Spectrophotometric Studies on Fe (II)-2 Hydroxy5-methyl-benzophenone-ethylenediamine-anil Complex

Rasayan Bhavan, Saurashtra University, Bhavnagar. Manuscript received 4 September 1973 ; accepted 11 December 1973 Ferrous iron forms a reddish brown coloured complex with 2-Hydroxy-5-methyl-benzophenone-ethylenedia­mine-anil (HMBEA) in the pH range 2.5-3.0. The complex exhibits maximum absorption at 520 run and 480 nm. The composition of the complex (1:1) has been determined by Job's method of continuous variation, mole ratio method and slope ratio method employing spectrophotometric data. The dissociation constant and the stability constant at 30° are 5.775 x 10-7 and 1.732 x 106, respectively. The standard free energy of formation of the complex is -8.706 kcal/mole and the molecular extinction coefficient is 8.3 x 108 at 520 nm. The quantitative estimation of Fe2+ at pH 2.5-3.0 was done and the composition of the complex (1:1) was established by oxide method also