The development of selective PNP Ligand stabilized Co complex catalysts

• Applicant: Professor Dr. Rhett Kempe
• Subject Area: Inorganic Molecular Chemistry - Synthesis and Characterisation
• Term: from 2017 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 361806216

The sustainable handling of the resources of our planet is a central challenge of humankind. Chemistry with its high demand of diverse resources and loaded with negative connotations has the chance to play a forerunner role hereby; firstly, since chemical key expertise is needed and, secondly, to improve acceptance in society and to attract more young people to our science. Noble metals are rare and expensive and are used diversely, for instance as catalysts. Many 3d-metals (transition metals of the 4th period) are abundant and very inexpensive. The replacement of noble metals by abundantly available and inexpensive 3d-metals in diverse chemical applications serves the above discussed science philosophy. Aim of the project proposal is the development of novel cobalt complex-catalysts for catalytic reactions that have been mediated by noble metals so far.In our preliminary work, published in JACS (2x) and Angew. Chemie (1x), we could develop novel highly active cobalt catalysts for important catalytic reactions. We propose the following interlinked sup-projects.Hydrogenation: In preliminary work, we could show that cobalt catalysts are an interesting alternative to noble metal catalysts in the hydrogenation of C=O bonds. Right now, we do not understand how the catalytic cycle runs and how the substrates become activated at the cobalt complex. Thus, we plan mechanistic studies permitting then a more rational catalyst design. The broad scope of our cobalt catalyst system in ketone hydrogenation suggests the development of related chiral catalysts, which is planned by us. Alkylation reaction using alcohols: In our project related publications, we could demonstrate a certain potential of our Co catalyst class in alkylation reactions using alcohols as the alkylation agents. Consequently, we propose to investigate the alkylation of ketones, of methyl-azaarenes and of alcohols. Such reactions proceed more efficient in the presence of bases, which permits a simple catalyst activation.Novel reactions: One of the most interesting question in 3d-metal catalysis is the one for novel catalytic reactions, which cannot be mediated by noble metals. In our published preliminary work, we discovered selectivity profiles that have not been seen for noble metals yet. The development of novel reactions based on such a selectivity seems feasible. In addition, we are interested in a novel C-C coupling reaction. Non-published preliminary work indicates a potential of our Co catalyst in such a reaction.

• DFG Programme: Research Grants