CO_(2)响应性L-脯氨酸基纳米反应器的构筑及其催化性能

Construction and catalytic performance of CO_(2) responsive nanoreactors containing L-proline moieties

采用可逆加成-断裂链转移(RAFT)分散聚合法制备了一系列固载L-脯氨酸、CO_(2)响应性结构单元甲基丙烯酸二乙氨基乙酯(DEA)含量不同的mPEG_(22)-b-P[BnMA_(x)-co-L-ProlA_(n)]-b-PDEA_(y)PBL-b-PD-(DEA)_(m)(m=0,1,2,3)和单体序列结构不同的mPEG_(22)-b-P(L-ProlA)-b-P[BnMA-co-DEA](PL-b-PBD)聚合物。利用核磁共振氢谱(^(1)H NMR)、X射线光电子能谱(XPS)和凝胶渗透色谱(GPC)对聚合物的化学结构及相对分子量分布进行了表征。采用动态光散射(DLS)对聚合物的自组装行为及形成纳米反应器后的CO_(2)响应性进行了研究。同时,结合耗散粒子动力学(DPD)模拟探究了聚合物亲疏水单体比例和序列结构对聚合物自组装结构的影响。最后,将制备的纳米反应器用于水相催化直接不对称Aldol反应,结果表明,PBL-b-PD-(DEA)_(2)具有最佳的催化性能[96%conv.,93/7(anti/syn),94%ee]。该研究为探究聚合物自组装结构对其催化性能的影响提供了新思路。

A series of copolymers of mPEG_(22)-b-P[BnMA_(x)-co-L-ProlA_(n)]-b-PDEA_(y)PBL-b-PD-(DEA)_(m)(m=0,1,2,3)with different content of CO_(2)-responsiveness diethylaminoethyl methacrylate(DEA)and mPEG_(22)-b-P(L-ProlA)-b-P[BnMA-co-PDEA](PL-b-PBD)with different sequence structure were fabricated by reversible addition fragmentation chain transfer(RAFT)dispersion polymerization.The chemical structure and molecular weight distribution of the copolymers were carried out by 1H nuclear magnetic resonance spectra(1H NMR spectra),X-ray photoelectron spectroscopy(XPS)and gel permeation chromatography(GPC).Dynamic light scattering(DLS)was used to investigate the selfassembly behavior of the copolymers and the CO_(2)-responsiveness of the nanoreactors.Moreover,dissipative particle dynamics(DPD)studies showed that the self-assemble structure of nanoreactors could be turned by controlling the monomer contents distribution and sequence structure of hydrophilic and hydrophobic.Finally,the nanoreactors were used to catalyze asymmetric Aldol reaction of cyclohexanone and 4-nitrobenzaldehyde in water.The results indicated that PBL-b-PD-(DEA)_(2) gave the Aldol product with high conv.,anti/syn and ee(96%,97/3,94%).This study provided a promising approach for exploring the self-assembly structure of copolymers on its catalytic performance.