MRI: Acquisition of a High-Brilliance X-Ray Diffractometer for Fundamental Materials and Catalysis Research and Education at Howard University

这项主要研究仪器(MRI)奖支持在霍华德大学购买双源单晶X射线衍射仪，霍华德大学是历史上的黑人大学(HBCU)。这一能力为霍华德大学的基础材料和催化研究注入了活力，提供了将单晶X射线衍射(SC-X射线)分析的优势扩展到非晶态系统的应用机会，如液体和非晶态固体、化学战剂的分解、分析物检测、能量存储、化石能源转换、分子开关和记忆存储。SC-X射线衍射法是目前确定分子结构最有效的技术之一。通过将聚焦的x射线束照射到晶体上，人们可以确定原子在分子中是如何连接的，这些原子是如何在空间上定向的，以及分子是如何在晶体中堆积在一起的。原子和分子排列的知识可以更好地理解分子是如何发挥作用的。这最终可能导致设计新材料，揭示生物有机体是如何运作的，并开发新的疗法来减轻人类的痛苦。产生的X射线束的强度允许对具有挑战性的样品进行快速分析。这一工具创建和加强了大西洋中部地区的现有合作，并增强了研究能力。衍射仪还加强了霍华德大学的化学教育，并为学员提供了使用美国国家实验室先进设施的基础。这些活动激励了未被充分代表的少数群体追求化学和结晶学，从而使国家学术、政府和工业劳动力进一步多样化。所获得的高亮度单晶X射线衍射仪具有双微聚焦钼和铜源，具有多层光学元件，像素阵列探测器，工作在无快门数据采集模式，以及在80-400K范围内进行数据采集的温度控制系统。双源配置允许快速收集高质量的衍射数据，以执行微晶和粉末样品的详细分析。高通量单色X射线可以分析弱衍射微晶体。受益于新仪器的项目涉及以下研究：(1)作为预制结晶基质的新型金属-有机骨架(MOF)，用于通过“结晶海绵法”进行涉及非晶态化合物的分子结构阐明/机理研究；(2)用于催化应用的碳硼酰配体设计，例如化学战剂(CWA)的分解；(3)用于分析物检测的各向异性纳米颗粒复合合成(通过表面增强拉曼光谱)；(4)用于介电储能的嵌段共聚物强度；(5)通过大气压金属-有机化学气相沉积(AP-MOCVD)生成用于化石能源转换过程的氧化铁(II)核壳微粒的配体合成，(6)用于开关和存储器存储的自旋交叉络合物的研究，以及(7)用于制造新的自旋交叉材料和类药物分子的应用的催化序列设计衍生杂环支架。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。

This Major Research Instrumentation (MRI) award supports the acquisition of a dual-source single-crystal x-ray diffractometer at Howard University, a Historically Black University (HBCU). This capability invigorates fundamental materials and catalysis research at Howard University, offering application opportunities in extending the benefits of single-crystal x-ray diffraction (SC-XRD) analysis to non-crystalline systems such as liquids and amorphous solids, decomposition of chemical warfare agents, analyte detection, energy storage, fossil energy conversion, molecular switches, and memory storage. SC-XRD is one of the most powerful techniques available to determine molecular structure. By shining a focused x-ray beam on a crystal, one can determine how atoms are connected in a molecule, how these atoms are spatially oriented, and how molecules are packed together in a crystal. Knowledge of atomic and molecular arrangement allows for a better understanding of how molecules function. This can ultimately lead to designing new materials, to revealing how living organisms operate, and to developing new therapeutics to alleviate human suffering. The strength of the generated x-ray beams permits rapid analysis of challenging samples. This instrument creates and fortifies existing collaborations and enhances research capability in the Mid-Atlantic region. The diffractometer also strengthens chemical education at Howard University and provides trainees a foundation to use advanced facilities at US national laboratories. These activities inspire underrepresented minorities to pursue chemistry and crystallography leading to further diversification of the national academic, governmental, and industrial workforce.The acquired high-brilliance single-crystal x-ray diffractometer features dual microfocus Mo and Cu sources with multilayer optics, a pixel array detector that operates in a shutterless data acquisition mode, and a temperature control system for data collection within a range of 80–400 K. The dual-source configuration allows for the rapid collection of high-quality diffraction data to perform detailed analyses of microcrystalline and powder samples. The high-flux monochromatic x-rays permits the analysis of weakly-diffracting microcrystals. The projects that benefit from the new instrument involves the study of: (1) novel metal-organic frameworks (MOFs) as preformed crystalline matrices for use in molecular structure elucidation / mechanistic investigations involving non-crystalline compounds through the “crystalline sponge method”, (2) carboranyl ligand design for catalysis in applications such as the decomposition of chemical warfare agents (CWA), (3) anisotropic nanoparticle composite synthesis for use in analyte detection through surface-enhanced Raman spectroscopy, (4) block copolymer strength for applications in dielectric energy storage, (5) ligand synthesis for iron(II) oxide core-shell microparticle generation through atmospheric pressure metal-organic chemical vapor deposition (AP-MOCVD) for application in fossil energy conversion processes, (6) investigation of spin crossover complexes for application in switches and memory storage, and (7) design of catalytic sequential processes to derivatize heterocyclic scaffolds for application in creating new spin crossover materials and drug-like molecules.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.