'Molecular Nanoparticles' of Magnetic Perovskite Manganites and Other Metal Oxides

磁性钙钛矿锰酸盐和其他金属氧化物的“分子纳米颗粒”

• 批准号: 1900321
• 负责人: George Christou
• 金额: $ 48万
• 依托单位: University of Florida
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-08-01 至 2022-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1900321&HistoricalAwards=false
• 关键词: Molecular; Nanoparticles; Magnetic; Perovskite; Manganites

In this project, funded by the Chemical Structure, Dynamics & Mechanisms-B Program of the Chemistry Division, Professor George Christou of the Department of Chemistry at the University of Florida is using synthetic chemistry methods to prepare nanoparticles of important metal oxides that are identical in size and shape. Such "molecular nanoparticles" (molecules less than one billionth of a meter in size) address an important current challenge in nanoscience, namely how to avoid mixtures of sizes and shapes, and thus of properties. Most current preparations of nanoparticles result result in various particle sizes and shapes in the same batch. The project is initially targeted at making molecular nanoparticles of cerium dioxide and manganite perovskites, materials of widespread importance in industrial and medical applications, as well as potentially new quantum device technologies. Professor Christou and his group carry out a number of outreach, education and international activities. They participate in the annual Chemistry Day at the Mall in Gainesville, targeted at K-12 students, teachers and parents, and the local community and media. Undergraduate research students participate in hands-on research gaining important skills for graduate work or employment. Professor Christou organizes the Showcase Symposium at the annual meeting of the Florida ACS Local Section, and also organizes the annual Florida Inorganic and Materials Symposium student meeting, which involves 14 Florida PhD-granting universities, and undergraduate and community colleges. Internationally, he co-organizes two biennial workshops, the Current Trends in Molecular and Nanoscale Magnetism (2021), and the North America-Greece-Cyprus Workshop on Paramagnetic Materials (2020, 2022), which include many talks from students and postdocs. Finally, the team continues to collaborate with national and international groups, providing samples for specialized physics studies, and assisting synthetic chemists in the magnetic characterization of their materials.Synthesis of truly monodisperse (identical) nanoparticles and their structural characterization at atomic resolution are extremely important challenges in nanoscience. For many nanoscale materials important to the development of next-generation electronic, magnetic, catalytic, and biomedical systems/devices, the top-down approach has limitations as the fabrication of monodisperse nanoparticles becomes more and more difficult with decreasing size. The bottom-up molecular approach provides an alternative route if high nuclearity clusters that have the same structure as the bulk material can be synthesized. Such "molecular nanoparticles" bring the advantages of molecular chemistry to nanoscience, particularly true monodispersity, solubility, and crystallinity. This synthetic approach is especially available nanoscale metal oxides, which are of scientific and technological importance. Breakthroughs in cluster chemistry to produce truly monodisperse nanoparticles of manganite perovskites and cerium dioxide have recently been achieved by the Professor George Christou's group, opening up new directions that promise knowledge generation at the nanoscale.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.

