PUB - Publikationen an der Universität Bielefeld

Carbon cluster ions C-n(+.), (n = 10-13) 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 C6H6-xFx (x = 0-6) 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 C6H6-xFx is observed, C-10(+.) and C-13(+.) react by collision control with benzene and the difluorobenzenes studied, However, the efficiencies decrease irregularly with the number of F atoms and C-i3(+.) is unreactive toward C6F6 and 1,2,4,5-C6H2F4. The primary reaction product of C-10(+.) and C-13(+.) is the adduct ion [Cn+6H6-xFx](+.), A, of the carbon cluster ion and the fluorinated benzene, and C-13(+.) produces additionally ions A - H, For all C-n(+.) the primary product ions form secondary product ions A(2) by addition of a second C6H6-xFx 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 C-n(+.) and C6H6-xFx do not correspond to electrostatically bound complexes but that strong covalent bonding has occurred.