Synthesis, chiroptical properties, and chiral recognition ability of optically active polymethacrylamides having various tacticities

The radical polymerization of optically active methacrylamides, such as N+R)-(+)-alpha-methylbenzyl]methacrylamide, N-[(R)-(-)-1-cyclohexylethyl]methacrylamide, N-[(R)-(+)-1-(1-naphthyl)ethyllmethacrylamide, and N-((1R,2S)-(-)-1-(2-indanol)methacrylamide, was carried out under various conditions. The polymerization in the presence of ytterbium trifluoromethanesulfonate [Yb(OTf)(3)] produced isotactic-rich polymers compared with those obtained without the Lewis acid. The specific rotations and the circular dichroism spectral patterns of the obtained polymers varied with the tacticities, suggesting that the tacticities influence the secondary structures of the polymers. The IR spectra of the polymers indicated that the isotactic polymers favorably formed intramolecular hydrogen bonds. The chiral recognition ability of the optically active polymers immobilized on silica gel was evaluated as the chiral stationary phases for high-performance liquid chromatography (HPLC).