EAGER: Nuclear Transmutation in Metal Organic Frameworks through Neutron Absorption

在化学系化学合成项目的支持下，华盛顿州立大学的张强和Zachariah Heiden致力于开发一种创新的方法，通过核变形在金属-有机骨架中创建独特的混合金属结构，并研究它们在辐照下的稳定性。金属-有机骨架是将金属离子与有机分子连接起来形成的结构，在自然界中可以是一维、二维或三维的。这样的结构可以被认为是带有孔或口袋的微观支架。这些口袋可以达到结构体积的90%，这意味着它们像海绵一样高度多孔。传统的方法很难创建具有特定混合金属物种的这些结构，但这种新的变形方法可能是克服这一重大限制的关键。如果成功，这种方法产生的材料有望具有独特的性能，可能会给传感器技术、催化剂开发和能够吸附特定物质的材料等各个领域带来重大进展。这个项目的一个重要方面是调查这些材料在极端条件下的行为。这些知识可能有助于创造出能够承受外层空间等恶劣环境的材料，或者可以改善核废料管理的材料。该项目将为学生，特别是那些来自代表不足的群体的学生提供独特的机会，在张博士和海登的指导下，获得关于多孔材料合成和核反应堆操作的实践培训和经验。资助的研究旨在将核变形应用于金属-有机骨架(MOF)，以引入二次金属中心，并研究其在中子辐照下的稳定性。这些新材料在中子辐射下的弹性将根据它们的元素组成、结构和中子剂量进行严格评估。在监测衰变过程的同时，可以通过调整中子辐照通量来控制由中子剂量决定的活化同位素水平。将这些二次金属中心结合到MOF结构中的预期结果是目标MOF的稳定性和电子性质都发生了显著变化。例如，在钒MOF中引入铬有望提高材料的稳定性。钒MOF中铬的形成也有望改变MOF的电子性质，因为铬离子的大小、酸性和氧化还原化学与V离子不同。该项目将探索这些材料在中子通量下的配位化学和结构动力学。这一高风险/高潜力奖励项目有可能发现开发具有增强性能和功能的先进材料的创新方法，从而可能对材料科学领域做出重大贡献。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

With the support of the Chemical Synthesis program in the Division of Chemistry, Qiang Zhang and Zachariah Heiden of Washington State University aim to develop an innovative way to create unique mixed-metal structures in metal-organic frameworks through nuclear transmutation and study their stability under irradiation. Metal-organic frameworks are made by linking metal ions with organic molecules to form structures that can be one, two, or three-dimensional in nature. Such structures can be considered as microscopic scaffolds with holes or pockets. These pockets can be up to 90% of the volume of the structures, which means they are highly porous like a sponge. Traditional methods have struggled to create these structures with specific mixed metal species, but this new transmutation approach could be the key to overcoming this significant limitation. If successful, the materials resulting from this approach are expected to have unique properties that could potentially bring significant advances to various fields such as sensor technology, catalyst development, and materials that can absorb specific substances. A vital aspect of this project is the investigation into how these materials behave under extreme conditions. This knowledge could help in creating materials that can withstand harsh environments such as outer space, or that can improve nuclear waste management. The project will offer unique opportunities for students, particularly those from underrepresented groups, to get hands-on training and experience in porous materials synthesis and nuclear reactor operation under the guidance of Drs. Zhang and Heiden.The funded research aims to apply nuclear transmutation within metal-organic frameworks (MOFs) to introduce secondary metal centers and study their stability under neutron irradiation. The resilience of these new materials under neutron radiation will be rigorously assessed based on their elemental composition, structure, and neutron dose. The level of activated isotopes, which is determined by the neutron dosage, can be controlled by adjusting the neutron irradiation flux while monitoring decay processes. The anticipated consequence of incorporating these secondary metal centers into the MOF structure is a significant alteration in both the stability and electronic properties of the target MOFs. For instance, the introduction of chromium into vanadium MOFs is expected to enhance material stability. The formation of chromium within vanadium MOFs is also expected to alter the electronic properties of the MOF, as the size, acidity and redox chemistry of Cr ions are different from those of the V ions. The project will probe the coordination chemistry and structural dynamics of these materials under neutron flux. This high risk/high potential reward project has the potential to uncover innovative methodologies for developing advanced materials with enhanced properties and functionalities, thereby potentially making a significant contribution to the field of materials science.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.