Modeling and Thermodynamic Values of Complex Equilibrium of Cobalt(II) with Diethylenetriaminepentaacetic Acid in Aqueous Solution

Ghusoon Faidhi Hameed(1), Fawzi Yahya Wadday(2*), Nahla Shakir Salman(3)

(1) Department of Chemistry, Faculty of Education, Al-Qadisiyah University, Al-Qadisiyah, Iraq
(2) Department of Chemistry, Faculty of Science, Kufa University, Al-Najaf, Iraq
(3) Department of Chemistry, Faculty of Education, Al-Qadisiyah University, Al-Qadisiyah, Iraq
(*) Corresponding Author


The paper reports the study of the complex formation of cobalt (II) with diethylenetriaminepentaacetic acid (DTPA, H5L) based on spectrophotometric (SF) and potentiometric data (pH). Complexes of different compositions were found, and equilibrium constants, as well as the stability constants of these complexes, were determined. Accumulation of complexes in proportion is calculated based on the acidity of the medium. The experimental data have been carried out by using mathematical models to assess the solution's possible existence with a wide spectrum of complex particles and to point out those which are quite sufficient to copy the experimental data. In addition, thermodynamic parameters (ΔG°, ΔH°, and ΔS°) for the studying complexes were calculated according to the values of stability constant (KST) at 25 °C obtained from the temperature dependence of stability constant by using van’t Hoff equation.


cobalt; stability constants; spectrophotometer; potentiometer

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[1] Dyatlova, N.M., Temkina, V.Y., and Popov, K.I., 1988, Kompleksony i kompleksonaty metallov (Complexones and Compexonates of Metals), Khimiya, Moscow.

[2] Martak, F., Cahyani, N.W.D., Nugraheni, Z.V., and Utomo, W.P., 2016, Properties and toxicity of cobalt(II) complex with 2,4,5-triphenyl-1H-imidazole ligand, Indones. J. Chem., 16 (3), 260–267.

[3] Rawat, K.S., Kumar, R., and Singh, S.K., 2019, Topographical distribution of cobalt in different agro-climatic zones of Jharkhand state, India, Geol. Ecol. Landsc., 3 (1), 14–21.

[4] Hall, L.H., Spijkerman, J.J., and Lambert, J.L., 1968, Preparation and coordination studies of the complex acid, dihydrogen diethylene-triaminepentaacetatoferrate(III) dihydrate, and several of its metal (I) salts, J. Am. Chem. Soc., 90 (8), 2044–2048.

[5] Sugiyarto, K.H., Kusumawardani, C., and Wulandari, K.E., 2018, Synthesis and structural analysis of powder complex of tris(bipyridine)cobalt(II) trifluoromethanesulfonate octahydrate, Indones. J. Chem., 18 (4), 696–701.

[6] El-Sherif, A.A., Shoukry, M.M., Abd Elkarim, A.T., and Barakat, M.H., 2014, Protonation equilibria of biologically active ligands in mixed aqueous organic solvents, Bioinorg. Chem. Appl., 2014, 626719.

[7] Sucipto, T.H., Churrotin, S., Setyawati, H., Mulyatno, K.C., Amarullah, I.H., Ueda, S., Kotaki, T., Sumarsih, S., Wardhani, P., Bendryman, S.S., Aryati, A., Soegijanto, S., and Kameoka, M., 2017, Inhibitory activity of cobalt(II)–morin complex against the replication of dengue virus type 2, IJTID, 6 (6), 141–144.

[8] Rakhmanin, Y.A., 2016, Actualization of methodological problems of regimentation of chemical pollutions on the environment, Gig. Sanit., 95 (8), 701–707.

[9] Cui, P., Yin, Q., Gong, J., Wang, Y., Hao, H., Xie, C., Bao, Y., Zhang, M., Hou, B., and Wang, J., 2013, Thermodynamic analysis and correlation of solubility of candesartan cilexetil in aqueous solvent mixtures, Fluid Phase Equilib., 337, 354–362.

[10] Wang, Z., Long, Z.W., Long, C.Y., and Zhang, W., 2015, On the thermodynamic properties of the spinless Duffin-Kemmer-petiau oscillator in noncommutative plane, Adv. High Energy Phys., 2015, 901675.

