Norbornadiene is an

organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. The ...

and a bicyclic

hydrocarbon In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic, and their odors are usually weak or ex ...

. Norbornadiene is of interest as a metal-binding

ligand In coordination chemistry, a ligand is an ion or molecule (functional group) that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's electr ...

, whose complexes are useful for

homogeneous catalysis In chemistry, homogeneous catalysis is catalysis by a soluble catalyst in a solution. Homogeneous catalysis refers to reactions where the catalyst is in the same phase as the reactants, principally in solution. In contrast, heterogeneous catalysis ...

. It has been intensively studied owing to its high reactivity and distinctive structural property of being a

diene In organic chemistry a diene ( ) (diolefin ( ) or alkadiene) is a covalent compound that contains two double bonds, usually among carbon atoms. They thus contain two alk''ene'' units, with the standard prefix ''di'' of systematic nomenclature. ...

that cannot isomerize (isomers would be anti-Bredt

alkenes In organic chemistry, an alkene is a hydrocarbon containing a carbon–carbon double bond. Alkene is often used as synonym of olefin, that is, any hydrocarbon containing one or more double bonds.H. Stephen Stoker (2015): General, Organic, an ...

). Norbornadiene is also a useful dienophile in Diels-Alder reactions.

Synthesis

Norbornadiene can be formed by a Diels-Alder reaction between

cyclopentadiene Cyclopentadiene is an organic compound with the chemical formula, formula C5H6.LeRoy H. Scharpen and Victor W. Laurie (1965): "Structure of cyclopentadiene". ''The Journal of Chemical Physics'', volume 43, issue 8, pages 2765-2766. It is often ab ...

and

acetylene Acetylene (systematic name: ethyne) is the chemical compound with the formula and structure . It is a hydrocarbon and the simplest alkyne. This colorless gas is widely used as a fuel and a chemical building block. It is unstable in its pure ...

Reactions

Quadricyclane Quadricyclane is a strained, multi-cyclic hydrocarbon with the formula CH2(CH)6. A white volatile colorless liquid, it is highly strained molecule (78.7 kcal/mol). Isomerization of quadricyclane proceeds slowly at low temperatures.Petrov, V. A; ...

, a valence

isomer In chemistry, isomers are molecules or polyatomic ions with identical molecular formulae – that is, same number of atoms of each element – but distinct arrangements of atoms in space. Isomerism is existence or possibility of isomers. Iso ...

, can be obtained from norbornadiene by a

photochemical reaction Organic photochemistry encompasses organic reactions that are induced by the action of light. The absorption of ultraviolet light by organic molecules often leads to reactions. In the earliest days, sunlight was employed, while in more modern times ...

when assisted by a sensitizer such as

acetophenone Acetophenone is the organic compound with the formula C6H5C(O)CH3. It is the simplest aromatic ketone. This colorless, viscous liquid is a precursor to useful resins and fragrances. Production Acetophenone is formed as a byproduct of the cumene p ...

: :

Synthesis of quadricyclane from norbornadiene

The norbornadiene-quadricyclane couple is of potential interest for

solar energy Solar energy is radiant light and heat from the Sun that is harnessed using a range of technologies such as solar power to generate electricity, solar thermal energy (including solar water heating), and solar architecture. It is an essenti ...

storage when controlled release of the

strain energy In physics, the elastic potential energy gained by a wire during elongation with a tensile (stretching) force is called strain energy. For Linear elasticity, linearly elastic materials, strain energy is: : U = \frac 1 2 V \sigma \epsilon = \frac ...

stored in quadricyclane back to norbornadiene is made possible. Norbornadiene is reactive in

cycloaddition In organic chemistry, a cycloaddition is a chemical reaction in which "two or more Unsaturated hydrocarbon, unsaturated molecules (or parts of the same molecule) combine with the formation of a cyclic adduct in which there is a net reduction of th ...

reactions. Norbornadiene is also the starting material for the synthesis of

diamantane Diamantane (also called congressane) is an organic compound that is a member of the diamondoids. These are cage hydrocarbons with structures similar to a subunit of the diamond lattice. It is a colorless solid that has been a topic of research si ...

and

sumanene Sumanene is a polycyclic aromatic hydrocarbon and of scientific interest because the molecule can be considered a fragment of buckminsterfullerene. ''Suman'' means " sunflower" in both Hindi and Sanskrit. The core of the arene is a benzene ring an ...

and it is used as an

transfer agent for instance in reaction with 3,6-di-2-pyridyl-1,2,4,5-tetrazine.

As a ligand

Norbornadiene is a versatile ligand in

organometallic chemistry Organometallic chemistry is the study of organometallic compounds, chemical compounds containing at least one chemical bond between a carbon atom of an organic molecule and a metal, including alkali, alkaline earth, and transition metals, and so ...

, where it serves as a two-electron or four-electron donor. The norbornadiene analogue of

cyclooctadiene rhodium chloride dimer Cyclooctadiene rhodium chloride dimer is the organorhodium compound with the formula Rh2Cl2(C8H12)2, commonly abbreviated

hCl(COD) HCL may refer to: Science and medicine * Hairy cell leukemia, an uncommon and slowly progressing B cell leukemia * Harvard Cyclotron Laboratory, from 1961 to 2002, a proton accelerator used for research and development * Hollow-cathode lamp, a sp ...

or Rh2Cl2(COD)2. This yellow-orange, air-stable compound is a widely used precursor to homogeneous catalysis, h ...

is widely used in

. (Norbornadiene)molybdenum tetracarbonyl is used as a source of "Mo(CO)₄", exploiting the lability of the diene ligand in this case. Chiral, ''C''₂-symmetric dienes derived from norbornadiene have also been described. One example is tetracarbonyl(norbornadiene)chromium(0),{{cite journal , title = High yield synthesis and structures of some achiral and chiral (diphosphine)tetracarbonylchromium(0) chelate complexes with tetracarbonyl(norbornadiene)chromium(0) as complexation reagent , author1=Markus Strotmann , author2=Rudolf Wartchow , author3=Holger Butenschön , name-list-style=amp , journal =

Arkivoc ''Arkivoc'' (''Archive for Organic Chemistry'') is a peer-reviewed open access scientific journal covering all aspects of organic chemistry. It is published by the non-profit organization Arkat USA, which was established in 2000 through a personal ...

, pages = KK–1112F , year = 2004 , url = http://www.arkat-usa.org/ark/journal/2004/I13_Krohn/1112/KK-1112F.asp which is a useful source of " chromium tetracarbonyl," e.g. in reactions with phosphine

References

Dienes Bicyclic compounds Cyclopentenes

Synthesis

Reactions

As a ligand

See also

References