Enantioselective Trِgerʹs Base Synthetic Receptors

Synthetic receptors selective for the enantiomers of Trögerʹs base (1), a compound containing chiral nitrogen atoms, have been prepared by the molecular imprinting of 1 in methacrylic acid–ethylene glycol dimethacrylate copolymers. Spectroscopic evaluation of the self-assembly phase, prior to polymerization, demonstrated the formation of template-functional monomer adducts of Kdiss 0.7 ± 0.1 mM at 293 K in chloroform. The synthetic receptors demonstrated enantioselectivity when used as HPLC chiral stationary phases; enantioseparation factors (α) of up to 4.8 ± 0.2 are reported. Baseline resolution of racemic 1 was readily achieved. Furthermore, the influence of water on polymer–ligand selectivity was examined, which yielded insights into the molecular basis for ligand selectivity in these synthetic receptors.