Dibenzylideneacetone or dibenzalacetone, often abbreviated dba, is an

organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. T ...

with the formula C₁₇H₁₄O. It is a pale-yellow solid insoluble in water, but soluble in ethanol. It was first prepared in 1881 by the German chemist

Rainer Ludwig Claisen Rainer Ludwig Claisen (; 14 January 1851 – 5 January 1930) was a German chemist best known for his work with condensations of carbonyls and sigmatropic rearrangements. He was born in Cologne as the son of a jurist and studied chemistry at the u ...

(1851–1930) and the Swiss chemist Charles-Claude-Alexandre Claparède (14 April 1858 – 1 November 1913).

Preparation

The ''trans'',''trans'' isomer can be prepared in high yield and purity by condensation of benzaldehyde and

acetone Acetone (2-propanone or dimethyl ketone), is an organic compound with the formula . It is the simplest and smallest ketone (). It is a colorless, highly volatile and flammable liquid with a characteristic pungent odour. Acetone is miscib ...

with sodium hydroxide in a water/ethanol medium followed by recrystallization. : This reaction, which proceeds via the intermediacy of benzylideneacetone, is often performed in

organic chemistry Organic chemistry is a subdiscipline within chemistry involving the scientific study of the structure, properties, and reactions of organic compounds and organic materials, i.e., matter in its various forms that contain carbon atoms.Clayden, ...

classes, and is called Claisen-Schmidt condensation.

Reactions and derivatives

Prolonged exposure to sunlight initiates +2

cycloaddition In organic chemistry, a cycloaddition is a chemical reaction in which "two or more unsaturated molecules (or parts of the same molecule) combine with the formation of a cyclic adduct in which there is a net reduction of the bond multiplicity". T ...

s, converting it to a mixture of dimeric and trimeric

cyclobutane Cyclobutane is a cycloalkane and organic compound with the formula (CH2)4. Cyclobutane is a colourless gas and commercially available as a liquefied gas. Derivatives of cyclobutane are called cyclobutanes. Cyclobutane itself is of no commercia ...

cycloadducts.

Uses

Dibenzylideneacetone is used as a component in sunscreens and as a

ligand In coordination chemistry, a ligand is an ion or molecule ( functional group) that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's elec ...

in organometallic chemistry. For example, it is a component of the catalyst

tris(dibenzylideneacetone)dipalladium(0) Tris(dibenzylideneacetone)dipalladium(0) or d2(dba)3is an organopalladium compound. The compound is a complex of palladium(0) with dibenzylideneacetone (dba). It is a dark-purple/brown solid, which is modestly soluble in organic solvents. Becau ...

. It is a labile ligand that is easily displaced by

triphenylphosphine Triphenylphosphine (IUPAC name: triphenylphosphane) is a common organophosphorus compound with the formula P(C6H5)3 and often abbreviated to P Ph3 or Ph3P. It is widely used in the synthesis of organic and organometallic compounds. PPh3 exists ...

, hence it serves a useful entry point into

palladium Palladium is a chemical element with the symbol Pd and atomic number 46. It is a rare and lustrous silvery-white metal discovered in 1803 by the English chemist William Hyde Wollaston. He named it after the asteroid Pallas, which was itself na ...

(0) chemistry.

References

{{reflist Enones Sunscreening agents