N-heterocyclic carbenes are well known, but their analogs where the carbon is swapped for nitrogen to form a nitrenium ligand were unknown. Researchers have now filled the gap among main-group analogs of N-heterocyclic carbenes (NHCs) by replacing the carbon with an isoelectronic nitrogen cation to form a nitrenium.
This novel entity acts as a ligand for transition metals forming strong bonds with the metal as confirmed by unambiguous X-ray crystallography and solution studies with selective nitrogen-15-labeling. Additional experiments and computational analysis demonstrates that these novel ligands are poor sigma-donor but a good π-donor.
The team is now making more examples and investigating the ligand complexes as catalysts.