Diphenyl-2-pyridylphosphine

Diphenyl-2-pyridylphosphine is an organophosphorus compound with the formula P(C6H5)2(2-C5H4N). It is the most widely used mono-pyridylphosphine ligand.[1] Other mono-pyridylphosphines ligands (3-, 4-) are not common in chemical literature; however, tris-pyridylphosphines have been thoroughly investigated as ligands in transition metal complexes used for catalysis. Pyridylphosphines, including diphenyl-2-pyridylphosphine, may bind transition metals as monodentate or bidentate ligands4. Diphenyl-2-pyridylphosphine behaves as a P-bound monodentate ligand, or a P,N-bound bidentate ligand. Diphenyl-2-pyridylphosphine is a sought after ligand for its ability to relay protons to transition metals such as palladium(II) in homogeneous catalysis.[2]

Diphenyl-2-pyridylphosphine
Skeletal formula of diphenyl-2-pyridylphosphine
Space-filling model of the diphenyl-2-pyridylphosphine molecule
Names
Preferred IUPAC name
2-(Diphenylphosphanyl)pyridine
Other names
2-(Diphenylphosphino)pyridine
Diphenyl-2-pyridylphosphine
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.157.265 Edit this at Wikidata
UNII
  • InChI=1S/C17H14NP/c1-3-9-15(10-4-1)19(16-11-5-2-6-12-16)17-13-7-8-14-18-17/h1-14H ☒N
    Key: SVABQOITNJTVNJ-UHFFFAOYSA-N ☒N
  • InChI=1/C17H14NP/c1-3-9-15(10-4-1)19(16-11-5-2-6-12-16)17-13-7-8-14-18-17/h1-14H
    Key: SVABQOITNJTVNJ-UHFFFAOYAU
  • C1=CC=C(C=C1)P(C2=CC=CC=C2)C3=CC=CC=N3
Properties
C17H14NP
Molar mass 263.280 g·mol−1
Appearance White crystalline solid
Melting point 85 °C (185 °F; 358 K)
Boiling point 163 °C (325 °F; 436 K)
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
GHS07

Acute toxicity (oral, dermal, inhalation), category 4 Skin irritation, category 2 Eye irritation, category 2 Skin sensitization, category 1 Specific Target Organ Toxicity – Single exposure, category 3

Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Synthesis

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Diphenyl-2-pyridylphosphine is prepared from 2-lithiopyridine with chlorodiphenylphosphine:[3]

Diphenyl-2-pyridylphosphine is an integral ligand in the Pd(II) catalyzed carbonylation of alkynes. The pi-donor ability of one bidentate P,N-coordinated ligand is highly stabilizing to the metal center.[4] While a second monodentate, N-protonated ligand transfers protons to the metal to be used in catalysis.[4] The role of the pyridyl group in this catalytic cycle is evident when the ligand is replaced by triphenyl phosphine, and rates of catalysis a greatly decreased. This catalytic process is an important step in the production of polymers, and other fine chemicals.[3]

RC2H + CO + XH + Pd cat → RCCH2COX + RCHCHCOX Pd cat = Pd(OAc)2/Ph2PPy/ CH3SO3H R=alkyl, aryl X=OH, OR’, NR2’ Scheme 1: Carbonylation of alkynes by cationic Pd(II) catalyst with a diphenyl-2-pyridylphosphine ligand.

References

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  1. ^ Kluwer, Alexander M.; Ahmad, Irshad; Reek, Joost N.H. (2007). "Improved synthesis of monodentate and bidentate 2- and 3-pyridylphosphines". Tetrahedron Letters. 48 (17): 2999. doi:10.1016/j.tetlet.2007.02.127.
  2. ^ Drent, E.; Arnoldy, P.; Budzelaar, P.H.M. (1994). "Homogeneous catalysis by cationic palladium complexes. Precision catalysis in the carbonylation of alkynes". Journal of Organometallic Chemistry. 475: 57. doi:10.1016/0022-328X(94)84007-5.
  3. ^ a b BrüCk, Andreas; Ruhland, Klaus (2009). "Investigation of the Dynamic Solution Behavior of Chloro(diene)rhodium(I) Phosphine Complexes with a Pendant Unsaturated Heterocycle at Phosphorus (2-pyridyl, 2-imidazyl; diene = COD, NBD)". Organometallics. 28 (22): 6383. doi:10.1021/om900324a.
  4. ^ a b Doherty, S; Knight, J; Bentham, M. (2006). "The first insoluble polymer-bound palladium complexes of 2-pyridyldiphenylphosphine: Highly efficient catalysts for the alkoxycarbonylation of terminal alkynes". Chem. Commun.: 88–90. doi:10.1039/b512556a.

Further reading

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  • Scrivanti, A.; Bertoldini, M.; Beghetto, V.; Matteoli, U.; Venzo, A. (2009). "Protonation of palladium(II)-allyl and palladium(0)-olefin complexes containing 2-pyridyldiphenylphosphine". Journal of Organometallic Chemistry. 694: 131. doi:10.1016/j.jorganchem.2008.09.063.