Facile Synthesis of Optically Active and Thermoresponsive Star Block Copolymers Carrying Helical Polyisocyanide Arms and Their Thermo-Triggered Chiral Resolution Ability
Facile Synthesis of Optically Active and Thermoresponsive Star Block Copolymers Carrying Helical Polyisocyanide Arms and Their Thermo-Triggered Chiral Resolution Ability
复制标题
携带螺旋多异氰化物臂的光学活性和热响应星形嵌段共聚物的简便合成及其热触发手性拆分能力
DOI：
10.1021/acsmacrolett.7b00875
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发表时间：
2018
影响因子：
5.8
通讯作者：
Wu Zong Quan
中科院分区：
文献类型：
--
作者：
Wang Qian;Chu Ben Fa;Chu Jia Hong;Liu Na;Wu Zong Quan
制备了一种左旋螺旋型聚苯基异氰酸酯，其两端分别含有降冰片烯和Pd（II）配合物。降冰片烯末端通过开环复分解聚合（ROMP）与双降冰片烯连接体进行核心交联，得到一种星形聚合物，其左旋旋臂外部装饰有Pd（II）单元。交联反应后，螺旋臂的旋光活性保持不变。星型共聚物表面的Pd（II）单元被一个新的苯基异氰化物延伸链，该苯基异氰化物带有三个亲水的三甘醇单甲基链，从而形成带有螺旋臂的两亲性星型嵌段共聚物。这种星形嵌段共聚物在较低的临界溶液温度（LCST）约为55℃时表现出优异的热响应性。这种具有光学活性和热响应性的星形聚合物可以在低于LCST的温度下对外消旋甲基苄醇溶液的s -对映体进行对映选择性捕获，在高于LCST的温度下沉淀，在溶液中留下r -对映体。分离的对映体的对映体过量量（ee）可达75%。
A left-handed helical poly(phenyl isocyanide) bearing a norbornene unit and a Pd(II) complex on each terminus was prepared. The norbornene terminus was core cross-linked with a bisnorbornene linker via ring-opening metathesis polymerization (ROMP), yielding a star polymer carrying left-handed helical arms decorated with Pd(II) units at the exterior. The optical activities of the helical arms were maintained after the cross-linking reaction. The Pd(II) units on the surface of the star polymer were chain extended with a new phenyl isocyanide bearing three hydrophilic triethylene glycol monomethyl chains, which afforded an amphiphilic star block copolymer carrying helical arms. Such a star block copolymer showed excellent thermoresponsiveness with the lower critical solution temperature (LCST) around 55 °C. This optically active and thermoresponsive star polymer can enantioselectively capture theS-enantiomer of racemic methyl benzyl alcohol solution at a temperature lower than the LCST and precipitated when the temperature was higher than the LCST, leaving theR-enantiomer in the solution. The enantiomeric excess (ee) of the isolated enantiomer is up to 75%.