MIXED-LIGAND COMPLEXES OF NI(II), CU(II), TH(IV) AND UO2(II) WITH SOME BENZOIC-ACID DERIVATIVES AND AMINO-ACIDS

The ternary complexes, Cu(II)-salicyclic acid-amino acids, Ni(II)-sali cylic acid-aspartic acid, Th(IV)-salicylic or thiosalicylic acid-amino acids, and UO2(II)-salicylic acid-amino acids, have been synthesized. The amino acids used were glycine, alanine, serine, valine, leucine a nd aspartic acid. It is suggested that the synthesis of the ternary co mplexes examined depends on the basicity of both the primary ligand (s alicylic and thiosalicylic acids) and the secondary ligand (amino acid ), as well as the nature of the metal ion. The isolated complexes were characterized by chemical analyses and IR spectra. The stoichiometry and apparent formation constant values of the ternary complexes formed in solution have been determined spectrophotometrically and the stabi lity of the complexes is discussed in terms of the nature of the amino acid used.