New Pyridine ONN-Pincer Gold and Palladium Complexes: Synthesis, Characterization and Catalysis in Hydrogenation, Hydrosilylation and CC Cross-Coupling Reactions

The ONN-tridentate unsymmetrical pincer 2- [6- (pyrrolidin-1 -ylmethyl)pyridin-2-yl]phenol and N-tert-butyl-1-{[6-(2-hydroxyphenyl)pyridin-2-yljmethyl)pyrrolidine-2-carboxamide ligands were synthesized by an easy method in high purity and good yields. All the organic compounds were characterized by elemental analysis, mass spectrometry, IR and 1 H and 13 CNMR spectroscopy. Palladium(II) and gold(III) complexes have been prepared as air-stable solids, with the ONN-tridentate ligand after deprotonation of the hydroxy group, the coordination of the metal ion is completely stereospecific and gives rise to only one diastereoisomer. These complexes were shown to be very active catalysts in the hydrogenation (80 % ee was achieved with the chiral gold complex), hydrosilylation and C-C coupling, Suzuki and Heck, reactions, under mild conditions.