Reactions of atomic metal anions in the gas phase: competition between electron transfer, proton abstraction and bond activation

J Phys Chem A. 2011 Dec 8;115(48):14006-12. doi: 10.1021/jp2086736. Epub 2011 Nov 10.

Abstract

Bare metal anions K(-), Rb(-), Cs(-), Fe(-), Co(-), Ni(-), Cu(-), and Ag(-), generated by electrospray ionization of the corresponding oxalate or tricarballylate solutions, were allowed to react with methyl and ethyl chloride, methyl bromide, nitromethane, and acetonitrile in the collision hexapole of a triple-quadrupole mass spectrometer. Observed reactions include (a) the formation of halide, nitride, and cyanide anions, which was shown to be likely due to the insertion of the metal into the C-X, C-N, and C-C bonds, (b) transfer of H(+) from the organic molecule, which is demonstrated to most likely be due to the simple transfer of a proton to form neutral metal hydride, and (c) in the case of nitromethane, direct electron transfer to form the nitromethane radical anion. Interestingly, Co(-) was the only metal anion to transfer an electron to acetonitrile. Differences in the reactions are related to the differences in electron affinity of the metals and the Δ(acid)H° of the metals and organic substrates. Density functional theory calculations at the B3-LYP/6-311++G(3df,2p)//B3-LYP/6-31+G(d) level of theory shed light on the relative energetics of these processes and the mechanisms by which they take place.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetonitriles / chemistry
  • Anions / chemistry*
  • Chemistry, Physical*
  • Electron Transport
  • Electrons
  • Ethyl Chloride / chemistry
  • Gases / chemistry*
  • Metals / chemistry*
  • Methane / analogs & derivatives
  • Methane / chemistry
  • Methyl Chloride / chemistry
  • Nitroparaffins / chemistry
  • Oxalates / chemistry
  • Protons*
  • Quantum Theory
  • Solutions
  • Spectrometry, Mass, Electrospray Ionization
  • Thermodynamics
  • Tricarboxylic Acids / chemistry

Substances

  • Acetonitriles
  • Anions
  • Gases
  • Metals
  • Nitroparaffins
  • Oxalates
  • Protons
  • Solutions
  • Tricarboxylic Acids
  • Ethyl Chloride
  • Methyl Chloride
  • Methane
  • tricarballylic acid
  • nitromethane
  • acetonitrile