Ferrocenium hexafluorophosphate

Ferrocenium hexafluorophosphate is an organometallic compound with the formula [Fe(C5H5)2]PF6. This salt is composed of the cation [Fe(C5H5)2]+ and the hexafluorophosphate anion (PF
6
). The related tetrafluoroborate is also a popular reagent with similar properties. The ferrocenium cation is often abbreviated Fc+ or Cp2Fe+. The salt is deep blue in color and paramagnetic.

Ferrocenium hexafluorophosphate
Names
IUPAC name
Ferrocenium hexafluorophosphate
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.157.410 Edit this at Wikidata
  • InChI=1S/2C5H5.F6P.Fe/c2*1-2-4-5-3-1;1-7(2,3,4,5)6;/h2*1-5H;;/q;;-1;
    Key: PCJFEGIXYOQEQD-UHFFFAOYSA-N
  • [CH-]1C=CC=C1.[Fe+3].[CH-]1C=CC=C1.F[P-](F)(F)(F)(F)F
Properties
C10H10F6FeP
Molar mass 330.999 g·mol−1
Appearance dark blue powder
Density 1.808 g/cm3
Melting point (decomposes)
Solubility in acetonitrile Soluble[citation needed]
Structure
monoclinic
P21/c
a = 13.429(3) Å, b = 9.547(2) Å, c = 9.547(2) Å
α = 90°, β = 93.31(3)°, γ = 90°[2]
1215.8(5) Å3
Hazards
GHS labelling:
GHS07: Exclamation mark
Warning
H315, H319, H335
P261, P305+P351+P338
Safety data sheet (SDS) External MSDS
Related compounds
Other anions
Ferrocenium tetrafluoroborate
Related compounds
Ferrocene
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Ferrocenium salts are one-electron oxidizing agents, and the reduced product, ferrocene, is relatively inert and readily separated from ionic products. The ferrocene–ferrocenium couple is often used as a reference in electrochemistry. In acetonitrile solution that is 0.1 M in NBu4PF6, the Fc+/Fc couple is +0.641 V with respect to the normal hydrogen electrode.[3]

Preparation and structure

edit

Commercially available, this compound may be prepared by oxidizing ferrocene with ferric salts followed by addition of hexafluorophosphoric acid.[3]

The compound is monoclinic with well-separated cation and anion; the PF
6
may rotate freely. The average Fe-C bond length is 2.047 Å, which is virtually indistinguishable from the Fe-C distance in ferrocene.[2]

References

edit
  1. ^ "Ferrocenium hexafluorophosphate 388297". Sigma-Aldrich.
  2. ^ a b R. Martinez; A. Tiripicchio (1990). "Structure of ferrocenium hexafluorophosphate". Acta Crystallogr. C46 (2): 202–205. doi:10.1107/S0108270189005883.
  3. ^ a b Connelly, N. G.; Geiger, W. E. (1996). "Chemical Redox Agents for Organometallic Chemistry". Chem. Rev. 96 (2): 877–910. doi:10.1021/cr940053x. PMID 11848774.