New palladium complexes with S- or Se-containing Schiff-base ligands as efficient catalysts for the Suzuki-Miyaura cross-coupling reaction of aryl bromides with phenylboronic acid under aerobic conditions

Four palladium chelate complexes with S- or Se-containing substituted salicylaldehyde Schiff-base derivatives have been synthesized. Spectroscopic and crystallographic data indicate that, in the complexes, the deprotonated salicylaldehyde ligand is bound to the metal in an O,N,S (or Se)-terdentate coordination mode, forming one six- and one five-membered chelate ring. The complexes are thermally and air stable and efficiently catalyze the Suzuki-Miyaura crosscoupling of aryl bromides with phenylboronic acid in air.