Electron Transfer and Ligand Addition to Atomic Mercury Cations in the Gas Phase:  Kinetic and Equilibrium Studies at 295 K

Abstract

Results are reported for experimental measurements of the room-temperature chemical reactions between ground-state Hg*+ ions and 16 important environmental and biological gases: SF6, CO, CO2, N2O, D2O, CH4, CH3F, O2, CH3Cl, OCS, CS2, NH3, C6F6, NO2, NO*, and C6H6. The inductively coupled plasma/selected-ion flow tube tandem mass spectrometer used for these measurements has provided both rate and equilibrium constants. Efficient electron transfer (>19%) is observed with CS2, NH3, C6F6, NO2, NO*, and C6H6, molecular addition occurs with D2O, CH4, CH3F, CH3Cl, and OCS, and SF6, CO, CO2, N2O, and O2 showed no measurable reactivity with Hg*+. Theory is used to explore the stabilities and structures of both the observed and unobserved molecular adducts of Hg*+, and reasonable agreement is obtained with experimental observations, given the uncertainties of the theory and experiments. A correlation is reported between the Hg*+ and proton affinities of the ligands investigated. Solvation of Hg*+ with formic acid was observed to increase the rate of electron transfer from NO* by more than 20%.

Formation of Peptide Radical Cations (M+·) in Electron Capture Dissociation of Peptides Adducted with Group IIB Metal Ions

“…In a comprehensive study of the reactivity of Hg + , Bohme and coworkers [61] concluded that Hg + can ionize organic molecules with ionization energy lower than 10.1 eV. Herein, we proposed that the peptide radical cation M +• was generated through an "electron capture induced spontaneous electron transfer" model.…”

“…Theoretically, the energetic of the electron transfer reaction is governed by: [57], it is obvious that electron transfer from the peptide moiety to any of the monovalent Group IIB metal ions is energetically feasible. In the literature, the phenomenon of electron transfer from gas phase organic molecules to monovalent metal ions has been examined extensively [58][59][60][61]. Bohme and cow- …”

Ligation kinetics as a probe for gas-phase ligand field effects: Ligation of atomic transition metal cations with ammonia at room temperature

“…13 Of the remaining thirdrow cations, Pt þ and Au þ reacted by ligation that is dominated by relativistic effects, 5,6 and Hg þ reacts with ammonia by electron transfer. 14 As an indication of the quality of our experimental measurements, we provide our experimental results for the ammonia ligation of the first-row cations Cr þ , Fe þ , Co þ , and Zn þ (see Figure 1) and the second-row cations Mo þ , Ru þ , Rh þ , and Cd þ (see Figure 2).…”

“…13 Of the remaining third-row cations, Pt + and Au + reacted by ligation that is dominated by relativistic effects, 5,6 and Hg + reacts with ammonia by electron transfer. 14…”