权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Insertion polymerization of electron-deficient vinyl monomers

缺电子乙烯基单体的插入聚合

基本信息

批准号：
164875938
负责人：
Professor Dr. Stefan Mecking
金额：
--
依托单位：
Arbeitsgruppe Chemische Materialwissenschaft
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2010
资助国家：
德国
起止时间：
2009-12-31 至 2019-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/164875938?language=en
关键词：
Insertion polymerization electron deficient vinyl

项目摘要

Catalytic polymerization of ethylene and propylene is one of the most well-studied chemical reactions. By stark contrast, an insertion polymerization of electron deficient polar-substituted vinyl monomers is a long-standing challenge. Only recently, linear copolymerizations of ethylene with a scope of monomers including even acrylic acid have been realized. In the first funding period a comprehensive picture was gained of factors governing insertion chain growth and catalyst deactivation. Catalyst design was advanced and novel polymeric materials evolved. We now focus on overcoming the identified intrinsic limitations of insertion (co)polymerization of polar vinyl monomers.Coordination of the functional group of the free monomer, and in particular of the repeat units gener¬ated by insertion, blocks coordination sites reversibly and hinders catalysis. To overcome this problem, a selective binding of the functional groups to appropriate sites in the catalyst is pursued. An interaction of functional groups of the monomer with carefully placed complementary hydrogen-bonding motifs in the bidentate ligand of neutral Pd(II) catalysts is sought to favor olefin coordination over binding of the incoming monomers functional groups. In extension of this concept also to the polar groups of already incorporated monomer, a diversion of their binding away from chelating coordination blocking the active sites is aimed for. An alternative approach to resolve this problem - potentially also providing new copolymer microstructures - is a combination of ethylene insertion chain growth with free-radical growth of polar monomer segments. Monteil (Macromolecules 2011, 44, 3293) suggested that neutral Ni(II) salicylaldiminato complexes polymerize ethylene and methyl methacrylate (MMA) to (multi)block copolymers. Our preliminary studies confirm that an insertion chain growth of ethylene and radical polymerization of MMA occur simultaneously, and both reactions are interdependent. To unravel the mechanisms operative here and devise generic concepts to insertion/radical 'shuttling' polymerizations, polymerizations with (13C labeled) Ni-aryl and Ni-methyl precursors will be pursued, combined with polymer endgroup analysis. Further, the role of the metal in generating and scavenging radicals will be illuminated by studies of (salicylaldiminato)Ni(I) species prepared for this purpose. This comprises their reactivity under polymerization conditions as well as stoichiometric reactions with the active species of insertion chain growth.Stereocontrol by space-filling repulsive interactions, established for propylene, is not applicable here. We have devised an asymmetric substitution of moderate bulk at a P-donor adjacent to the bound olefin as a concept to control acrylate insertion. This serves as a starting point to develop stereoregular chain growth via remote rigid linkers. In further course, the aforementioned concepts of attractive interactions can come into play.

乙烯和丙烯的催化聚合是研究最多的化学反应之一。与之形成鲜明对比的是，缺乏电子的极性取代的乙烯基单体的插入聚合是一个长期的挑战。直到最近，才实现了乙烯与甚至包括丙烯酸在内的单体的线性共聚。在第一个资助期，全面了解了影响插入链增长和催化剂失活的因素。催化剂的设计是先进的，新的聚合材料出现了。我们现在的重点是克服已知的极性乙烯基单体插入(共)聚合的固有局限性。自由单体的官能团的协调，特别是插入产生的重复单元的协调，可逆地阻断配位并阻碍催化。为了克服这一问题，寻求将官能团选择性地结合到催化剂中的适当位置。寻求单体的官能团与中性Pd(II)催化剂的双齿配体中精心布置的互补氢键基序的相互作用，以有利于烯烃配位而不是引入的单体官能团的结合。将这一概念扩展到已并入单体的极性基团，目的是转移它们的结合，使其远离螯合配位，从而阻断活性中心。解决这一问题的另一种方法--也可能提供新的共聚物微结构--是乙烯插入链增长与极性单体链段的自由基增长相结合。Monteil(大分子2011，44,3293)提出了中性的Ni(II)水杨醛缩合物使乙烯和甲基丙烯酸甲酯(MMA)聚合成(多)嵌段共聚物。我们的初步研究证实，乙烯的插入链增长和MMA的自由基聚合同时发生，并且这两个反应是相互依赖的。为了揭示这里的作用机理，并设计出插入/自由基“穿梭”聚合的一般概念，将继续进行具有(13C标记)Ni-芳基和Ni-甲基前体的聚合，并结合聚合物端基分析。此外，金属在产生和清除自由基中的作用将通过为此目的而制备的(水杨醛)镍(I)物种的研究来阐明。这包括它们在聚合条件下的反应性以及与插入链增长的活性物种的化学计量反应。为丙烯建立的空间填充排斥相互作用的立体控制在这里不适用。我们设计了一种在结合烯烃附近的P-给体上进行中等体积的不对称取代作为控制丙烯酸酯插入的概念。这是通过远程刚性连接物发展立体规则链增长的起点。在进一步的课程中，前面提到的吸引人的互动概念也可以发挥作用。

项目成果

期刊论文数量（5）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Catalytic Chain Transfer Polymerization to Functional Reactive End Groups for Controlled Free Radical Growth

催化链转移聚合至功能性反应性端基以控制自由基生长

DOI：
10.1021/acs.macromol.0c00241
发表时间：
2020
期刊：
Macromolecules
影响因子：
5.5
作者：
Stadler;Sonja M;Göttker-Schnetmann;Amelie S;Fischer;Stephan R. R;Mecking;Stefan
通讯作者：
Stefan

Reactivity of Functionalized Vinyl Monomers in Insertion Copolymerization