Preparation, characterization, and chiral recognition of optically active polymers containing pendent chiral units via reversible addition-fragmentation chain transfer polymerization

摘要

Optically active polymers bearing chiral units at the side chain were prepared via reversible addition-fragmentation chain transfer (RAFT) polymerization in the presence of 2,2-azobisisobutyronitrile (AIBN)/benzyl dithiobenzoate (BDB), using a synthesized 6-O-p-vinylbenzyl-1,2:3,4-Di-O-isopropylidene-D-galactopyranose (VBPG) as the monomer. The experimental results suggested that the polymerization of the monomer proceeded in a living fashion, providing chiral group polymers with narrow molecular weight distributions. The optically active nature of the obtained poly (6-O-p-vinylbenzyl-1,2:3,4-Di-O-isopropylidene-D-galactopyranose) (PVBPG) was studied by investigating the dependence of specific rotation on the molecular weight of PVBPG and the concentration of PVBPG in tetrahydrofuran (THF). The results showed the specific rotation of PVBPG increased greatly with the decrease of the concentration of the PVBPG homopolymer. In addition, the effect of block copolymers of PVBPG on the optically active nature was also investigated by preparing a series of diblock copolymers of poly(methyl methacrylate) (PMMA)-b-PVBPG, polystyrene (PS)-b-PVBPG, and poly(methyl acrylate) (PMA)-b-PVBPG. It was found that both the homopolymer and the diblock copolymers possessed specific rotations. Finally, the ability of chiral recognition of the PVBPG homopolymer was investigated via an enantiomer-selective adsorption experiment.