Synthesis, Chiroptical Properties, and Chiral Recognition Ability of Optically Active Polymethacrylamides Having Various Tacticities

Abstract

ABSTRACT:The radical polymerization of optically active methacrylamides, such asand N-[(1R,2S)-(À)-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).

Stereospecific Living Radical Polymerization: Dual Control of Chain Length and Tacticity for Precision Polymer Synthesis

“…400 The stereospecific radical polymerization was further applied for the optically active methacrylamides bearing a bulky chiral auxiliary under various conditions using Yb(OTf) 3 and Y(OTf) 3 . 402,403 The tacticity influenced the intramolecular hydrogen bond formation, the higher order structure, and the chiral recognition ability, which would show a different ability as the chiral stationary phase for HPLC resolution of the various racemates upon subsequent immobilization on silica gel. Similar effects of Lewis acids for enhancing the isospecificity was reported for the radical polymerization of acrylonitrile and VAc with fairly large amounts of Mg or Co halides, in which the Lewis acids form almost 1:1 complexes with the monomers.…”

Synthesis and chiral recognition of helical poly(phenylacetylene)s bearing l‐phenylglycinol and its phenylcarbamates as pendants

“…One of the key points of this separation technique is to design and prepare the efficient chiral stationary phases (CSPs) with high chiral recognition abilities. Although polysaccharide derivatives, especially the phenylcarbamates and benzoates of cellulose and amylose with high chiral recognition abilities have been developed as the popular CSPs for a wide range of chiral compounds, various optically active synthetic polymers with a controllable helical sense have also been applied as the CSPs for the HPLC separation of enantiomers in the last two decades . Among the synthetic polymers, the helical poly(phenylacetylene) derivatives bearing chiral pendants have been proved to be good candidates as novel CSPs for the HPLC separation of enantiomers due to their helical structures induced by chiral pendants .…”

Asymmetric Radical Polymerization of N-Phenylmethacrylamides

“…The optically active polymers may show a chiral recognition as well as other optically active polymethacrylamides. 8 …”