carbanionic diphosphin ligands

• Applicant: Professor Dr. Jens Beckmann
• Subject Area: Inorganic Molecular Chemistry - Synthesis and Characterisation
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 562942739

The introduction of novel ligands and substituents in organometallic chemistry allows the exploration of new compounds classes and is closely associated with gaining knowledge. We recently introduced the 2,6-bis(dipenylphosphino)phenyl substituent, 2,6-(Ph2P)2C6H3, which was instrumental for the synthesis of photo- and electroluminescent coinage metal complexes with sometimes very high quantum yields. Through the development of an efficient synthesis route for the preparation of 2,6-(Ph2P)2C6H3Br and the related lithium organyl 2,6-(Ph2P)2C6H3Li, the same substituent now also accessible for other metals and non-metals. By the Staudinger reaction, e.g. the reaction with aryl azides, such as mesityl azide, and the reaction with borane, respectively, the phosphorus atoms in 2,6-(Ph2P)2C6H3Br can be modified to give the reagents 2,6-(Ph2PNMes)2C6H3Br and 2,6-(Ph2PBH3)2C6H3Br, which are now available as novel pincer substituents. Preliminary investigations reveal that metal-halide exchange reaction can yield the reagents 2,6-(Ph2PNMes)2C6H3MgCl‧THF and 2,6-(Ph2PBH3)2C6H3Li. These reagents should provide access to other metals and non-metal by salt metathesis and transmetallation. The three substituents offer tremendous potential for exploratory s-, p-, d- und f-block chemistry, which shall be further pursued. The target molecules possess potentially interesting optoelectronic properties and unusual bond situations (mixed valent and subvalent species, metallophilic and quasi agostic interactions, multiple Z-type complexes) that are formed by intramolecular coordination of the Ph2P-, Ph2PNMes- and Ph2PBH3 groups, respectively. They are useful for the potential preparation of organic light emitting diodes (OLEDs), for the activation of small molecules and as hydrogen storage.

• DFG Programme: Research Grants