Wenger group

 

 

Inorganic Photophysics and Photochemistry, Fundamentals of Solar Energy Conversion and Artificial Photosynthesis

 

Our group investigates elementary chemical reactions for solar energy conversion and artificial photosynthesis. Key topics are:

Our research is molecule-based, and our focus is on understanding functional principles.

Our methods include synthesis of organic molecules and coordination complexes, time-resolved laser spectroscopy, and some electrochemistry. We call this a “make and measure” approach.

 

New photoactive metal complexes, photoredox catalysis

Mo_isocyanide

Many of the most widely employed sensitizers of photochemical reactions and solar energy conversion processes are made from precious metals such as iridium or ruthenium. We explore how more earth-abundant metals can be used for the same purpose. The main challenge is to obtain long-lived excited states which result in luminescence and in exploitable redox chemistry. We achieve this with careful ligand design and the synthesis of new classes of metal complexes. Synthetic work is complemented by electrochemical and optical spectroscopic studies.

Büldt, L. A.; Guo, X.; Prescimone, A.; Wenger, O. S. Angew. Chem. Int. Ed. 2016, 55, 11247.

Büldt, L. A.; Guo, X.; Vogel, R.; Prescimone, A.; Wenger, O. S. J. Am. Chem. Soc. 2017, 139, 985.

 

Charge accumulation

pentad

Many fuel-forming reactions rely on multi-photon multi-electron chemistry which is usually performed with sacrificial reagents. This is not sustainable because sacrificial donors or acceptors are expensive and energy-rich. We have found ways to avoid the use of such substances for light-driven charge accumulation in purely molecular systems. Currently we explore how this process can be made more efficient and how it can be used for energy storage in a more general fashion.

Orazietti, M.; Kuss-Petermann, M.; Hamm, P.; Wenger, O. S. Angew. Chem. Int. Ed. 2016, 55, 9407.

Kuss-Petermann, M.; Orazietti, M.; Neuburger, M.; Hamm, P.; Wenger, O. S. J. Am. Chem. Soc. 2017, 139, 5225.

Kuss-Petermann, M.; Wenger, O. S. Chem. Eur. J. 2017, doi: 10.1002/chem.201701456.

 

Photo-induced electron and proton transfer

dist_dep

We discovered that electron transfer reactions can become faster when the distance between a donor and an acceptor is increased, and we studied many examples of proton-coupled electron transfer (PCET). Fundamental investigations of this type are important because they help us understand mechanisms and functional principles which are the key for mimicking natural photosynthesis. These investigations are based on tailor-made model compounds and on time-resolved laser spectroscopies.

Kuss-Petermann, M.; Wenger, O. S. Angew. Chem. Int. Ed. 2016, 55, 815.

Kuss-Petermann, M.; Wenger, O. S. J. Am. Chem. Soc. 2016, 138, 1349.

 

Photo-generation of biologically useful fuels

In a collaborative research project funded by the NCCR Molecular Systems Engineering, we aim to use solar light to convert NAD+ to NADH (nicotinamide adenosine dinucleotide). The latter can fuel various enzymatic reactions, which opens the possibility of performing biochemistry with visible light as the energy source. We use metal complexes to absorb light and to initiate hydride transfer from sacrificial reagents to catalysts, which are then able to react with NAD+. The long-term vision is to transfer electrons across a membrane in order to perform light-driven enzymatic chemistry in a closed compartment surrounded by a membrane.

 

Molecular wires for charge and energy transfer

wires

We explored numerous organic mixed-valent compounds and other molecules which act as wires that can conduct charges and energy. Such systems are of interest for example for lighting devices such as organic light emitting diodes (OLEDs). Our research focus is on the development of new charge transfer pathways in novel compounds. In some cases, we exploit supramolecular interactions to control the charge transfer efficiencies, and we collaborate with colleagues from physics and the Swiss Nanoscience Institute who investigate charge transport across single molecules.

Chen, J.; Wenger, O. S. Chem. Sci. 2015, 6, 3582.

 

Collaborations

Dr. Pierre Dechambenoit, Université de Bordeaux, France

Prof. Josef Hamacek, Université d'Orléans, France

Prof. Peter Hamm, University of Zurich, Switzerland

Prof. Andreas Hauser, Université de Genève, Switzerland

Prof. Carmen Herrmann, University of Hamburg, Germany

Prof. Helge Lemmetyinen, Tampere University of Technology, Finland

Prof. Markus Meuwly, University of Basel, Switzerland

Prof. Franc Meyer, Georg-August-Universität Göttingen, Germany

Prof. Cornelia G. Palivan, University of Basel, Switzerland

Prof. Dietmar Stalke, Georg-August-Universität Göttingen, Germany

Prof. Eric Vauthey, Université de Genève, Switzerland

Prof. Thomas R. Ward, University of Basel, Switzerland