Kinetics and Mechanisms of the Reduction of Chromium(VI) by 2-Mercaptoethanesulfonic Acid in Aqueous Solution: Difference in the Mechanistic Process of Reduction with Noncarboxylate Thiols

Verfasser / Beitragende:
[Dwight C. Ramdon, Donovan A. Dixon, Tara P. Dasgupta]
Ort, Verlag, Jahr:
2003
Enthalten in:
BioInorganic Reaction Mechanisms, 5/1(2003-01-01), 47-58
Format:
Artikel (online)
ID: 37887117X
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024 7 0 |a 10.1515/irm-2003-0106  |2 doi 
035 |a (NATIONALLICENCE)gruyter-10.1515/irm-2003-0106 
245 0 0 |a Kinetics and Mechanisms of the Reduction of Chromium(VI) by 2-Mercaptoethanesulfonic Acid in Aqueous Solution: Difference in the Mechanistic Process of Reduction with Noncarboxylate Thiols  |h [Elektronische Daten]  |c [Dwight C. Ramdon, Donovan A. Dixon, Tara P. Dasgupta] 
520 3 |a The kinetics of the reaction of chromium(VI) with 2-mercaptoethanesulfonic acid (MESA) has been studied spectrophotometrically at wavelength, 435 nm, and ionic strength, I, of 0.50 mol dm-3 (NaClO4) over the ranges: 16.0 < θ < 29.5 °C, 2.6 < pH < 7.1 (citric acid-phosphate buffer), [Cr(VI)]T = 2.0 χ 10-4 mol dm-3, 1.0 χ 10-2 < [MESA]T < 4.0 χ 10-2 mol dm-3. The reaction occurs giving clear indication of the formation of an intermediate, which is assumed to be a typical Cr(VI)-thioester. The decay of the thioester then occurs via a series of electron transfer reactions to give Cr(III). The formation and decay rates of this intermediate have been investigated kinetically and a detailed mechanism for the overall reaction proposed. Experimental data were fitted to rate equations derived from this mechanism. The specific rate constants and corresponding activation parameters were also deduced. The results show that MESA without carboxylate groups, react differently when compared to other thiols having such groups present. This confirms the participating role of carboxylate groups in the formation of the Cr(VI)-thioester. The catalytic effect of added Zn2+ was investigated and its overall role in the reaction of Cr(VI) with MESA was explained. 
540 |a © 2014 by Walter de Gruyter Berlin/Boston 
690 7 |a reduction kinetics  |2 nationallicence 
690 7 |a chromium(VI)  |2 nationallicence 
690 7 |a 2-mercaptoethanesulfonic acid  |2 nationallicence 
690 7 |a thioester  |2 nationallicence 
700 1 |a Ramdon  |D Dwight C.  |4 aut 
700 1 |a Dixon  |D Donovan A.  |4 aut 
700 1 |a Dasgupta  |D Tara P.  |4 aut 
773 0 |t BioInorganic Reaction Mechanisms  |d De Gruyter  |g 5/1(2003-01-01), 47-58  |x 2191-2483  |q 5:1<47  |1 2003  |2 5  |o irm 
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950 |B NATIONALLICENCE  |P 700  |E 1-  |a Dixon  |D Donovan A.  |4 aut 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Dasgupta  |D Tara P.  |4 aut 
950 |B NATIONALLICENCE  |P 773  |E 0-  |t BioInorganic Reaction Mechanisms  |d De Gruyter  |g 5/1(2003-01-01), 47-58  |x 2191-2483  |q 5:1<47  |1 2003  |2 5  |o irm 
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