Hydroflux Syntheses — Reactions in Ultrabasic Media at Moderate Temperatures

Hydroflux 合成 â 中等温度下超碱性介质中的反应

• 批准号: 438795198
• 负责人: Professor Dr. Michael Ruck
• 金额: --
• 依托单位: Professur für Anorganische Chemie II
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/438795198?language=en
• 关键词: Hydroflux; Syntheses; Reactions; Ultrabasic; Media

Hydroflux synthesis, using very highly concentrated alkaline solutions, is a promising new time-, energy-, and atom-efficient synthesis approach, especially but not exclusively for oxides and hydroxides. The conditions differ from those in hydrothermal reactions as well as those in alkaline salt melts. Previous work has shown that the range of main-group and transition elements that can be reacted, as well as of the oxidation states that can be addressed, is much wider than initially expected. We will explore the potential of hydroflux synthesis and gain further knowledge about the crucial reaction parameters and the ongoing chemical processes. Key chemical, structural, and physical properties of the obtained solid products shall be determined. We will specifically follow two directions. First, the low activity of water in the hydroflux provides options for a virtually anhydrous acid-base chemistry at moderate temperature. Common mineral acids and their anhydrides will be reacted with the aim of crystallizing metal salts of complex anions with various degree of protonation and condensation. There is a high probability that the compounds formed are new, will have non-centrosymmetric structures and exhibit non-linear optical properties. Second, the redox chemistry under hydroflux conditions will be investigated. The tabulated electrochemical standard potentials no longer apply, particularly in systems that depend on pH. Together with the hygroscopic properties of hydroflux, this makes soluble oxometalates in intermediate oxidation states unexpectedly strong reducing agents whose potential will be explored. On the other hand, there is a lively redox chemistry between oxide, peroxide, superoxide and molecular oxygen depending on the pH and the alkali metal cation of the flux. By using solid oxygen sources or hydrogen peroxide solutions, the oxidation potential can be increased in a controlled manner, which will be studied in detail and exploited to stabilize high oxidation states of transition metals.

使用非常高浓度的碱性溶液的水通量合成是一种有前途的新的时间，能量和原子效率的合成方法，特别是但不限于氧化物和氢氧化物。其反应条件既不同于水热反应，也不同于碱性盐熔体反应。以前的工作表明，可以反应的主族和过渡元素的范围，以及可以解决的氧化态，比最初预期的要宽得多。我们将探索水通量合成的潜力，并获得有关关键反应参数和正在进行的化学过程的进一步知识。应确定所得固体产品的关键化学、结构和物理性质。我们将具体遵循两个方向。首先，水通量中水的低活性为在中等温度下的几乎无水的酸碱化学提供了选择。常见的无机酸和它们的酸酐将反应，目的是结晶具有不同程度的质子化和缩合的络合阴离子的金属盐。所形成的化合物很可能是新的，具有非中心对称结构并表现出非线性光学性质。其次，将研究在氢通量条件下的氧化还原化学。列表中的电化学标准电位不再适用，特别是在依赖于pH值的系统中。连同hydroflux的吸湿特性，这使得处于中间氧化态的可溶性草酸盐意外地成为强还原剂，其电位将被探索。另一方面，氧化物、过氧化物、超氧化物和分子氧之间存在活跃的氧化还原化学反应，这取决于焊剂的pH值和碱金属阳离子。通过使用固体氧源或过氧化氢溶液，可以以受控的方式增加氧化电位，这将被详细研究并用于稳定过渡金属的高氧化态。