SusChEM: Rigid and Flexible Linker Systems for Superior Immobilized Catalysts

SusChEM：用于优质固定化催化剂的刚性和柔性连接体系统

• 批准号: 1300208
• 负责人: Janet Bluemel
• 金额: $ 39万
• 依托单位: Texas A&M University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-08-01 至 2017-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1300208&HistoricalAwards=false
• 关键词: SusChEM; Rigid; Flexible; Linker; Systems

The NSF Chemical Catalysis Program supports the efforts of Professor Janet Bluemel of Texas A&M University to investigate homogeneous and immobilized molecular nickel catalysts in order to clarify the processes by which metal complexes decompose to form nanoparticles. Nickel(0) catalysts are immobilized on surfaces via phosphine linkers chosen from a broad range of mono-, di-, and tridentate ligands that incorporate flexible alkyl chains or rigid tetraphenylelement cores. Strategic ligand selection helps discriminate between dimerization on the surface and agglomeration as the crucial step in the eventual nanoparticle formation. The cyclotrimerization of phenylacetylene is used as a model reaction to study the selectivity and activity of the immobilized catalysts and to monitor potential nanoparticle formation. The dynamics of metal complex migration from one uncoordinated phosphine linker to the next on the surface is quantified using 31P T1 relaxation times and HRMAS NMR data. Metal complexes other than Ni(0) and different catalytic reactions are also investigated to probe the general applicability of the insights gained with the model catalytic system. Immobilized catalysts have the potential to improve industrial scale chemical processes and thus, this project may improve the environmental sustainability of large scale chemical synthesis by providing general methodologies for the preparation and use of non-precious metal catalysts with superior activities, selectivities, and lifetimes. Graduate and undergraduate students involved in the project receive interdisciplinary training and gain experience in advanced techniques for the characterization of amorphous materials.The Chemical Catalysis Program supports the efforts of Professor Janet Bluemel of the Texas A&M University to compare differences in homogeneous and immobilized catalysts. During homogeneous catalysis, nanoparticles can form from the metal catalyst resulting in a suspension of heterogeneous catalysts in solution. Starting from immobilized catalysts, the same process leads to nanoparticle formation on the surface. This uncontrollable scenario is undesirable because it is not predictable, not generally preventable, and may change the selectivity of the catalyst or shorten its lifetime, diminishing the recyclability of the catalyst. This research project investigates homogeneous and immobilized molecular nickel catalysts in order to clarify the processes associated with metal catalyst decomposition (e.g. decomposition on the surface or agglomeration in solution) to form nanoparticles. This project has the potential to improve the environmental sustainability of large scale chemical synthesis by providing general methodologies for the preparation and use of non-precious metal catalysts with superior activities, selectivities, and lifetimes. Graduate and undergraduate students involved in the project receive interdisciplinary training, collaborate internationally, and gain experience in advanced analytical techniques.

NSF化学催化计划支持德克萨斯A M大学的Janet Bluemel教授研究均相和固定化分子镍催化剂的努力，以澄清金属络合物分解形成纳米颗粒的过程。 镍（0）催化剂通过膦连接体固定在表面上，所述膦连接体选自包含柔性烷基链或刚性四苯基元素核的广泛的单齿、二齿和三齿配体。 策略性配体选择有助于区分表面上的二聚化和团聚，这是最终形成纳米颗粒的关键步骤。 苯乙炔的环三聚反应被用作模型反应，研究固定化催化剂的选择性和活性，并监测潜在的纳米粒子的形成。 使用31P T1弛豫时间和HRMAS NMR数据，从一个未配位的膦连接体到下一个表面上的金属络合物迁移的动力学进行量化。 还研究了Ni（0）以外的金属络合物和不同的催化反应，以探索模型催化体系所获得的见解的普遍适用性。 固定化催化剂具有改善工业规模化学过程的潜力，因此，本项目可以通过提供制备和使用具有上级活性、选择性和寿命的非贵金属催化剂的一般方法来改善大规模化学合成的环境可持续性。 参与该项目的研究生和本科生将接受跨学科的培训，并获得表征非晶材料的先进技术的经验。化学催化计划支持德克萨斯A M大学的Janet Bluemel教授的努力，以比较均相催化剂和固定化催化剂的差异。 在均相催化过程中，纳米颗粒可以由金属催化剂形成，导致非均相催化剂在溶液中的悬浮液。 从固定化催化剂开始，相同的过程导致在表面上形成纳米颗粒。 这种不可控的情况是不期望的，因为它是不可预测的，通常不可预防的，并且可能改变催化剂的选择性或缩短其寿命，从而降低催化剂的可再循环性。 本研究项目研究均相和固定化分子镍催化剂，以澄清与金属催化剂分解（例如表面分解或溶液中团聚）形成纳米颗粒相关的过程。 该项目通过提供制备和使用具有上级活性、选择性和寿命的非贵金属催化剂的一般方法，具有改善大规模化学合成的环境可持续性的潜力。 参与该项目的研究生和本科生接受跨学科培训，进行国际合作，并获得先进分析技术的经验。