apl. Prof. Dr. Uwe Ritter
Director of Institute
phone: +49 3677 69 3603
e-mail: uwe.ritter@tu-ilmenau.de
guest adress: Weimarer Str. 25, 98693 Ilmenau, Curiebau room 206
post adress: PO Box 10 05 65, 98684 Ilmenau
Hydrocarbons consist only of carbon and hydrogen atoms and are encountered in many forms in everyday life. As long chains, hydrocarbons form the plastics polyethylene (PE) and polypropylene (PP), which are used in packaging, for example. Due to their chemical nature, these are particularly stable, which makes them difficult to process and process further.
We address this challenge by developing new catalysts that can activate and functionalize the C-H bond in hydrocarbons. The long-term goal is to enable the conversion of PE and PP into valuable plastics.
To achieve this goal, we rely synthetically on transition metal complexes such as [Rh(PMe3)2(CO)(Cl)]. We use NMR spectroscopy to clarify fundamental mechanistic questions in order to develop new catalysts. To this end, we combine our experimental results with quantum chemical calculations and train molecular machine learning models in order to penetrate into previously unexplored chemical areas.
Publications
- T. Huang, R. Geitner, A. Croy, S. Gräfe, Tailoring Phosphine Ligands for Improved C-H Activation: Insights from Δ-Machine Learning, Digital Discovery2024, 3, 1350-1364,DOI: 10.1039/D4DD00037D.
- T. Huang, S. Kupfer, M. Richter, S. Gräfe, R. Geitner, Bidentate Rh(I)-Phosphine Complexes for the C-H Activation of Alkanes: Computational Modeling and Mechanistic Insight, ChemCatChem2022, 14, e202200854, DOI: 10.1002/cctc.202200854.
Publications
- P. Endres, T. Schuett, S. Zechel, M. D. Hager, R. Geitner, U. S. Schubert, Investigation of the Cooperative-Effects of Lewis-and Brønstedt Acids in Homogeneously Catalyzed OME Fuel Synthesis by Inline-NMR Monitoring, RSC Adv.2024, 14, 14942-14948, DOI: 10.1039/D4RA00744A.
- R. Geitner, Trend Report Physical Chemistry 2022: In situ spectroscopy and catalysis, Nachr. Chem.2022, 70, 64-67, DOI: 10.1002/nadc.20224122539.
- T. Schuett, I. Anufriev, P. Endres, S. Stumpf, I. Nischang, S. Hoeppener, A User-Guide for Polymer Purification Using Dialysis, Polym. Chem.2024, 14, 92-101, DOI: 10.1039/D2PY00972B.
- R. Geitner, A. Gurinov, T. Huang, S. Kupfer, S. Gräfe, B. M. Weckhuysen, Reaction Mechanism of Pd-Catalyzed "CO-Free" Carbonylation Reaction Uncovered by In Situ Spectroscopy: The Formyl Mechanism, Angew. Chem. Int. ed.2021, 60, 3422-3427, DOI: 10.1002/anie.202011152.
Nuclear magnetic resonance (NMR) spectroscopy is a widely used method in chemistry and materials science to decipher unknown molecular structures or to observe chemical transformations at the molecular level.
At the Group, we use NMR spectroscopy to observe molecules at work in solution in order to understand and specifically improve reactions. Specifically, we perform mechanistic and kinetic studies based on ex-situ and in-situ recorded 1D and 2D NMR spectra. We also use inline flow methods to make complex reaction setups accessible to NMR spectroscopy.
We not only investigate interesting chemical reactions, but also develop new methods to improve in situ NMR spectroscopy. Specifically, the department is working on a three-year DFG-funded project to investigate special, so-called NOAH pulse sequences (GE 3112/8-1).
For NMR measurements, we operate a modern 500 MHz AvanceNeo Bruker NMR spectrometer, which was procured with funds from the TAB and the EU via the ERDF structural program (2022 FGI 0002). We also use a 300 MHz NMR spectrometer and a 60 MHz Magritek benchtop device for our work at the Institute of Chemistry and Biotechnology.
