Ferrocenium tetrafluoroborate

Ferrocenium tetrafluoroborate is an organometallic compound with the formula [Fe(C5H5)2]BF4. This salt is composed of the cation [Fe(C5H5)2]+ and the tetrafluoroborate anion (BF
4
). The related hexafluorophosphate 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 salts are sometimes used as one-electron oxidizing agents, and the reduced product, ferrocene, is inert and readily separated from ionic products. The ferrocene–ferrocenium couple is often used as a reference in electrochemistry. The standard potential of ferrocene-ferrocenium is dependent on specific electrochemical conditions.[2]

Ferrocenium tetrafluoroborate
Names
IUPAC name
Ferrocenium tetrafluoroborate
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.156.161 Edit this at Wikidata
EC Number
  • 627-836-4
  • C1=C[CH-]C=C1.[Fe+3].C2=C[CH-]C=C2.F[B-](F)(F)F
Properties
C10H10BFeF4
Molar mass 272.84 g/mol
Appearance dark blue powder
Melting point 178 °C (352 °F; 451 K) (decomposes)
Solubility in acetonitrile Soluble[citation needed]
Hazards[1]
GHS labelling:
GHS05: Corrosive
Danger
H314
P280, P305+P351+P338, P310
Safety data sheet (SDS) External MSDS
Related compounds
Related compounds
Ferrocene
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Preparation

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Commercially available, this compound may be prepared by oxidizing ferrocene typically with ferric salts followed by addition of fluoroboric acid.[2] A variety of other oxidants work well also, such as nitrosyl tetrafluoroborate.[3] Many analogous ferrocenium salts are known.[4]

Structure

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According to X-ray crystallography, the structures of the metallocene component of FcBF4 and the parent ferrocene are very similar. The Fe-C distances in the cation are 209.5 pm, about 2% longer than the Fe-C distances in ferrocene. [5]

References

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  1. ^ "Ferrocenium tetrafluoroborate 482358". Sigma-Aldrich.
  2. ^ a b Connelly, N. G.; Geiger, W. E. (1996). "Chemical Redox Agents for Organometallic Chemistry". Chemical Reviews. 96 (2): 877–910. doi:10.1021/cr940053x. PMID 11848774.
  3. ^ Nielson, Roger M.; McManis, George E.; Safford, Lance K.; Weaver, Michael J. (1989). "Solvent and electrolyte effects on the kinetics of ferrocenium-ferrocene self-exchange. A reevaluation". J. Phys. Chem. 93 (5): 2152. doi:10.1021/j100342a086.
  4. ^ Le Bras, J.; Jiao, H.; Meyer, W. E.; Hampel, F.; Gladysz, J. A. (2000). "Synthesis, Crystal Structure, and Reactions of the 17-Valence-Electron Rhenium Methyl Complex [(η5-C5Me5)Re(NO)(P(4-C6H4CH3)3)(CH3)]+ B(3,5-C
    6
    H
    3
    (CF
    3
    )
    2
    )
    4
    : Experimental and Computational Bonding Comparisons with 18-Electron Methyl and Methylidene Complexes". J. Organomet. Chem. 616: 54–66. doi:10.1016/S0022-328X(00)00531-3.
  5. ^ Scholz, Stefan; Scheibitz, Matthias; Schödel, Frauke; Bolte, Michael; Wagner, Matthias; Lerner, Hans-Wolfram (2007). "Difference in Reactivity of Triel Halides EX3 Towards Ferrocene". Inorganica Chimica Acta. 360 (10): 3323–3329. doi:10.1016/j.ica.2007.03.049.