Aisha A. Al-Abbassi1 , Matali Hassn 1 , Aisha Maimoon1 , Khadija A. Ahmida1 , Noria Belkhar1 , Adel M. Najar 2*
Stability constants of two and three complexes resulting from interactions of Fe(II) with Catechol (CAT) and Ascorbic Acid (AA) at equilibrium, were studied spectrophotometrically, potentiometrically and conductometrically. However, ferrous binary complex of vitamin C more stable than Fe(II) binary complex of catechol as stability constant revealed. The log K2 values of CAT and AA/Fe(II) complexes recorded at 11.588 and 8.899 respectively. In ternary system; the stoichiometric ratio between M:L(AA):L(CAT) kept constant at 1:1:1. Experimentally; the Δlog K coefficients were calculated; the positive values indicated that the ternary complexes is more stable than the binary complexes. However, addition of AA and Back tea to Fe (II) reported that disappear of d-d transition which indicate that the Fe-polyphenols complexes were not formed. Theoretically, molecular geometry and electronic structure of the molecules were calculated and discussed using DFT.