Synthesis, characterization, Suzuki-Miyaura and Mizoroki-Heck cross-coupling reactions of Schiff base-Pd(II) complexes

Abstract

Cross-coupling reactions are powerful and versatile tools mainly for the formation of carbon-carbon bonds in modern organic synthesis. The cross-coupling reactions catalyzed by palladium complexes have attracted a great deal of attention of researchers in recent years. Two new mononuclear Schiff base-Pd(II) complexes (1, 2) were synthesized and characterized by FT-IR, UV-Vis, NMR (1H and 13C), ESI-MS, CHNS analysis, magnetic susceptibility, molar conductivity, melting points, thermogravimetric analysis in addition to powder X-ray diffraction and SEM-EDX analysis. Depending on spectral and magnetic measurements, the suggested geometrical shapes of these complexes were reported. Further, Suzuki-Miyaura and Mizoroki-Heck cross-coupling reactions, using K2CO3 as base and Et-OH+H2O (1:2) ration as solvent under atmospheric conditions, were carried out with the synthesized complexes in the presence of various aryl halides, phenylboronic acid, and styrene. Schiff base-Pd(II) complexes (1, 2) were found to provide very good yields in Suzuki-Miyaura and Mizoroki-Heck cross-coupling reactions. The results showed that electron-donating and electron-withdrawing substituents on the aryl halides might produce coupling products in perfect yield in the presence of Pd(II) complexes 1 and 2.