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Title:
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Intermediate and ion-pair formation in the outer-sphere reactions between azido-pentacyanocobaltate(III) and iron(II) polypyridyl complexes in aqueous medium |
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Author:
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Ogunlusi, G.O.; Ige, J.; Oyetunji, O.A.; Ojo, J.F. |
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Abstract:
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The kinetics of the reactions between azidopentacyanocobaltate(III), Co(CN)5N3
3-, and iron(II) polypyridyl
complexes, Fe(LL)3
2? (LL = bipy, phen), have been studied in both neutral and acidic aqueous solutions at
I = 0.1 mol dm-3 NaCl. The reactions were carried out
under pseudo-first-order conditions in which the concentration
of Fe(LL)32+ was kept constant, and the second-order
rate constants obtained for the reactions at 35 C were within the range of 0.156–0.219 dm3 mol-1 s-1 for LL = bipy and 0.090–0.118 dm3 mol-1 s-1 for LL = phen.
Activation parameters were measured for these systems. The
dependence of reaction rates on acid was studied in the range
[H+] = 0.001–0.008 mol dm-3. The reaction in acid medium shows interesting kinetics. Two reactive species were identified in acid medium, namely, the protonated cobalt
complex and the azido-bridged binuclear complex. The electron-transfer process is proposed to go by mixed outerand
inner-sphere mechanisms in acid medium, in which
electron transfer through the bridged inner-sphere complex
(k5) is slower than through the outer-sphere path (k4). |
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Description:
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Symbols may not appear as they are in the original abstracts. |
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URI:
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http://hdl.handle.net/10311/1035
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Date:
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2009 |
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Publisher:
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Springer Science+Business Media B.V., http://www.springer.com/chemistry/journal/11243 |
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xmlui.dri2xhtml.METS-1.0.item-link:
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http://www.springerlink.com/content/h121m16l1127g185/fulltext.pdf
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xmlui.dri2xhtml.METS-1.0.item-type:
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Published Article |