München 2004 – wissenschaftliches Programm

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MS: Massenspektrometrie

MS 8: Cluster

MS 8.3: Vortrag

Donnerstag, 25. März 2004, 17:00–17:15, HS 112

Cluster size and charge dependence reactions of the highly exothermic azidoacetonitrile on anionic and cationic rhodium clusters — •Iulia Balteanu, O. Petru Balaj, Brigitte Fox, Martin Beyer, and Vladimir Bondybey — Institut für Physikalische und Theoretische Chemie 2, Technische Universität München, Lichtenberg Str. 4, 85748 Garching

Gas-phase reactions of anionic and cationic rhodium clusters with azidoacetonitrile are studied by Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry under near-thermal conditions. All anionic and large cationic clusters react by adding [C₂,H₂] in consecutive steps, either by forming interstitial carbides and nitrides or by adding two CN groups to the cluster surface. Small cationic clusters behave differently, with the unimolecular decomposition of the azide determining the reactivity. Saturation is identified via the size-dependent efficiency of consecutive reaction steps. The present results are the first study of organic azides on transition metal clusters. The observed selectivity of the reaction is in contrast to the high exothermicity of any reaction with azide species. The cationic cluster reactivity shows a gradual transition from gas-phase to surface-like behavior with increasing cluster size.