U. Achatz et al., Methane activation by platinum cluster ions in the gas phase: effects of cluster charge on the Pt-4 tetramer, CHEM P LETT, 320(1-2), 2000, pp. 53-58
The reactions of cationic and anionic platinum clusters Pt-n(+/-), n = 1 -
9, with methane CH4 are investigated under single collision conditions in a
Fourier-Transform Ion Cyclotron Resonance Mass Spectrometer. The reaction
of the platinum clusters proceeds through the activation of C-H bonds of me
thane and leads to the subsequent elimination of molecular hydrogen H-2, to
form the final metal-carbene complex Ptn+/-CH2,. The cation cluster reacti
ons proceed in general with collision rate whereas the anion cluster reacti
ons are more than an order of magnitude slower. The platinum tetramer anion
is unique among all the clusters studied, reacting more efficiently than t
he corresponding cation. Tentative interpretation in terms of electronic an
d geometric effects is performed. (C) 2000 Elsevier Science B.V. All rights
reserved.