Reactions of Pd(II) with a series of potentially tridentate nitrogen ligands—II solution studies

Potentiometric and conductometric titrations of the system Pd(II) and pyridine-2-aldehyde-2′-pyridylhydrazone in aqueous solution show that only one proton per atom of Pd is titratable; i.e. only one mole of ligand coordinates with each Pd. [PdL₂] does not form in aqueous solution. Job's method of continuous variations was applied and a computer calculation on a model system was used to estimate equilibrium constants. PMR investigations suggest the ligand in [PdL₂] undergoes isomerization about the imine bond.