Novel Ligands for Transition-Metal Catalysis

Invention Summary:

N-heterocyclic carbenes (NHCs) are tremendously valuable ligands in homogeneous catalysis. IPr (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) represents the most important NHC. Rutgers scientists have developed novel, sterically bulky, easily accessible NHC ligand IPr# (referred to as “hash” series) that can be utilized as ancillary ligands in a broad range of catalytic reactions. These catalysts can activate unconventional and strong bonds with broad generality, providing ligands with extreme steric hindrance around the transition metal which is critical for catalysis and isolation of unstable intermediates.

The activity of IPr# has been evaluated in palladium-catalyzed cross-coupling reactions, such as amide N-C(O) Suzuki cross-coupling, C-Cl Buchwald-Hartwig amination, Amide N–C(O) transamidation, Ester C–O amidation, C-H activation and C-S sulfur metathesis, with good to excellent yields.

Furthermore, a direct three step synthesis method of the novel catalyst has been developed using modular alkylation of aniline, an industrial chemical that is available in bulk. The synthesis pathway can also be used for facile preparation of electronically and sterically different analogues such as bis(imino)acenaphthalene ligands, highlighting the capacity of this design platform.

Market Applications:

  • Synthesis of fine chemicals, functional materials or polymers


  • Simple synthesis from inexpensive and readily available materials
  • Extreme steric hindrance around the metal center
  • Flexibility in the synthesis of its wingtip analogous
  • Ease of variation in HOMO and LUMO properties

Intellectual Property & Development Status:

Patent pending. Available for licensing and/or research collaboration.

Patent Information:
For Information, Contact:
Deborah Perez
Associate Director, Physical Sciences & Ag
Rutgers University
Chemical and petrochemical industry