Synthesis and Chemistry of Trichalcogenophosphonates

在过去的三十年中，由于其作为离子交换剂、吸附剂、传感器、质子导体、非线性光学材料、催化剂和广泛的客体嵌入的宿主的潜力和实际应用，金属有机膦酸盐得到了广泛的研究。它们也被广泛用作分子簇和超分子网络自组装的关键构建块。与之形成鲜明对比的是，含有这些含氧金属有机膦酸盐同系物的较重的硫（硫、硒、碲）引起的关注要少得多，这主要是因为缺乏可靠的合成途径来合成这些系统。然而，我们最近报道了一种清洁和高产的方法来生产这种含有三个硫原子或三个硒原子代替金属有机膦中的三个氧原子的三氯基膦酸盐。我们现在建议利用我们在这一领域的最新进展，对这些新化合物的反应性和配位化学进行全面的研究，并扩展我们的合成路线，以制备含有两个或多个三卤代膦酸盐基团的新化合物。将研究这些新化合物和材料的各种应用，包括作为去除受污染供水中的汞和砷等重金属污染物的新型多孔材料。基于有机膦酸盐的材料已经在水处理中用于去除水垢，其中硬钙金属离子与有机膦酸盐基团中的硬氧原子强烈结合。在我们的新化合物中，用更大、更软的硫原子取代一个或多个氧，将产生一种新的材料，能够与更大、更软的金属离子（如汞阳离子）紧密结合，从而将它们从供水系统中清除。此外，我们将研究使用这些三卤代膦酸盐化合物作为合成有机和生物有机化合物的试剂，例如将酮（R2C=O）转化为硫酮（R2C=S）。预计它们在极性溶剂中的溶解度比现有试剂高得多，这一反应将允许使用不那么苛刻的绿色化学条件（更低的温度和更少的溶剂）。

Metal organophosphonates have been extensively studied over the last thirty years due to their potential and practical applications as ion exchangers, sorbents, sensors, proton conductors, nonlinear optical materials, catalysts and hosts for the intercalation of a broad spectrum of guests. They have also been widely used as key building blocks in the self-assembly of molecular clusters and supramolecular networks. In stark contrast the heavier chalcogen (sulphur, selenium, tellurium) containing homologs of these oxygen containing metal organophosphonates have attracted far less attention, predominately due to a lack of a reliable synthetic route to these systems. However, we have recently reported upon a clean and high yielding route to such trichalcogenophosphonates containing three sulphur or three selenium atoms in place of the three oxygen atoms in metal organophosphonates. We now propose to exploit our recent advances in this area by carrying out a full study on the reactivity and coordination chemistry of these new compounds as well as extending our synthetic route to prepare novel compounds containing two or more trichalcogenophosphonate groups.These new compounds and materials will be studied for a variety of applications including as new porous materials for the removal of heavy metal contaminants such as mercury and arsenic from contaminated water supplies. Organophosphonate based materials are already used in water treatment for the removal of limescale whereby the hard calcium metal ion binds strongly to the hard oxygen atoms in the organophosphonate group. Replacement of one or more of the oxygens with the larger, softer sulphur atom in our new compounds will result in a new material capable of binding strongly to larger, softer metal ions such as mercury cations, hence removing them from the water supply.In addition we will study the use of these trichalcogenophosphonate compounds as reagents for the synthesis of organic and bio-organic compounds, for example in the conversion of ketones (R2C=O) to thioketals (R2C=S). It is expected that their much increased solubility in polar solvents over existing reagents for this reaction will allow the use of less harsh and more green-chemistry conditions (lower temperatures and less solvent).