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The effect of isotopic substitution on the chirality of a self-assembled helix

Nature Chemistry volume 3, pages 4246 (2011) | Download Citation

Abstract

N,N′,N″-trialkylbenzene-1,3,5-tricarboxamides (BTAs) self-assemble by means of strong, threefold α-helix-type intermolecular hydrogen bonding into well-defined, helical, one-dimensional columnar aggregates. When a stereogenic centre is introduced into the alkyl side chains of these BTAs, strong Cotton effects are observed in dilute apolar solutions, indicating the preference for one helical conformation over the other. Here, we report the creation of a helical sense preference in self-assembled BTAs by introducing deuterium/hydrogen isotope chirality into the alkyl side chains. We determine the relative stabilities of the left- and right-handed helical conformations of these deuterated supramolecular polymers by performing a conformational analysis. Our findings show that the results of deuterium/hydrogen substitution in BTA-based supramolecular polymers and helical polyisocyanates are very similar, although the formation mechanisms differ. The selectively deuterated BTAs discussed here represent the first example of supramolecular chirality resulting from isotope substitution.

  • Compound C33H54D3N3O3

    N1,N3,N5-Tri((S)-1-2H-octyl)-benzene-1,3,5-tricarboxamide

  • Compound C33H54D3N3O3

    N1,N3,N5-Tri((R)-1-2H-octyl)-benzene-1,3,5-tricarboxamide

  • Compound C33H57N3O3

    (S)-N1-(Octan-2-yl)-N3,N5-dioctylbenzene-1,3,5-tricarboxamide

  • Compound C33H57N3O3

    (R)-N1-(Octan-2-yl)-N3,N5-dioctylbenzene-1,3,5-tricarboxamide

  • Compound C33H57N3O3

    N1,N3,N5-Trioctylbenzene-1,3,5-tricarboxamide

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References

  1. 1.

    et al. Chiral studies across the spectrum of polymer science. Acc. Chem. Res. 34, 672–680 (2001).

  2. 2.

    et al. The macromolecular route to chiral amplification. Angew. Chem. Int. Ed. 38, 3138–3154 (1999).

  3. 3.

    , , & Macromolecular stereochemistry: a cooperative deuterium isotope effect leading to a large optical rotation. J. Am. Chem. Soc. 110, 4063–4065 (1988).

  4. 4.

    Cooperative conformational transitions in linear macromolecules undergoing chiral perturbations. Prog. Polym. Sci. 26, 667–720 (2001).

  5. 5.

    Theoretical study of helix induction on a polymer chain by hydrogen-bonding chiral molecules. Macromolecules 37, 605–613 (2004).

  6. 6.

    , & Helical polymers: synthesis, structures and functions. Chem. Rev. 109, 6102–6211 (2009).

  7. 7.

    , & Memory of macromolecular helicity assisted by interaction with achiral small molecules. Nature 399, 449–451 (1999).

  8. 8.

    & Amplification of chirality in dynamic systems. Angew. Chem. Int. Ed. 46, 8948–8968 (2007).

  9. 9.

    , , , & Asymmetrically substituted benzene-1,3,5-tricarboxamides: self-assembly and odd–even effects in the solid state and in dilute solution. Chem. Eur. J. 15, 2071–2080 (2009).

  10. 10.

    et al. Chiral amplification in columns of self-assembled N,N′,N″-tris((S)-3,7-dimethyloctyl)benzene-1,3,5-tricarboxamide in dilute solution. Chem. Lett. 292–293 (2000).

  11. 11.

    , & Insight into the mechanisms of cooperative self-assembly: the ‘sergeants-and-soldiers’ principle of chiral and achiral C3-symmetrical discotic triamides. J. Am. Chem. Soc. 130, 606–611 (2008).

  12. 12.

    , , & Sergeants-and-soldiers principle in chiral columnar stacks of disc-shaped molecules with C3 symmetry. Angew. Chem. Int. Ed. 36, 2648–2651 (1997).

  13. 13.

    , , , & ‘Majority-Rules’ operative in chiral columnar stacks of C3-symmetrical molecules. J. Am. Chem. Soc. 127, 5490–5494 (2005).

  14. 14.

    et al. Tuning the extent of chiral amplification by temperature in a dynamic supramolecular polymer. J. Am. Chem. Soc. 132, 611–619 (2010).

  15. 15.

    et al. Probing the limits of the majority-rules principle in a dynamic supramolecular polymer. J. Am. Chem. Soc. 132, 620–626 (2010).

  16. 16.

    et al. C 3-symmetrical self-assembled structures investigated by vibrational circular dichroism. Chirality 20, 1016–1022 (2008).

  17. 17.

    , , & Macromolecular stereochemistry: Helical Sense Preference in optically active polyisocyanates. Amplification of a conformational equilibrium deuterium isotope effect. J. Am. Chem. Soc. 111, 8850–8858 (1989).

  18. 18.

    , & Probing the solvent-assisted nucleation pathway in chemical self-assembly. Science 313, 80–83 (2006).

  19. 19.

    & Macromolecular stereochemistry: the out-of-proportion influence of optically active comonomers on the conformational characteristics of polyisocyanates. The sergeants and soldiers experiment. J. Am. Chem. Soc. 111, 6452–6454 (1989).

  20. 20.

    , , & Majority rules in the copolymerization of mirror image isomers. J. Am. Chem. Soc. 117, 4181–4182 (1995).

  21. 21.

    Amplification of chirality in helical supramolecular polymers: the majority rules principle. Macromolecules 37, 3894–3898 (2004).

  22. 22.

    et al. A helical polymer with a cooperative response to chiral information. Science 268, 1860–1866 (1995).

  23. 23.

    et al. Molecular-weight dependence of the optical rotation of poly((R)-2-deuterio-n-hexyl isocyanate). Macromolecules 28, 1016–1024 (1995).

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Acknowledgements

The authors thank M. M. L. Nieuwenhuizen and T. M. Hermans for assistance with 2D- and 2H-NMR, C. Duxbury and A. Heise from DSM Research for their support during the initial experiments, P. J. M. Stals for providing compounds 2 and 3 and M. M. Green for intriguing discussions. This work was supported by the NRSC-C foundation and the Netherlands Organization for Scientific Research (Spinoza-NWO).

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  1. Institute for Complex Molecular Systems and Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands

    • Seda Cantekin
    • , Diederik W. R. Balkenende
    • , Maarten M. J. Smulders
    • , Anja R. A. Palmans
    •  & E. W. Meijer

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Contributions

S.C. performed the experimental work and wrote most of the manuscript. D.W.R.B. contributed to the synthesis of the materials and M.M.J.S. to data analysis. A.R.A.P. and E.W.M. conceived and designed the concepts. All authors contributed to the conception of the experiments and discussion of the results, and commented on the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to Anja R. A. Palmans or E. W. Meijer.

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DOI

https://doi.org/10.1038/nchem.889