1. Novel Water-Soluble N-Heterocyclic Carbene
Chelates for Transition Metal Catalysts
Elizabeth T. Papish, Department of Chemistry, Drexel University, Philadelphia PA, 19104
N-Heterocyclic carbene (NHC) ligands have the potential to replace phosphines and make hydrogenation reactions greener, more robust and more efficient. We plan to use bulky imidazole and water-soluble triazole rings to design novel bidentate and tridentate carbene ligands for transition metal complexes. Our NHC ligands will be unique in their ability to 1) create three metal-carbon bonds with a geometry similar to tris(pyrazolyl)borate complexes, 2) allow the formation of coordinatively unsaturated, highly active metal centers, and 3) allow electronic modification through triazole based carbenes. Thus far we have focused our efforts on making metal hydride complexes with NHC ligands.
Results:
Various hydride sources → decomposition
Removal of CO by photolysis → decomposition
Removal of CO with Me3NO → no reaction
(R = Me, iPr, tBu)
Future Directions:
1. Synthesis and characterization
2. Testing for stoichiometric or catalytic hydrogenation of polar double bonds