WATEROX · Polynuclear manganese and manganese calcium complexes: searching for water oxidation catalysts

The project deals with the synthesis and characterization of polynuclear Mn and Mn/Ca complexes as potential water oxidation catalysts. The “direct synthesis” approach in which zerovalent metals or metal oxides are employed as starting material will be used for the preparation of the polynuclear complexes. The isolated complexes will be identified by analytical methods (atomic absorption, CHN-analysis) and characterized by IR, UV-Vis, EPR spectroscopy, magnetochemistry, electrochemistry and single crystal X-ray diffraction analysis. Their catalytic activity in the reaction of chemical water oxidation by Ru(III) polypyridyl complexes will be tested. In the next step of the project, an oxidant will be generated by light irradiation from a Ru(II) polypyridyl complex and a sacrificial electron acceptor. The systems, in which the photooxidant not covalently linked to the Mn or Mn/Ca complex, will be investigated focusing on oxygen evolution measurement, EPR spectroscopy for the observation of electron-transfer from the Mn catalyst to Ru photosensitizer and by laser flash photolysis for kinetic evaluation of this process. In returning phase, reactive functional groups will be introduced into the most active manganese containing complexes. These building blocks then will be employed by Consortium for the synthesis of photocatalytic dyads and triads.