סמינר בכימיה אורגנית: Nitrenium ions: Ligands, Reagents, Catalysts

Abstract:

N-heterocyclic carbenes (NHCs) have received a spectacular development in the last few decades. Possessing unique chemical properties, NHCs have found wide application in organometallic chemistry and catalysis. Not surprisingly, the chemistry of the main-group NHC-analogs (NEN species; E = B-, Ga-, Si, Ge, Sn, Pb, P+, As+, Sb+), isoelectronic and isostructural to NHC, has attracted a great interest. The missing link in this series of ligands and catalysts was the nitrogen counterpart - the N-Heterocyclic Nitrenium ion (NHN). It is defined as a divalent cationic nitrogen center bearing a lone pair of electrons and an accessible vacant p-orbital in its singlet state.

In my lecture, we will discuss versatile chemistry of NHN species. We will demonstrate coordination ability of these unusual cationic ligands, analyze their properties and their utilization in stabilization of elusive species.1,2 Mainly, we will demonstrate that nitrenium ions can be used as Lewis acids.3 We will discuss versatile and intriguing reactivity of nitrenium in organocatalysis, frustrated Lewis pairs chemistry4 and radical-based chemistry.5 In addition, we will reveal how the fundamental understanding of the nitrenium properties led us to the development of triazenolysis reaction - an aza-version of the canonical alkene ozonolysis.6

References:

1 Nat. Chem. 2011, 5, 525.

2 Chem.Sci. 2014, 5, 1305.

3 J. Am. Chem. Soc. 2017, 139, 4062.

4 Angew. Chem. Int. Ed. 2020, 59, 23476.

5 J. Am. Chem. Soc. 2022, 144, 23642.

6 Nat. Chem. 2024, doi.org/10.1038/s41557-024-01653-3.