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Tetrakis(triphenylphosphine)palladium(0)



Tetrakis(triphenylphosphine)palladium(0)
General
Systematic name Tetrakis(triphenylphosphine)palladium(0)
Other names TPP palladium(0)
Molecular formula C72H60P4Pd
Molar mass 1155.56 g/mol
Appearance Bright yellow crystals
CAS number [14221-01-3]
Properties
Density and phase  ? g/cm3, ?
Solubility in water Insoluble
In benzene,
dichloromethane,
chloroform
Approx 5 g/100ml
Melting point decomposes around 115 °C
Structure
Molecular shape tetrahedral
Coordination
geometry
four triphenylphosphine unidentate
ligands attached to a central Pd(0)
atom in a tetrahedral geometry
Crystal structure  ?
Dipole moment 0 D
Hazards
MSDS External MSDS
Main hazards PPh3 is an irritant
NFPA 704
1
2
0
 
R/S statement R: n/a
S: S22, S24/25
RTECS number Unregistered
Supplementary data page
Structure and
properties
n, εr, etc.
Thermodynamic
data
Phase behaviour
Solid, liquid, gas
Spectral data UV, IR, NMR, MS
Related compounds
Related complexes chlorotris(triphenylphosphine)rhodium(I)
tris(dibenzylideneacetone)dipalladium(0)
Related compounds triphenylphosphine
Except where noted otherwise, data are given for
materials in their standard state (at 25 °C, 100 kPa)
Infobox disclaimer and references

Tetrakis(triphenylphosphine)palladium(0) is the chemical compound Pd[P(C6H5)3]4, often abbreviated Pd(PPh3)4, or even PdP4. It is a bright yellow crystalline solid that becomes brown upon decomposition in air.

Additional recommended knowledge

Preparation, structure, and properties

This complex is prepared in two steps from Pd(II) precursors:

PdCl2 + 2 PPh3cis-PdCl2(PPh3)2
cis-PdCl2(PPh3)2 + 2 PPh3 + 2.5 N2H4 → Pd(PPh3)4 + 0.5 N2 + 2 N2H5+Cl-

Reductants other than hydrazine can be employed.

The four P atoms are at the corners of a tetrahedron surrounding the palladium(0) center. This structure is typical for four-coordinate 18e complexes.[1] The corresponding complexes Ni(PPh3)4 and Pt(PPh3)4 are also well known. Such complexes reversibly dissociate PPh3 ligands in solution, releasing the 16e M(PPh3)3. Thus, reactions attributed to Pd(PPh3)4 in fact arise from Pd(PPh3)3 or even Pd(PPh3)2.

If the tetrakis(triphenylphosphine)palladium (0) is an orange brown, triturate with methanol and filter to give the desired yellow powder. Store under nitrogen in the fridge.

Applications

Pd(PPh3)4 is widely used as a catalyst for coupling reactions.[2] Prominent applications include the Heck reaction and Suzuki coupling. These processes begin with the oxidative addition of an aryl halide to the Pd(0) center:

Pd(PPh3)4 + ArBr → PdBr(Ar)(PPh3)2 + 2 PPh3

References

  1. ^ C. Elschenbroich, A. Salzer ”Organometallics : A Concise Introduction” (2nd Ed) (1992) from Wiley-VCH: Weinheim. ISBN 3-527-28165-7
  2. ^ Homogeneous Catalysis: Understanding the Art” by P. W. van Leeuwen, Springer; 2005. ISBN 1-4020-3176-9
 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Tetrakis(triphenylphosphine)palladium(0)". A list of authors is available in Wikipedia.
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