In order to control climate change, it is necessary to move away from fossil resources. A critical area in this context is the mobility sector. While smaller and lighter vehicles can be easily electrified, this is not readily possible for heavy goods vehicles, ships and aircraft. A major advantage of chemical energy sources is their high energy density.
Together with Friedrich Schiller University Jena, we are researching the synthesis of oxymethylene ethers as an alternative fuel. These molecules can be burned in engines just like conventional petrol or diesel, but due to their high oxygen content they produce almost no particulate matter. By reducing the CO2 released, electrochemical and biotechnical processes can be used to establish a circular economy for these green fuels.
Publications
- R. Geitner, T. Schuett, S. Zechel, U. S. Schubert, Advancements and Challenges in the Synthesis of Oxymethylene Ethers (OMEs) as Sustainable Transportation Fuels, Chemistry-A European Journal2024, DOI: 10.1002/chem.202401570.
- P. Endres, T. Schuett, J. Kimmig, S. Zechel, M. D. Hager, R. Geitner, Oxymethylene Ether (OME) Fuel Catalyst Screening Using In Situ NMR Spectroscopy, Chem. Eur. J.2023, 29, e202203776, DOI: 10.1002/chem.202203776.
Publications
- A. L. Fink, A. G. Groß, F. Puch, R. Geitner, Photolysis of ortho-Nitrobenzyl Esters: Kinetics and Substituent Effects, ACS Omega 2025, 10, 57560–57567, DOI: 10.1021/acsomega.5c08422.
- F. Puch, A. Fink, M. Schlosser, T. Welzel, R. Geitner, Reversibly Cross-Linked Polyamide 6 Using 1-(5-(Aminoethyl)-2-nitrophenyl)Ethanol as Photolabile Cross-Linker, Macromol. Mater. Eng.2025, e00220, DOI: 10.1002/mame.202500220
Together with the Plastics Technology department, we are working on establishing new processes for recycling fiber composites. Fiber composites combine the properties of plastics and glass or carbon fibers by incorporating the fibers into the plastic. This ensures a significant improvement in mechanical strength, but also means that the composites have been difficult to recycle up to now, as the fibers have to be separated from the surrounding plastic.
To solve this challenge, we are pursuing the approach of introducing a photoswitch at the interface between the plastic and fiber, which can be selectively switched in the recycling process to break the bond between the plastic and fiber at the molecular level.
The Group is part of the Ilmenau School of Green Electronics, a graduate school for research into sustainable electronic components and algorithms and for the qualification of new specialists in this progressive field. The project is funded for four years by the Carl Zeiss Foundation.
At the ISGE, we are researching the production of new self-healing, electrically conductive plastics. Together with the
Group of Theoretical Solid State Physics, we are pursuing an interdisciplinary approach for the description and optimization of molecular self-healing.
Publications
- J. Hack, M. Jordan, A. Schmitt, M. Raru, H. S. Zorn, A. Seyfarth, I. Eulenberger, Ilm-NMR-P31: An Open-Access 31P Nuclear Magnetic Resonance Database and Data-Driven Prediction of 31P NMR Shifts, J. Cheminform.2023, 15, 122, DOI: 10.1186/s13321-023-00792-y.
In addition to the development and use of NMR spectroscopy for the analysize of various chemical reactions, we at the Group of Physical Chemistry/Catalysis are also actively working on the development of new methods for the interpretation of NMR spectra. To this end, we are building electronic, freely accessible databases and developing new machine learning methods for predicting NMR shifts. The focus of our work is on previously underrepresented nuclei such as 31P, 11B and 103Rh, which are relevant for our catalytic research.
The pure interpretation of unknown signals is only one project, as we are also fundamentally concerned with the analysizing of models in the context of "Explainable AI", i.e. the explanation of decision-making by artificial intelligence. To this end, we are working together with the Group of Mathematics of Data Science.
