Coordination and Atom Transfer Chemistry at Surfaces of Polyoxometalate Anions

该奖项来自无机、生物无机和有机金属化学项目，主要研究无机化学领域，涉及由氧原子连接在一起的钼或钨原子的大簇，称为多氧阴离子。这些物质作为催化金属氧化物表面的模型近年来受到广泛关注，并且作为高活性和多用途的均相催化剂也受到广泛的研究。在水和非水溶剂中，钼和钨的大多氧阴离子表面上的反应性的发展被视为一种方法(a)导致新的化合物类别和均相催化剂，(b)模拟在金属氧化物的非均相催化中重要的过程。多阴离子表面的“活化”是通过还原来实现的，例如将氧钼（VI）还原为水钼（IV），或者通过合成含有一个或多个低价杂原子的多阴离子来代替W（VI）或Mo（VI）。活化的聚阴离子结合多种中性配体，特别是在无水溶剂中。通过选择合适的杂原子和氧化态，多阴离子配体配合物可以进行原子向配体转移或从配体转移。这种原子转移倾向将用于发展涉及聚阴离子表面上一个或几个相邻位点的化学计量或催化氧原子转移。这项工作的延伸有望导致合理合成含有末端多键基团的多阴离子，而不是氧（如亚胺，肼），从而产生新的反应性。

This award from the Inorganic, Bioinorganic and Organometallic Chemistry Program is in the area of inorganic chemistry and deals with large clusters of either molybdenum or tungsten atoms tied together by oxygen atoms, known as polyoxoanions. These species have become the focus of much attention recently as models of catalytic metal oxide surfaces, and are also under intensive investigation as highly active and versatile homogeneous catalysts. Development of reactivity on the surfaces of large polyoxoanions of molybdenum and tungsten in aqueous and nonaqueous solvents is seen as a way (a) to lead to new classes of compounds and homogeneous catalysts and (b) to model processes that are important in heterogeneous catalysis on metal oxides. "Activation" of polyanion surfaces is achieved by reduction, e.g. oxomolybdenum(VI) to aquomolybdenum(IV), or by synthesis of polyanions containing one or more lower-valent heteroatoms in place of W(VI) or Mo(VI). The activated polyanions bind a variety of neutral ligands, especially in anhydrous solvents. With appropriate choice of heteroatom and oxidation state, polyanion-ligand complexes undergo atom transfer, either to or from the ligand. This tendency toward atom transfer will be used to develop stoichiometric or catalytic oxygen atom transfer involving one or several adjacent sites on the polyanion surface. An extension of this work is expected to lead to rational synthesis of polyanions containing terminal multiply-bonded groups other than oxo oxygen (e.g. imido, hydrazido) with consequent novel reactivity.