title: Apparent activation of H2O and elimination of H2 from gas-phase mixed-metal complexes containing silver, calcium and deprotonated glycine.
abstract: BACKGROUND
  Ion trap mass spectrometry was used to study the reactivity of species derived from gas-phase, mixed-metal complexes, [Ag2 Xx(Gly-H)3 ](+) , where Xx = Ca, Mg, Sr and Ag, and in particular the apparent activation of an H2 O ligand added during an ion-molecule reaction.
  
  
  METHODS
  Precursor [Ag2 Xx(Gly-H)3 ](+) complexes were formed by electrospray ionization (ESI) using spray solutions in which AgNO3 , XxNO3 and glycine were mixed in a 1:1:3 molar ratio. Specific species for study of ion-molecule reactions were created in a "top down" fashion using collision-induced dissociation (CID). Ion-molecule reactions were performed by selective isolation and storage in a linear ion trap, where reactions with adventitious H2 O can occur.
  
  
  RESULTS
  Multiple stages of CID of [Ag2 Ca(Gly-H)3 ](+) resulted in the formation of [AgHCa(Gly-H)](+) . An ion-molecule reaction of this ion produced a peak 16 mass units higher which is hypothesized to be a result of addition of H2 O followed by loss of H2 . This reaction was studied further by replacing Ca with Mg, Sr and Ag; as well as by incorporating deuterium-labelled glycine into the complex.
  
  
  CONCLUSIONS
  The experimental results showed the following pattern for the apparent rates of reaction: Mg > Sr > Ca. When silver is the only metal present there is an addition of water but no loss of H2 . DFT and MP2 calculations help identify plausible pathways for decomposition of H2 O and formation of H2.
authors.affiliation: Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, PA, 15282, USA.
authors.forename: Sandra
authors.initials: S
authors.lastname: Osburn
authors.affiliation: Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, PA, 15282, USA.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Plaviak
authors.affiliation: Sto-Rox High School, McKees Rocks, PA, 15136, USA.
authors.forename: Jordan
authors.initials: J
authors.lastname: Pestok
authors.affiliation: Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, PA, 15282, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Van Stipdonk