Dinuclear Pd(II) complexes containing bis-O,N-bidentate Schiff base ligands: Synthesis, characterization, DFT study and application as Suzuki–Miyaura coupling catalysts

Abstract

The reaction of binucleating Schiff base ligands with [PdCl2(PPh3)2] and [Pd(OAc)2] afforded a new family of binuclear palladium(II) Schiff base complexes of the type [Pd2(L)2] and [Pd2Cl2(PPh3)2(L)]. All the palladium complexes are air stable and fully characterized by elemental analysis, FT-IR, UV–Vis and 1H NMR spectral methods. These palladium(II) Schiff base complexes exhibit characteristic metal to ligand charge transfer (MLCT) transitions. Quantum mechanical calculations were also performed to investigate the electronic structure, assign the vibrational spectra and to determine the nature of the frontier molecular orbitals and absorption spectra of the above complexes. These palladium(II) Schiff base complexes exhibited good catalytic activity in the carbon–carbon Suzuki coupling reaction of different aryl halides using phenyl boronic acid.