respectively. MS/MS spectra of [(R)₂Sn(Cys-H)]⁺ complexes are characterized by numerous fragmentation processes, notably associated with elimination of NH₃ and (C,H₂,O₂). Several dissociation routes are characteristic of each given organic species. Upon collision, both the [(R)₃Sn(Gly)]+ and [(R)₃Sn(Cys)]⁺ complexes are associated with elimination of the intact amino acid, leading to the formation of [(R)₃Sn]⁺ cation. But for the latter complex, two additional fragmentation processes are observed, associated with the elimination of NH₃ and C₃H₄O₂S. Calculations indicate that the interaction between organotins and cysteine is predominantly electrostatic but also exhibits a considerable covalent character, which is slightly more pronounced in tri-organotin complexes. A preferred bidentate interaction of the type -η²-S-NH₂, with sulfur and the amino group, is observed. As for the [(R)₃Sn(Cys)]⁺ complexes, their stability is due to the combination of the hydrogen bond taking place between the amino group and the sulfur lone pair and the interaction between the carboxylic oxygen atom and the metal.

Mots clés: Copyrights; Complexation; Chemical reactions; Amino acids; Calculations; Mass spectrometry; Phase interfaces; Organometallics; Gases; Hydrogen bonds; Positive ions; Spectrometry; Tin compounds; Ab initio calculations; Covalent character; Fragmentation process; Gas-phase reactions; Organo-tin complexes; Organotins; Quantum calculation; Tin; ammonia; cation; cysteine derivative; organotin compound; sulfur; peptide fragment; ab initio calculation; Article; chemical interaction; density functional theory; dissociation; electrospray mass spectrometry; elimination reaction; fragmentation reaction; gas; positive ion electrospray; priority journal; chemical model; chemistry; procedures; Cysteine; Models; Chemical; Organotin Compounds; Peptide Fragments; Mass; Electrospray Ionization; Static Electricity; Tandem Mass Spectrometry; Volatilization

Domaines: Chimie-Physique [physics.chem-ph]

Latifa Latrous, Jean-Yves Salpin, Violette Haldys, Emmanuelle Léon, Catarina Correia, et al.. Gas-phase interactions of organotins compounds with cysteine. Journal of Mass Spectrometry, 2016, 51 (11), pp.1006-1015. ⟨10.1002/jms.3812⟩. ⟨hal-01389126⟩