different molecular 8 s molecules were obtained with a ratio of 56:37:7, as shown
in Fig. 21. Owing to the temperature controlled chemoselective reaction, they
successfully separated the chiral molecular 8 molecules from the racemic system
of a [2]rotaxane based on sulfonamide. The exact positions of the thread’s two
ends were both determined by experimental data (MS and NMR) and molecular
dynamics studies. The chirality of molecular 8 depended on both the cycloenantiomerism and helical chirality of the molecular 8 architecture. Hence the pure
enantiomers of molecular 8 exhibited obvious Cotton effects. This work not only
provided us with a new kind of molecular structure but also explained the chiral
optical properties of mechanically interlocked molecular 8 structures in detail.
Fig. 20 Synthetic route of pseudo[1]catenane and gemini-catenanes based on pillar[5]arene.
*Only (pS)-enantiomers are shown for clarity purpose [42]
Fig. 21 Construction of molecular figures-of-eight and three different molecular 8 s were obtained
with a ratio of 56:37:7 from left to right [43]
100
S.-H. Li et al.