Syntheses, structures, and properties of two dinuclear palladium (II) complexes of a single macrocyclic hexaaza ligand with two hydroxyethyl pendants

Two dinuclear palladium (II) complexes, trans-[Pd2LCl2](ClO4)2 · 2H2O and cis-[Pd2LCl2]Cl2 · 2H2O, of a single macrocyclic ligand with two hydroxyethyl pendants, L (L = 3,6,9,16,19,22-hexaaza-6,19-bis(2-hydroxyethyl)tricyclo[22,2,2,211,14]triaconta-1,11,13,24,27,29-hexaene), have been synthesized as “inorganic proteases” and analyzed by X-ray diffraction method. The two complexes-mediated hydrolytic cleavage of amide bond in acetyl methionyl alanine has been monitored by 1H NMR, showing a moderate hydrolytic rate at 50 °C and pH ca. 1.0. The pendent hydroxyl group is responsible for the hydrolytic reaction.