MIXED-LIGAND COMPLEXES OF PALLADIUM(II) INVOLVING PROPANE 1,2,3-TRIAMINE AS PRIMARY LIGAND AND AMINO-ACIDS, PEPTIDES, OR DNA UNITS AS SECONDARY LIGANDS

The acid-base equilibria of propane 1,2,3-triamine (PTA) and the forma tion equilibria of binary and ternary complexes of palladium(II) with PTA as primary ligand and amino acid, peptide, and DNA subunits as sec ondary ligand have been investigated. Pd(II) is found to form a 1:1 co mplex with PTA. The ternary complexes are formed in a stepwise mechani sm, whereby PTA first binds to Pd(II) and then ligates to the secondar y ligand. The hydrolysis of the Pd-PTA complex and the deprotonation o f the amide residues in the peptide complexes are discussed in relatio n to physiological conditions.