Unsymmetrical ONO-type pincer complexes of palladium(II) containing amino acid barbiturate derivatives: Synthesis, characterization, and catalytic applications in Suzuki-Miyaura cross-coupling reaction

New two tridentate pincer ligands were prepared by the reaction between the selected amino acids and 1,3-dimethyl barbituric acid. The corresponding Pd(II) complexes were synthesized from the treatment of palladium(II) acetate with the prepared ligands in presence of an ancillary ligand such as pyridine, triph-enylphosphine, or 1-methylimidazole. All ligands and Pd(II) complexes were characterized by standard spectroscopic and analytical techniques. The crystal and molecular structures of two complexes were de-termined by single-crystal X-ray diffraction revealing a slightly distorted square-planar geometry around the metal center to which the ligand bonded in an ONO-tridentate fashion. The catalytic activities of Pd(II) complexes were evaluated in the Suzuki-Miyaura coupling reaction of phenylboronic acid with the different aryl halides. They showed good activity for 4-substituted aryl bromide with phenylboronic acid.(c) 2022 Elsevier B.V. All rights reserved.

Automated summary

New tridentate pincer ligands and their corresponding Pd(II) complexes were synthesized and characterized. The crystal and molecular structures of two complexes were determined by X-ray diffraction. The Pd(II) complexes exhibited good catalytic activity in the Suzuki-Miyaura coupling reaction.