Institute of Organic Chemistry, Johannes Gutenberg University, Duesbergweg 10-14, 55128, Mainz, Germany.
Macromol Rapid Commun. 2020 Jan;41(1):e1900282. doi: 10.1002/marc.201900282. Epub 2019 Jul 28.
Multiple hydroxamic acids are introduced at poly(ethylene glycol) (PEG) via copolymerization of ethylene oxide with a novel epoxide monomer containing a 1,4,2-dioxazole-protected hydroxamic acid (HAAGE). AB- and ABA-type di- and triblock copolymers as well as statistical copolymers of HAAGE and ethylene oxide are prepared in a molecular weight range between 2600 and 12 000 g mol with low dispersities (Ð < 1.2). Cleavage of the acetal protecting group after the polymerization is achieved by mild acidic treatment, releasing multiple free hydroxamic acids tethered to the polyether backbone. The chelation properties of different polymer architectures (statistical versus diblock and ABA triblock) are investigated and compared with regard to the number and position of hydroxamic acids. Separation of the hydroxamic acid units by at least 5 ethylene glycol monomer units is found to be essential for high Fe(III) binding efficiency, while block copolymers are observed to be the best-suited architecture for polymer network and hydrogel formation via Fe(III) chelation.
通过将环氧乙烷与含有 1,4,2-二恶唑保护的羟肟酸（HAAGE）的新型环氧化物单体共聚，在聚乙二醇（PEG）上引入了多个羟肟酸。在分子量为 2600 至 12000g/mol 且分散度较低（Ð < 1.2）的范围内，制备了 AB 型和 ABA 型二嵌段和三嵌段共聚物以及 HAAGE 和环氧乙烷的无规共聚物。聚合后通过温和的酸性处理可实现缩醛保护基的裂解，释放出多个通过聚醚主链连接的游离羟肟酸。研究了不同聚合物结构（无规、二嵌段和 ABA 三嵌段）的螯合性能，并比较了羟肟酸的数量和位置。发现羟肟酸单元之间至少有 5 个乙二醇单体单元的分离对于获得高的 Fe(III)结合效率是必不可少的，而嵌段共聚物被观察到是通过 Fe(III)螯合形成聚合物网络和水凝胶的最佳结构。
