- Norbornadiene
-
Norbornadiene 
Bicyclo[2.2.1]hepta-2,5-dieneOther names2,5-NorbornadieneIdentifiers CAS number 121-46-0 
PubChem 8473 EC number 204-472-0 Jmol-3D images Image 1 - C1C2C=CC1C=C2
Properties Molecular formula C7H8 Molar mass 92.14 g/mol Density 0.906 g/cm³ Melting point -19 °C, 254 K, -2 °F
Boiling point 89 °C, 362 K, 192 °F
Solubility in water Insoluble Hazards R-phrases R11 S-phrases S9 S16 S29 S33 
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)Infobox references Norbornadiene is an organic compound. This bicyclic hydrocarbon is the most stable diolefin derived from the norbornane and norbornene. Norbornadiene is primarily of interest as a ligand in homogeneous catalysis, but it has been heavily studied due to its high reactivity and distinctive structural property of being a diene that cannot isomerize.
Contents
Synthesis
Norbornadiene forms via the Diels-Alder reaction between a cyclopentadiene and an alkyne.
Reactions
Quadricyclane, a valence isomer, can be obtained from norbornadiene by a photochemical reaction when assisted by a sensitizer such as acetophenone:[1]
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
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.
References
- ^ Smith, Claiborune D. (1988), "Quadricyclane", Org. Synth., http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv6p0962; Coll. Vol. 6: 962
- ^ Gregory W. Sluggett, Nicholas J. Turro, and Heinz D. Roth (1997). "Rh(III)-Photosensitized Interconversion of Norbornadiene and Quadricyclane". J. Phys. Chem. A 101: 8834–8838. doi:10.1021/jp972007h.
- ^ Diamantane in Organic Syntheses Coll. Vol. 6, p.378; Vol. 53, p.30 Online Article
- ^ Ronald N. Warrener and 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". Molecules 6: 353–369. doi:10.3390/60400353. http://www.mdpi.org/molecules/papers/60400353.pdf.
- ^ Ryo Shintani, Tamio Hayashi "Chiral Diene Ligands for Asymmetric Catalysis" Aldrich Chimica Acta 2009, vol. 42, number 2, pp. 31-38.
- ^ Markus Strotmann, Rudolf Wartchow, and 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. http://www.arkat-usa.org/ark/journal/2004/I13_Krohn/1112/KK-1112F.asp.
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