This paper describes, at a molecular level, the organometallic chemistry that occurs during the adsorption of Fe3(CO)12 and Fe(CO)5 on silica, alumina, magnesia, and zinc oxide. Fe(CO)5 and Fe3(CO)12 are only weakly adsorbed on silica. In contrast on alumina, magnesia, and zinc oxide there is formation of the anionic hydride HFe3(CO)11−M+ (M = Al, Mg, Zn), which has been characterized in the adsorbed state by infrared, UV, and 1H NMR spectroscopy and which has been extracted from the surface by ion exchange with Et4NCl. The results indicate that the surface hydroxyl group of alumina, magnesia, or zinc oxide can make a nucleophilic attack at the coordinated CO as it occurs in solution with formation of the stable surface hydrido cluster. The result is also the first example of a grafted cluster where the grafting occurs by ionic interaction with a surface cation of the oxide lattice. It is possible that the anionic cluster interacts with such a surface cation via the oxygen lone pair of the bridging carbonyl ligand.
ASJC Scopus subject areas
- Colloid and Surface Chemistry