Luminescent Hybrid Materials for Photocatalysis and Sensing

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The aim of this project is the preparation and detailed characterization of multi-functionalized porous polymers. This includes metal-organic frameworks as well as purely organic porous polymers such as conjugated microporous polymers. Due to their high surface areas and high pore volumes, these materials allows for a good accessibility and high densities of functional groups. As functional groups, different metal complexes and fluorophores will be investigated, which will be applied in two different areas. As a first application, these materials will be used as heterogeneous catalysts for photochemical reactions. Generally, these reactions require two functional groups, i.e. the catalytically active center and a photosensitizer. The photosensitizer shows a much higher absorption than the active center and thus provides the required energy for the catalytical process. So far, the photosensitizer has only ever been used homogeneously dissolved in the reaction mixture, thus requiring an additional purification step after the reaction. In this project, for the first time, both the catalytically active center and the photosensitizer will be incorporated into one porous framework. Hence a completely heterogeneous catalyst will be obtained.The second application consists of porous polymers for the simultaneous detection of various gases. State of the art sensors usually offer high sensitivities, but suffer from susceptibility to false signals due to cross sensitivities, as they are developed for the detection of a single analyte. Again, in this part of the project, different functional groups, e.g. fluorophores will be incorporated into a single porous network. This will allow for a simultaneous detection of several analytes. Combining the sensor responses of different functional groups will allow for a sensitive and much more selective detection.The understanding of the electron transfer processes as well as the reaction mechanisms is of great importance for both main objectives. Thus, these processes will be investigated by different spectroscopic and time-resolved methods and will be correlated to the structural properties of the materials. The findings and information received will contribute to a better understanding of heterogeneous catalysts and multi-functional sensors. Hence a rational design of new, more efficient materials will be possible.