Conclusions
- The Nodes in single half-twist
Möbius systems may alleviate by overtwisting
and/or C-H mixing.
- The properties of Double-twist
Möbius/Listing Conjugated cycles are conceptually easier
than single-twist systems, but differ in subtle but
significant ways from them.
- Double-twist systems (and pericyclic
transition states) are highly chiral and often also
highly aromatic.
- Although loss of π-resonance energy
is nominally higher than for single-twist systems, much if
not all is recovered by writhing into 3D
space.
- Additionally the Twist/Writhe may allow
much relief of steric and angular strain
- A substituted C14 annulene
and C10 pericyclic electrocyclic look good
candidates for synthetic attention
- Higher order twists up to six might be
chemically feasible but are probably not
aromatic.
- Doubly-aromatic, 2/4-fold-twisted
Möbius/Listing conjugated manifolds using
allenes/alkynes for synthetic
investigation.
- Molecules with large amounts of
writhe as well as twist (supercoiled systems) worthy
of more attention.
© H. S. Rzepa, 2006.