Triphenylphosphine dichloride

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Triphenylphosphine dichloride
Structural formula Dichlorotriphenylphosphine-2D.png
Structural formula
Ball-and-stick model Dichlorotriphenylphosphine-molecular-from-xtal-1998-3D-balls.png
Ball-and-stick model
Space-filling model Dichlorotriphenylphosphine-molecular-from-xtal-1998-3D-vdW.png
Space-filling model
Names
Preferred IUPAC name
Dichlorotri(phenyl)-λ5-phosphane
Other names
Dichlorotriphenylphosphorane
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.107.819 OOjs UI icon edit-ltr-progressive.svg
PubChem CID
UNII
  • InChI=1S/C18H15Cl2P/c19-21(20,16-10-4-1-5-11-16,17-12-6-2-7-13-17)18-14-8-3-9-15-18/h1-15H X mark.svgN
    Key: ASWXNYNXAOQCCD-UHFFFAOYSA-N X mark.svgN
  • ClP(Cl)(c1ccccc1)(c1ccccc1)c1ccccc1
Properties
(C6H5)3PCl2
Molar mass 333.19 g·mol−1
AppearanceColorless solid
Melting point 176 °C (349 °F; 449 K) [1] , 85-100 °C [2] , 85 °C (decomposes) [3]
Reacts
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
May cause severe skin and eye injury and cancer. If the chemical is let to enter the drains, there is a risk of explosion. [3]
GHS labelling:
GHS-pictogram-flamme.svg GHS-pictogram-acid.svg GHS-pictogram-silhouette.svg
Danger
H228, H314, H350
P210, P240, P241, P260, P264, P280, P301+P330+P331, P302+P361+P354, P304+P340, P305+P354+P338, P316, P321, P363, P370+P378, P405, P501
Related compounds
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Triphenylphosphine dichloride is an organophosphorus compound with the chemical formula (C6H5)3PCl2, often abbreviated as Ph3PCl2, where Ph is phenyl. It 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]

Contents

Structure

In polar solvents such as acetonitrile, Ph3PCl2 adopts an ionic phosphonium salt structure, [Ph3PCl]+Cl− (chlorotriphenylphosphonium chloride), [4] whereas in non-polar solvents like diethyl ether it exists as a non-solvated trigonal bipyramidal molecule. [5] Two [Ph3PCl]+ species can also adopt an unusual dinuclear ionic structure—both interacting with a Cl− via long Cl–Cl contacts. [4]

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]

Ph3PCl2 can also be obtained by the reaction of iodobenzene dichloride (PhICl2) and triphenylphosphine. [6]

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 Victor Grignard, J. Savard (1931). Comptes rendus de l'Académie des sciences . 192: 592–5.{{cite journal}}: 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 https://www.sigmaaldrich.com/GB/en/sds/aldrich/378755?userType=anonymous
  4. 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". Chemical Communications (22): 2521–2522. doi:10.1039/CC9960002521.
  5. ↑ 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.
  6. ↑ Carle, M. S., Shimokura, G. K. and Murphy, G. K. (2016), Iodobenzene Dichloride in the Esterification and Amidation of Carboxylic Acids: In-Situ Synthesis of Ph3PCl2. Eur. J. Org. Chem., 2016: 3930–3933. {{DOI:10.1002/ejoc.201600714}}
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