CTM Centre Tecnològic, Avda. Bases de Manresa, 1, 08240, Manresa, Spain.
Dalton Trans. 2011 Aug 21;40(31):7976-82. doi: 10.1039/c0dt01672a. Epub 2011 Jul 8.
The formation of uranyl-peroxide complexes was studied at alkaline media by using UV-Visible spectrophotometry and the STAR code. Two different complexes were found at a H(2)O(2)/U(VI) ratio lower than 2. A graphical method was used in order to obtain the formation constants of such complexes and the STAR program was used to refine the formation constants values because of its capacity to treat multiwavelength absorbance data and refining equilibrium constants. The values obtained for the two complexes identified were: UO(2)(2+) + H(2)O(2) + 4OH(-) <−> UO(2)(O(2))(OH)(2)(2-) + 2H(2)O: log β°(1,1,4) = 28.1 ± 0.1 (1). UO(2)(2+) + 2H(2)O(2) + 6OH(-) <−> UO(2)(O(2))(2)(OH)(2)(4-) + 4H(2)O: log β°(1,2,6) = 36.8 ± 0.2 (2). At hydrogen peroxide concentrations higher than 10(-5) mol dm(-3), and in the absence of carbonate, the UO(2)(O(2))(2)(OH)(2)(4-) complex is predominant in solution, indicating the significant peroxide affinity of peroxide ions for uranium and the strong complexes of uranium(VI) with peroxide.
在碱性介质中通过使用 UV-可见分光光度法和 STAR 代码研究了铀过氧化物配合物的形成。在 H 2 O 2 / U(VI) 比低于 2 的情况下发现了两种不同的配合物。使用图形方法获得了这些配合物的形成常数，并且由于其处理多波长吸光度数据和精制平衡常数的能力，使用 STAR 程序来精制形成常数值。鉴定出的两种配合物的获得值为：UO 2 (2+) + H 2 O 2 + 4OH - <−> UO 2 (O 2 )(OH) 2 (2-) + 2H 2 O: log β°(1,1,4) = 28.1 ± 0.1 (1)。UO 2 (2+) + 2H 2 O 2 + 6OH - <−> UO 2 (O 2 )(2)(OH)(2)(4-) + 4H 2 O: log β°(1,2,6) = 36.8 ± 0.2 (2)。在过氧化氢浓度高于 10 -5 mol dm -3 且不存在碳酸盐的情况下，UO 2 (O 2 )(2)(OH)(2)(4-) 配合物在溶液中占优势，表明过氧离子对铀的过氧亲和力和铀(VI)与过氧的强配合物显著。
