Dr. Kai Zhang "Conjugated porous polymers for visible light photocatalysis: a metal-free alternative"
Max Planck Institute for Polymer Research, Mainz, Germany
What |
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When |
Jul 01, 2015 from 02:15 PM to 03:00 PM |
Where | Seminarraum A, FMF, Stefan-Meier-Str. 21, Freiburg |
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Sunlight is a clean and inexhaustible source of renewable energy. Especially, the visible range of the solar spectrum accounts for 44% of the total energy as opposed to only 3% from the ultraviolet (UV) light. Inspired by nature’s ability to convert solar energy in photocatalytic processes, organic chemists have developed a vast number of photocatalysts in order to mimic the nature process. As a result, many molecular inorganic, transition metal-based complexes or organic dye compounds that absorb significantly in the visible spectrum were intensely studied to harvest solar energy and catalyze organic photochemical reactions. Nevertheless, there are still some intrinsic drawbacks associated with these homogeneous systems, for instance, high cost, toxicity of these rare metals, as well as limited availability in nature, and their additionally required post-reaction purification step for catalyst removal. It is therefore of great desire to develop stable, reusable and transition metal-free photocatalysts for organic synthesis. Compared to homogeneous catalysts, heterogeneous catalysts enjoy the advantage that they can be easily recycled by simple filtration due to their insoluble nature.
In this talk, a new class of non-metallic, polymer-based materials, in particular, conjugated porous polymers, combining photoactive π-electron backbone and highly porous properties, will be presented as an efficient and stable platform for heterogeneous visible light-promoted chemical transformations, such as molecular oxygen activation, selective oxidation of organic sulfides, C-C bond formation, reductive dehalogenation reaction, visible light-initiated free radical polymerization.
invited by Dr. Michael Sommer