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.
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.
^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/jp9703871.{{cite journal}}: CS1 maint: multiple names: authors list (link)
