Studies on Stereocontrol of Free-Radical Polymerization

1.研究了（R，R）-N，N '-双（3，5-二叔丁基亚水杨基）-1，2-环己二胺合钴（II）（1）对甲基丙烯酸甲酯、甲基丙烯酸苄酯、甲基丙烯酸异丙酯和甲基丙烯酸叔丁酯自由基聚合的立体化学的影响。在叔丁酯聚合中，rrrr五单元组含量比1减少了12%。由其他单体如醋酸乙烯酯、苯乙烯和丙烯酸酯得到的聚合物的立构规整度也受到所加入的自由基络合物的影响，其中影响的大小取决于单体和络合物的组合。虽然β-氢消除（终止反应）发生在甲基丙烯酸酯聚合，得到ω-末端不饱和聚合物的甲基丙烯酸酯，丙烯酸酯，苯乙烯，和乙酸乙烯酯使用钴配合物的聚合证明了类似生活的传播。在丙烯酸酯聚合的情况下，证实了嵌段共聚的可能性.在山梨酸酯聚合反应中，含1的配合物在区域化学控制中是有效的，除了具有未反应的侧链乙烯基的具有1，2-或3，4-结构的低聚物之外，还得到具有1，4-反式结构的相对高分子量聚合物。配合物的存在抑制了寡聚体的产生.以手性薄荷醇为原料，采用光学活性过氧化物（引发剂）和硫醇（链转移剂）引发甲基丙烯酸1-苯基二苯并环己酯聚合，得到了具有过量单手螺旋度的光学活性螺旋聚合物.甲基丙烯酸1-苯基二苯并辛二酯在1存在下的聚合导致光学活性的螺旋聚合物，其通过GPC分离得到纯单手螺旋部分。

1. The presence of cobaltus complexes including (R,R)-N,N'-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexanediaminatocobalt (II) (1) was found to affect stereochemistry of free-radical polymerization of methyl, benzyl, isopropyl, and t-butyl methacrylates. In the polymerization of t-butyl ester, a decrease of 12% in rrrr pentad content was observed based on 1. Tacticity of polymers obtained from the other monomers such as vinyl acetate, stirene, and acrylates were also affected by the added radical complex where the magnitude of the effect varied depending on the combination of monomer and complex.2. Living-like propagation was demonstrated for the polymerization of methacrylates, acrylates, stirene, and vinyl acetate using cobaltus complexes although beta-hydrogen elimination (a termination reaction) took place in the methacrylate polymerization to give omega-end unsaturated polymers. In the case of acrylate polymerization, possibility of block copolymerization was suggested.3. Complexes including 1 was effective in regiochemistry control in sorbate polymerization which gives a relatively high-molecular-weight polymer with 1,4-trans structure in addition to oligomers with 1,2-or 3,4-structures having unreacted pendent vinyl group. The presence of the complex suppressed the production of the oligomers.4. Polymerization of 1-phenyldibenzosuberyl methacrylate using optically active peroxides (initiator) and thiols (chain transfer agent) based on chiral menthol gave optically active, helical polymer with excess single-handed helicity.5. Polymerization of 1-phenyldibenzosuberyl methacrylate in the presence of 1 resulted in optically active, helical polymer which gave purely single-handed helical fractions by GPC separation.