NNN Pincer Palladium(II) Complexes with N-(2-(1H-Pyrazol-1-yl)Phenyl)-Picolinamide Ligands: Synthesis, Characterization, and Application to Heck Coupling Reaction

A series of novel NNN pincer palladium(II) complexes with N-(2-(1H-pyrazol-1-yl)phenyl)-picolinamide ligands 6 were prepared and characterized by spectroscopic methods. In addition, the molecular structures of complexes 6a and 6i have also been determined by X-ray single-crystal diffraction. The obtained palladium(II) catalysts showed efficient catalytic activity toward the Heck coupling of aryl bromides with olefins. Under the optimal reaction conditions, the expected various styrenes were obtained in moderate to high yields.