Kinetics of the chromium(III)/L-glutamic acid complexation reaction: Formation, decay, and UV-vis spectrum of a long-lived intermediate

被引:3
作者
Perez-Benito, Joaquin F. [1 ]
Nicolas-Rivases, Joan [1 ]
机构
[1] Univ Barcelona, Fac Quim, Dept Ciencia Mat & Quim Fis, Secc Quim Fis, Marti & Franques 1, E-08028 Barcelona, Spain
关键词
chromium(III); complexation reaction; kinetics; L-glutamic acid; long-lived intermediate; PEPTIDE-BOND FORMATION; CRYSTAL-STRUCTURE; AMINO-ACIDS; CHROMIUM; OXIDATION; WATER; EDTA; PERMANGANATE; ION; DECOMPOSITION;
D O I
10.1002/kin.21185
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
The kinetics of the aqueous reaction of Cr(III) with either L-glutamic acid or sodium hydrogen L-glutamate at pH 2.46-5.87 have been followed by means of absorbance readings. The rate of formation of the reaction products showed acceleration-deceleration periods, caused by the accumulation and posterior decay of an intermediate in nonnegligible concentration. A double-exponential integrated rate law allowed obtaining two rate constants for each absorbance-time experimental series, associated with the appearance (k(1)) and decay (k(2)) of the long-lived intermediate. An increase of the initial concentrations of either hydrogen L-glutamate (apparent kinetic orders < 1) or hydroxide (kinetic orders = 1) ions resulted in an increase of both k(1) and k(2), but addition of an inert electrolyte (KNO3) resulted in opposite effects on k(1) (decrease) and k(2) (increase). The experimental activation energies were 83 +/- 10 (for k(1)) and 95 +/- 5 (for k(2)) kJ mol(-1). The electronic spectrum of the low reactivity detected intermediate resembled more closely to that of the blue/green reactant than that of the violet reaction product. The low number of protons set free by the complexating hydrogen L-glutamate ligand seems to suggest that some polymerization of the coordinated amino acid (to form a di- or tripeptide) might take place. The available experimental data indicate that the coordination of the organic ligand must be preceded by the breakdown of a strong Cr(III)-H2O chemical bond in the slow steps of the mechanism.
引用
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页码:591 / 603
页数:13
相关论文
共 63 条
[1]   Kinetics and mechanism of the reaction between chromium(III) and picolinic acid in weak acidic aqueous solution [J].
Abdel-Messih, M. F. ;
Abou-Gamra, Z. M. .
MONATSHEFTE FUR CHEMIE, 2012, 143 (02) :211-216
[2]  
Abdel-Messih MF, 2013, ADV CHEM ENG SCI, V3, P98
[3]  
Arthur JR, 2000, CELL MOL LIFE SCI, V57, P1825
[4]   CHROMIUM COMPLEXES DERIVED FROM MOLECULAR-OXYGEN [J].
BAKAC, A ;
ESPENSON, JH .
ACCOUNTS OF CHEMICAL RESEARCH, 1993, 26 (10) :519-523
[5]  
Barreto JC, 2005, CHEM ED, V10, P196
[6]   Reduction of hypervalent chromium in acidic media by alginic acid [J].
Bertoni, Fernando A. ;
Bellu, Sebastian E. ;
Gonzalez, Juan C. ;
Sala, Luis F. .
CARBOHYDRATE POLYMERS, 2014, 114 :1-11
[7]  
Budiasih KS, 2013, WORLD ACAD SCI ENG T, V78, P1905
[8]   Role of chromium in human health and in diabetes [J].
Cefalu, WT ;
Hu, FB .
DIABETES CARE, 2004, 27 (11) :2741-2751
[9]   Characterization of the Organic Component of Low-Molecular-Weight Chromium-Binding Substance and Its Binding of Chromium [J].
Chen, Yuan ;
Watson, Heather M. ;
Gao, Junjie ;
Sinha, Sarmistha Halder ;
Cassady, Carolyn J. ;
Vincent, John B. .
JOURNAL OF NUTRITION, 2011, 141 (07) :1225-1232
[10]  
Coetzee J.F., 1969, Solute-solvent Interactions