Palladium(II) acetate

Palladium(II) acetate

Chembox new
Name = Palladium(II) acetate
ImageFile = Palladium(II) acetate.jpg
ImageName = Palladium(II) acetate
IUPACName = Palladium(II) acetate
OtherNames = Palladium diacetate
hexakis(acetato)tripalladium
bis(acetato)palladium
Section1 = Chembox Identifiers
SMILES = C(CO)OPdO(CO)C
CASNo = 3375-31-3
RTECS = AJ1900000

Section2 = Chembox Properties
Formula = C4H6O4Pd
MolarMass = 224.50 g/mol
Appearance = Brown yellow solid
Density = 2.19 g/cm³
Solubility = low
MeltingPt = 205 °C (478 K), decomposes
BoilingPt = decomp.

Section3 = Chembox Structure
Coordination = Square Planar
CrystalStruct = monoclinic
Dipole = 0 D

Section7 = Chembox Hazards
ExternalMSDS = [http://www.gfschemicals.com/Search/MSDS/2425MSDS.PDF MSDS]
MainHazards = considered nonhazardous
RPhrases = 41
SPhrases = 24/25

Section8 = Chembox Related
OtherAnions = Palladium(II) chloride
OtherCations = Platinum(II) acetate

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 related platinum. It is soluble in many organic solvents.

tructure

Palladium(II) acetate is 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.cite journal | author = Skapski, A C.; M. L. Smart | title = The Crystal Structure of Trimeric Palladium(II) Acetate | journal = J. Chem. Soc. D | year = 1970 | pages = 658b-659 | doi = 10.1039/C2970000658b]

Preparation

It can be prepared in two steps from palladium sponge, hot glacial acetic acid, and nitric acid via the intermediacy of the dinitrate:cite journal | author = Bakhmutov, V. I.,; Berry, J. F.; Cotton, F. A.; Ibragimov, S.; Murillo, C. A. | title = Non-Trivial Behavior of Palladium(II) Acetate | journal =Dalton Transactions | year = 2005 | pages = 1989–1992 | doi = 10.1039/b502122g] ["High Purity Homogeneous Catalyst." "Engelhard". Sept. 2005. Engelhard Corp. 24 Feb. 2006..] ::Pd + 2 HNO3 → Pd(NO3)2 + H2::Pd(NO3)2 + 2 CH3COOH → Pd(O2CCH3)2 + 2 HNO3An excess of palladium sponge is used to ensure that all HNO3 is consumed.

Uses

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.Toreki, R. "Allyl Ligands." The Organometallic HyperTextBook. 20 Nov. 2003. Chemglass. 01 Apr. 2006.] 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.Suggs, J W. "Palladium: Organometallic Chemistry." Encyclopedia of Inorganic Chemistry. Ed. R B. King. 8 vols. Chichester: Wiley, 1994.]

Examples of palladium(II) acetate catalyzed reactions are:
*Vinylation: An example is the Heck reaction
*Rearrangement of Acyclic Dienes: An example is the Cope reaction
*Carbonylation reaction: carboxylation of aryl halides and benzyl chloride derivatives in ionic liquid media (l-butyl-3-methylimidazolium hexafluorophosphate, tetrafluoroborate, and Aliquat336 )
*Reductive amination of aldehydes or ketones using potassium formate.cite journal | author = Basu, B., Satadru J., Mosharef H. B., and Pralay D. | title = A Simple Protocol for the Direct Reductive Amination of Aldehydes and Ketones Using Potassium Formate and Catalytic Palladium Acetate | journal = ChemInform | volume = 34 | issue = 30 | year = 2003 | pages = 555–557 | doi = 10.1002/chin.200330069]
*Wacker process: the oxidation of ethylene in water to form acetaldehyde (precursor to poly(vinyl acetate), a common glue).
*Buchwald-Hartwig synthesis of aryl amines from aryl halides/pseudohalides and primary or secondary amines.cite web | publisher = Organic Chemistry Portal | url = http://www.organic-chemistry.org/namedreactions/buchwald-hartwig-reaction.shtm | title = Buchwald-Hartwig Cross Coupling Reaction]

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)3BrPd(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.Gooben, L J. "Research Area "New Pd-Catalyzed Cross-Coupling Reactions"" 28 Feb. 2006.]

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)2OrgSynth | author =
Richard F. Heck | title = Aldehydes from Allylic Alcohols and Phenylpalladium Acetate: 2-Methyl-3-Phenylpropionaldehyde | collvol = 6 | collvolpages = 815 | prep = cv6p0815
]

Palladium(II) acetate reacts with acetylacetone to produce Pd(acac)2, a precursor to Pd(0).Fact|date=January 2008

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

References


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