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New complexanes. VII. Stability constants of the 1,3-di-amino-2-propanol-N,N,N',N'-tetraacetic acid chelates of certain bivalent metal cations

J. Majer, E. Dvořáková, and M. Nagyová

Komenský University, Bratislava

Abstract: cf. CA 65, 3305b. The chelate forming properties of the 1,3-diamino-2-propanol-N,N,N',N'-tetraacetic acid (I) with some bivalent cations were studied by potentiometric neutralization titrns. The dissocn. consts. and the stability consts. of I with these cations were detd.: Mg²⁺, Ca²⁺, Sr²⁺, Ba²⁺, Mn²⁺, Fe²⁺, and Pb²⁺. The more stable chelates Cu²⁺, Zn²⁺, and Cd²⁺ were evaluated by the Schwarzenbach method (S. and Freitag, CA 46, 4414e) of exchange equil. The measurements were carried out at ionic strength μ = 0.1 (KNO₃) and 20°. The alc. OH group decreases the basicity of N in amino groups which results in the lowering of pK values and in a decrease of the stability of the metal chelates. The stability const. was decreased to the greatest extent in the Mg chelate, while Sr and Ba chelates were not affected. The effect of the alc. OH group of I was similar to that of the 1,3-diaminopropane-N,N,N',N'-tetraacetic acid.

Full paper in Portable Document Format: 205a313.pdf (in Slovak)

Chemical Papers 20 (5) 313–320 (1966)