Controlling Intersystem Crossing in Transition Metal Complexes for Selective Switching Between Singlet and Triplet Reactivity

• Applicant: Dr. Till Schmidt-Räntsch
• Subject Area: Inorganic Molecular Chemistry - Synthesis and Characterisation
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 567156931

One of the main goals of photochemistry is to convert visible light into chemical energy, similar to photosynthesis, since sunlight is the cleanest and most abundant renewable energy source available on earth. This is achieved by excitation of molecules with light, leading to electronically excited states. The behavior of each state correlates with its specific properties. The aim of this project is to lay the fundamental basis for controlling photochemical behavior via the excitation wavelength. The result would be that different chemical elementary processes, e.g. energy transfer or electron transfer, within a molecule can be triggered selectively through a change of wavelength. In the long term, the knowledge obtained is especially attractive for synthetic chemistry, since it can lead to the development of novel routes in drug synthesis or in the production of fine chemicals. Typically, higher excited states relax to the lowest excited state by ultrafast processes, hindering usability of the higher states. Through rational molecular design of a new class of metal complexes, these ultrafast processes shall be suppressed. By systematic variation of the metal and coordinated ligands, molecular design factors will be identified that allow realization of this completely new photophysical concept. Work packages in this project involve prescreening of possible complexes by computational chemistry, synthesis and characterization of suitable complexes as well as characterization of excited states by a variety of spectroscopic and computational methods. The most promising complexes will be used in different photochemical reactions in order to evaluate the general applicability of the developed concept. The group of Prof. Dr. Oliver Wenger at University of Basel provides an excellent research environment for this endeavor due to their photochemical and photophysical expertise, as well as their technical equipment and infrastructure. During this postdoctoral stay, I hope to expand my knowledge in the fields of optical (transient) spectroscopy, computational chemistry and photophysics/photochemistry in general.

• DFG Programme: WBP Fellowship
• International Connection: Switzerland
• Host: Professor Dr. Oliver S. Wenger