[11] Kumar, A., Rout, S., Ghosh, M., Singhal, R.K., and Ravi, P.M., 2013, Thermodynamic parameters of U (VI) sorption onto soils in aquatic systems, SpringerPlus, 2 (1), 530.

[12] Batool, F., Akbar, J., Iqbal, S., Noreen, S., and Bukhari, S.N.A., 2018, Study of isothermal, kinetic, and thermodynamic parameters for adsorption of cadmium: An overview of linear and nonlinear approach and error analysis, Bioinorg. Chem. Appl., 2018, 343724.

[13] Hussein, A.A., Karem, L.K.A., and Mohammed, S.S., 2020, Preparation, diagnosis, thermodynamic and biological studies of new complexes derived from heterocyclic ligand, Syst. Rev. Pharm., 11 (5), 445–450.

[14] Nwabanne, J.T., 2012, Kinetics and thermodynamics study of oil extraction from fluted pumpkin seed, IJMSE, 3 (2), 11–15.

[15] Anwer, M., Muqtader, M., Iqbal, M., Ali, R., Almutairy, B.K., Alshetaili, A., Alshahrani, S.M., Aldawsari, M.F., Alalaiwe, A., and Shakeel, F., 2019, Estimating the solubility, solution thermodynamics, and molecular interaction of aliskiren hemifumarate in alkylimidazolium based ionic liquids, Molecules, 24 (15), 2807.

[16] Blokhina, S.V., Sharapova, A.V., Ol’khovich, M.V., Volkova, T.V., Proshin, A.N., and Perlovich G.L., 2017, Thermodynamic aspects of solubility and solvation of bioactive bicyclic derivatives in organic solvents, J. Chem. Eng. Data, 62 (12), 4288–4295.

[17] Jastrzab, R., Kaczmarek, M.T., Tylkowski, B., and Odani, A., 2018, Computer analysis of potentiometric data of complexes formation in the solution, Phys. Sci. Rev., 3 (3), 140.

[18] Singh, J., Srivastav, A.N., Singh, N., and Singh, A., 2019, “Stability constants of metal complexes in solution” in Stability and Applications of Coordination Compounds, IntechOpen Limited, London, UK, 90183.

[19] Plyasunova, N.V., Zhang, Y., and Muhammed, M., 1998, Critical evaluation of thermodynamics of complex formation of metal ions in aqueous solutions. V. Hydrolysis and hydroxo-complexes of Co2+ at 298.15 K, Hydrometallurgy, 48 (2), 153–169.

[20] Mehdi, S.H., and Budesinsky, B.W., 1974, Protonated metal complexes of diethylenetriaminepentaacetic acid (DTPA), J. Coord. Chem., 3 (4), 287–292.

[21] Jelecevic, A. Horn, D., Eigner, H., Sager, M., Liebhard, P., Moder, K., and Vollprecht, D., 2019, Kinetics of lead release from soils at historic mining and smelting sites, determined by a modified electro-ultrafiltration, Plant Soil Environ., 65, 298–306.

[22] Remy, G., 1966, A Course of Inorganic Chemistry, Vol. 2, Mir, Moscow.

[23] Kornev, V.I., and Alabdulla, G.F., 2017, Simulation of equilibria of formation of mono-and polynuclear heteroligand cobalt(II) and nickel(II) complexonates in aqueous solutions, Russ. J. Inorg. Chem., 62 (8), 1127–1133.

[24] Krajewska, B., and Brindell, M., 2016, Thermodynamic study of competitive inhibitors’ binding to urease, J. Therm. Anal. Calorim., 123 (3), 2427–2439.

[25] Tamiji, Z., Yazdanipour, A., and Niazi, A., 2018, Spectrophotometric and thermodynamic study on the dimerization equilibrium of neutral red in the water and micelle environments by chemometrics methods, Int. J. Exp. Spectrosc. Tech., 3, 15.

[26] Baikusheva-Dimitrova, G., Genieva, S., and Yankova, R., 2017, Synthesis, thermal behavior and thermodynamic data of hafnium selenite tetraaqua complex dihydrate, Int. J. Sci. Eng. Appl. Sci., 2 (3), 137–144.


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