Development of New Synthetic Methodology for Polymers with Controlled Molecular Weight Using Metalloporphyrins as Initiators

以金属卟啉为引发剂开发可控分子量聚合物的新合成方法

基本信息

批准号：
62430020
负责人：
INOUE Shohei
金额：
$ 20.22万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (A)
财政年份：
1987
资助国家：
日本
起止时间：
1987 至 1989
项目状态：
已结题

项目摘要

The present research project has developed a novel, widely applicable synthetic methodology for polymers with controlled molecular weight by using metalloporphyrins as initiators. Aluminum porphyrins are the representative initiator, which bring about effectively the living polymerizations of heterocyclic monomers such as epoxides, lactones and lactide, and vinyl monomers such as methacrylic and acrylic esters and methacrylonitdle, affording the polymers of controlled molecular weight with narrow molecular weight distribution. Living, alternating copolymerizadon of epoxides with carbon dioxide or cyclic anhydride is also possible using aluminum porphyrin as initiator coupled with quaternary onium salts. Mechanistic studies have demonstrated that all these polymerizations proceed at the central aluminum. atom axial ligand bond of the initiator. It should be of interest to note that some of the above polymerizations are dramatically accelerated by the photoexcitation of the porphyrin lig … More and with visible light. Zinc complexes of N-subsdtuted porphyrins are found also effective for the living polymerizations of epoxides and episulfides (three-membered cyclic thioethers), where the former case has provided a novel example of visible light-induced living polymerization. By taking advantage of the wide applicability of metalloporphyrins as initiators for living polymerizations, a variety of block copolymers with uniform, controlled block lengths have been synthesized. Of further interest to note is a discovery of the new concept, immortal polymerization, which is superior to living polymerization in the sense that immortal polymerization enables the synthesis of polymers with narrow molecular weight distribution with the number of the polymer molecules more than that of the initiator molecules. Immortal polymerization is very effective for molecular design of terminally functional (end-reactive, end-polymerizable, telechelic, and star-shaped) polymers and oligomers with uniform molecular weights. In addition to aluminum and zinc porphyrins, manganese porphyrins are also effective as initiators for the immortal polymerization of epoxides. Less

本研究项目开发了一种新型的、广泛适用的合成方法，以金属卟啉作为引发剂，以铝卟啉为代表的引发剂，有效地实现了环氧化物、内酯和丙交酯等杂环单体的活性聚合。和乙烯基单体，如甲基丙烯酸酯、丙烯酸酯和甲基丙烯腈，提供可控分子量的聚合物环氧化物与二氧化碳或环酸酐的活性交替共聚也可以使用铝卟啉作为引发剂与季鎓盐结合进行。值得注意的是，上述一些加速聚合反应是由卟啉配体的光激发引起的。研究发现，N-取代卟啉的锌配合物对于环氧化物和环硫化物（三元环硫醚）的活性聚合也有效，其中前一种情况提供了可见光诱导活性聚合的新例子。利用金属卟啉作为活性聚合引发剂的广泛适用性，各种具有均匀、受控嵌段长度的嵌段共聚物已被开发出来。更值得关注的是新概念“永生聚合”的发现，其优于活性聚合，因为永生聚合能够合成具有窄分子量分布且聚合物分子数量大于活性聚合的聚合物。除了铝和锌之外，永生聚合对于具有均匀分子量的末端功能（末端反应性、末端可聚合、遥爪和星形）聚合物和低聚物的分子设计非常有效。卟啉、锰卟啉也是环氧化物永生聚合的有效引发剂。