Heterometallic Polyhydride Compounds: Synthesis and Reactivity (Chemistry)

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Hydrogenation, the addition of hydrogen to other atoms or molecules, is an extremely important chemical process. For example, hydrogenation is involved in the conversion of corn oil to margarine and in the utilization of coal for chemical synthesis, and will undoubtedly be involved also in future practical schemes for the utilization of solar energy. The focus of this research project is the synthesis of metal-hydrogen compounds of metals which can hydrogenate other compounds or catalyze hydrogenation reactions. This project involves the synthesis and investigation of the reactivity of compounds optimized for hydrogen transfer to reducible substrates such as CO, carbon dioxide and olefins. Such compounds contain two different metals, either two transition metals or a transition metal and a highly electropositive metal (Zn, Y, Sm ....), as well as numerous hydride ligands. Three different classes of synthetic procedures will be used for these heterometallic hydrides. In preliminary work the reduction of carbon dioxide by one heterobimetallic polyhydride has been observed. Since it can be argued that unpaired electron density should promote such hydrogenations from both a kinetic and a thermodynamic point of view, monomeric metallic polyhydrides with unpaired electrons will also be synthesized. Both monomeric and heterobimetallic polyhydrides will be characterized in terms of their dynamic processes ( e.g. by EPR spectroscopy ) and their chemical reactivity.