Tetracoordinate diamidato-bis(phosphanyl) metal systems: Synthesis, characterization, and electrochemical analysis of palladium(II) complexes

Square planar diamidato-bis(phosphanyl) palladium(II) complexes have been prepared and characterized. Most products precipitate out of THF solution on reaction of the parent ligand with Pd(OAc)2 in the presence of 2 equiv. of base at 50 °C overnight. The solution and solid state structure of each complex is reported based on multinuclear NMR and X-ray analyses, respectively. The effects of carboxamido nitrogen coordination on the stabilization of the metal center from reduction were studied using cyclic voltammetry. The irreversible peak reduction potential of each complex was greater by approximately −340 mV to −590 mV as compared to Pd(PPh3)2Cl2 indicating that carboxamido nitrogen coordination protects the Pd(II) center from reduction.

Graphical abstractTetracoordinated diamidato-bis(phosphanyl) palladium(II) complexes were prepared on reaction of the parent ligand, Pd(OAc)2, and 2 equiv. of base in THF at 50 °C. Characterization of the complexes in solution and solid state are reported. Cyclic voltammetry studies indicate that the amidato bonding stabilizes the complex from reduction.Figure optionsDownload full-size imageDownload as PowerPoint slide