Schiff Base-Pd(II) Complexes Containing Pyridine and Thiophene Rings: Synthesis, Characterization, Suzuki-Miyaura C-C Coupling Reactions

Abstract

New Schiff base-palladium(II) complexes (1a-d) were synthesized with the reaction of Schiff base ligand and [PdCl2(CH3CN)2]. Pd(II) complexes (1a-d) were solid and stable to moisture and air. Their structures were characterized through the spectroscopic techniques including microanalysis, FT-IR, UV-Vis, proton (1H) and carbon (13C) NMR, mass spectrometry. The data obtained from the spectroscopic techniques showed that Schiff base-Pd(II) complexes 1a, 1b and 1c were formed through the coordination of azomethine nitrogen and carbonyl/hydroxyl oxygen atoms, while 1d complex coordinated only azomethine nitrogen atom of the Schiff base. All complexes were found to have square plane. In addition, Pd(II) complexes (1a-d) were investigated in Suzuki-Miyaura coupling reactions of different aryl bromides using phenylboronic acid. The reactions were carried out in a mixed aqueous EtOH/H2O (1/3) at room temperature with K2CO3 as the base for 1 hour. The Pd(II) complexes (1a-d) used as catalysts exhibited perfect catalytic activity in the Suzuki-Miyaura reaction.