Mobius ladder molecule

Figure 16. Some topologically chiral molecular graphs, (a) The Simmons-Paquette molecule.74 (b) Walba s 3-rung Mobius ladder molecule.75 (c) [4](l,l )[4](3,3 )[3](4 4 )-Ferrocenophan-16-one.76 (d) Triple-layered naphthalenophane.78 Unlabeled vertices represent carbon atoms, and hydrogen atoms are suppressed for clarity. Only one enantiomer of each molecule is shown.

The first flexible, topologically chiral K3j3 molecule is the so-called three-rung Mobius ladder 63 (Fig. 15). It was synthesized by D. M. Walba et al. in 1982 [85] and is represented on Fig. 15, together with several presentations of its graph (64-66). It is important to notice that the rungs of the ladder are different from... 

A directed knot synthesis relying upon the Mobius strip principle was conceived by Schill and coworkers [41-50] who synthesized the doubly bridged tetraamino-p-benzoquinone 9. Connection of three such molecules by long chains should give the molecular ladder 10, precursor of the three half-twist-containing Mobius strip 11 (Figure 8). 

Randomness, strongly related to the threefold twisting required for precursors like 8, may be reduced or even eliminated if the starting ladder-shaped molecule contains three half-twists prior to cyclisation. In the latter case, the Mobius strip approach may become a true directed synthesis. 

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