Metal-ligand interactions: gas-phase transition metal cluster carbonyls

Experimental studies of the interactions of small transition-metal cluster anions with carbonyl ligands are reviewed and compared with neutral and cat ionic clusters. Under thermal conditions, the reaction rates of transition- metal clusters with carbon monoxide are measured as a function of cluster s ize. Saturation limits for carbon monoxide addition can be related to the g eometric structures of the clusters. Both energy-resolved threshold collisi on-induced dissociation experiments and time-resolved photodissociation exp eriments are used to measure metal-carbonyl binding energies. For platinum and palladium trimer anions, the carbonyl binding energies are assigned to different geometric binding sites. Platinum and palladium cluster anions ca talyse the oxidation of carbon monoxide to carbon dioxide in a full catalyt ic cycle at thermal energies.