Palladium(II) acetate

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Palladium(II) acetate
Palladium(II)-acetate-2D.png
Pd(OAc)2.jpg
Pd(OAc)2-trimer-from-xtal-Mercury-3D-balls-A.png
Polymeric-Pd(OAc)2-from-xtal-2004-Mercury-3D-balls-A.png
Names
IUPAC name
Palladium(II) acetate
Other names
Palladium diacetate
hexakis(acetato)tripalladium
bis(acetato)palladium
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.020.151 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 222-164-4
PubChem CID
RTECS number
  • AJ1900000
UNII
  • InChI=1S/2C2H4O2.Pd/c2*1-2(3)4;/h2*1H3,(H,3,4);/q;;+2/p-2 Yes check.svgY
    Key: YJVFFLUZDVXJQI-UHFFFAOYSA-L Yes check.svgY
  • InChI=1/2C2H4O2.Pd/c2*1-2(3)4;/h2*1H3,(H,3,4);/q;;+2/p-2
    Key: YJVFFLUZDVXJQI-NUQVWONBAH
  • ionic form:[Pd+2].[O-]C(=O)C.[O-]C(=O)C
  • coordination form (cyclic trimer):O0[C-](C)O[Pd+2]3(O[C-](C)O1)O[C-](C)O[Pd+2]1(O[C-](C)O2)O[C-](C)O[Pd-2]02O[C-](C)O3
Properties
Pd(CH3COO)2
Molar mass 224.51 g/mol
AppearanceBrown yellow solid
Density 2.19 g/cm3
Melting point 205 °C (401 °F; 478 K) decomposes
low
Structure
monoclinic
square planar
0 D
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
considered nonhazardous
GHS labelling: [1]
GHS-pictogram-acid.svg GHS-pictogram-exclam.svg GHS-pictogram-pollu.svg
Danger
H317, H318, H410
P261, P272, P273, P280, P302+P352, P305+P351+P338
Safety data sheet (SDS)
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).
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Palladium(II) acetate is a chemical compound of palladium described by the formula [Pd(O2CCH3)2]n, abbreviated [Pd(OAc)2]n. It is more reactive than the analogous platinum compound. Depending on the value of n, the compound is soluble in many organic solvents and is commonly used as a catalyst for organic reactions. [2]

Contents

Structure

With a 1:2 stoichiometric ratio of palladium atoms and acetate ligands, the compound exists as molecular and polymeric forms with the trimeric form being the dominant form in the solid state and in solution. Pd achieves approximate square planar coordination in both forms.

As prepared by Geoffrey Wilkinson and coworkers in 1965 and later characterized 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. It has a trimeric structure, consisting of an equilateral triangle of Pd atoms each pair of which is bridged with two acetate groups in a butterfly conformation. [3] [4]

Palladium(II) acetate can also be prepared as a pale pink form. According to X-ray powder diffraction, this form is polymeric. [5]

Preparation

Palladium acetate, in trimeric form, can be prepared by treating palladium sponge with a mixture of acetic acid and nitric acid. An excess of palladium sponge metal or nitrogen gas flow are required to prevent contamination by the mixed nitrito-acetate (Pd3(OAc)5NO2). [6] [7]

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

Relative to the trimeric acetate, the mixed nitrate-acetate variant has different solubility and catalytic activity. Preventing, or controlling for the amount of, this impurity can be an important aspect for reliable use of palladium(II) acetate. [8]

Palladium(II) propionate is prepared analogously; other carboxylates are prepared by treating palladium(II) acetate with the appropriate carboxylic acid. [3] Likewise, palladium(II) acetate can be prepared by treating other palladium(II) carboxylates with acetic acid. This ligand exchange starting with a purified other carboxylate is an alternative way to synthesize palladium(II) acetate free from the nitro contaminant. [8]

Palladium(II) acetate is prone to reduction to Pd(0) in the presence of reagents which can undergo beta-hydride elimination such as primary and secondary alcohols as well as amines. When warmed with alcohols, or on prolonged boiling with other solvents, palladium(II) acetate decomposes to palladium. [3]

Catalysis

Palladium acetate is a catalyst for many organic reactions, especially alkenes, dienes, and alkyl, aryl, and vinyl halides to form reactive adducts. [9]

Reactions catalyzed by palladium(II) acetate:

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. [15]

Precursor to other Pd compounds

Palladium acetate is used to produce other palladium(II) compounds. For example, phenylpalladium acetate, used to isomerize allyl alcohols to aldehydes, is prepared by the following reaction: [16]

Hg(C6H5)(OAc) + Pd(OAc)2 → Pd(C6H5)(OAc) + Hg(OAc)2

Palladium(II) acetate reacts with acetylacetone (the "acac" ligand) to produce Pd(acac)2.

