Role of electrostatic interaction in the processes of complex formation

Aspects of the theory of associate mixtures formed as a result of electrostatic interaction between their components are discussed. We obtained equations, convenient for comparison with the experiment, that elucidate the dependence of the association constant on the dielectric susceptibility of the solvent. The experimental results of the associates studied, which were composed of a diazo-salt cation and an anion of a xanthene dye, are described satisfactorily by the theoretical dependences, but with a smaller equilibrium distance between the associate component. We have shown that the smaller equilibrium distances are due to the fact that the dependence of the dielectric susceptibility of the solvent on the distance (r) for small distances between the interacting ions is not taken into account in the qualitative theory.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 22, No. 5, pp. 591–596, September–October, 1986.