Palladium(II) acetate

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Palladium(II) acetate
Palladium(II) acetate
200px
200px
Names
IUPAC name
Palladium(II) acetate
Other names
Palladium diacetate
hexakis(acetato)tripalladium
bis(acetato)palladium
Identifiers
3375-31-3 YesY
ChemSpider 146827 YesY
Jmol 3D model Interactive image
PubChem 167845
RTECS number AJ1900000
  • InChI=1S/2C2H4O2.Pd/c2*1-2(3)4;/h2*1H3,(H,3,4);/q;;+2/p-2 YesY
    Key: YJVFFLUZDVXJQI-UHFFFAOYSA-L YesY
  • InChI=1/2C2H4O2.Pd/c2*1-2(3)4;/h2*1H3,(H,3,4);/q;;+2/p-2
    Key: YJVFFLUZDVXJQI-NUQVWONBAH
  • [Pd+2].[O-]C(=O)C.[O-]C(=O)C
Properties
Pd(CH3COO)2
Molar mass 224.50 g/mol
Appearance Brown yellow solid
Density 2.19 g/cm3
Melting point 205 °C (401 °F; 478 K) decomposes
Boiling point decomposes
low
Structure
monoclinic
Square Planar
0 D
Vapor pressure {{{value}}}
Related compounds
Other anions
 Palladium(II) chloride
Other cations
 Platinum(II) acetate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
YesY verify (what is YesYN ?)
Infobox references

Palladium(II) acetate is a chemical compound of palladium described by the formula Pd(O2CCH3)2 or Pd(OAc)2. It is considered more reactive than the analogous platinum compound. It is soluble in many organic solvents.

Structure

As prepared by Wilkinson and coworkers in 1965, and later studied by Skapski and Smart in 1970 by single crystal X-ray diffraction, palladium(II) acetate is a red-brown solid that crystallizes as monoclinic plates. Its structure was determined to be trimeric, consisting of an equilateral triangle of Pd atoms each pair of which is bridged with two acetate groups in a butterfly conformation. Each metal atom achieves approximate square planar co-ordination.[1][2]

On the other hand, palladium(II) acetate prepared in a slightly different way was isolated as a pale pink powder, whose structure was determined by X-ray powder diffraction to consist of infinite chains in which the coordination geometry around each Pd is true square planar.[3]

Preparation

Palladium acetate can be prepared by refluxing palladium sponge with hot glacial acetic acid and nitric acid. An excess of palladium sponge metal is used to prevent contamination by PdNO3·OAc.[4][5]

Pd + 4 HNO3 → Pd(NO3)2 + 2 NO2 + 2 H2O
Pd(NO3)2 + 2 CH3COOH → Pd(O2CCH3)2 + 2 HNO3

Palladium(II) propionate is prepared analogously; other carboxylates are prepared by reacting palladium(II) acetate with the appropriate carboxylic acid.[1]

Reactions

When warmed with alcohols, or on prolonged boiling with other solvents, palladium(II) acetate decomposes to palladium.[1]

Uses

Catalysis

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See also: Palladium-catalyzed coupling reactions

Palladium acetate is a catalyst for many organic reactions by combining with many common classes of organic compounds such as alkenes, dienes, and alkyl, aryl, and vinyl halides to form reactive adducts. Alkenes and π-allyl coordination to palladium(II) acetate involves sigma-type donation from the pi orbital of the alkene or π-allyl with concomitant pi-backbonding into an empty pi* orbital on the alkene or π-allyl. The greater the sigma donation to the metal is, the greater the pi-backbonding. The greater the pi-backbonding is, the greater the reduction in the bond order of the alkene or π-allyl.[6] Reduction of the alkenes or π-allyl by coordination to palladium(II) acetate reverses the reactivity of the organic ligand allowing them to undergo reactions with nucleophiles rather than electrophiles.[7]

Examples of palladium(II) acetate catalyzed reactions are:

Pd(O2CCH3)2 converts aryl bromides into aryltrimethylsilanes, an important functional group in many organic compounds including the fungicide "Latitude".

RC6H4Br + Si2(CH3)6 → RC6H4Si(CH3)3 + Si(CH3)3Br

Pd(O2CCH3)2 is compatible with the electronic properties of aryl bromides, and unlike other methods of synthesis, this method does not require high pressure equipment.[11]

Precursor to other Pd compounds

Palladium acetate is used to produce other palladium(II) compounds. For example, phenylpalladium acetate, used to isomerize allylic alcohols to aldehydes, is prepared by the following reaction:

Hg(C6H5)(CH3COO) + Pd(CH3COO)2 → Pd(C6H5)(O2CCH3) + Hg(O2CCH3)2[12]

Palladium(II) acetate reacts with acetylacetone to produce Pd(acac)2, a precursor to Pd(0).[citation needed]

Light or heat reduce palladium acetate to give thin layers of palladium and can produce nanowires and colloids.[4]

See also

References

  1. ↑ 1.0 1.1 1.2 Lua error in package.lua at line 80: module 'strict' not found.
  2. ↑ Lua error in package.lua at line 80: module 'strict' not found.
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  4. ↑ 4.0 4.1 Lua error in package.lua at line 80: module 'strict' not found.
  5. ↑ "High Purity Homogeneous Catalyst." Engelhard. Sept. 2005. Engelhard Corp. 24 Feb. 2006.<http://www.engelhard.com/documents/High%20Purity%20Homo%20Cat%20_Pd-acetate_%20A4%20Revised%20Final.pdf>.
  6. ↑ Toreki, R. "Allyl Ligands." The Organometallic HyperTextBook. 20 Nov. 2003. Chemglass. 01 Apr. 2006<http://www.ilpi.com/organomet/allyl.html>.
  7. ↑ Suggs, J W. "Palladium: Organometallic Chemistry." Encyclopedia of Inorganic Chemistry. Ed. R B. King. 8 vols. Chichester: Wiley, 1994.
  8. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  9. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  10. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  11. ↑ Gooben, L J. "Research Area "New Pd-Catalyzed Cross-Coupling Reactions"" 28 Feb. 2006<http://www.mpi-muelheim.mpg.de/kofo/bericht2002/pdf/2.1.8_gossen.pdf>.
  12. ↑ Lua error in package.lua at line 80: module 'strict' not found.; Lua error in package.lua at line 80: module 'strict' not found.
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