Preferred Label : homoaromatic;
IUPAC definition : Whereas in an aromatic molecule there is continuous overlap of p-orbitals over a cyclic
array of atoms, in a homoaromatic molecule there is a formal discontinuity in this
overlap resulting from the presence of a single sp 3 hybridized atom at one or several
positions within the ring; p-orbital overlap apparently bridges these sp 3 centres,
and features associated with aromaticity are manifest in the properties of the compound.
Pronounced homoaromaticity is not normally associated with neutral molecules, but
mainly with species bearing an electrical charge, e.g. the 'homotropylium' cation,
(C sub 8 /sub H sub 9 /sub sup class plus /sup ): In bis, tris, (etc.) homoaromatic
species, two, three, (etc.) single sp 3 centres separately interrupt the π-electron
system.;
Origin ID : H02839;
See also
Whereas in an aromatic molecule there is continuous overlap of p-orbitals over a cyclic
array of atoms, in a homoaromatic molecule there is a formal discontinuity in this
overlap resulting from the presence of a single sp 3 hybridized atom at one or several
positions within the ring; p-orbital overlap apparently bridges these sp 3 centres,
and features associated with aromaticity are manifest in the properties of the compound.
Pronounced homoaromaticity is not normally associated with neutral molecules, but
mainly with species bearing an electrical charge, e.g. the 'homotropylium' cation,
(C sub 8 /sub H sub 9 /sub sup class plus /sup ): In bis, tris, (etc.) homoaromatic
species, two, three, (etc.) single sp 3 centres separately interrupt the π-electron
system.
