ON THE FORMATION OF IRON(III) BENZOYLACETANILIDE COMPLEXES - STRUCTURAL, ELUCIDATION BY TGA, IR, ELECTRONIC-SPECTRA, CONDUCTANCE AND POTENTIOMETRIC STUDIES

Two new series of iron(III) benzoylacetanilide complexes have been prepared and characterized by elemental analysis, TGA, IR, electronic spectra and conductance measurements. The elemental analyses show that the composition of the solid complexes produced have 1:2 and 1:3 (M:L) molar ratios. TGA and IR spectra indicated that the bonding in 1:3 (M:L) complexes takes place through the enolic-OH group and anilied N- linkage only while 1:2 (M:L) complexes it takes place through interaction of carboxy OH or SH together with the enolic OH group through H+ ion displacement. Electronic spectra indicated octahedral geometry around Fe(III) ion. Conductometric and potentiometric titrations indicated the formation of 1:1, 1:2 and 1:3 (M:L) complexes in solutions. The values of the conditional stability constants calculated by potentiometric techniques depend on molecular structure. Deviation of the pK1 vs log K plots slopes from unity is attributed mainly to steric effect, pi-electron back donation from the metal ion or structural changes in the ligand.

AKILA L SALEH ,A ELDEKKN ,SAMY M ABUELWAFA ,MOHAMED ABD ELMOTTALEB ,ABD EL RAHEEM ,