Effect of acid and ionic strength on the kinetics of electron transfer reaction of n-(2-hydroxy-ethyl) ethylenediamine-n, n’, n’-triacetatocobaltate (ii) complex with hypochlorite ion in aqueous acidic medium

  • Abstract
  • Keywords
  • References
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  • Abstract

    The influence of acid and ionic strength on the rate of electron transfer reaction of N-(2-hydroxy-ethyl)ethylenediamine-N,N’,N’-triacetatocobaltate(II)(hereafter, complex with Hypochlorite ion in aqueous nitric acid medium have been studied at I = 0.2 mol dm-3(NaNO3), [H+] = 1 × 10-2 mol dm-3, , T = 300 ± 1 K and λmax = 525 nm. Stoichiometric study showed 1:1 `mole ratio. The rate law derived from the kinetic study under pseudo first order condition is . The rate constant of reaction,  varies inversely with acid concentration, [H+]. The overall rate law is therefore represented as: . The reaction displayed positive salt effect which suggests the activated complex was made up of similar charged species. The reaction was catalysed by addition of formate, HCOO- and potassium, K+ ions and the Michaelis-Menten’s plot gave zero intercept indicating the absence of intermediate complex. A reaction mechanism via an outer-sphere pathway is proposed for this reaction.



  • Keywords

    Aminocarboxylate; Electron Transfer Reaction; Hyphochlorite; Ionic Strength; Kinetics.

  • References

      [1] Anderegg, G.; Arnaud-Neu, F.; Delgado, R.; Felcman, J.; Popov, K. (2005). "Critical evaluation of stability constants of metal complexes of complexones for biomedical and environmental applications* (IUPAC Technical Report)". Pure Appl. Chem. 77 (8): 1445–1495. https://doi.org/10.1351/pac200577081445.

      [2] Michihiko, K. and Sakayu, S. (1999). Cobalt proteins. European journal of Biochemistry. 261(1), 1- 9. https://doi.org/10.1046/j.1432-1327.1999.00186.x.

      [3] Vuckovic, G.; Antonijevic-Nikolic, M.; Tanaskovic, S.B.; and Zivkovic-Rodovanovic, V. (2011). New Cu (II) and Co (II) octaazamacrocyclic complexes with 2-amino-3-phenylpropanoic acid. J. serb. Hem Soc. 76(5), 719 – 731. https://doi.org/10.2298/JSC101201062V.

      [4] Onu, A.D., Iyun, J.F. and Idris, S.O. (2009) The Kinetics of the Reduction of Tetraoxoiodate (VII) by n-(2-Hydroxyethyl) Ethylenediaminetriacetatocobaltate(II) Ion in Aqueous Perchloric Acid. Transition Metal Chemistry, 34, 849-853. https://doi.org/10.1007/s11243-009-9273-1.

      [5] Onu, A. D. (2010) Kinetics and mechanism of redox reactions of two aminocarboxylatocobaltate (II) compexes with oxy-anions and hydrogen peroxide in aqueous acidic medium. PhD. Dessetation Ahmadu Bello University Zaria, Nigeria.

      [6] Onu, A.D., Iyun, J.F. and Idris, O.S. (2015) Kinetics and Stoichiometry of the Reduction of HydrogenPeroxide by an Aminocarboxylactocobaltate (II) Complex in Aqueous Medium. Open Journal of Inorganic Chemistry, 5, 75-82. https://doi.org/10.4236/ojic.2015.54009.

      [7] Onu, A.D., Iyun, J.F. and Idris, S.O. (2008). Reduction reaction of [CoHEDTAOH2]- with NO2- in aqueous perchloric acid medium: Kinetics and Mechanisms, CHEMCLASS Journal Zaria.

      [8] Onu, A.D., Iyun, J.F. and Idris, S.O. (2016). Oxidation of ethylenediaminetetraacetatocobaltate (II) complex by hydrogen peroxide in aqueous acidic medium: A Kinetics study, J. Chem. Soc. Nigeria, 41(2) 81 – 86.

      [9] Naik, R. M., Srivastava, A., Tiwara, A. K., Yadav, S.B. S. and Verma, A. K. (2007). Kinetic and mechanism studies of amine-n-polycarboxylates complexes of cobalt (II) by periodate ions in aqueous mrdium. J. Iran. Chem. Soc., 4(1): 63 – 71. https://doi.org/10.1007/BF03245804.

      [10] Naik, R.M.; Kumar, B.; Rai, J.; Rastogi, R. and Yadav S.B.S. (2010). Kinetics and mechanism of oxidation of hexamethylenediaminetetraacetatocobaltate(II) complex by periodate ion in aqueous medium. E-journal of chemistry, 7(51), 5391 – 5399. https://doi.org/10.1155/2010/180576.

      [11] Mansour, A.M. (2003) Kinetics and Mechanism of the Oxidation of [N-(2-Hydroxyethyl) Ethylenediamine-N’,N’,N’-Triacetatocobalt(II) by Vanadate Ion. Transition Metal Chemistry, 28, 276-279. https://doi.org/10.1023/A:1022966528585.

      [12] Mohammed, Y., Iyun, J.F. and Idris, S.O. (2010). Silver – catalyzed proxydisulphate oxidationof malachite green in aqueous acidic medium: Kinetic and mechanistic approach.International Journal of Chemistry, 20(2), 105 – 112

      [13] Perumareddi, J.R., Ramachandra, V.R., Rayudu, G.V.S., Bunzli, J.C.G. and Vinny, R.S. (2003). Modern Aspects of Rare Earths and their Complexes. (1st Ed.). Burlington Elsevier. p. 38. ISBN 0080536689

      [14] Abdel-Khalek, A.A., Khalil, M.M. and Khaled, E.S.H. (1993) Kinetics of Oxidation of [N-(2-hydroxyethyl)-Ethylene-Diamine-N, N’, N’-Triacetato] Cobalt (II) by N Bromosuccinimide. Transition Metal Chemistry, 18, 153-157. https://doi.org/10.1007/BF00139946.

      [15] Perveen, A.; Nezemoleslam, T. and Naqvi, I.I. (2013). Preparation of cobalt(III) complexes with trans-1,2-diaminocyclohexane-N,N,N’,N’-tetraacetic acid (CDTA) and ethylenediamminetetraacetic acid (EDTA), African Journal of Pure and Applied Chemistry.7(6).218-224.

      [16] Jiann-Kuo W. (1987). Kinetics of the Reduction of hypochlorite ion. Journal of Electrochemical Society Volume 134, Issue 6, 1462-1467. https://doi.org/10.1149/1.2100690.

      [17] Idris, S.O., Tanimu, A., Iyun, J.F. and Mohammed, Y. (2015). Kinetics and mechanism of malachite green oxidation by hypochlorite ion in aqueous acidic medium. American Chemical Science Journal, 5(2): 185-193. https://doi.org/10.9734/ACSJ/2015/12705.

      [18] Wilkins R.G. (2002): Kinetics and mechanism of reactions of transition metal complexes, 2nd Ed., Wiley-VCH Verlag GmbH &Co., pp. 65-130.

      [19] Benson, D. (1969). Mechanism of inorganic reactions in solution. McGraw- Hill U.K., pp. 153.

      [20] Atkins, P.W. and de Paula, J. (2002). Physical Chemistry. 7th Ed., Oxford University Press, p.962.




Article ID: 17281
DOI: 10.14419/ijac.v7i1.17281

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