Periodic Reporting for period 4 - N2FEED (N2 as Chemical Feedstock – Synthetic Nitrogen Fixation beyond Haber-Bosch) Reporting period: 2019-12-01 to 2020-11-30 Summary of the context and overall objectives of the project Synthetic nitrogen fixation (Haber-Bosch Process) is one of the most important industrial processes providing ammonia as the feedstock for basically all nitrogen containing compounds, such as fertilizers but also many polymers or pharmaceuticals. In order to circumvent the high energy consumption and low ammonia yields associated with the HBP, we strive to circumvent the ammonia generation step and synthesize N-containing chemicals by direct N2 functionalization at ambient conditions. Catalytic platforms will be developed that split N2 into molecular nitrides and allow for subsequent C–N bond formation. The electron rich transition metal complexes with functional pincer ligands used in this project represent a fundamentally new approach in synthetic N2 fixation. The overall N2 functionalization effort will be broken down into three elementary steps, i.e. N2 splitting, de-/hydrogenation of metal bound N-species, and C–N bond formation. These subprojects are examined individually with a combination of modern synthetic, physical inorganic, and computational methods. These results will finally enable the rational design of homogeneous catalysts for direct nitrogen transfer from N2 into organic products. Besides this primary goal, secondary objectives are to make important contributions to related topics, such as C–N coupling by nitrenoid transfer or the use of nitrogen compounds, especially ammonia, as chemical fuels in energy storage schemes. Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far During the first stage, we have successfully worked on the three work packages of the project:A) In the first work package we have continued to examine N2 splitting. New platforms were developed that undergo this challenging reaction and the chemical parameters that control the thermochemistry and kinetics of this reaction were examined.B) Special emphasis was put on the coupling of charge and proton transfer which is of relevance for electrochemical approaches. Electrochemical N2 splitting was observed for the first time as proof-of-principle and is currently optimized.C) We developed an efficient platform the enables the transfer of dintrogen from N2 into acetonitrile. This result already represents the realization of an important objective of the project. Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far) This project advances the state-of-the-art of nitrogen fixation by:1. Providing fundamentally new routes for the sustainable synthesis of nitrogen containing chemicals; impact is expected on the energy consumption and feedstock basis for such chemicals.2. Giving insights into the relevance of correlated processes, such as thermal or photochemical proton coupled electron transfer, for multi electron redox transformations such as N2 fixation. These results will be instrumental for catalyst design also for other challenging reactions.
