Optically Active Polymer Via One-Pot Combination of Chemoenzymatic Transesterification and RAFT Polymerization: Synthesis and Its Application in Hybrid Silica Particles

A novel strategy for the preparation of hybrid particles of optically active polymer and silica is developed via combination of chemoenzymatic transesterification, reversible addition-fragmentation chain transfer (RAFT) polymerization, and click reaction for the first time. During this procedure, Novozym 435 is employed to catalyze the transesterification between 2,2,2-trifluoethyl methacrylate monomer and 2-octanol to form the target monomer (R)-OMA, which synchronously participates in RAFT polymerization to obtain a new polymer with transformed optically active side groups. Compared with RAFT polymerization, the transesterification reaction is much faster, with conversion ratio reaching 93% after 7 h; subsequently, the polymerization is nearly homo-polymerization of (R)-OMA. The molar fraction of (R)-OMA in the final polymer is about 97.8% with controlled molecular weight (M-n approximate to 6840 g mol(-1)) and a narrow polydispersity index (approximate to 1.25). Finally, the hybrid particles of silica and optically active polymer P((R)-OMA) are obtained by the thiol-ene click reaction. The Fourier transform infrared, X-ray photoelectron spectroscopy, and transmission electron microscopy results exhibit the successful graft of P((R)-OMA) polymer to the silica surface, and the P((R)-OMA) polymer in the hybrid particles is about 10 wt% from the TGA curves. These as-prepared hybrid particles combine excellent mechanical stability of silica and good chirality of polymer, making them promising for chromatographic resolution, catalytic synthesis, and (stereo-) selectivity applications.