Synthesis and Structural Characterization of Lanthanide Containing Polyoxoanions Functionalized by Peroxo Groups, and Investigation of Their Catalytic Properties

过氧基团功能化的含镧系多氧阴离子的合成、结构表征及其催化性能研究

• 批准号: 69077856
• 负责人: Professor Ulrich Kortz, Ph.D.
• 金额: --
• 依托单位: Department of Life Sciences and Chemistry
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2008
• 资助国家: 德国
• 起止时间: 2007-12-31 至 2010-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/69077856?language=en
• 关键词: Synthesis; Structural; Characterization; Lanthanide; Containing

We propose to synthesize novel polyoxotungstates substituted by lanthanide centers for which the terminal aqua ligands have been substituted by peroxo groups. To date no such species are known at all. We will also investigate the homogeneous and heterogeneous oxidation catalysis properties of this novel subclass of polyoxometalates (POMs). We will investigate the interaction of lanthanide ions with a variety of water-soluble polytungstate precursors, followed by functionalization using aqueous hydrogen peroxide. Our initial focus will be on the functionalization of known lanthanide-POMs, e.g. the spectacular 20-cerium containing 100- tungstogermanate [Ce20Ge10W100O376(OH)4(H2O)30]56- published very recently by our group.21 This species has a total of 30 terminal aqua ligands associated with the 20 cerium centers and hence represents a good candidate for functionalization with peroxo groups. Our novel lanthanide-peroxo-POMs will be characterized as usual by single-crystal X-ray diffraction, FTIR, TGA-DSC, multinuclear NMR (e.g. 183W, 31P, 29Si) and elemental analysis. The preliminary catalytic tests (e.g. peroxide-based oxidation of olefins) will also be carried out at Jacobs University. Incorporation of lanthanides into lacunary polytungstate frameworks has already resulted in several POMs with interesting properties in the areas of luminescence, magnetism, and Lewis acid-type catalysis. Due to their larger size and coordination number, compared to 3d transition metals, lanthanide ions cannot be fully inserted into the vacant sites of the lacunary POM precursors, usually resulting in 2 or more terminal, sterically accessible and labile water ligands. This in turn allows for substitution of those water molecules by organic ligands (incl. chiral ones) or for coordination to other POM fragments leading to very large discrete, molecular architectures or extended frameworks. To date some peroxo-POMs are known and they are very good oxidation catalysts.29 On the other hand, no lanthanide-peroxo-POMs have ever been reported. We believe that such POMs should exist, as formation of side-on -peroxo bridged lanthanide based coordination complexes are well known.30

我们提出了一种以镧系中心取代的新型多氧钨酸盐，其末端的水配体已被过氧基取代。到目前为止，还没有发现这样的物种。我们还将研究这种新型亚类多金属氧酸盐（pom）的均相和多相氧化催化性能。我们将研究镧系离子与各种水溶性多钨酸盐前驱体的相互作用，然后使用过氧化氢进行功能化。我们最初的重点将放在已知的镧系聚甲醛的功能化上，例如我们小组最近发表的引人注目的20-铈含100-钨酸盐[Ce20Ge10W100O376(OH)4(H2O)30]56该物种共有30个末端水配体与20个铈中心相连，因此代表了与过氧基功能化的良好候选者。我们的新型镧系过氧化物聚有机化合物将通过单晶x射线衍射、红外光谱、热重分析、多核核磁共振（如183W、31P、29Si）和元素分析进行表征。初步催化试验（如烯烃的过氧化物氧化）也将在雅各布斯大学进行。将镧系元素加入到多孔多钨酸盐框架中，已经产生了几种在发光、磁性和路易斯酸型催化方面具有有趣性质的pom。与三维过渡金属相比，镧系离子由于具有较大的尺寸和配位数，不能完全插入到空腔POM前体的空位上，通常产生2个或更多的末端，具有空间可及性和不稳定的水配体。这反过来又允许用有机配体（包括手性配体）取代这些水分子，或与其他POM片段配位，从而形成非常大的离散分子结构或扩展框架。到目前为止，人们已经知道了一些过氧聚甲醛，它们是很好的氧化催化剂另一方面，从未有过镧系过氧化物聚甲醛的报道。我们相信这样的pom应该存在，因为众所周知的是侧对-过氧桥接镧系配合物的形成