Fulvalenes

A fulvalene is a hydrocarbon obtained by formally cross-conjugating two rings through a common exocyclic double bond.[1] The name is derived from the si

Fulvalenes
Fulvalenes
Fulvalenes

A fulvalene is a hydrocarbon obtained by formally cross-conjugating two rings through a common exocyclic double bond.[1] The name is derived from the similarly structured fulvenes which lack one ring. Pentafulvalene (2) is also called simply fulvalene, the parent structure of this class. Triapentafulvalene (3) is also known as calicene from the words calix or chalice because of its wine-glass appearance.

In general, the parent fulvalenes are very unstable; for instance, the parent triafulvalene (1) has never been synthesized. On the other hand, stable fulvalenes can be obtained by proper substitution or benzannulation. Several members should be stabilized taking into account a dipolar mesomeric form with for instance sesquifulvalene 4, which can be thought of as a tropylium cation joined to a cyclopentadienyl anion (both stable and aromatic). In this compound the dipolar structure is calculated to contribute 23% to the total structure.

Fulvalenes as a ligand

Tungsten fulvalene complex

Fulvalenes forms stable organometallic complexes that can be formally considered derivatives of the dianion C10H82−, akin to two bonded cyclopentadienyl anions. Ferrocene was isolated from an attempted synthesis of pentafulvalene. Many compounds are known, especially for the early transition metals.[2] The bond joining the two rings in some fulvalene complexes can break reversibly.[3]

References

  1. ^ The Fulvalenes, Brian Halton, Eur. J. Org. Chem. 2005, 3391–3414 doi:10.1002/ejoc.200500231
  2. ^ Marta González-Maupoey, Vanessa Tabernero and Tomás Cuenca "Early transition metal fulvalene complexes" Coordination Chemistry Reviews 2009, Volume 253, Pages 1854-1881. doi:10.1016/j.ccr.2009.02.013
  3. ^ Boese, R. J.; Cammack, K.; Matzger, A. J.; Pflug, K.; Tolman, W. B.; Vollhardt, K. P. C.; Weidman, T. W. "Photochemistry of (Fulvalene)tetracarbonyldiruthenium and Its Derivatives: Efficient Light Energy Storage Devices" Journal of the American Chemistry Society 1997, volume 119, p. 6757-6773. doi:10.1021/ja9707062

Content Disclaimer

Informasi ini disarikan dari Wikipedia dan disajikan kembali untuk tujuan edukasi. Konten tersedia di bawah lisensi CC BY-SA 3.0. Kami tidak bertanggung jawab atas ketidakakuratan data yang bersumber dari kontribusi publik tersebut.

  1. The information displayed on this website is sourced in part or in whole from Wikipedia and has been adapted for the purpose of restating it. We strive to provide accurate and relevant information, however:
  2. There is no guarantee of absolute accuracy. Wikipedia is an open, collaborative project that can be edited by anyone, so information is subject to change.
  3. It is not intended to constitute professional advice. The content displayed is for informational and educational purposes only. For important decisions (e.g., medical, legal, or financial), please consult a professional.
  4. Content copyright. Wikipedia is licensed under the Creative Commons Attribution-ShareAlike License (CC BY-SA). This means that content may be reused with appropriate attribution and shared under a similar license.
  5. Responsible use. Any risk arising from the use of information from this website is entirely the responsibility of the user.