Chiral Polyurea with L-Lysinyl Residue Aimed for Optical Resolution

Abstract

Novel polyurea was synthesized from lysinyl residue, L-lysine-4-nitroanilide (L-Lys-4-NA) and 1,4-phenylene diisocyanate (1,4-PDI). The polyurea thus prepared gave durable self-standing membranes. The polyurea was converted into molecular recognition materials by using Z-D-Glu or Z-L-Glu as a print molecule. The Z-D-Glu molecularly imprinted membrane adsorbed the D-isomer of Glu in preference to the corresponding L-isomer and vice versa. Even though the polyurea consisted of L-lysinyl residue, both Z-D-Glu and Z-L-Glu worked as print molecules to construct molecular (chiral) recognition sites in the membrane. Those two types of molecularly imprinted membrane show chiral separation abilities, adopting a concentration gradient or an applied potential difference as a driving force for membrane transport.

Molecularly Imprinted Chitin Nanofiber Membranes: Multi-Stage Cascade Membrane Separation within the Membrane

“…Contrary to the previous study [24], both enantiomers, such as D-and L-enantiomer of Ac-Phe-OH, worked well as print molecules toward chitin, though chitin consists of N-acetylglucosamine units, which are connected β-1,4 linkage. Nanofiber membranes imprinted by Ac-D-Phe-OH showed Denantiomer adsorption selectivity and vice versa like molecularly imprinted membranes from cellulose acetate [22,30], oligopeptide tweezers [31] and chiral polyurea [32][33][34][35]. In the case of molecularly imprinted membranes from synthetic polymers with no chiral center, both enantiomers worked well as print molecules [36,37], as expected.…”