Herrmann's catalyst is made by reaction of palladium(II) acetate with tris(o-tolyl)phosphine. [17]

Structure of Herrmann's catalyst. HerrmannCat.png
Structure of Herrmann's catalyst.

Light or heat reduce palladium acetate to give thin layers of palladium and can produce nanowires and colloids. [6]

See also

Related Research Articles

The Heck reaction is the chemical reaction of an unsaturated halide with an alkene in the presence of a base and a palladium catalyst to form a substituted alkene. It is named after Tsutomu Mizoroki and Richard F. Heck. Heck was awarded the 2010 Nobel Prize in Chemistry, which he shared with Ei-ichi Negishi and Akira Suzuki, for the discovery and development of this reaction. This reaction was the first example of a carbon-carbon bond-forming reaction that followed a Pd(0)/Pd(II) catalytic cycle, the same catalytic cycle that is seen in other Pd(0)-catalyzed cross-coupling reactions. The Heck reaction is a way to substitute alkenes.

The Stille reaction is a chemical reaction widely used in organic synthesis. The reaction involves the coupling of two organic groups, one of which is carried as an organotin compound (also known as organostannanes). A variety of organic electrophiles provide the other coupling partner. The Stille reaction is one of many palladium-catalyzed coupling reactions.

The Suzuki reaction or Suzuki coupling is an organic reaction that uses a palladium complex catalyst to cross-couple a boronic acid to an organohalide. It was first published in 1979 by Akira Suzuki, and he shared the 2010 Nobel Prize in Chemistry with Richard F. Heck and Ei-ichi Negishi for their contribution to the discovery and development of noble metal catalysis in organic synthesis. This reaction is sometimes telescoped with the related Miyaura borylation; the combination is the Suzuki–Miyaura reaction. It is widely used to synthesize polyolefins, styrenes, and substituted biphenyls.

The Sonogashira reaction is a cross-coupling reaction used in organic synthesis to form carbon–carbon bonds. It employs a palladium catalyst as well as copper co-catalyst to form a carbon–carbon bond between a terminal alkyne and an aryl or vinyl halide.

Organopalladium chemistry is a branch of organometallic chemistry that deals with organic palladium compounds and their reactions. Palladium is often used as a catalyst in the reduction of alkenes and alkynes with hydrogen. This process involves the formation of a palladium-carbon covalent bond. Palladium is also prominent in carbon-carbon coupling reactions, as demonstrated in tandem reactions.

<span class="mw-page-title-main">Wacker process</span> Chemical reaction

The Wacker process or the Hoechst-Wacker process refers to the oxidation of ethylene to acetaldehyde in the presence of palladium(II) chloride and copper(II) chloride as the catalyst. This chemical reaction was one of the first homogeneous catalysis with organopalladium chemistry applied on an industrial scale.

The Hiyama coupling is a palladium-catalyzed cross-coupling reaction of organosilanes with organic halides used in organic chemistry to form carbon–carbon bonds. This reaction was discovered in 1988 by Tamejiro Hiyama and Yasuo Hatanaka as a method to form carbon-carbon bonds synthetically with chemo- and regioselectivity. The Hiyama coupling has been applied to the synthesis of various natural products.

In organic chemistry, the Buchwald–Hartwig amination is a chemical reaction for the synthesis of carbon–nitrogen bonds via the palladium-catalyzed coupling reactions of amines with aryl halides. Although Pd-catalyzed C–N couplings were reported as early as 1983, Stephen L. Buchwald and John F. Hartwig have been credited, whose publications between 1994 and the late 2000s established the scope of the transformation. The reaction's synthetic utility stems primarily from the shortcomings of typical methods for the synthesis of aromatic C−N bonds, with most methods suffering from limited substrate scope and functional group tolerance. The development of the Buchwald–Hartwig reaction allowed for the facile synthesis of aryl amines, replacing to an extent harsher methods while significantly expanding the repertoire of possible C−N bond formations.

<span class="mw-page-title-main">1,1'-Bis(diphenylphosphino)ferrocene</span> Chemical compound

1,1-Bis(diphenylphosphino)ferrocene, commonly abbreviated dppf, is an organophosphorus compound commonly used as a ligand in homogeneous catalysis. It contains a ferrocene moiety in its backbone, and is related to other bridged diphosphines such as 1,2-bis(diphenylphosphino)ethane (dppe).

