Synthesis of Pd(II) complexes with P-N-OH ligands derived from 2-(diphenylphosphine)-benzaldehyde and various aminoalcohols and their catalytic evaluation on Suzuki-Miyaura couplings in aqueous media

[Display omitted] •3 potentially tridentate P-N-OH ligands were made from aminoalcohols and 2-(diphenylphosphine)-benzaldehyde.•The ligands were reacted with [Pd(COD)Cl2] to yield complexes either bidentate P-N of tridentate P-N-OH ligands.•The coordination was determined by the α-substituent in the amino, to be bidentate when R = H and tridentate when R ≠ H.•The three complexes attained performed well as catalysts in Suzuki-Miyaura couplings. The reactivity of a series of P-N-OH ligands derived from aminoalcohols and 2-(diphenylphosphine)-benzaldehyde was explored towards [Pd(COD)Cl2] leading to a series of Pd(II) complexes having the ligands behaving either in a bidentate P-N or a tridentate P-N-OH manner. The complexes were fully characterized including the unequivocal determination of the molecular structures of all compounds by single crystal X-ray diffraction analysis. Interestingly, the ligands bearing α–substituted amines bind to the metal in a tridentate fashion through the P, N and OH atoms, while the ligand having the unsubstituted amine coordinated to Pd(II) center in a P-N bidentate manner. Furthermore, the catalytic activity of these complexes was explored in Suzuki-Miyaura couplings promoted by microwaves in aqueous media, affording yields up to 91% of biphenyls in 5 min.