Mimic of Enzyme Behavior by Smart Block Copolymers

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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.