kinetically stoppered in solution, there is compelling evidence to suggest that the
same folded superstructure with extended donor–acceptor stacking contributes
heavily to the dynamic solution-state structure. This folding motif influences the
physical size of the corresponding macromolecules, making them more compact
than their parent threads, even as they double their molecular weights as a result of
the added rings. By systematically investigating a large family of homologous
oligorotaxanes, we have been able to describe in more detail the nature of their
translational isomerism and dynamics. Computational input on these polyelectrolytes appears to be highly sensitive to the chosen methodology; conflicting results
on the degree of folding call for deeper investigation by chemical theorists.
The generality of this folding phenomenon and potential utility of mixed-stack
packing will make donor–acceptor mechanically interlaced foldamers attractive to
materials scientists interested in tuning the mechanical and multiferroic properties
of charge-transfer materials, either in solution or the solid state. For example, could
this accordion-like folding motif be leveraged in the context of molecular springs or
elastomers? Could the ferroelectric properties of crystalline donor–acceptor mixed
stacks be translated to plastics by appropriately engineering the secondary structures and transition temperatures of these polymers? Indeed, the future holds many
exciting possibilities for this emerging class of compounds that lie at the intersection of mechanically interlocked molecules and synthetic foldamers.
References
1. Gan Q, Ferrand Y, Bao C, Kauffmann B, Gre ´lard A, Jiang H, Huc I (2011) Science 331:1172
2. Zhang K-D, Zhao X, Wang G-T, Liu Y, Zhang Y, Lu H-J, Jiang X-K, Li Z-T (2011) Angew
Chem Int Ed 50:9866
3. Zhang K-D, Zhao X, Wang G-T, Liu Y, Zhang Y, Lu H-J, Jiang X-K, Li Z-T (2012)
Tetrahedron 68:4517
4. Gellman SH (1998) Acc Chem Res 31:173
5. Hill DJ, Mio MJ, Prince RB, Hughes TS, Moore JS (2001) Chem Rev 101:3893
6. Licini G, Prins LJ, Scrimin P (2005) Eur J Org Chem 2005:969
7. Li X, Yang D (2006) Chem Commun 2006 (32): 3367
8. Seebach D, Gardiner J (2008) Acc Chem Res 41:1366
9. Horne WS, Gellman SH (2008) Acc Chem Res 41:1399
10. Li Z-T, Hou J-L, Li C (2008) Acc Chem Res 41:1343
11. Pilsl LKA, Reiser O (2011) Amino Acids 41:709
12. Martinek TA, Fu ¨lo ¨p F (2012) Chem Soc Rev 41:687
13. Huc I (2004) Eur J Org Chem 2004:17
14. Smaldone RA, Moore JS (2008) Chem Eur J 14:2650
15. Saraogi I, Hamilton AD (2009) Chem Soc Rev 38:1726
16. Haldar D, Schmuck C (2009) Chem Soc Rev 38:363
17. Zhang D-W, Zhao X, Hou J-L, Li Z-T (2012) Chem Rev 112:5271
18. Cheng RP (2004) Curr Opin Struct Biol 14:512
19. Goodman CM, Choi S, Shandler S, DeGrado WF (2007) Nat Chem Biol 3:252
20. Guichard G, Huc I (2011) Chem Commun 47:5933
21. Roy A, Prabhakaran P, Baruah PK, Sanjayan GJ (2011) Chem Commun 47:11593
Mechanically Interlaced and Interlocked Donor–Acceptor Foldamers
291
same folded superstructure with extended donor–acceptor stacking contributes
heavily to the dynamic solution-state structure. This folding motif influences the
physical size of the corresponding macromolecules, making them more compact
than their parent threads, even as they double their molecular weights as a result of
the added rings. By systematically investigating a large family of homologous
oligorotaxanes, we have been able to describe in more detail the nature of their
translational isomerism and dynamics. Computational input on these polyelectrolytes appears to be highly sensitive to the chosen methodology; conflicting results
on the degree of folding call for deeper investigation by chemical theorists.
The generality of this folding phenomenon and potential utility of mixed-stack
packing will make donor–acceptor mechanically interlaced foldamers attractive to
materials scientists interested in tuning the mechanical and multiferroic properties
of charge-transfer materials, either in solution or the solid state. For example, could
this accordion-like folding motif be leveraged in the context of molecular springs or
elastomers? Could the ferroelectric properties of crystalline donor–acceptor mixed
stacks be translated to plastics by appropriately engineering the secondary structures and transition temperatures of these polymers? Indeed, the future holds many
exciting possibilities for this emerging class of compounds that lie at the intersection of mechanically interlocked molecules and synthetic foldamers.
References
1. Gan Q, Ferrand Y, Bao C, Kauffmann B, Gre ´lard A, Jiang H, Huc I (2011) Science 331:1172
2. Zhang K-D, Zhao X, Wang G-T, Liu Y, Zhang Y, Lu H-J, Jiang X-K, Li Z-T (2011) Angew
Chem Int Ed 50:9866
3. Zhang K-D, Zhao X, Wang G-T, Liu Y, Zhang Y, Lu H-J, Jiang X-K, Li Z-T (2012)
Tetrahedron 68:4517
4. Gellman SH (1998) Acc Chem Res 31:173
5. Hill DJ, Mio MJ, Prince RB, Hughes TS, Moore JS (2001) Chem Rev 101:3893
6. Licini G, Prins LJ, Scrimin P (2005) Eur J Org Chem 2005:969
7. Li X, Yang D (2006) Chem Commun 2006 (32): 3367
8. Seebach D, Gardiner J (2008) Acc Chem Res 41:1366
9. Horne WS, Gellman SH (2008) Acc Chem Res 41:1399
10. Li Z-T, Hou J-L, Li C (2008) Acc Chem Res 41:1343
11. Pilsl LKA, Reiser O (2011) Amino Acids 41:709
12. Martinek TA, Fu ¨lo ¨p F (2012) Chem Soc Rev 41:687
13. Huc I (2004) Eur J Org Chem 2004:17
14. Smaldone RA, Moore JS (2008) Chem Eur J 14:2650
15. Saraogi I, Hamilton AD (2009) Chem Soc Rev 38:1726
16. Haldar D, Schmuck C (2009) Chem Soc Rev 38:363
17. Zhang D-W, Zhao X, Hou J-L, Li Z-T (2012) Chem Rev 112:5271
18. Cheng RP (2004) Curr Opin Struct Biol 14:512
19. Goodman CM, Choi S, Shandler S, DeGrado WF (2007) Nat Chem Biol 3:252
20. Guichard G, Huc I (2011) Chem Commun 47:5933
21. Roy A, Prabhakaran P, Baruah PK, Sanjayan GJ (2011) Chem Commun 47:11593
Mechanically Interlaced and Interlocked Donor–Acceptor Foldamers
291