在这个由化学部化学结构、动力学和机理b项目资助的项目中，佛罗里达大学化学系的George Christou教授正在使用合成化学方法制备大小和形状相同的重要金属氧化物纳米颗粒。这种“分子纳米粒子”（小于十亿分之一米大小的分子）解决了纳米科学当前的一个重要挑战，即如何避免尺寸和形状的混合，从而避免性质的混合。目前大多数纳米颗粒的制备结果是在同一批次中产生各种大小和形状的颗粒。该项目最初的目标是制造二氧化铈和锰矿钙钛矿的分子纳米颗粒，这些材料在工业和医疗应用中具有广泛的重要性，以及潜在的新量子器件技术。Christou教授和他的团队开展了一些外联、教育和国际活动。他们在盖恩斯维尔的购物中心参加一年一度的化学日，目标是K-12学生，教师和家长，以及当地社区和媒体。本科研究生参与实践研究，获得研究生工作或就业的重要技能。Christou教授在佛罗里达ACS本地分会的年度会议上组织了展示研讨会，并组织了年度佛罗里达无机和材料研讨会学生会议，该会议涉及14所佛罗里达授予博士学位的大学，以及本科和社区学院。在国际上，他共同组织了两个两年一次的研讨会，即分子和纳米磁性的当前趋势（2021年）和北美-希腊-塞浦路斯顺磁性材料研讨会（2020年，2022年），其中包括许多学生和博士后的会谈。最后，该团队继续与国内和国际团体合作，为专门的物理研究提供样品，并协助合成化学家对其材料进行磁性表征。真正的单分散（相同）纳米颗粒的合成及其在原子分辨率上的结构表征是纳米科学中极其重要的挑战。对于许多对下一代电子、磁性、催化和生物医学系统/设备的发展很重要的纳米材料来说，自上而下的方法有局限性，因为单分散纳米颗粒的制造随着尺寸的减小变得越来越困难。如果可以合成具有与块状材料相同结构的高核簇，则自下而上的分子方法提供了另一种途径。这种“分子纳米粒子”为纳米科学带来了分子化学的优势，特别是真正的单分散性、溶解度和结晶性。这种合成方法尤其适用于具有重要科学技术意义的纳米级金属氧化物。George Christou教授的团队最近在团簇化学方面取得了突破，生产出了真正的单分散的锰、钙钛矿和二氧化铈纳米颗粒，为纳米级的知识生成开辟了新的方向。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Unusual Mn5 cluster with a ‘twisted bow-tie’ topology and MnIIMnIII2MnIV2 oxidation states: Synthesis, structure, and magnetic properties

• DOI: 10.1016/j.poly.2021.115141
• 发表时间: 2021-03
• 期刊: Polyhedron
• 影响因子: 2.6
• 作者: Ashlyn R. Hale;Philippa King;K. Abboud;G. Christou

High nuclearity structurally – related Mn supertetrahedral T4 aggregates

高核结构相关的 Mn 超四面体 T4 聚集体

• DOI: 10.1039/d1cc01815a
• 发表时间: 2021
• 期刊: Chemical Communications
• 影响因子: 4.9
• 作者: Skordi, Katerina;Anastassiades, Antonis;Fournet, Adeline D.;Kumar, Rahul;Schulze, Michael;Wernsdorfer, Wolfgang;Christou, George;Nastopoulos, Vassilios;Perlepes, Spyros P.;Papatriantafyllopoulou, Constantina
• 通讯作者: Papatriantafyllopoulou, Constantina

Expansion of the Family of Molecular Nanoparticles of Cerium Dioxide and Their Catalytic Scavenging of Hydroxyl Radicals

二氧化铈分子纳米颗粒家族的扩展及其对羟基自由基的催化清除

• DOI: 10.1021/acs.inorgchem.0c03133
• 发表时间: 2021
• 期刊: Inorganic Chemistry
• 影响因子: 4.6
• 作者: Mitchell, Kylie J.;Goodsell, Justin L.;Russell-Webster, Bradley;Twahir, Umar T.;Angerhofer, Alexander;Abboud, Khalil A.;Christou, George
• 通讯作者: Christou, George

Rare nuclearities in Mn/oxo cluster chemistry: Synthesis and characterization of a mixed-valence {MnII/III11} complex bearing acetate and salicylhydroximate(-3) bridging/chelating ligands

• DOI: 10.1016/j.poly.2021.115298
• 发表时间: 2021-05
• 期刊: Polyhedron
• 影响因子: 2.6
• 作者: E. Koumousi;Gerasimi Lazari;S. Grammatikopoulos;Constantina Papatriantafyllopoulou;M. Manos;S. Perlepes;A. Tasiopoulos;G. Christou;T. Stamatatos

Analysis of spin frustration in an FeIII7 cluster using a combination of computational, experimental, and magnetostructural correlation methods

结合计算、实验和磁结构相关方法分析 FeIII7 团簇中的自旋挫败

• DOI: 10.1016/j.poly.2022.116045
• 发表时间: 2022
• 期刊: Polyhedron
• 影响因子: 2.6
• 作者: Hale, Ashlyn R.;Aebersold, Lucas E.;Peralta, Juan E.;Foguet-Albiol, Dolos;Abboud, Khalil A.;Christou, George
• 通讯作者: Christou, George