Derivatized and Nanoscale Polyoxometalate Cluster Anions

迈克尔·T·波普博士，乔治城大学化学系，由无机化学、生物无机化学和金属有机化学项目资助，研究多金属氧酸盐物种的化学。这项研究旨在开发以下有机衍生物：(A)含有10-30个钨原子和一到几种其他原子类型的多钨阴离子，可用作进一步衍生化的场所；(B)大量、可溶的纳米级离散多氧阴离子，包含100个金属原子。在Rh上衍生含Rh的(A)型络合物的能力将被用来将多金属氧酸盐与核糖体偶联，以确定X射线数据的相态。将准备额外的(A)类物种，并在多个地点进行衍生。这些物种可用于支撑剂，以将催化活性的多氧阴离子连接到聚合物底物上，用于选择性电子密度成像，以及其他应用。(B)类络合物的例子是一个76-阴离子，其中包含12个As、16个Ln、148个W和524个O原子以及36个水分子。该阴离子可溶于水，并已进行了结晶学表征。将为这一物种的类似物设计合成策略，其中As被其他第15族原子取代，以及那些包含各种稀土元素的类似物。将设计出更大星系团的准备工作。这些大阴离子的水解性、结构、电化学性质等将在溶液中进行研究。这些方法将被设计成将这些簇状阴离子偶联到设计的、扩展的组件中。多金属氧酸盐是由金属原子和氧原子组成的大离子。它们之所以令人感兴趣，是因为它们完全是无机的，因此在许多条件下应该相当坚固。这项研究将探索这两类离子的化学。第一个包含10-30个金属原子，其中心可以与其他化学物种相连。第二类是由包含数百个原子的纳米大小的非常大质量的离子组成的。这两个类都不寻常，因为它们溶解在水中，在水中稳定。它们在离子交换和主客体材料、催化剂、导电和磁性材料以及显示器件等方面具有潜在的应用前景。

Dr Michael T. Pope, Chemistry Department, Georgetown University, is supported by the Inorganic, Bioinorganic, and Organometallic Chemistry Program, to investigate the chemistry of polyoxometalate species. This research is directed towards developing robust, water-stable, functionalized organic derivatives of (a) polytungstate anions containing 10-30 tungsten atoms and one to several other atom types that can be used as sites of further derivatization and (b) massive, soluble discrete polyoxoanions of nanoscale dimensions that contain 100+ metal atoms. The ability to derivatize rhodium containing type (a) complexes at the rhodium will be used to couple the polyoxometalate to ribosomes for phasing of x-ray data. Additional type (a) species will be prepared with multiple sites for derivatization. These species can be utilized for supporting agents to attach catalytically active polyoxoanions to polymer substrates, for selective electron-density imaging, and other applications. Type (b) complexes are exemplified by a 76- anion containing 12 As, 16 Ln, 148 W, and 524 O atoms plus 36 water molecules. This anion is water soluble and has been crystallographically characterized. Synthetic strategies will be designed for analogues of this species in which As is substituted by other group 15 atoms and for those that contain a variety of lanthanides. The preparation of even larger clusters will be devised. The hydrolytic stability, structures, electrochemistry and other properties will be investigated in solution for these large anions. Methods will be designed to couple these clusters anions into designed, extended assemblies. The polyoxometalates are a large ions composed of metal and oxygen atoms. They are of interest because they are wholly inorganic, and thus should be quite robust under many conditions. This investigation will explore the chemistry of two classes of these ions. The first contains 10-30 metal atoms and has centers that can be linked to other chemical species. The second class is composed of very massive ions that contain hundreds of atoms and are nano-sized. Both classes are unusual for because they dissolve in and are stable in water. They have potential applications as ion-exchange and host/guest materials, catalysts, conducting and magnetic materials, and display devices.