Acetylacetonate, C5H7O2-, is the conjugate base of 2,4-pentanedione. It is commonly abbreviated acac. This anion forms complexes with many transition metal ions. Some examples include: Mn(acac)3, VO(acac)2, Fe(acac)3, and Co(acac)3. These compounds are typically soluble in organic solvents. They are widely used as catalyst precursors. An anion is an ion with negative charge. ... In chemistry, the term transition metal (sometimes also called a transition element) has two possible meanings: It commonly refers to any element in the d-block of the periodic table, including zinc and scandium. ... A catalyst (Greek: καταλÏτης, catalytÄ“s) is a substance that accelerates the rate (speed) of a chemical reaction without itself being transformed or consumed by the reaction (see also catalysis). ...
The acetylacetonateanion forms complexes with many transition metal ions wherein both oxygen atoms bind to the metal to form a six-membered chelate ring.
The IR spectra of O-bonded acetylacetonates are characterized by relatively low-energy νCO bands of 1535 cm
Precursor to heterocycles: Acetylacetone is a versatile precursor to heterocycles.
It has been found that chromium acetylacetonates and zirconium acetylacetonates are particularly effective latent accelerators, for the anhydride cure of epoxy coating compositions used in impregnating and encapsulating the coils of high voltage capability electrical devices, when used in conjunction with selected organic carboxylic acids, acting as co-accelerators.
The mechanism is believed to involve partial ligand displacement or rearrangement of the acetylacetonate compound by interaction with a carboxylic acid molecule (or molecules) to form a new catalytic species.
As can be seen, in a chromium acetylacetonate system, samples 2, 3, 4 and 5 show a dramatic improvement in gel time over the control sample, showing their effectiveness as a coaccelerator, without any deleterious effect on pot life or electrical properties.
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