Solid-State Molecular Organometallic (SMOM) Chemistry: Transition-metal catalysed hydroformylation reactions in the molecular single-crystal
Final Report Abstract
The main goal of this project was to gain a fundamental understand of the reactivity of organometallic complexes in the solid-state and to investigate their potential activity in industrially relevant catalytic processes. In particular, the hydroformylation of light gaseous alkenes is an ideal candidate to study this because it captures all of these open questions and is a million ton process in industry. The research activities were originally planned for the University of York in Great Britain. Unfortunately, due to massive travel restrictions regarding to COVID-19, the project was started in a well-equipped lab at the University of Regensburg. Regular meetings and seminar via Zoom allowed fruitful scientific exchange with the group of Prof. Weller. In the first months, not only the synthesis of organic ligands and organometallic complexes was performed, but also an interesting variation of Steinle’s cobalt hydroformylation catalyst. The counterion BF4– was substituted by [BArF4]– and a few interesting new complexes were obtained. These compounds were characterised by spectroscopic methods and single-crystal X-ray crystallography. Depending on the steric demand of the chelating phosphorus ligand squareplanar or tetrahedral cobalt species of [(R2P–(CH2)n–PR2)Co(acac)]BArF4 were formed. These crystalline complexes were investigated under an atmosphere of dihydrogen, carbon monoxide, and nitrogen monoxide. The analysis of these reactions is a difficult research objective and will need more time then I spent on it. This project is definitely promising and the aim of this research plan is possible. Due to the fact, that the lab work was done in Regensburg, a second collaboration project between the Weller and Wolf group was started. The combination of non-coordinating phosphorus cations and highly-reactive metalate anions should provide a platform of interesting complexes for several catalytic applications. I was able to synthesise a new substituted tetraaryl phosphorus cation, which was fully characterised and subsequently reacted with transition metal anions. It is not clear if the reaction worked but it looked promising and will be investigated further.
