Sterically and electronically modified pyridines as ligands for the stabilization of reactive main group element compounds

• Applicant: Dr. Tobias Böttcher
• Subject Area: Inorganic Molecular Chemistry - Synthesis and Characterisation
• Term: from 2016 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 319235580

The aim of this research proposal is the development of sterically and electronically modified pyridines as ligands for the stabilization of reactive main group element compounds. The functionalization of the 2,6-positions at the 2,6-Position of pyridine with electropositive diazaboryl groups results in a significant increase of the electron density at the pyridine’s nitrogen atom and thus to its basicity due to their +I-effect. The amine nitrogen atoms of the diazaboryl groups are weakly basic and can serve as hemilabile donor functions. Calculations show that this ligand system can stabilize highly reactive main group fragments like [SiCl]+ of AlCl and provide them as synthons for further chemical reactions. To prevent unwanted reactivities at the 4-position of the pyridine, it is necessary to protect the position with a suitable functional group. It could be shown by calculations that a substituent with a +M-Effect further increases the basicity additionally to the +I-effect of the substituents at the 2,6-positions. The application of (NacNac)M- (M = Zn, Mg) as a functional highly electropositive group in ligand design shall be demonstrated. The project with the anionic pyridine ligand substituted with mesityl-groups at the 2,6-positions and a triphenylborate-group at the 4-position, shall be completed with some concluding experiments.

• DFG Programme: Research Grants