Studies Toward Uranium(VI) and Chromium(III) Biochemical Speciation
Author | : Wei Xie |
Publisher | : |
Total Pages | : 234 |
Release | : 2009 |
Genre | : Chromium |
ISBN | : |
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This dissertation focuses on the bioinorganic chemistry of two metal ions, uranium(VI), as the uranyl cation, [UO22+], and chromium(III), in conditions designed to explore their biological speciation. The solution thermodynamic interactions of uranyl with amino acids and the kinetics of solvolysis of chromium(III) complexes were investigated. The formation of complexes of the uranyl cation [UO22+] with histidine, cysteine, tyrosine and their derivatives (N-acetylhistidine, N-acetyltyrosine, S-methylcysteine, and N-acetylcysteine) were determined by potentiometric, UV-visible, florescence, and NMR measurements. The interaction between these ligands and the uranyl cation is mainly through carboxylate donors. At 25°C, the cumulative formation constant for the uranyl histidine complex, [UO2(HisH2)(OH)2]+, is 8.53; the stepwise formation constant of the uranyl-histidine interaction is