diketonate

A diketonate is a type of ligand commonly encountered in coordination chemistry. It is derived from a beta-diketone, which is an organic compound containing two ketone functional groups separated by a single methylene group. The most well-known example of a diketonate ligand is acetylacetonate, often abbreviated as acac.

When a beta-diketone deprotonates, it forms an enolate anion. This enolate anion is resonance-stabilized, meaning the negative charge is delocalized across the oxygen atoms and the carbon atom between the two carbonyl groups. This resonance stabilization makes the enolate anion a relatively stable species and a good nucleophile.

The diketonate ligand typically coordinates to a metal ion in a bidentate fashion, meaning it binds to the metal center through two points of attachment. In the case of acetylacetonate, coordination occurs through both oxygen atoms. This chelation, the formation of a ring structure involving the metal and the ligand, results in stable metal complexes. These complexes are often referred to as metal diketonates.

Metal diketonates have a wide range of applications. They are frequently used as precursors in the synthesis of metal oxides and other inorganic materials, often via techniques like chemical vapor deposition (CVD). They can also serve as catalysts in various organic reactions, as well as in analytical chemistry for metal ion detection and separation. The solubility and volatility of metal diketonates can be tuned by modifying the organic substituents on the beta-diketone backbone.