Synthesis and Chemistry of Trichalcogenophosphonates

金属有机膦酸盐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、催化剂和嵌入客体的主体等潜在的和实际的应用，在过去的三十年中得到了广泛的研究。它们也被广泛用作分子簇和超分子网络自组装的关键构件。与此形成鲜明对比的是，这些含氧金属有机膦酸盐的含较重硫族元素（硫、硒、碲）的同系物吸引的关注要少得多，主要是由于缺乏这些体系的可靠合成路线。然而，我们最近报道了一种清洁和高产率的路线，得到含有三个硫或三个硒原子代替金属有机膦酸盐中的三个氧原子的三硫代膦酸盐。我们将利用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，制备含有两个或多个三硫代膦酸酯基团的新型化合物，这些新化合物和材料将被研究用于各种应用，包括作为新型多孔材料用于去除重金属污染物如汞和砷来自受污染的水源。基于有机膦酸酯的材料已经用于水处理以去除水垢，由此硬钙金属离子与有机膦酸酯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，将产生一种新材料，该材料能够与更大、更软的金属离子如汞阳离子强烈结合，从而将它们从供水中去除。此外，我们将研究这些三硫代膦酸酯化合物作为合成有机化合物和生物有机化合物的试剂的用途，例如在酮（R2C=O）向硫代缩酮（R2C=S）的转化中。预计它们在极性溶剂中的溶解度比用于该反应的现有试剂高得多，这将允许使用不太苛刻和更绿色的化学条件（较低的温度和较少的溶剂）。

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).