Palladium and Ruthenium Complexes with bidentate Ligands - Preparation and Catalytic activity

In this work, bidentate azo-contained ligand (E)-4-(pyridin-2-yldiazenyl)phenol (4) and (E)-2-(phenyldiazenyl)pyridine (5) were synthesized. Complexes containing these ligands including [(4)PdCl2] (4aa)、[(4)Pd(TFA)2] (4ab)、[(4)Pd(CH3)Cl] (4b)、[(5)PdCl2] (5a)、[(2-(2’-hydroxy-arylazo)pyridine)PdCl] (5b) and [(4)(terpyridine)RuCl] (4d) were prepared. Complex 4aa、4b and 4d have been characterized by NMR,ESI-MASS,FAB-MASS and X-ray crystallography. Because of the characteristic of hygroxy group, the use of UV-Vis analyzer investigate influence of pH changes caused by complexes. Discussion on catalysis, the choice of Suzuki coupling reaction to compare this series of palladium metal complexes differ in catalytic activity, as well as various substituents reacted rate differences, and then explore the reaction mechanism. Deprotoned ligand in the base environment can enhance the solubility in water. So that it maintains its catalytic activity in the aqueous phase, realizing the concept of green chemistry.