Catalytic Consequences of Stable Open Metal Clusters Synthesized Via Oxidative Treatments

Oxidative treatment of single metal carbonyl complexes has been shown in literature to activate the metal complex for catalysis.  We hypothesize that a similar in-situ oxidative treatment of supported metal carbonyl clusters or chemoselective oxidation of the Ir₄ precursor will also create open sites, and that these treatments will result in a more active catalyst for hydrogenation reactions.  Open sites consist of CO vacancies, which typically result in cluster instability during catalysis.  We achieve stability and structural integrity via attachment of calixarene phosphine ligands to the Ir₄ cluster core.  We test this hypothesis of creating more catalytically active, yet stable, open metal clusters by using the structure insensitive C₂H₄ hydrogenation reaction.