Triphenylphosphine dichloride

Triphenylphosphine dichloride
Names
IUPAC name
Dichlorotriphenyl-λ5-phosphane
Other names
Dichlorotriphenylphosphorane
Identifiers
2526-64-9 YesY
Properties
C18H15Cl2P
Molar mass 333.19 g/mol
Melting point 176 °C (349 °F; 449 K)[1] 85-100 °C[2]
Related compounds
Related compounds
Phosphoranes
Triphenylphosphine
Phosphorus trichloride
Phosphorus pentachloride
Phosphorus halides
Tetraphenylphosphonium chloride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
YesY verify (what is YesYN ?)
Infobox references

Triphenylphosphine dichloride, Ph3PCl2, is a chlorinating agent widely used in organic chemistry. Applications include the conversion of alcohols and ethers to alkyl chlorides, the cleavage of epoxides to vicinal dichlorides and the chlorination of carboxylic acids to acyl chlorides.[2]

Structure

In polar solvents such as acetonitrile or dichloromethane solutions, Ph3PCl2 adopts an ionic phosphonium salt structure, [Ph3PCl+]Cl,[3] whereas in non-polar solvents like diethyl ether it exists as a non-solvated trigonal bipyramidal molecule.[4] Two [Ph3PCl+] species can also adopt an unusual dinuclear ionic structureboth interacting with a Cl via long Cl–Cl contacts.[3]

Synthesis

Triphenylphosphine dichloride is usually prepared fresh by the addition of chlorine to triphenylphosphine.

Ph3P + Cl2 → Ph3PCl2

Both reagents are typically used in solution to ensure the correct stoichiometry.[2]

Alternatively, Ph3PCl2 can be obtained by chlorination of triphenylphosphine oxide with, for example, phosphorus trichloride, as in Grignard's original 1931 synthesis.[1]

References

  1. 1 2 V. Grignard, J. Savard (1931). Compt. Rend. 192: 592–5. Missing or empty |title= (help)
  2. 1 2 3 e-EROS Encyclopedia of Reagents for Organic Synthesis, doi:10.1002/047084289X.rt371
  3. 1 2 S. M. Godfrey, C. A. McAuliffe, R. G. Pritchard, J. M. Sheffield (1996). "An X-ray crystallorgraphic study of the reagent Ph3PCl2; not charge-transfer, R3P–Cl–Cl, trigonal bipyramidal or [R3PCl]Cl but an unusual dinuclear ionic species, [Ph3PCl+⋯Cl–⋯+CIPPH3]Cl containing long Cl–Cl contacts". Chem. Commun. (22): 2521–2522. doi:10.1039/CC9960002521.
  4. S. M. Godfrey, C. A. McAuliffe, J. M. Sheffield (1998). "Structural dependence of the reagent Ph3PCl2 on the nature of the solvent, both in the solid state and in solution; X-ray crystal structure of trigonal bipyramidal Ph3PCl2, the first structurally characterised five-coordinate R3PCl2 compound". Chem. Commun. (8): 921–922. doi:10.1039/a800820e.
This article is issued from Wikipedia - version of the Monday, November 02, 2015. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.