Simple Synthesis of a Stable, Novel Class of Metal Ligand

Technology #17268

Questions about this technology? Ask a Technology Manager

Download Printable PDF

Image Gallery
Simple synthesis of a stable, novel class of carbene anchor
Professor Jeremiah Johnson
Department of Chemistry, MIT
External Link (
Aleksandr Zhukhovitskiy
Department of Chemistry, MIT
Managed By
Jon Gilbert
MIT Technology Licensing Officer
Patent Protection

Persistent Carbene Adducts and Related Methods

US Patent Pending
Cycloelimination of Imidazolidin-2-ylidene N-HeterocyclicCarbenes:Mechanism and Insights into the Synthesis of Stable“NHC-CDI” Amidinates
Chem. Eur. J., 2015, 21, 5685-5688


The synthesis of N-heterocyclic carbene-bis(aryl) carbodiimide (NHC-CDI) is a fundamental discovery, for which specific applications are currently being explored. NHC-CDIs are a novel structural class of molecule with potential application as ligands for Lewis acidic species (e.g., transition metal cations). The development of novel ligand classes is critical to the discovery of transition metal catalysts and crucial to the fields of organometallic chemistry and materials science. Additionally, NHC-CDIs absorb visible light and emit violet-indigo fluorescence upon complexation, rendering them suitable as novel optical sensors for transition metals. 

Problem Addressed

The development of ligands with distinctive properties and reactivity is critical to the discovery of new metal catalysts. This method of production of a novel metal ligand class (NHC-CDIs) is easily performed and results in a uniquely bench-stable construct that exhibits robust binding and ligand properties.


Since the first demonstration of their potential stability, isolation, and storability, NHCs have become pervasive in both experimental and commercial applications as electron-rich, neutral ligands. One of the most widely used classes of NHCs—1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene, known as “SIMes”—are commercially available and widely used as ligands and catalysts. Upon heating, NHCs of the SIMes family can be converted via a [3+2]-cycloelimination process to a novel class of NHCs known as NHC-CDI amidinates, notably useful as novel ligand scaffolds for Lewis acidic metals. Isolable NHC-CDI adducts have been reported only once previously, and were structurally distinctive from those generated as described above, rendering them less practical for commercial use. NHC-CDI adducts generated via [3+2]-cycloelimination reactions of NHCs of the SIMes family are uniquely stable at both ambient conditions and in the presence of moisture. Additionally, upon complexation, NHC-CDIs absorb visible light and emit violet-indigo fluorescence, conferring optical sensor functionality. 


  • Easily synthesized via commercially available and air-stable NHCs
  • Stable under ambient conditions for months and in the presence of moisture for at least 3 days
  • Novel ligand for Lewis acidic metals
  • Optical sensor capabilities