Preparation of optically active poly(N-propargylamide) gels and their application in chiral recognition

Abstract

Optically active gels based on helical N-propargylamide polymers were prepared using a one-pot two-step methodology: the pre-formation of helical N-propargylamide copolymer (defined as N=N-HP) and the preparation of gels bearing the helical copolymers. To prepare N=N-HP, N-propargylamide M1, which contained -N=Nfunctional group, and M2, which provided helical polymer chains for the resulting copolymers, underwent copolymerizations in the presence of (nbd)Rh+B-(C6H5)4 as a catalyst. -N=N- groups in N=N-HP acted as an initiator to induce the free radical polymerization of styrene, yielding the designed gels. Trimethylol propane triacrylate (TMPTA) was used to improve the cross-linking degree of the gels. The obtained gels were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and circular dichroism (CD) spectroscopy measurements. The gels showed high optically activity, resulting from the helical structures of the N-propargylamide polymer chains. Preferential adsorption towards (R)-(+)-1-phenylethylamine in the two enantiomers was observed in the obtained gels, demonstrating the potentials of such gels in chiral recognition and chiral resolution. Open image in new window