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Eur. J. Mass Spectrom. 3, 121 - 126 (1997) |
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Reactions of selected carbon cluster ions Cn+" (n = 1013) with fluorinated benzenes C6H6xFx (x = 06) | ||
Jing Sun and Hans-Friedrich Grützmacher* |
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ABSTRACT: | ||
Carbon cluster ions Cn+" (n =1013) were prepared specifically from appropriate perchloroarenes by electron impact induced dechlorination in the external ion source of a Fourier transform ion cyclotron resonance (FT-ICR) spectrometer, and were reacted with benzene and fluorinated benzenes C6H6xFx(x = 06). In all cases where reaction occurred, strictly pseudo-first order reaction kinetics are observed. No distinct correlation between the reaction efficiency and the ionization energy or dipole moment of C6H6xFx is observed. C10+" and C13+" react by collision control with benzene and the difluorobenzenes studied. However, the efficiencies decrease irregularly with the number of F atoms and C13+" is unreactive toward C6F6 and 1,2,4,5-C6H2F4. The primary reaction product of C10+" and C13+" is the adduct ion [Cn+6H6xFx]+", A, of the carbon cluster ion and the fluorinated benzene, and C13+" produces additionally ions A H. For all Cn+" the primary product ions form secondary product ions A2 by addition of a second C6H6xFx molecule to ion A. The structure of some of the product ions were probed by collision-induced dissociation (CID) within the FT-ICR cell. In no case was back-dissociation into the reactants a major process. Besides the losses of H, F and HF, the CID products correspond to fragment ions whose formation require deep seated rearrangements of the adduct of the reactants. Therefore, it is concluded that the reaction products of Cn+" and C6H6xFx do not correspond to electrostatically bound complexes but that strong covalent bonding has occurred. | ||
Keywords: Carbon cluster, ion/molecule reactions, FT-ICR spectrometry, fluorobenzenes, CID. |
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