Kinetics and Mechanism of Oxidation of Hexamethylenediaminetetraacetatocobaltate(II) Complex by Periodate Ion in Aqueous Medium
The kinetics and mechanism of oxidation of [CoII HDTA]4- (Where HDTA=Hexamethylenediamine tetraacetic acid} by periodate ion has been studied in aqueous acidic medium. The reactions has been investigated spectrophotometrically at λmax = 580 nm under pseudo- first -order condition by taking large exc...
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Wiley
2010-01-01
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| Series: | E-Journal of Chemistry |
| Online Access: | http://dx.doi.org/10.1155/2010/180576 |
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| author | R. M. Naik B. Kumar J. Rai R. Rastogi S. B. S. Yadav |
| author_facet | R. M. Naik B. Kumar J. Rai R. Rastogi S. B. S. Yadav |
| author_sort | R. M. Naik |
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| description | The kinetics and mechanism of oxidation of [CoII HDTA]4- (Where HDTA=Hexamethylenediamine tetraacetic acid} by periodate ion has been studied in aqueous acidic medium. The reactions has been investigated spectrophotometrically at λmax = 580 nm under pseudo- first -order condition by taking large excess of oxidant [IO4] at pH = 4.0±0.02, I = 0.1 M (CH3COONa + NaNO3).and temperature = 30± 0.1 °C The electron transfer reaction between [CoII HDTA] 4- and [IO4-] obeys inner sphere reaction pathway through the formation of long-lived intermediate complex which finally get converted into a corresponding [CoIIIHDTA] 3- complex as final reaction product. The experimental observations have shown that the reaction obey first- order dependence in [CoII HDTA] 4--. The variation of pseudo-first-order rate constants (kobs) with[IO4-], keeping other reaction variables fixed at constant value was found to obey the rate law: kobs=a[IO4-]2/b+c[IO4-], which is consistent with a three step mechanistic scheme. The values of kobs are almost constant with increasing pH, which can be attributed to the reaction of deprotonated form of [CoIII HDTA] 4- complex only, in the entire pH region. Eyring’s equation has been used to calculate the thermal or activation parameters and found to be, ΔH# = 28.69 kJ mole–1; ΔS# = – 481.13 J K-1 mole–1 respectively and support the proposed mechanistic scheme. |
| format | Article |
| id | doaj-art-6eb04e123a9c407b84f31db4730935a7 |
| institution | Kabale University |
| issn | 0973-4945 2090-9810 |
| language | English |
| publishDate | 2010-01-01 |
| publisher | Wiley |
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| series | E-Journal of Chemistry |
| spelling | doaj-art-6eb04e123a9c407b84f31db4730935a72025-02-03T07:25:14ZengWileyE-Journal of Chemistry0973-49452090-98102010-01-017S1S391S39910.1155/2010/180576Kinetics and Mechanism of Oxidation of Hexamethylenediaminetetraacetatocobaltate(II) Complex by Periodate Ion in Aqueous MediumR. M. Naik0B. Kumar J. Rai1R. Rastogi2S. B. S. Yadav3Department of Chemistry University of Lucknow, Lucknow-226 007, IndiaDepartment of Chemistry University of Lucknow, Lucknow-226 007, IndiaDepartment of Chemistry University of Lucknow, Lucknow-226 007, IndiaDepartment of Chemistry University of Lucknow, Lucknow-226 007, IndiaThe kinetics and mechanism of oxidation of [CoII HDTA]4- (Where HDTA=Hexamethylenediamine tetraacetic acid} by periodate ion has been studied in aqueous acidic medium. The reactions has been investigated spectrophotometrically at λmax = 580 nm under pseudo- first -order condition by taking large excess of oxidant [IO4] at pH = 4.0±0.02, I = 0.1 M (CH3COONa + NaNO3).and temperature = 30± 0.1 °C The electron transfer reaction between [CoII HDTA] 4- and [IO4-] obeys inner sphere reaction pathway through the formation of long-lived intermediate complex which finally get converted into a corresponding [CoIIIHDTA] 3- complex as final reaction product. The experimental observations have shown that the reaction obey first- order dependence in [CoII HDTA] 4--. The variation of pseudo-first-order rate constants (kobs) with[IO4-], keeping other reaction variables fixed at constant value was found to obey the rate law: kobs=a[IO4-]2/b+c[IO4-], which is consistent with a three step mechanistic scheme. The values of kobs are almost constant with increasing pH, which can be attributed to the reaction of deprotonated form of [CoIII HDTA] 4- complex only, in the entire pH region. Eyring’s equation has been used to calculate the thermal or activation parameters and found to be, ΔH# = 28.69 kJ mole–1; ΔS# = – 481.13 J K-1 mole–1 respectively and support the proposed mechanistic scheme.http://dx.doi.org/10.1155/2010/180576 |
| spellingShingle | R. M. Naik B. Kumar J. Rai R. Rastogi S. B. S. Yadav Kinetics and Mechanism of Oxidation of Hexamethylenediaminetetraacetatocobaltate(II) Complex by Periodate Ion in Aqueous Medium E-Journal of Chemistry |
| title | Kinetics and Mechanism of Oxidation of Hexamethylenediaminetetraacetatocobaltate(II) Complex by Periodate Ion in Aqueous Medium |
| title_full | Kinetics and Mechanism of Oxidation of Hexamethylenediaminetetraacetatocobaltate(II) Complex by Periodate Ion in Aqueous Medium |
| title_fullStr | Kinetics and Mechanism of Oxidation of Hexamethylenediaminetetraacetatocobaltate(II) Complex by Periodate Ion in Aqueous Medium |
| title_full_unstemmed | Kinetics and Mechanism of Oxidation of Hexamethylenediaminetetraacetatocobaltate(II) Complex by Periodate Ion in Aqueous Medium |
| title_short | Kinetics and Mechanism of Oxidation of Hexamethylenediaminetetraacetatocobaltate(II) Complex by Periodate Ion in Aqueous Medium |
| title_sort | kinetics and mechanism of oxidation of hexamethylenediaminetetraacetatocobaltate ii complex by periodate ion in aqueous medium |
| url | http://dx.doi.org/10.1155/2010/180576 |
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