Novel five-membered ( κ 2 −C, N ) -palladacyclic complexes were prepared from the reaction of the corresponding acetate-bridged palladacycle dimer with N-heterocyclic carbene (NHC) ligands in high yields. Palladacyclic complexes (3) were fully characterized by elemental analysis and 1 H and 13 C NMR spectroscopy. Palladacyclic complexes were tested as catalyst for the C-C bond forming reaction. These complexes were found to be efficient catalysts for the Suzuki-Miyaura reaction of aryl bromides.

The novel ruthenium(II) complexes [RuCl 2 (NHC)(p-cymene)], 3a-e, containing 1-alkyl-3-benzylimidazol-2-ylidene ligands were prepared. All synthesized compounds were characterized by NMR spectroscopy and elemental analyses. Ru(II)-NHC complexes were tested as catalysts for the transfer hydrogenation of acetophenone, showing modest to high activity in this reaction. The results revealed that efficiencies depend on the substituents of the benzene ring of the benzyl on the N atom of the NHC ring.