Helikal-chirale synthetische Polymere als neue Alignment Medien - New chiral alignment media based on helically chiral synthetic polymers

The goal of our work is to explore the potential of synthetic helically chiral polymers as alignment media for the determination of anisotropic NMR parameters such as residual dipolar couplings (RDC's) or residual chemical shift anisotropy (RCSA). The main focus will be on the development of chiral, non-racemic phases (lyotropic liquid crystalline (LLC) or crosslinked gels) allowing for the enantiodifferentiating measurement of these parameters in non-aqueous environments. The data aquired should be used to determine the relative and absolute configuration of compounds being of interest due to their biological activity (e.g. natural products) or their importance to understand stereochemical aspects of chemical reactions (e.g. reactive intermediates in asymmetric catalysis). Based on the results of the first funding period we intend to work with polyacetylenes, polyisocyanides and polyguanidines due to their known ability to form liquid crystalline phases and their favourable chiroptical properties. To combine alignment properties with enantiodifferentiation and to separate these two modes of action at the same time we intend to work on a number of different crosslinking strategies. In this context the development of thermoreversible gels will be of particular interest. This way the strain induced alignment technique (SAG) may be combined with enantiodifferentiation and sample preparation will be facilitated decisively.

DFG-Verfahren Forschungsgruppen

Teilprojekt zu FOR 934:  Relative and absolute configurations of dissolved molecules by NMR-spectroscopy in orienting media