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By study of the distribution of copper(II) and l-proline (Pro) ions between an aqueous phase and a resin phase with l-proline groupings on a polystyrene matrix (R ), the conditional stability constants of fixed-site R (2) Cu and sorbed R CuPro complexes have been determined and a method for calculation of the constants for alkaline and neutral media is proposed. The values obtained reflect the actual behaviour of the system, and strongly depend on the ph and the ionic strength of the solution in equilibrium with the resin phase. It was established that this dependence and the high values of the conditional constants of complex formation in comparison with the stability constants of low molecular-weight model compounds are due to the donnan distribution of the low molecular-weight participants and to the effect of the electrostatic field of the polyanion. The distribution of the fixed-site ligands on the resin causes considerable differences in the stability of individual fixed-site R Cu complexes and their capacity to enter into reactions with ligands in the aqueous phase.

The dissociation constants of the carboxyl groups (pK(a1) = 2.2, n = 1.8) and amino groups (pK(a2) = 9.5, n(2) = 1.6) of a sorbent prepared by reacting l-proline with a cross-linked chloromethylated styrene polymer have been determined by potentiometric titration. The potentiometrically measured stability constants of the Cu(II) complexes of the resin (logbeta(1) = 6.9 and log beta(2) = 12.4) were found to be close to the values for the Cu(II) complexes of N-benzyl-l-proline. For complexed resins of alpha-amino-acid type the pH-values of decomplexation do not appear to be directly correlated with the stability constants.