N-Heterocyclic carbene–carbodiimide (NHC–CDI) betaine adducts: synthesis, characterization, properties, and applications. Issue 8 (26th January 2021)

• Record Type: Journal Article
• Authors: Lamb, Jessica R.; Brown, Christopher M.; Johnson, Jeremiah A.
• Is Part Of: Chemical science. Volume 12:Issue 8(2021)
• Page Start: 2699
• Page End: 2715
• Publication Date: 2021-01-26
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/d0sc06465c
• Languages: English
• ISSNs: 2041-6520

Abstract

Abstract : N -heterocyclic carbene-carbodiimide betaine adducts are zwitterionic amidinate-like structures with tunable properties that have applications as ligands, junctions in supramolecular polymers, and stabilizers for radical cations. Abstract : N -Heterocyclic carbenes (NHCs) are an important class of reactive organic molecules used as ligands, organocatalysts, and σ-donors in a variety of electroneutral ylide or betaine adducts with main-group compounds. An emerging class of betaine adducts made from the reaction of NHCs with carbodiimides (CDIs) form zwitterionic amidinate-like structures with tunable properties based on the highly modular NHC and CDI scaffolds. The adduct stability is controlled by the substituents on the CDI nitrogens, while the NHC substituents greatly affect the configuration of the adduct in the solid state. This Perspective is intended as a primer to these adducts, touching on their history, synthesis, characterization, and general properties. Despite the infancy of the field, NHC–CDI adducts have been applied as amidinate-type ligands for transition metals and nanoparticles, as junctions in zwitterionic polymers, and to stabilize distonic radical cations. These applications and potential future directions are discussed.