MIXED LIGAND CHELATES OF COPPER(2)

Potentiometric studies of the interaction between Cu(II) and various bidentate chelating agents are described. Chelation reaction steps are given for those single ligand chelates of Cu(II) formed in solution in a 1:1 and a 1:2 molar ratio of Cu(II) with the respective ligands, and for those mixed ligand chelates of Cu(II) formed in solution in a 1:1:1 molar ratio of Cu(II) to one of a series of diprotonated diamine primary ligands, and one of a series of secondary acidic ligands. Formation constants for the corresponding single ligand chelates and mixed ligand chelates of Cu(II) were calculated. The series of primary ligands employed was 1,10-phenanthroline, N-hydroxyethylethylenediamine, N, N, N′, N′-tetramethylethylenediamine, and 2,2′-dipyridyl; the series of secondary ligands employed was 1,2-dihydroxybenzene-3,5-disulfonic acid, 1,8-dihydroxy-3,6-naphthalenedisulfonic acid, pyrocatechol, 8-hydroxy-5-quinolinesulfonic acid, salicylic acid, 5-sulfosalicylic acid, and oxalic acid. © 1969.