Polyacetylenes as a new alignment medium to measure residual dipolar couplings for chiral organic molecules

Liquid crystal solutions derived from polyacetylenes are used as an alignment medium to measure residual dipolar couplings (RDCs) in NMR for chiral organic molecules such as strychnine or menthol. The advantages of this new medium are the straightforward and easy synthesis and a reasonable small quadrupolar splitting of the deuterium signal indicating the desired alignment behavior. The obtained RDCs can be back calculated and used for structure verification. The spectra of the two enantiomers of menthol reveal different RDCs.