Lewis Pair Catalyzed Regioselective Polymerization of (
<i>E</i>
,
<i>E</i>
)‐Alkyl Sorbates for the Synthesis of (AB)
<sub>
<i>n</i>
</sub>
Sequenced Polymers
Lewispairs were applied for living/controlled and 1,4-selective polymerization of sustainable (E,E)-alkyl sorbates. Poly((E,E)-alkyl sorbates) could be further converted into various polymers with strict (AB)nsequence structures, such as poly(sorbic acid), poly(propylene-alt-methyl acrylate), poly(propylene-alt-acrylic acid), poly(propylene-alt-allyl alcohol), and poly(ethylene-alt-2-butylene).
路易斯对应用于可持续(E,E)-烷基山梨酸酯的活性/受控和1,4-选择性聚合。聚((ê,ë) -烷基山梨酸酯)可被进一步转化为各种聚合物具有严格的(AB)Ñ序列结构,如聚(山梨酸),聚(丙烯ALT -甲基丙烯酸酯),聚(丙烯ALT -丙烯酸),聚(丙烯ALT -烯丙基醇),和聚(乙烯- ALT -2-丁烯)。
Living Ring-Opening Polymerization of Lactones by <i>N</i>-Heterocyclic Olefin/Al(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub> Lewis Pairs: Structures of Intermediates, Kinetics, and Mechanism
the tetrahedral intermediate, followed by the rate-determining ring-opening step to regenerate the zwitterionic species that re-enters into the next chain propagation cycles. Owning to the living features and lack of transesterification side reactions possessed uniquely by this Lewis pair polymerization system, well-defined di- and triblock copolymers with narrow molecular weight distributions (Đ = 1
强路易斯酸Al(C 6 F 5)3与强路易斯碱N-杂环烯烃(NHO)结合,可共同促进内酯的活性开环(共)聚合,以δ-戊内酯(δ- VL)和ε-己内酯(ε-CL)。获得了中到高分子量的线性(共)聚酯(M w高达855 kg / mol),并且大多数都表现出较窄的分子量分布(Đ低至1.02)。对关键反应中间体的结构,动力学和聚合物结构的详细研究已导致了聚合机理,因为引发涉及Al(C 6 F5)通过NHO 3活化的单体形成结构特征的两性离子四面体中间体,然后将其开环以产生活性两性离子物质。在繁殖周期中,该开环的两性离子物质及其同系物攻击被Al(C 6 F 5)3活化的进入单体,生成四面体中间体,然后进行速率确定的开环步骤以再生两性离子物质,重新进入下一个链传播周期。由于该路易斯对聚合体系独特的活性特征和缺乏酯交换副反应的缘故,分子量分布窄的定义明确的二嵌段和三嵌段共聚物(Đ = 1.06-1.1
Highly efficient cyclotrimerization of isocyanates using N-heterocyclic olefins under bulk conditions
of isocyanurates could be achieved from N-heterocyclic olefin mediated organocatalytic cyclotrimerization of a wide range of isocyanates under bulk conditions. Experimental details coupled with structural characterization of the key intermediates led to comprehensive mechanistic studies of cyclotrimerization.