PALLADIUM(II) COMPLEXES OF N-SULFONYLAMINO ACIDS .2. COORDINATION BEHAVIOR UNDER STRONGLY ACIDIC CONDITIONS

The ligation of a series of N-sulfonylamino acids (H(2)L) to Pd2+ was investigated by means of d.c. polarography, H-1 NMR and electronic spectroscopy. The first amino acid is found to bind to the metal under extremely acidic conditions, with an apparent pK(NH) value of about 1, while an additional molecule binds with a pK(NH) ranging from 3.1 to 3.7 for the different amino acids. These nitrogen-deprotonated complexes appear not to involve carboxylate complexes as stable precursors. Proton NMR spectroscopy indicates the presence of geometric isomers for the [PdL(2)](2-) species.