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首页> 外文期刊>Dalton transactions: An international journal of inorganic chemistry >Speciation in the aqueous H~+/H_2VO_4~-/H_2O_2/phosphate system
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Speciation in the aqueous H~+/H_2VO_4~-/H_2O_2/phosphate system

机译：H〜+ / H_2VO_4〜-/ H_2O_2 /磷酸盐水溶液中的形态

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The speciation in the aqueous H~+/H_2VO_4~-/phosphate (dihydrogen phosphate,P ) and H~+/H_2VO_4~-/H_2O_2/P systems has been determined in the physiological medium of 0.150 M Na(Cl) at 25 deg C.A combination of multinuclear NMR integral and chemical shift (Bruker AMX500) as well as potentiometric data (glass electrode) have been collected and treated simultaneously by the computer program LAKE.The pK_a-values for phosphoric acid have been determined by potentiometric and ~(31)P NMR chemical shift data,and have been found to be 1.85 +-0.02,6.69 +- 0.02 and 11.58 +- 0.07.The errors given are 3sigma.Altogether nine vanadate-phosphate species have been found in the ternary H~+/H_2VO_4~-/P~- system in the pH region 1-11,with the following compositions:VP,VP_2 and V_(14)P.Equilibrium is very slow in acidic solutions,requiring more than 3 months for the formation of V_(14)P species.On the other hand,less than 15 min are needed for equilibration at neutral and alkaline pH.In the quaternary H~+/H_2VO_4~-/H_2O_2/P~- system,four new species have been found in addition to all binary and ternary complexes.They are of VXP and VX_2P compositions,where X denotes the peroxo ligand.~(51)V and ~(31)P NMR chemical shifts,compositions and formation constants are given,and equilibrium conditions are illustrated in distribution diagrams as well as the fit of the model to the experimental data.Biological and medical relevance of the species is also discussed and physiological conditions are modelled.
机译：已在25°C的0.150 M Na（Cl）生理介质中确定了H〜+ / H_2VO_4〜-/磷酸盐（磷酸二氢盐，P）和H〜+ / H_2VO_4〜-/ H_2O_2 / P系统中的形态。通过计算机程序LAKE收集并同时处理了多核NMR积分和化学位移（Bruker AMX500）的CA组合以及电位数据（玻璃电极），并通过电位计确定了磷酸的pK_a值，〜（31 ）P NMR化学位移数据，分别为1.85 + -0.02、6.69 +-0.02和11.58 +-0.07。给定的误差为3σ。在三元H〜+ /中共发现9种钒酸磷酸盐pH范围1-11中的H_2VO_4〜-// P〜-体系具有以下成分：VP，VP_2和V_（14）P。在酸性溶液中平衡非常缓慢，形成V_（需要3个月以上） 14）P物种。另一方面，在中性和碱性pH值下平衡所需的时间少于15分钟。在四价H〜+ / H_2VO_4〜-/ H_2O_2 / P〜-系统中，除了所有二元和三元复合物外，还发现了四个新物种。它们是VXP和VX_2P组成，其中X表示过氧配体。〜（51）V和〜（31给出了P NMR的化学位移，组成和形成常数，并在分布图中说明了平衡条件，以及模型与实验数据的拟合。还讨论了该物种的生物学和医学意义，并对生理条件进行了建模。

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