An approach to glycerol dendrimers and pseudo-dendritic polyglycerols
An approach to glycerol dendrimers and pseudo-dendritic polyglycerols
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DOI：
10.1021/ja994363e
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发表时间：
2000-03-29
影响因子：
15
通讯作者：
Stumbé, JF
中科院分区：
文献类型：
--
作者：
Haag, R;Sunder, A;Stumbé, JF
具有支对支结构的大分子，如树状大分子和超支化聚合物，由于其独特的分子特征和性质，近年来引起了人们越来越多的兴趣。一类很有前途的高支化分子是脂肪族聚醚多元醇。由于它们的惰性结构单元和多个反应链末端，它们作为催化剂和功能有机分子的载体具有很大的潜力。此外，它们优异的水溶性和生物相容性使它们成为有价值的聚合物治疗化合物。到目前为止，文献中只报道了三种脂肪族聚醚树状大分子。它们是在繁琐重复的多步合成中制备的，这显然是许多应用的限制因素。超支化脂肪族聚醚，另一方面，方便地一步制备。5,6由于聚合反应的统计，它们是同分异构体的混合物，具有一定的多分散性，除了枝晶和末端构建单元外，通常还含有不同数量的线性单元。迄今为止，已知两种用于制备超支化脂肪族聚醚多元醇的单体：3-羟甲基-3-乙基氧乙烷5和甘油。6只有后一种是市售的，允许在引发剂（核心）掺入、分子量（Mn: 1000-10000）和低多分散度（Mw/Mn< 1.5）方面进行控制。一个具有挑战性的问题是基于拓扑结构和多分散性的差异来比较超支化聚合物和枝状大分子的结构-性能特征。7,8为此，需要无线性单元的超支化聚合物。到目前为止，文献中描述了两种策略：(i)使用特殊单体，其中线状单位的形成比树突单位的形成更不利9,10和（ii）
Macromolecules with a branch-on-branch structure, such as dendrimers and hyperbranched polymers, have attracted increasing interest over the past few years due to their unique molecular features and properties. 1, 2 A promising class of these highly branched molecules are aliphatic polyether polyols. Due to their inert building blocks and multiple reactive chain ends they possess promising potential as supports for catalysts and functional organic molecules. In addition, their excellent water solubility and biocompatibility renders them as valuable compounds for polymer therapeutics. 3So far, only three examples of aliphatic polyether dendrimers have been reported in the literature. 4 They have been prepared in tedious repetitive multistep syntheses, which are obviously a limiting factor for many applications. Hyperbranched aliphatic polyethers, on the other hand, are conveniently prepared in one step. 5, 6 Due to the statistics of the polymerization reaction they are a mixture of isomers, possess a certain polydispersity, and usually contain varying amounts of linear units in addition to dendritic and terminal building units. To date, two monomers for the preparation of hyperbranched aliphatic polyether polyols are known: 3-hydroxymethyl-3-ethyl oxetane5 and glycidol. 6 Only the latter one is commercially available and permits control in terms of initiator (core) incorporation, molecular weight (Mn: 1000-10000) and low polydispersities (Mw/Mn< 1.5). A challenging issue is the comparison of structure-property profiles of hyperbranched polymers and dendrimers based on the difference in topology and polydispersity. 7, 8 To this end, hyperbranched polymers without linear units are required. So far, two strategies have been described in the literature:(i) the use of peculiar monomers, in which the formation of linear units is less favorable than the formation of dendritic ones9, 10 and (ii) the