Biferrocene - Misplaced Pages

Organometallic compound

Biferrocene
Names

IUPAC name 1,1"-Biferrocene
Identifiers
CAS Number	1287-38-3
3D model (JSmol)	Interactive image
ChemSpider	10157133
PubChem CID	11984633
InChI InChI=1S/C10H8.2C5H5.2Fe/c1-2-6-9(5-1)10-7-3-4-8-10;21-2-4-5-3-1;;/h1-8H;21-5H;;/q-6;2*-1;;Key: CEMHVYUXQJEPPO-UHFFFAOYSA-N
SMILES C1=CC=C1..C2=C(C=C2)(C=C3)C=C3..C1=CC=C1
Properties
Chemical formula	C₂₀H₁₈Fe₂
Molar mass	370.054 g·mol
Appearance	dark orange solid
Melting point	239–240 °C (462–464 °F; 512–513 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C , 100 kPa). Infobox references

Chemical compound

Biferrocene is the organometallic compound with the formula ₂. It is the product of the formal dehydrocoupling of ferrocene, analogous the relationship between biphenyl and benzene. It is an orange, air-stable solid that is soluble in nonpolar organic solvents.

Biferrocene can be prepared by the Ullmann coupling of iodoferrocene. Its one-electron oxidized derivative ₂ attracted attention as a prototypical mixed-valence compound.

A related compound is biferrocenylene, ₂ wherein all cyclopentadienyl rings are coupled. Formally, biferrocene is derived from one fulvalene ligand, and biferrocenylene is derived from two.

Reactions

Biferrocene can easily be converted into a mixed-valence complex, which is called biferrocenium. This cation is a class II type (0.707 > α > 0) mixed-valence complex according to the Robin-Day classification.

Derivatives

Aminophosphine ligands with biferroceno substituents have been prepared as catalysts for asymmetric allylic substitution and asymmetric hydrogenation of alkenes.

Related compounds

Bis(fulvalene)diiron

References

M. D. Rausch (1961). "Ferrocene and Related Organometallic π-Complexes. IV. Some Ullmann Reactions of Haloferrocenes". J. Org. Chem. 26 (6): 1802–1805. doi:10.1021/jo01065a026.
^ Cowan, D. O.; LeVanda, C.; Park, J.; Kaufman, F. (1973). "Organic Solid State. VIII. Mixed-Valence Ferrocene Chemistry". Acc. Chem. Res. 6: 1–7. doi:10.1021/ar50061a001.
Xiao, Li; Weissensteiner, Walter; Mereiter, Kurt; Widhalm, Michael (2002-03-08). "Novel Chiral Biferrocene Ligands for Palladium-Catalyzed Allylic Substitution Reactions". The Journal of Organic Chemistry. 67 (7): 2206–2214. doi:10.1021/jo016249w. ISSN 0022-3263. PMID 11925230.
Zirakzadeh, Afrooz; Groß, Manuela A.; Wang, Yaping; Mereiter, Kurt; Weissensteiner, Walter (2014-04-09). "Walphos versus Biferrocene-Based Walphos Analogues in the Asymmetric Hydrogenation of Alkenes and Ketones". Organometallics. 33 (8): 1945–1952. doi:10.1021/om401074a. ISSN 0276-7333. PMC 4006446. PMID 24795493.