Binding of phosphate, pyrophosphate, and hexacyanoferrate(II) by fully N-methyl substituted polyantmonium cations in aqueous solution

In this study, we determined the stability of some fully N-methyl substituted polycation-inorganic polyanion complexes by potentiometric measurements at t ) 25 °C. As for other previously studied similar systems, the stability of ALHr species (A ) amine; L ) inorganic polyanion; r ) 1, 2, ... m, with m g n, n ) maximum protonation degree of the amine) is a function of the charges involved in the formation equilibrium. The basicity of the polyanion also plays a fairly significant role. The stability of these species is compared with that of analogous species of unsubstituted amines and with that of polyammoniumcarboxylate complexes. Simple predictive stability relationships are given.