Metals exist in solution coordinated to ligands to form coordination complexes, which can act as catalysts for important chemical transformations. Among most ubiquitous classes of ligands are β-diketonates, of which the ligand acetylacetonate or "acac" is the most common. Metal acetylacetonates are widely used in a variety of important chemical applications; however, their use in catalysis is limited because they tend to form complexes that are coordinatively saturated, meaning that they don't easily permit substrates to bind.
We have designed and synthesized a series of β-diketonate ligands that are functionalized with large m-terphenyl groups that prevent coordinative saturation at the metal. These new ligands provide a platform for detailed investigations into catalytic mechanisms that should help us discover and optimize new catalytic chemical transformations that could have an impact in the synthesis of organic chemicals. β-diketonate ligands coordinate to metals in vastly different ways than other ligands that have been investigated. In particular, they are weak σ-bond donors like water, but strong π-acceptors, like cyanide. This provides a unique electronic environment that could open the door to discovery of new reactivity and chemical transformations.
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