Step-growth "click" coupling of telechelic polymers prepared by atom transfer radical polymerization
Step-growth "click" coupling of telechelic polymers prepared by atom transfer radical polymerization
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DOI：
10.1021/ma050370d
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发表时间：
2005-05-03
期刊：
影响因子：
5.5
通讯作者：
Matyjaszewski, K
中科院分区：
文献类型：
--
作者：
Tsarevsky, NV;Sumerlin, BS;Matyjaszewski, K
介绍。过去十年发展起来的可控/活性自由基聚合（CRP） 1方法不仅可以制备具有预定分子量和窄分子量分布的聚合物，而且还可以制备大量以前无法获得的聚合物材料。已经报道了许多梯度共聚物和嵌段共聚物的例子，以及具有复杂结构的聚合物，包括聚合物刷、4星、5和超支化聚合物。目前应用最广泛的CRP方法有原子转移自由基聚合（ATRP）、7-9可逆加成-破碎链转移聚合（RAFT）、10,11氮氧化物介导聚合、12,13和退化转移聚合。重要的是，ATRP生产的聚合物含有末端卤素原子，可以在各种端基转化中成功衍生，主要是亲核取代。官能团引发剂的使用使得制备同质或异质远螺旋聚合物成为可能。因此，ATRP是一种有吸引力的技术，用于合成定义明确的端功能化聚合物。聚合物链末端的卤素原子被叠氮阴离子16,17取代是非常有效的，当随后进行还原时，会得到氨基端聚合物。有机叠氮化物可用于多种化学转化。Huisgen, 20,21对炔的环加成反应进行了深入研究，生成取代三唑的混合物。当反应在催化量的CuI配合物存在下进行时，它只生成1,4 -二取代三唑。22,23这种反应与其他1,3 -偶极环加成反应（如由路易斯酸催化的叠氮化物和腈之间的反应）和其他高产率反应通常被称为“咔嗒反应”。点击式合成方法因其产量接近定量和对副反应的敏感性低而具有吸引力。因此，它们在需要官能团高转化的制备方法中特别重要，例如，在阶梯生长聚合过程中。一些点击反应已经成功地应用于聚合物和材料化学。已经报道了高效制备具有良好定义的聚合物四唑，25或树状大分子，26两亲嵌段共聚物，27交联嵌段共聚物囊泡，28和具有三唑单元的粘合剂29。点击反应也用于合成功能化聚氧降冰片烯30和嵌段共聚物31，并且是应用于由ATRP制备的聚合物（如原子转移自由基偶联32或）的其他偶联反应的方便替代
Introduction. The methods of controlled/living radical polymerization (CRP) 1 developed in the past decade allow for the preparation of not only polymers with predetermined molecular weight and narrow molecular weight distribution but also a plethora of previously unattainable polymeric materials. Numerous examples of gradient2 and block3 copolymers have been reported as well as polymers with complex architectures, including polymer brushes, 4 stars, 5 and hyperbranched6 polymers. The most widely used CRP methods are atom transfer radical polymerization (ATRP), 7-9 reversible addition-fragmentation chain transfer (RAFT) polymerization, 10, 11 nitroxide-mediated polymerization, 12, 13 and degenerative transfer polymerization. 14 Importantly, the polymers produced by ATRP contain terminal halogen atom (s) and can be successfully derivatized in various end group transformations, chiefly nucleophilic substitutions. The use of functional initiators makes it possible to prepare either homo-or heterotelechelic polymers. 15 Thus, ATRP is an attractive technique for the synthesis of well-defined end-functionalized polymers.The nucleophilic substitution of a halogen atom from a polymer chain end by an azide anion16, 17 is very efficient and, when followed by reduction, leads to amino-terminated polymers. Organic azides can be used for a variety of chemical transformations. 18, 19 Cycloaddition reactions with alkynes, thoroughly studied by Huisgen, 20, 21 produce a mixture of substituted triazoles. When the reaction is carried out in the presence of a catalytic amount of CuI complexes, it yields 1, 4-disubstituted triazoles exclusively. 22, 23 This reaction along with other 1, 3-dipolar cycloadditions (such as the reaction between azides and nitriles catalyzed by Lewis acids) and other high-yield reactions are often termed “click reactions”. 24 Click-type synthetic procedures are attractive because of their near quantitative yields and low susceptibility to side reactions. As such, they are particularly important in preparative methods in which high conversion of functional groups is desirable, eg, in step-growth polymerization processes. Some click reactions have already been successfully used in polymer and materials chemistry. The efficient preparation of well-defined polymeric tetrazoles, 25 or dendrimers, 26 amphiphilic block copolymers, 27 cross-linked block copolymer vesicles, 28 and adhesives29 with triazole units has been reported. Click reactions were also used in the synthesis of functionalized poly (oxynorbornenes) 30 and block copolymers31 and are a convenient alternative to other coupling reactions applied to polymers prepared by ATRP (such as atom transfer radical coupling32 or