Studies on the Growing Species in Living Cationic Polymerization and Synthesis of Various Types of Living Polymers

活阳离子聚合成功的关键是为特定的生长端明智地选择反相。即，适当的亲核反离子稳定生长端，导致活性阳离子聚合。为了推广活性阳离子聚合的原理，我们研究了在极性溶剂中游离自由离子可能参与的活性阳离子聚合的可行性。异丁基乙烯基醚（IBVE）的活性聚合。HCI-IBVE加合物(1)/ZnCl_2体系在CH_2Cl_2和EtNo_2/CH_2Cl_2混合物中催化活性聚合，而EtAlCl_2体系催化活性聚合。在这些极性介质中，两种体系得到的聚合物具有非常相似的低等规性（介观<约等于>56%），表明传播反应是由自由离子介导的。因此，无论溶剂极性如何，或自由离子或离子对的参与如何，活性阳离子聚合都需要一个合适的亲核反阴离子。对t-丁氧基斯蒂烯（tBOS）的活性聚合。为了证明自由离子和其他可阳离子聚合单体的活性聚合的可行性，在极性溶剂中，以1/ZnCl_2为引发体系，在15℃的温度下，对具有较高反应活性的苯乙烯衍生物进行了阳离子聚合研究。虽然tBOS在相对较高的温度下聚合，但正如IBVE观察到的那样，在自由离子存在的情况下也发生了活性聚合。总之，活性阳离子聚合可以在强极性介质中实现，其中离解的自由离子种类参与了传播反应。这是活性阳离子聚合的第一个例子，其传播反应是由自由离子介导的。此外，由于本研究开发了新的反应条件，在以前报道的反应条件下无法进行活性聚合的各种单体将获得新型的活性聚合物。少

A key to successful living cationic polymerization is the judicious choice of a counterion for a particular growing end. Namely, a suitably nucleophilic counterion stabilize the growing end to lead to living cationic polymerization. To generalize the principle for living cationic polymerization, we examined the feasibility of living cationic polymerization in polar solvents where the dissociated free ionic species may be involved.Living Polymerization of Isobutyl Vinyl Ether(IBVE). At-78ﾟC,living polymerization was induced with the HCI-IBVE adduct(1)/ZnCl_2 system in CH_2Cl_2 and a EtNo_2/CH_2Cl_2 mixture, whereas similar systems with EtAlCl_2 led to conventional cationic polymerization. In these polar media, both systems gave polymers with very similar and low isotacticity (meso<approximately equal>56%), indicating that the propagating reaction is mediated by free ions. Thus, regardless of solvent polarity, or involvement of free ions or ion pairs, living cationic polymerization requi … More res a suitably nucleophilic counteranion.Living polymerization of p-t-Butoxystirene (tBOS). To demonstrate the feasibility of living polymerization by free ions other cationically polymerizable monomers, cationic polymerization of tBOS,which has higher reactivity among stirene derivatives, was examined with the 1/ZnCl_2 initiating system at-15ﾟC in polar solvents. Although tBOS was polymerized at a relatively higher temperature, living polymerization also occurred in the presence of the free ionic species as observed with IBVE.In summary, living cationic polymerization can be achieved in a strongly polar medium, where the dissociated free ionic species is involved in the propagating reaction. This is the first example of living cationic polymerization whose propagating reaction is mediated by free ions. In addition, now that the novel reaction conditions have been developed in this study, new types of living polymers would be obtained from a variety of monomers whose living polymerization have not been operable under the reaction conditions reported before. Less