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| Norbornadiene | |
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| IUPAC name | Bicyclo[2.2.1]hepta-2,5-diene |
| Other names | 2,5-Norbornadiene |
| Identifiers | |
| CAS number | 121-46-0 |
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| 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 |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox references |
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Norbornadiene is a bicyclic hydrocarbon. The molecule can be envisioned as a 1,4-cyclohexadiene bridged in the para positions by a methylene group. The compound is related to norbornene in which one of the double bonds is saturated. Norbornadiene and related compounds are of great scientific interest because of the unusual geometry and high reactivity.
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Synthesis
The norbornadiene framework is based on a Diels-Alder reaction between a cyclopentadiene and an alkyne.
Reactions
Quadricyclane is a highly toxic norbornadiene isomer. It can be obtained from norbornadiene by a photochemical reaction when assisted by a sensitizer such as acetophenone. 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.1
Quadricyclane is very reactive towards dienophiles in cycloaddition reactions. Norbornadienes also form organometallic complexes, where it can act as a two-electron or four-electron donor. Sandwich compounds such as tetracarbonyl(norbornadiene)chromium(0),2 which is a useful reagent for transferring chromium tetracarbonyl to bidentate phosphine ligands, are known.
Norbornadiene is also the starting material for the synthesis of diamantane 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.3
References
- ^ 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:.
- ^ 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.
- ^ 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, http://www.mdpi.org/molecules/papers/60400353.pdf.
Further reading
- Quadricyclane in Organic Syntheses Coll. Vol. 6, p.962; Vol. 51, p.133 Online article
- Diamantane in Organic Syntheses Coll. Vol. 6, p.378; Vol. 53, p.30 Online Article
