Synthesis of Stereoregular Living Polymers from Substituted Acetylenes and Design of Polymerization Catalysts

聚合物的分子量分布和立体结构必须明确，这样聚合物才能表现出优异的性能和功能。本文研究了以取代乙炔为原料合成立体规则活性聚合物的方法，并开发了用于此目的的新型催化剂。钼基催化剂对叔丁基乙炔（tBA）立体定向活性聚合——MoOCl_4-n-Bu_4Sn-EtOH（1:1: 1）催化剂对tBA的聚合得到了具有窄MWDs （Mw/Mn=1.12，顺式97%）的立体规则活性聚合物。在0和-30℃的甲苯中，聚合物的Mn与单体用量成正比增加，而MWD仍然很窄，这一事实证实了这种聚合的活性。采用^<13> - C核磁共振谱法测定了聚合物的顺式含量。MoCl_5-n-Bu_4Sn-EtOH（1:1: 1）体系（Mw/Mn=1.24, cis 90%）得到了类似但稍差的结果。一种富顺式活性聚[（邻甲基苯基）乙炔]（oMePA）的合成——mooc_4 -n- bu_4sn - etoh催化剂在甲苯中聚合得到了一种富顺式活性聚合物顺式77%，Mw/Mn=1,21。在30℃下聚合得到的产物与在0℃下聚合得到的产物相似，而在30℃下聚合得到的聚合物表现出更宽的MWD和更低的顺式含量。基于moocl_4的活性聚合新催化剂体系的开发——本研究尝试开发以Et_3Al为助催化剂的活性聚合新催化剂体系。以[o-（三氟甲基）苯基]乙炔为单体，在苯醚中进行聚合，温度为30℃。最后，用MoOCl_4-Et_3Al-EtOH以1:1:4的比例得到了MWD很窄（Mw/Mn=1.02）的聚合物。

The molecular weight distribution (MWD) and steric structure of a polymer should be well defined so that the polymer would exhibit excellent properties and functions. The present study deals with the synthesis of stereoregular living polymers from substituted acetylenes and development of novel catalysts useful for such purposes.1. Stereospecific living polymerization of tert-butylacetylene (tBA) by Mo-based catalysts-The polymerization of tBA by the MoOCl_4-n-Bu_4Sn-EtOH (1 : 1 : 1) catalyst led to living and stereoregular polymers with narrow MWDs (Mw/Mn=1.12 ; cis 97%) . The living nature of this polymerization was confirmed by the fact that, in toluene at 0 and -30ﾟC,the Mn of the polymer increases in direct proportion to monomer consumption, while the MWD remains narrow. The cis content of polymer was evaluated by ^<13>C NMR spectroscopy. Similar but somewhat inferior results were obtained with the MoCl_5-n-Bu_4Sn-EtOH (1 : 1 : 1) system (Mw/Mn=1.24 ; cis 90%) .2. Synthesis of a cis-rich, living poly [ (o-methylphenyl) acetylene] (oMePA) -Polymerization of oMePA by MoOCl_4-n-Bu_4Sn-EtOH catalyst in toluene at 0ﾟC provided a cis-rich living polymer ; cis 77%, Mw/Mn=1,21. The polymerization at-30ﾟC gave results similar to those for 0ﾟC,whereas the polymer obtained at 30ﾟC exhibited a broader MWD and a lower cis content.3. Development of MoOCl_4-based new catalyst systems for living polymerization-In this study, we tried to develop new catalyst systems for the living metathesis polymerization using Et_3Al as cocatalyst. [o- (Trifluoromethyl) phenyl] acetylene was used as monomer, and polymerizations were carried out in anisole at 30ﾟC.Eventually, a polymer with very narrow MWD (Mw/Mn=1.02) could be obtained by use of MoOCl_4-Et_3Al-EtOH at 1 : 1 : 4 ratio.