Tris(dibenzylideneacetone)dipalladium(0)
Encyclopedia
Trisdipalladium(0) or Pd2(dba)3 is an organometallic complex based on palladium
Palladium
Palladium is a chemical element with the chemical symbol Pd and an atomic number of 46. It is a rare and lustrous silvery-white metal discovered in 1803 by William Hyde Wollaston. He named it after the asteroid Pallas, which was itself named after the epithet of the Greek goddess Athena, acquired...

 and dibenzylideneacetone
Dibenzylideneacetone
Dibenzylideneacetone or dibenzalacetone, often abbreviated dba, is an organic compound with the formula C17H14O. It is a bright-yellow solid insoluble in water, but soluble in ethanol. Dibenzylideneacetone is used as a sunscreen component and as a ligand in organometallic chemistry, for instance in...

 used in organic chemistry
Organic chemistry
Organic chemistry is a subdiscipline within chemistry involving the scientific study of the structure, properties, composition, reactions, and preparation of carbon-based compounds, hydrocarbons, and their derivatives...

. It was discovered in 1970.

Preparation and structure

It is prepared from dibenzylideneacetone
Dibenzylideneacetone
Dibenzylideneacetone or dibenzalacetone, often abbreviated dba, is an organic compound with the formula C17H14O. It is a bright-yellow solid insoluble in water, but soluble in ethanol. Dibenzylideneacetone is used as a sunscreen component and as a ligand in organometallic chemistry, for instance in...

 and sodium tetrachloropalladate
Sodium tetrachloropalladate
Sodium tetrachloropalladate is an inorganic compound with the chemical formula Na2PdCl4. This salt, and the analogous alkali metal salts of the form M2PdCl4, may be prepared simply by reacting palladium chloride with the appropriate alkali metal chloride in aqueous solution...

. The complex has a dark-purple/brown color, and, because it is commonly recrystallized from chloroform, it is often supplied as the adduct Pd2(dba)3•CHCl3.

In Pd2(dba)3, the pair of Pd atoms are separated by 320 pm but are tied together by dba units. The Pd(0) centres are bound to the alkene parts of the dba ligand
Ligand
In coordination chemistry, a ligand is an ion or molecule that binds to a central metal atom to form a coordination complex. The bonding between metal and ligand generally involves formal donation of one or more of the ligand's electron pairs. The nature of metal-ligand bonding can range from...

s.

Applications

Pd2(dba)3 is used as a source of soluble Pd(0), in particular as a catalyst for various coupling reactions, in which it undergoes oxidation to Pd(II). Examples of reactions using this reagent are the Negishi coupling
Negishi coupling
The Negishi coupling is a cross coupling reaction in organic chemistry involving an organozinc compound, an organic halide and a nickel or palladium catalyst creating a new carbon-carbon covalent bond:* The halide X can be chloride, bromine or iodine but also a triflate or acetyloxy group with as...

, Suzuki coupling, Carroll rearrangement
Carroll rearrangement
The Carroll rearrangement is a rearrangement reaction in organic chemistry and involves the transformation of a β-keto allyl ester into a α-allyl-β-ketocarboxylic acid. This organic reaction is accompanied by decarboxylation and the final product is a γ,δ-allylketone...

, and Trost asymmetric allylic alkylation, as well as Buchwald–Hartwig amination. A related Pd(0) complex is tetrakis(triphenylphosphine)palladium(0)
Tetrakis(triphenylphosphine)palladium(0)
Tetrakispalladium is the chemical compound Pd[P3]4, often abbreviated Pd4, or even PdP4. It is a bright yellow crystalline solid that becomes brown upon decomposition in air.-Structure and properties:...

.
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