ESR characterization of hydrogen-producing bioinspired inorganic catalysts
Özlen Ferruh Erdem
Many microorganisms use molecular hydrogen as an energy source (H2 uptake) or protons as an electron sink (H2 evolution) via the hydrogen conversion redox reaction that is catalyzed by hydrogenases. Inspired from nature, synthetic catalysts which mimic the function of the active site of [FeFe] hydrogenases have been developed.1 Complexes which accommodate mononuclear iron(I-III) intermediates that feature hydride, phosphine, cyclopentadienyl, and pendant base ligands are of special interest. By means of a theory-supported spectroscopic approach (with FT-IR, EPR, Moessbauer, as well as DFT), it will be shown that not only the metal-core and direct ligands, but also the second coordination sphere have influence on the catalytic activity. It will be presented that for an iron hydrido catalyst, the catalytic direction of this class of monoiron compounds can be reversed by rational design of the ligands.2 Investigation of trapped intermediates in their diamagnetic and paramagnetic states provides a comprehensive understanding3 of the working principles of natural enzymes and bioinspired model compounds, and leads to newly designed, highly efficient catalysts.
Reminder: Tea and cookies will be in the seminar room before the seminar.