Reduction of the Aqueous Mercuric Ion by Sulfite: UV Spectrum of HgSO<sub>3</sub> and Its Intramolecular Redox Reaction
作者:Lisa Van Loon、Elizabeth Mader、Susannah L. Scott
DOI:10.1021/jp994268s
日期:2000.3.1
Aqueous hydrogen sulfite reacts with Hg2+ to form, in the absence of excess HSO3-, the HgSO3 complex, observed here for the first time. Its UV spectrum is described by e(234 nm) = (1.57 ± 0.05) × 104 M-1 cm-1. HgSO3 decomposes in an intramolecular redox reaction which is kinetically first-order. The rate constant is independent of [Hg2+], [HSO3-], [O2(aq)], and ionic strength. An acid-assisted pathway
在没有过量 HSO3- 的情况下,亚硫酸氢水溶液与 Hg2+ 反应形成 HgSO3 络合物,这是首次在此观察到。其紫外光谱由 e(234 nm) = (1.57 ± 0.05) × 104 M-1 cm-1 描述。HgSO3 在分子内氧化还原反应中分解,这是动力学一级的。速率常数与 [Hg2+]、[HSO3-]、[O2(aq)] 和离子强度无关。由于 HgSO3H+ 的贡献,酸辅助途径在 pH ≤ 1 时变得显着。HgSO3 的分子内反应速率是通过将 Hg0 产物捕获为 Hg22+ 来测量的;速率常数的值为 k0 = (0.0106 ± 0.0009) s-1,温度为 25.0 °C,pH 3。pH 3、ΔH‡ 和 ΔS‡ 的活化参数为 (105 ± 2) kJ/mol 和 (68 ± 6) J/mol·K,分别与单分子键断裂机制一致。