Reactions of atomic metal anions in the gas phase: competition between electron transfer, proton abstraction and bond activation.
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.
Chemistry Department, University of Ottawa, Ottawa, Canada K1N 6N5.
Sharon
S
Curtis
Jason
J
DiMuzio
Alex
A
Mungham
Julie
J
Roy
Dhiya
D
Hassan
Justin
J
Renaud
Paul M
PM
Mayer
D000097:Acetonitriles / Q000737:chemistry; D000838:Anions / Q000737:chemistry*; D002627:Chemistry, Physical; D004579:Electron Transport; D004583:Electrons; D005018:Ethyl Chloride / Q000737:chemistry; D005740:Gases / Q000737:chemistry*; D008670:Metals / Q000737:chemistry*; D008697:Methane / Q000031:analogs & derivatives / Q000737:chemistry; D008737:Methyl Chloride / Q000737:chemistry; D009595:Nitroparaffins / Q000737:chemistry; D010070:Oxalates / Q000737:chemistry; D011522:Protons; D011789:Quantum Theory; D012996:Solutions; D021241:Spectrometry, Mass, Electrospray Ionization; D013816:Thermodynamics; D014233:Tricarboxylic Acids / Q000737:chemistry
D000097:Acetonitriles; D000838:Anions; D005740:Gases; D008670:Metals; D009595:Nitroparaffins; D010070:Oxalates; D011522:Protons; D012996:Solutions; D014233:Tricarboxylic Acids; D005018:Ethyl Chloride; D008737:Methyl Chloride; D008697:Methane; C028021:tricarballylic acid; C008640:nitromethane; C032159:acetonitrile