Novel C,N-Donor Analogs of Nitrone and Pd/NHC Complexes Based Thereon

Novel 1,2,4-triazolium salts, 4-aryl-3-arylamino-1-(pyridin-2-yl)-1,2,4-triazolium bromides, were synthesized. These triazolium salts can be used as precursors of base-ionizable N-heterocyclic carbene (NHC) ligands capable of deprotonating the NH-acidic arylamino group. New Pd/NHC complexes, in which NHC acts as a bidentate C,N-donor chelating ligand, were prepared by metallation of the synthesized triazolium salts with palladium acetate. It was found that the obtained complexes have enhanced stability in strongly basic media and may be of interest as potential catalysts for cross-coupling reactions.