Abstract

Electron transfer underpins fundamental biological processes such as respiration and photosynthesis as well as modern technologies. Unpaired electrons play an important role in numerous such redox reactions but these can be difficult to capture. In this talk I will discuss how we are exploiting and developing electron paramagnetic resonance (EPR) based techniques in conjunction with electrochemistry and materials chemistry to gain mechanistic insights into electron-transfer reactions.

I will introduce film-electrochemical EPR spectroscopy (FE EPR ) as a tool to investigate redox-active molecules, including catalysts. With operando FE-EPR, using indium-tin-oxide electrodes, we showed that it is possible to gain new mechanistic insight by monitoring the evolution of radicals during catalysis in real time.1 I will further discuss our ongoing work on extending FE-EPR to metalloenzymes,2,3 and on exploring the properties of carbon nanotube structures as electrode materials.4 Lastly, I will discuss how our efforts to understand interfacial electron transfer have led to the improved efficiency of tin perovskite solar cells.5

Short Bio Maxie M. Rößler is Professor of Chemistry at Imperial College London. She earned her MChem degree from the University of Oxford and completed her DPhil in Inorganic Chemistry under Prof. Fraser Armstrong FRS in 2012. Maxie began her independent career at Queen Mary University of London in 2013 and joined Imperial in 2019, where she founded the Centre for Pulse EPR (PEPR). Her recent recognitions include being named the Blavatnik Awards in the UK Chemistry Laureate (2026), receiving the Royal Society of Chemistry Joseph Black Prize (2024) and the European Bioinorganic Chemistry Medal (2022). 1. Seif-Eddine, M. et al. Operando film-electrochemical EPR spectroscopy tracks radical intermediates in surface-immobilized catalysts. Nature Chemistry 2024 16:6 16, 1015–1023 (2024). 2. Facchetti, D., Dang, Y., Seif-Eddine, M., Geoghegan, B. L. & Roessler, M. M. Film-electrochemical EPR spectroscopy to investigate electron transfer in membrane proteins in their native environment. Chemical Communications 60, 12690–12693 (2024). 3. Abdiaziz, K., Salvadori, E., Sokol, K. P., Reisner, E. & Roessler, M. M. Protein film electrochemical EPR spectroscopy as a technique to investigate redox reactions in biomolecules. Chemical Communications 55, 8840–8843 (2019). 4. Dang, Y., Seif-Eddine, M., Ying, Z., Shaffer, M. S. P. & Roessler, M. M. Carbon Nanotube Electrodes as a Versatile Platform for Operando Film-Electrochemical EPR Spectroscopy. Manuscript under review (2026), doi.org/10.26434/chemrxiv-2026-t8sfs. 5. Fang, F. et al. Electron hopping in conjugated molecular wires with application to solar cells. Nature Chemistry 2026 1–9 (2026) doi:10.1038/s41557-025-02034-0.