Typically both oxygen atoms bind to the metal to form a six-membered chelate ring.
In some cases the chelate effect is so strong that no added base is needed to form the complex.
The acacM ring generally exhibits aromatic character, consistent with delocalized bonding in the monoanionic C3O2 portion.
An exception to the classical description presented above, the bis(pyridine) adduct of chromium(II) acetylacetonate features noninnocent acac2- ligand.
[5] Treatment of TiCl4 with acetylacetone gives TiCl2(acac)2, a red-coloured, octahedral complex with C2 symmetry: This reaction requires no base.
The complex TiCl2(acac)2 is fluxional in solution, the NMR spectrum exhibiting a single methyl resonance at room temperature.
Vanadium β-diketonate complexes are used as precatalysts in the commercial production of ethylene-propylene-diene elastomers (EPDM).
They are often evaluated for other applications related to redox flow batteries, diabetes and enhancing the activity of insulin, and as precursors to inorganic materials by CVD.
[7] Chromium(III) acetylacetonate, Cr(acac)3, is a typical octahedral complex containing three acac− ligands.
This particular complex, which has a three unpaired electrons, is used as a spin relaxation agent to improve the sensitivity in quantitative carbon-13 NMR spectroscopy.
The complex adopts a square planar structure, weakly associated into stacks in the solid state.
[9] Mo(acac)3, a purple, air sensitive complex, is prepared by salt metathesis from hexachloromolybdate.
[17] Iron(III) acetylacetonate, Fe(acac)3, is a red high-spin complex that is highly soluble in organic solvents.
Like the trimeric nickel complex, this tetramer shows ferromagnetic interactions at low temperatures.
[26] Nickel(II) bis(acetylacetonate) reacts with water to give the octahedral[27] adduct [Ni(acac)2(H2O)2], a chalky green solid.
Hexafluoroacetylacetonates and trifluoroacetylacetonates form complexes that are often structurally related to regular acetylacetonates, but are more Lewis acidic and more volatile.
The complex Eufod, Eu(OCC(CH3)3CHCOC3F7)3, features an elaborate partially fluorinated ligand.
One or both oxygen centers in acetylacetonate can be replaced by RN groups, giving rise to Nacac and Nacnac ligands.