Chemistry:Biferrocene
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| IUPAC name
1,1"-Biferrocene
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3D model (JSmol)
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PubChem CID
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| Properties | |
| C20H18Fe2 | |
| Molar mass | 370.054 g·mol−1 |
| 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 [77 °F], 100 kPa). | |
| Infobox references | |
Biferrocene is the organometallic compound with the formula [(C5H5)Fe(C5H4)]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.[1] Its one-electron oxidized derivative [(C5H5)Fe(C5H4)]2+ attracted attention as a prototypical mixed-valence compound.[2]
A related compound is biferrocenylene, [Fe(C5H4)2]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 [Fe(II)-Fe(III)] cation is a class II type (0.707 > α > 0) mixed-valence complex according to the Robin-Day classification.[2]
Derivatives
Aminophosphine ligands with biferroceno substituents have been prepared as catalysts for asymmetric allylic substitution[3] and asymmetric hydrogenation of alkenes.[4]
Related compounds
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.
- ↑ 2.0 2.1 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. http://dx.doi.org/10.1021/jo016249w.
- ↑ 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. PMID 24795493. PMC 4006446. http://dx.doi.org/10.1021/om401074a.
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