Understanding the coupling of nitrogen-carbon bonds in the electrosynthesis of N-C-based feedstock chemicals – A systematic study on porphyrin and phthalocyanine based catalysts

• Applicant: Professorin Dr. Inez Weidinger
• Subject Area: Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry ; Inorganic Molecular Chemistry - Synthesis and Characterisation
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 559380826

The electrosynthesis of N-C-based basic chemicals such as urea or methylamide by coupled electrolysis of abundant simple nitrogen- and carbon-containing precursor molecules has the potential to develop into a sustainable alternative to the traditional chemical processes used to date. However, there is currently little mechanistic understanding of this reaction that would allow the properties of suitable electrocatalysts to be specifically improved and a higher selectivity for a particular product to be achieved. For this reason, the present project will investigate the systematics of this coupling reaction by combining electrochemical and vibrational spectroscopic techniques. Porphyrin and phthalocyanine complexes immobilized on electrodes are used as catalysts. These molecular complexes are ideally suited for mechanistic studies, as the chemical environment of the active center can be set in a very defined manner. In the present project, a systematic investigation on the NCC coupling reaction of nitrate and CO2 as reactants is to be carried out. On the one hand, the central metal atom of molecular complexes is to be varied. On the other hand, these complexes are to be used as molecular units in two-dimensional organometallic frameworks. Hereby, the influence of a second metal on the N-C coupling will be analyzed. Finally, porphyrin complexes with a second coordination sphere will be tested. Electrochemical Raman spectroscopy will provide information on the structure of the macrocycle under catalytic conditions and monitor the binding of the C and N substrates. Electrochemical ATR-IR spectroscopy will be used as a complementary tool to understand the influence of functional ligands on catalysis and to allow a detailed study of the CO intermediate. Together with the electrochemical data and product analysis, it will be possible to better understand the mechanism of N-C coupling.

• DFG Programme: Research Grants