Mimic of Enzyme Behavior by Smart Block Copolymers

整个生物体内的化学转化只有在催化剂，也就是所谓的酶的作用下才能实现。酶是具有多种特性的天然聚合物。酶具有催化活性中心，该中心是由多肽序列的特殊折叠形成的。这种酶的活性可由环境参数控制。然而，通过破坏上层结构，酶就失去了活性。酶是底物特异性的，所有涉及酶的转化都在水介质中进行。该项目的长期目标是通过智能聚合物模拟酶的行为。为了开发模拟酶行为的材料，将制备具有催化活性位点的温度响应嵌段共聚物。合成的嵌段共聚物将具有AB嵌段共聚物结构，其中嵌段A为无规共聚物，具有温度响应并具有催化活性位点，嵌段B为均聚物，能够稳定胶束聚集体。聚合物的合成将主要通过控制自由基途径进行。在非常小的温度范围内，聚合物可以在水介质中的单体和胶束聚集体之间切换。在胶束状态下，聚合物形成催化活性位点。疏水底物将溶解在胶束聚集体的疏水核心中。硝基酚酯将成为研究智能嵌段共聚物催化活性的第一种模型化合物。这种化合物的水解将通过紫外/可见光谱进行监测。在后期阶段，还将研究可用于生成有机化合物的反应，如锇催化烯烃的氨基羟基化反应。将开发可受pH值、特殊离子存在等影响的人工酶的制备策略。

The entirety of chemical transformations in the organism is possible by the action of catalyst, so called enzymes, only. Enzymes are natural polymers with a variety of special features. Enzymes posses a catalytic active centre that is formed by a peculiar folding of the polypeptide sequence. The activity of the enzyme can be controlled by environmental parameters. However, by destroying the superstructure the enzyme looses its activity. Enzymes are substrate specific and all transformations involving enzymes are carried out in aqueous media. The long term goal of this project is the mimic of enzyme behaviour by smart polymers. In order to develop materials to mimic enzyme behaviour, temperature responsive block copolymers bearing catalytic active sites will be prepared. The synthesised block copolymers will have AB block copolymer structure with block A as random copolymer being temperature responsive and bearing catalytic active sites and block B as homopolymer being able to stabilise micellar aggregates. The synthesis of the polymers will be performed mainly by controlled radical pathways. In a very small temperature range the polymers can be switched between unimers and micellar aggregates in aqueous media. In the micellar state the polymers are forming the catalytic active site. Hydrophobic substrates will be solubilised in the hydrophobic core of the micellar aggregate. Nitrophenol esters will be first model compounds for the investigation of the catalytic activity of smart block copolymers. Hydrolysis of such compound will be monitored by UV/VIS spectroscopy. In a later stage also reactions that can be used to build up organic compounds, as Osmiumcatalysed aminohydroxylation of olefins, will be investigated. Strategies to prepare artificial enzymes that can be influenced by pH, presence of special ions etc. will be developed.