<span class="mw-page-title-main">Bis(triphenylphosphine)palladium chloride</span> Chemical compound

Bis(triphenylphosphine)palladium chloride is a coordination compound of palladium containing two triphenylphosphine and two chloride ligands. It is a yellow solid that is soluble in some organic solvents. It is used for palladium-catalyzed coupling reactions, e.g. the Sonogashira–Hagihara reaction. The complex is square planar. Many analogous complexes are known with different phosphine ligands.

The intramolecular Heck reaction (IMHR) in chemistry is the coupling of an aryl or alkenyl halide with an alkene in the same molecule. The reaction may be used to produce carbocyclic or heterocyclic organic compounds with a variety of ring sizes. Chiral palladium complexes can be used to synthesize chiral intramolecular Heck reaction products in non-racemic form.

<span class="mw-page-title-main">(1,1'-Bis(diphenylphosphino)ferrocene)palladium(II) dichloride</span> Chemical compound

[1,1'‑Bis(diphenylphosphino)ferrocene]palladium(II) dichloride is a palladium complex containing the bidentate ligand 1,1'-bis(diphenylphosphino)ferrocene (dppf), abbreviated as [(dppf)PdCl2]. This commercially available material can be prepared by reacting dppf with a suitable nitrile complex of palladium dichloride:

<span class="mw-page-title-main">Heck–Matsuda reaction</span>

The Heck–Matsuda (HM) reaction is an organic reaction and a type of palladium catalysed arylation of olefins that uses arenediazonium salts as an alternative to aryl halides and triflates.

<span class="mw-page-title-main">White catalyst</span> Chemical compound

The White catalyst is a transition metal coordination complex named after the chemist by whom it was first synthesized, M. Christina White, a professor at the University of Illinois. The catalyst has been used in a variety of allylic C-H functionalization reactions of α-olefins. In addition, it has been shown to catalyze oxidative Heck reactions.

Decarboxylative cross coupling reactions are chemical reactions in which a carboxylic acid is reacted with an organic halide to form a new carbon-carbon bond, concomitant with loss of CO2. Aryl and alkyl halides participate. Metal catalyst, base, and oxidant are required.

Dialkylbiaryl phosphine ligands are phosphine ligands that are used in homogeneous catalysis. They have proved useful in Buchwald-Hartwig amination and etherification reactions as well as Negishi cross-coupling, Suzuki-Miyaura cross-coupling, and related reactions. In addition to these Pd-based processes, their use has also been extended to transformations catalyzed by nickel, gold, silver, copper, rhodium, and ruthenium, among other transition metals.

In organic chemistry, vinylation is the process of attaching a vinyl group to a substrate. Many organic compounds contain vinyl groups, so the process has attracted significant interest, especially since the reaction scope includes substituted vinyl groups. The reactions can be classified according to the source of the vinyl group.

<span class="mw-page-title-main">Herrmann's catalyst</span> Organopalladium compound used as a catalyst

Herrmann's catalyst is an organopalladium compound that is a popular catalyst for the Heck reaction. It is a yellow air-stable solid that is soluble in organic solvents. Under conditions for catalysis, the acetate group is lost and the Pd-C bond undergoes protonolysis, giving rise to a source of "PdP(o-tol)3".

<span class="mw-page-title-main">Transition metal carboxylate complex</span> Class of chemical compounds

Transition metal carboxylate complexes are coordination complexes with carboxylate (RCO2) ligands. Reflecting the diversity of carboxylic acids, the inventory of metal carboxylates is large. Many are useful commercially, and many have attracted intense scholarly scrutiny. Carboxylates exhibit a variety of coordination modes, most common are κ1- (O-monodentate), κ2 (O,O-bidentate), and bridging.

Miyaura borylation, also known as the Miyaura borylation reaction, is a named reaction in organic chemistry that allows for the generation of boronates from vinyl or aryl halides with the cross-coupling of bis(pinacolato)diboron in basic conditions with a catalyst such as PdCl2(dppf). The resulting borylated products can be used as coupling partners for the Suzuki reaction.

