C-H bond activation at the surface of isolated homo- and heteronuclear transition metal clusters

We chose to investigate the C-H bond activation of small organic molecules by size selected transition metal clusters and under single collision conditions. Cluster ions of either charge states originate from a standard pulsed laser vaporization source, and they are made to react within the ion trap of a Fourier Transform Ion Cyclotron Resonance (FT-ICR) mass spectrometer. In general, most of the investigated Cobalt, Platinum, Rhodium and Tantalum clusters are found to be highly reactive towards the chosen substrates (methane, ethane, benzene derivatives and alcohols) with several dependencies of the reaction rate on the sizes of the clusters and on their charges. Among the cationic Con+ clusters we find intact adsorption of benzene for all clusters sizes with only Co13+ being able to activate the benzene molecule. Anionic Con- clusters show intact adsorption and activation for n larger than n=6 where for n=9 to 16 the activation is the dominant process. Current experiments on the activation of alkanes by mixed metal clusters are underway.