Living Radical Polymerization using Organic Selenium Compounds

有机硒化合物在有机化学中非常有用。我们发现，有机硒化合物(苯基二硒醚或二苯基二硒醚)在苯乙烯和甲基丙烯酸甲酯的自由基聚合中起到光干扰剂的作用，苯基苯基硒的碳-硒键在光照射下发生均裂，生成苯基硒和苯基自由基，而苯乙烯单体则插入到这些自由基中，得到相对分子质量更高的聚合物。由此得到的ω端带有苯基亚硒基的聚苯乙烯也可以作为聚合物的光敏剂，并可应用于嵌段共聚物的合成。进一步，用过氧化氢消除ω末端的苯基亚硒基，形成碳-碳双键，然后将所得聚苯乙烯转化为环氧端的聚苯乙烯，然后将大分子单体1，4-二(对叔丁基苯基亚硒甲基)苯用作双功能光干扰剂，用于苯乙烯和甲基丙烯酸甲酯的聚合。在甲基丙烯酸甲酯存在下，合成了一种新型的含硒乙烯基单体对苯基硒甲基苯乙烯，并与偶氮二异丁腈聚合得到了相应的均聚物。在甲基丙烯酸甲酯存在下，将该单体与苯乙烯的共聚物作为聚合物光辐射，有效地得到了接枝共聚物。另一方面，该单体在紫外光照射下发生均聚合，得到超支化聚苯乙烯。

Organic selenium compounds are very useful in organic chemistry. We found that the organic selenium compounds (benzyl phenyl senide or diphenyl diselenide) works as a photoiniferter in radical polymerization of styrene and methyl methacrylate.The carbon-selenium bond of benzyl phenyl selenide undergoes homolytic cleavage on photoirradiation to afford phenylseleno and benzyl radicals, and styrene monomer insert to these radicals to afford polymer with higher molecular weight. The resulting polystyrene having phenylseleno group at theω-end works also as a polymeric photoiniferter, and can apply to the synthesis of block copolymer. Further, the phenylseleno group at theω-end is eliminated by hydrogen peroxide to give carbon-carbon double bond and, followed the resulting polystyrene is converted to epoxy terminated polystyrene, and then macromonomer.1, 4-Bis (p-tert-butylphenylselenomethyl) benzene was used as a bifunctional photoiniferter for the polymerization of styrene and methyl methacrylate. Photoirradiation of telechelic polystyrene having phenylseleno groups at both ends as polymeric photoiniferter in the presence of methyl methacrylarte afforded effectively corresponding to the ABA type triblock copolymers.p-Phenylselenomethylstyrene was synthesized as a novel-selenium-containing vinyl monomer and polymerized with azobisisobutyronitrile to afford corresponding homopolymer. Photoirradiation of the copolymer of this monomer and styrene as a polymeric photoiniferter in the presence of methyl methacrylarte effectively afforded a graft copolymer. On the other hand, the homopolymerization of this monomer under UV irradiation gave a hyperbranched polystyrene.