Equilibrium Constants of the Complexation of Molybdate Ion with para-Sulfonatocalix [4] arene in aqueous media

Abstract

The complexation of sodium molybdate with para-sulfonatocalix [4] arene was studied in the<br />temperature range from 20 to 40 °C and pH = 5.8 by spectroscopic method in water solution. The<br />stability constants of complexes were calculated by the multiwavelength analysis of spectral data<br />using SQUAD program. The equilibrium constant, spectroscopic data, molar absorptivities and<br />concentrations of all species were adequately optimized by program when the chemical model<br />with 1:1 stoichiometry was considered in the calculation. The extracted values of molar<br />absorptivities and concentration- profile of the formed complex were reported. The logarithms of<br />the stability constants of complexes were calculated to be 3.672, 3.143, 2.986, 2.555, and 2.333<br />at20, 25, 30, 35and 40 °C respectively