Evaluation of Formation Constants, Molar Absorptivities of Metal Complexes, and Protonation Constants of Acids by Nonlinear Curve Fitting Using Microsoft Excel Solver and User-Defined Function

Abstract

A nonlinear curve fitting using Microsoft Excel Solver and user-defined function is described for the evaluation of formation constants and molar absorptivities of metal complexes from spectrophotometric data and evaluation of protonation constants of acids from potentiometric data. The procedure was applied to the spectrophotometric data of ML and ML 2complexes and potentiometric data of HL and H 2L acids. The obtained results were compared with those of available packages. The proposed procedure is simple and user friendly. In addition, dynamic displaying of the iterative calculation and search process, complete control of modeling processes by the user, make the procedure an ideal tool for the evaluation of important parameters such as formation constants and protonation constants.