Diphenyl-2-pyridylphosphine

Diphenyl-2-pyridylphosphine
IUPAC name Diphenyl-2-pyridylphosphine
Other names 2-(diphenylphosphino)-pyridine
Identifiers
CAS number	37943-90-1
PubChem	24864153
Jmol-3D images	Image 1
SMILES C1(P(C2=CC=CC=C2)C3=CC=CC=C3)=NC=CC=C1
Properties
Molecular formula	C17H14NP
Molar mass	263.27 g/mol
Appearance	white crystal
Melting point	85 °C, 358 K, 185 °F
Boiling point	163 °C, 436 K, 325 °F
Hazards
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
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

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 popular in chemical literature; however, tris-pyridylphosphines have been thoroughly investigated as ligands in transition metal complexes used for catalysis ⁷. Pyridylphosphines, including diphenyl-2-pyridylphosphine, may bind transition metals as monodentate or bidentate ligands4. Diphenyl-2-pyridylphosphine behaves as a P-bound monodentate ligand³, 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 homogenous catalysis.^[2]

Synthesis

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.^[5] 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 decreased³. 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 ligand⁶.

References

1. ^ Kluwer, A; Ahmad, I; Reek, J. Tetrahedron Lett. 2007, 48, 17, 2999-3001. DOI:10.1016/j.tetlet.2007.02.127. Improved synthesys of monodentate and bidentate 2- and 3-pyridylphosphines.
2. ^ Drent, E; Arnoldy, P; Budzelaar, R.H.M. "Homogenous catalysis by cationic palladium complexes. Precision catalysis in the carbonylation of alkynes" J. Organomet. Chem. 1994, volume 475, 57-63. doi:10.1016/0022-328X(94)84007-5.
3. ^ ^{a b} Bruck, A; Ruhlan, K. J. "Investigation of dynamic solution of chloro(diene)rhodium(I)phosphine complexes with a pendant unsaturated heterocycle ar phosphorous (2-pyridyl, 2-imidazyl; diene = COD, NBD)" J. Organomet. Chem. 2009, 28,22,638-6401. doi:10.1021/om9003249
4. ^ Doherty, S; Knight, J; Bentham, M. Chem. Commun. 2006, 88-90.
5. ^ Doherty, S; Knight, J; Bentham, M. Chem. Commun. 2006, 88-90.

See also

• Scrivanti, A; Bertoldini, M; et al. J. Organometallic Chem. 2009, 694, 131-136. DOI: 10.1016/j.jorganchem.2008.09.063. Protonation of palladium (II)-allyl and palladium (0)-olefin complexes containing 2-pyridyldiphenylphosphine