The ring current in cyclopropane
by Fowler, P. W.; Baker, J.; Lillington, M.
Mapping of induced current density using the coupled Hartree-Fock "ipsocentric" (CTOCD-DZ/ 6-31G**//RHF/6-31G**) method shows a ring current arising in the sigma framework of cyclopropane that is intense, diatropic and annular, and hence is consistent with the numerous literature attributions of sigma-aromaticity to this molecule. Localised orbital analysis shows that this current can be attributed to the set of three carbon-carbon bonds. In a similar analysis, the four carbon-carbon bonds of (planar constrained) cyclobutane are found to give rise to a central paratropic current. The maps are consistent with the view that cyclopropane is strongly sigma-aromatic, cyclobutane is weakly sigma-anti-aromatic, and the larger cycloalkane systems are essentially sigma-non-aromatic.
- Journal
- Theoretical Chemistry Accounts
- Volume
- 118
- Issue
- 1
- Year
- 2007
- Start Page
- 123-127
- URL
- https://dx.doi.org/10.1007/s00214-007-0253-2
- ISBN/ISSN
- 1432-2234; 1432-881X
- DOI
- 10.1007/s00214-007-0253-2