Synthesis of Tetrahedral Mixed-Metal Clusters of the Iron Triad. Preparation and Characterization of H2FeRu2Os(CO)13 and H2FeRuOs2(CO)13.

Transition metal cluster complexes have become a very important class of compounds, principally because of their potential in catalysis. Clusters have been shown to behave as catalysts in their own right and they hold considerable promise for serving as models for catalytic surfaces. Clusters comprised of two or more different transition metals in the cluster framework are particularly interesting in this regard because of possible bimetallic effects. Further, mixed-metal clusters have non-equivalent bonding sites. As such they are ideally suited for modeling studies which employ variable temperature NMR to follow the movements of substrates over their surfaces. One of the problems which has hampered studies of mixed-metal clusters is their relative lack of availability. Only a very few isostructural series have been achieved, and general synthetic methods for mixed-metal clusters are lacking. Carbonylmetalates have been widely used as synthetic reagents in cluster chemistry and several of the reported reactions appear to be adaptable to design. This is particularly true of the reactions of Knight and Mays who prepared a series of Group 7 - Group 8 tetrameric mixed-metal clusters through the addition of a carbonylmetalate to a closed M3CO12 trimer.