Stability Constants of Some Univalent Cation Complexes of Tetra-tert-butyl p-tert-Butylcalix[4]arene Tetraacetate in Nitrobenzene Saturated with Water

From extraction experiments and y-activity measurements, the exchange extraction constants corresponding to the general equilibrium M+ (aq) + NaL+ (nb) ⇔__ML+ (nb) + Na+ (aq) taking place in the two–phase water–nitrobenzene system (M+ = Li+, NH+ 4, Ag+, K+ Rb+, Tl+, Cs+; L = tetra-tert-butyl p-tert-butylcalix[4]arene tetraacetate; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Further, the stability constants of the ML+ complexes in water saturated nitrobenzene were calculated; they were found to increase in the series Cs+