Bicycloaromaticityinchemistry is an extension of the concept of homoaromaticity with two aromatic ring currents situated in a non-planar molecule and sharing the same electrons.[1] The concept originates with Melvin Goldstein who first reported about it in 1967.[2][3][4] It is of some importance in academic research. Using MO theory the bicyclo[3.2.2]nonatrienyl cation was predicted to be destabilised and the corresponding anion predicted to be stabilised by bicycloaromaticity.
Bicycloaromaticity has been studied by others in relation to the bicyclo[3.2.2]nonatrienyl cation [5][6] and in relation to specific carbanions.[7] In 2017 experimental evidence was reported for bicycloaromaticity (dual aromaticity) to exist in a bicyclic porphyrinoid.[1][8] This system has been described as aromatic with two ring systems of 26 (n=6) and 34 (n=8) electrons. By oxidation, another system was described as a triplet-state biradical, again considered aromatic by application of Baird's rule.
|
| ||||||||
|---|---|---|---|---|---|---|---|---|
| Intramolecular (strong) |
|
| ||||||
| Intermolecular (weak) |
| |||||||
| Bond cleavage |
| |||||||
| Electron counting rules |
| |||||||
