1,3,5‐Trideoxy‐1,3,5‐tris(dimethylamino)‐<i>cis</i>‐inositol, an Efficient Ligand for Hard Trivalent Metal Ions. Determination of the stability constants of the Fe^III, Al^III, and Cu^II complexes in aqueous solution

Abstract

Abstract The complexes [Fe(tdci) 2 ]Cl 3 and [Al(tdci) 2 ]Cl 3 (tdci = 1,3,5‐trideoxy‐1,3,5‐tris(dimethylamino)‐ cis ‐inositol) were prepared and characterized by mass spectrometry, NMR spectroscopy, and magnetic‐susceptibility measurements. The formation constants were determined in aqueous solution (25°, 0.1 M KCl) by potentiometric titration. p K values of H 3 (tdci) 3+ : 5.89, 7.62, 9.68; Fe III complexes: log β ML = 18.8, log β = 32.6; Al III complexes: log β ML = 14.3, logβ = 26.4. The protonated complex [FeH(tdci) 2 ] 4+ has also been identified. In contrast to the high stability of the Fe III and Al III complexes, only weak interactions of tdci with Cu II have been observed in aqueous solution (25°, 0.1 M KNO 3 ).