Determination of Solvatochromic Regression Coefficients for the Molybdenum(VI) Complex with Ethylenediamine‐N,N′‐diacetic Acid by Using Kamlet‐Abboud‐Taft Equation

The Solver, Microsoft Excel 2000 powerful optimization package, has been used to perform non‐linear least‐squares curve fitting on the basis of Gauss‐Newton method for the calculation of solvatochromic regression coefficients for the complexation of molybdenum(VI) with ethylenediamine‐N,N′‐diacetic acid and dissociation constants at 25°C and constant ionic strength 0.1 mol·L⁻¹ sodium perchlorate in different aqueous solutions of methanol. A combination of potentiometric and UV spectrophotometric methods have been used for experimental studies. Non specific and specific solute‐solvent interactions were interpreted by correlating the equilibrium data with solvent parameters using the Kamlet‐Abboud‐Taft solvatochromic equation. Finally the influence of the solvent on the stability of the complex was discussed on the basis of the correlation results and the contribution of α (hydrogen‐bond donor acidity), β (hydrogen‐bond acceptor basicity) and π* (dipolarity/polarizability) parameters.