Binding of fluoride and carbonate by open chain polyammonium cations

The formation of open chain polyammonium cation-fluoride and -carbonate complexes was studied by potentiometric and calorimetrictechniques at t = 25 ◦C. Several species of HiAL (A = amine; L = F−, CO32−) are formed in both systems with a mean stability logK = 1.0ζ(ζ = |zanion ×zcation|) and logK = 2.0ζ for fluoride and carbonate, respectively. The comparison with analogous systems (chloride and acetatefor fluoride and hydrogenphosphate, sulfate and malonate for carbonate) showed that fluoride and carbonate form the most stable specieswith open chain polyammonium cations, among low molecular weight anions. The N-alkyl substitution does not play negligible role in thestability of these complexes, the species formed by substituted amines being more stable.