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 spe ctroscopy. The first amino acid is found to bind to the metal under ex tremely acidic conditions, with an apparent pK(NH) value of about 1, w hile 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. Pro ton NMR spectroscopy indicates the presence of geometric isomers for t he [PdL(2)](2-) species.