FOR 1405:  Dynamics of Electron Transfer Processes within Transition Metal Sites in Biological and Bioinorganic Systems

• Subject Area: Chemistry ; Physics
• Term: from 2011 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 159419156

Structures and reactivities of chemical substances are highly affected by charge distributions. This appraisal holds not only for synthetic systems but for metallobiomolecules as well. Hence, transfer of charge density within these systems should result in structural changes on a molecular as well as on an atomic level and thus is predestinated to exert influence on the reaction behaviour of metalloproteins and metalloenzymes in a characteristic manner.
The catalytical activity of copper containing enzymes is a prominent example, which is based on this principle of charge transfer. These molecules attract considerable interest not only from a scientific point of view but also because of their technical importance as guides for industrial applications.
Within the scope of this Research Unit, we intend to make use of the optically excited charge transfer in such systems and related synthetic models in order to gain insights into the chronologies of the processes induced. The scientific approach is focussed on time-resolved investigations of suitable molecules in their excited states employing novel pump/probe techniques based on ultramodern pulsed photon sources.
The envisioned experiments are based on photons from large-scale facilities such as FLASH, PETRA III, ESRF, SLS and DORIS III in combination with laser-based photon sources. This approach allows to trigger biochemical processes and to study the resulting action of the molecular complex on a femto- to picosecond time scale. Based on charge-transfer transitions induced by visible to UV photons, the successive use of VUV and soft X-ray photons allows to study the following actions time resolved in a pump-probe configuration with atomic and orbital selectivity.
The Research Unit also acts as an interface between novel photon sources and their unique spectroscopic capabilities being currently developed in the field of physics a well as modern approaches in quantum theoretical physics in order to tackle important fundamental problems on the role of metals in modern biochemistry. With our results we intend to deliver the necessary boundaries and knowledge to improve tailor made oxidation catalysts, to finally understand biological charge-transfer processes, and to learn how copper affects pathological folding processes in proteins.

• DFG Programme: Research Units

Projects

• Charge transfer Raman, XES and (HR)XAS studies on Type Zero model complexes (Applicants Bauer, Matthias ;  Herres-Pawlis, Sonja )
• Cooperation Research Unit (Applicants Henkel, Gerald ;  Herres-Pawlis, Sonja )
• Cu-S complexes in the heart of biological electron transfer: the homodinuclear CuA site of Cytochrome-c oxidases and N2O reductases (Applicants Bauer, Matthias ;  Henkel, Gerald )
• Light induced charge transfer processes in bis-oxo and peroxo dicopper complexes for biomimetic hydroxylation (Applicants Herres-Pawlis, Sonja ;  Rübhausen, Michael )
• Theoretical Modeling of Bioinorganic Copper Complexes (Applicants Gerstmann, Uwe ;  Schmidt, Wolf Gero )
• Time-resolved studies on the dynamics of electronic charge transfer processes in bioinorganic complexes - development of technological foundations (Applicants Bauer, Matthias ;  Chapman, Ph.D., Henry N. ;  Henkel, Gerald ;  Rübhausen, Michael )

• Spokespersons: Professor Dr. Gerald Henkel; Professorin Dr. Sonja Herres-Pawlis