Norbornadiene

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Norbornadiene
Norbornadiene.png
Norbornadiene2.png
Norbornadiene3.png
Names
IUPAC name
Bicyclo[2.2.1]hepta-2,5-diene
Other names
2,5-Norbornadiene
Identifiers
3D model (JSmol)
ECHA InfoCard 100.004.066
EC Number 204-472-0
Properties
C7H8
Molar mass 92.14 g/mol
Density 0.906 g/cm3
Melting point −19 °C (−2 °F; 254 K)
Boiling point 89 °C (192 °F; 362 K)
Insoluble
Hazards
R-phrases (outdated) R11
S-phrases (outdated) S9 S16 S29 S33
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Norbornadiene is a bicyclic hydrocarbon and an organic compound. Norbornadiene is of interest as a metal-binding ligand, whose complexes are useful for homogeneous catalysis, it has been intensively studied owing to its high reactivity and distinctive structural property of being a diene that cannot isomerize (isomers would be anti-Bredt olefins). Norbornadiene is also a useful dienophile in Diels-Alder reactions.

Synthesis[edit]

Norbornadiene can be formed by a Diels-Alder reaction between cyclopentadiene and acetylene.

Norbornadiene synthesis

Reactions[edit]

Quadricyclane, a valence isomer, can be obtained from norbornadiene by a photochemical reaction when assisted by a sensitizer such as acetophenone:[1]

Synthesis of quadricyclane from norbornadiene.png

The norbornadiene-quadricyclane couple is of potential interest for solar energy storage when controlled release of the strain energy stored in quadricyclane back to norbornadiene is made possible.[2]

Norbornadiene is reactive in cycloaddition reactions. Norbornadiene is also the starting material for the synthesis of diamantane[3] and sumanene and it is used as an acetylene transfer agent for instance in reaction with 3,6-di-2-pyridyl-1,2,4,5-tetrazine.[4]

As a ligand[edit]

Norbornadiene is a versatile ligand in organometallic chemistry, where it serves as a two-electron or four-electron donor, the norbornadiene analogue of cyclooctadiene rhodium chloride dimer is widely used in homogeneous catalysis. Chiral, C2-symmetric dienes derived from norbornadiene have also been described.[5]

One example is tetracarbonyl(norbornadiene)chromium(0),[6] which is a useful source of "chromium tetracarbonyl," e.g. in reactions with phosphine ligands.

See also[edit]

  • Norbornane a saturated compound with the same carbon skeleton.
  • Norbornene a compound with the carbon same skeleton, but with one less double bond.

References[edit]

  1. ^ Smith, Claiborune D. (1988). "Quadricyclane". Organic Syntheses. ; Collective Volume, 6, p. 962 
  2. ^ Gregory W. Sluggett; Nicholas J. Turro & Heinz D. Roth (1997). "Rh(III)-Photosensitized Interconversion of Norbornadiene and Quadricyclane". J. Phys. Chem. A. 101 (47): 8834–8838. doi:10.1021/jp972007h. 
  3. ^ Diamantane in Organic Syntheses Coll. Vol. 6, p.378; Vol. 53, p.30 Online Article
  4. ^ Ronald N. Warrener & Peter A. Harrison (2001). "π-Bond Screening in Benzonorbornadienes: The Role of 7-Substituents in Governing the Facial Selectivity for the Diels-Alder Reaction of Benzonorbornadienes with 3,6-Di(2-pyridyl)-s-Tetrazine" (PDF). Molecules. 6 (4): 353–369. doi:10.3390/60400353. 
  5. ^ Ryo Shintani, Tamio Hayashi "Chiral Diene Ligands for Asymmetric Catalysis" Aldrich Chimica Acta 2009, vol. 42, number 2, pp. 31-38.
  6. ^ Markus Strotmann; Rudolf Wartchow & Holger Butenschön (2004). "High yield synthesis and structures of some achiral and chiral (diphosphine)tetracarbonylchromium(0) chelate complexes with tetracarbonyl(norbornadiene)chromium(0) as complexation reagent". Arkivoc: KK–1112F.