Biferrocene
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IUPAC name 1,1"-Biferrocene | |
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Chemical formula | 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
- 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.
- ^ a b 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.
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CpH | He | ||||||||||||||||||||
LiCp | Be | B | CpMe | N | C5H4O | F | Ne | ||||||||||||||
NaCp | MgCp2 | Al | Si | P | S | Cl | Ar | ||||||||||||||
K | CaCp2 | ScCp3 | TiCp2Cl2 (TiCp2Cl)2 | VCp2 VCpCh | CrCp2 (CrCp(CO)3)2 | MnCp2 | FeCp2 Fe(η5-C5H4Li)2 | CoCp2 CoCp(CO)2 | NiCp2 | Cu | Zn | Ga | Ge | As | Se | Br | Kr | ||||
Rb | Sr | Y(C5H5)3 | ZrCp2Cl2 ZrCp2ClH | NbCp2Cl2 | MoCp2H2 MoCp2Cl2 | Tc | RuCp2 RuCp(PPh3)2Cl | RhCp2 | PdCp(C3H5) | Ag | Cd | InCp | SnCp2 | Sb | Te | I | Xe | ||||
Cs | Ba | * | LuCp3 | HfCp2Cl2 | Ta | (WCp(CO)3)2 | ReCp2H | OsCp2 | IrCp2 | Pt | Au | Hg | TlCp | PbCp2 | Bi | Po | At | Rn | |||
Fr | Ra | ** | Lr | Rf | Db | Sg | Bh | HsCp2 | Mt | Ds | Rg | Cn | Nh | Fl | Mc | Lv | Ts | Og | |||
* | LaCp3 | CeCp3 | PrCp3 | NdCp3 | PmCp3 | SmCp3 | Eu | Gd | Tb | DyCp3 | Ho | ErCp3 | TmCp3 | YbCp3 | |||||||
** | Ac | ThCp3 ThCp4 | Pa | UCp4 | Np | Pu | Am | Cm | Bk | Cf | Es | Fm | Md | No |