Speaker
Description
Anisotropic NMR parameters become increasingly important in organic structure elucidation for the determination of conformations and relative configuration of natural products, synthesized compounds and catalysts.[1]
For anisotropic NMR parameters to be obtained suitable alignment media are necessary. The use of lyotropic liquid crystals from helically chiral polymers is especially intriguing in that respect as they additionally allow for enantiodiscrimination.[2]
We have recently synthesized several homopolypepides[3], which form lyotropic liquid crystals, are suitable for the measurement of anisotropic NMR observables, show excellent enantiodiscrimination and furthermore induce different orientations at different temperatures. They are thus considered thermoresponsive.
The possibility to induce different orientation at different temperatures thus alleviates the need to use more than one alignment medium in cases of ambiguity.
The intriguing properties of these new thermoresponsive alignment media will be described in this presentation.
References:
[1] For reviews see: : C. M. Thiele, Eur. J. Org. Chem. 2008, 5673-5685; V. Schmidts, Magn. Reson. Chem. 2017, 55, 54-60.
[2] For review see: P. Lesot, J. Courtieu, Prog. Nucl. Magn. Reson. Spectrosc. 2009, 55, 128-159.
[3] M. Schwab, D. Herold, C. M. Thiele, Chem. Eur. J. 2017, 23, 14576-14584; M. Schwab, V. Schmidts, C. M. Thiele, Chem. Eur. J. 2018, 24, 14373-14377; S. Jeziorowski, C. M. Thiele, Chem. Eur. J. 2018, 24, 15631-15637.