CHEMICAL-TRANSFORMATIONS OF A SIO2-SUPPORTED [FE5RHC(CO)(16)](-) CLUSTER AND CATALYSIS OF PROPYLENE HYDROFORMYLATION

Chemical transformations of SiO2-supported [Fe5RhC(CO)(16)](-) and [Fe 4RhC(CO)(14)](-) clusters in Ar, CO, and synthesis gas are studied by IR spectroscopy, Mossbauer spectroscopy, and transmission electron mic roscopy. It is shown that partial transformation of the [Fe5RhC(CO)(16 )](-) cluster to the [Fe4RhC(CO)(14)](-) cluster occurs immediately af ter its deposition on the substrate surface with the simultaneous form ation of Fe2+ ions. The complete conversion of the supported [Fe5RhC(C O)(16)](-) cluster to [Fe4RhC(CO)(14)](-) is observed at 323 K in the synthesis gas. At 373 to 423 K [Fe5RhC(CO)(16)](-) transforms into a m ixture of Fe4Rh2C(CO)(16), [Fe4RhC(CO)(14)](-), and [Fe3Rh3C(CO)(15)]( -) clusters. In the 523 to 623 K range, the supported [Fe5RhC(CO)(16)] (-) cluster decarbonylates completely to form bimetallic species less than or equal to 5 Angstrom in size. Silica-supported; FeRh clusters a re active in propylene hydroformylation at 423 to 473 K and form a mix ture of butyl alcohols and butyraldehydes.