References

  1. "520764 [Pd(OAc)2]3". Sigma-Aldrich. Retrieved 23 December 2021.
  2. Grennberg, Helena; Foot, Jonathan S.; Banwell, Martin G.; Roman, Daniela Sustac (2001). "Palladium(II) Acetate". Encyclopedia of Reagents for Organic Synthesis. pp. 1–35. doi:10.1002/047084289X.rp001.pub3. ISBN   978-0-470-84289-8.
  3. 1 2 3 T. A. Stephenson; S. M. Morehouse; A. R. Powell; J. P. Heffer; G. Wilkinson (1965). "667. Carboxylates of palladium, platinum, and rhodium, and their adducts". Journal of the Chemical Society (Resumed): 3632. doi:10.1039/jr9650003632.
  4. Skapski, A C.; M. L. Smart (1970). "The Crystal Structure of Trimeric Palladium(II) Acetate". J. Chem. Soc. D (11): 658b–659. doi:10.1039/C2970000658b.
  5. Kirik, S.D.; Mulagaleev, S.F.; Blokhin, A.I. (2004). "[Pd(CH3COO)2]n from X-ray Powder Diffraction Data". Acta Crystallogr. C . 60 (9): m449–m450. doi:10.1107/S0108270104016129. PMID   15345831.
  6. 1 2 Bakhmutov, V. I.; Berry, J. F.; Cotton, F. A.; Ibragimov, S.; Murillo, C. A. (2005). "Non-Trivial Behavior of Palladium(II) Acetate". Dalton Transactions (11): 1989–1992. doi:10.1039/b502122g. PMID   15909048.
  7. "High Purity Homogeneous Catalyst" (PDF). Engelhard. September 2005. Archived from the original (PDF) on 17 March 2006. Retrieved 24 February 2006.
  8. 1 2 Ritter, Stephen K. (May 2, 2016). "Chemists introduce a user's guide for palladium acetate". Chemical & Engineering News . 94 (18): 20–21. doi:10.1021/cen-09418-scitech1.
  9. Suggs, J W. "Palladium: Organometallic Chemistry." Encyclopedia of Inorganic Chemistry. Ed. R B. King. 8 vols. Chichester: Wiley, 1994.
  10. Keary M. Engle; Navid Dastbaravardeh; Peter S. Thuy-Boun; Dong-Hui Wang; Aaron C. Sather; Jin-Quan Yu (2015). "Ligand-Accelerated ortho-C-H Olefination of Phenylacetic Acids". Org. Synth. 92: 58–75. doi:10.15227/orgsyn.092.0058. PMC   4936495 . PMID   27397943.
  11. Nikitin, Kirill V.; Andryukhova, N.P.; Bumagin, N.A.; Beletskaya, I.P. (1991). "Synthesis of Aryl Esters by Pd-catalysed Carbonylation of Aryl Iodides". Mendeleev Communications. 1 (4): 129–131. doi:10.1070/MC1991v001n04ABEH000080.
  12. Basu, B., Satadru J., Mosharef H. B., and Pralay D. (2003). "A Simple Protocol for the Direct Reductive Amination of Aldehydes and Ketones Using Potassium Formate and Catalytic Palladium Acetate". ChemInform . 34 (30): 555–557. doi:10.1002/chin.200330069.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  13. Linli He; Shawn P. Allwein; Benjamin J. Dugan; Kyle W. Knouse; Gregory R. Ott; Craig A. Zificsak (2016). "Synthesis of α-Carboline". Org. Synth. 93: 272. doi: 10.15227/orgsyn.093.0272 .
  14. "Buchwald-Hartwig Cross Coupling Reaction". Organic Chemistry Portal.
  15. 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> Archived July 12, 2007, at the Wayback Machine
  16. Richard F. Heck. "Aldehydes from Allylic Alcohols and Phenylpalladium Acetate: 2-Methyl-3-Phenylpropionaldehyde". Organic Syntheses ; Collected Volumes, vol. 6, p. 815.
  17. Herrmann, W. A.; Brossmer, C.; Reisinger, C.-P.; Riermeier, T. H.; Öfele, K.; Beller, M. (1997). "Palladacycles: Efficient New Catalysts for the Heck Vinylation of Aryl Halides". Chemistry – A European Journal. 3: 1357–1364. doi:10.1002/chem.19970030823.
  18. Herrmann, W. A.; Brossmer, C.; Reisinger, C.-P.; Riermeier, T. H.; Öfele, K.; Beller, M. (1997). "Palladacycles: Efficient New Catalysts for the Heck Vinylation of Aryl Halides". Chemistry – A European Journal. 3 (8): 1357–1364. doi:10.1002/chem.19970030823.