New, Chemically Reactive Fullerene-Based Assemblies: Accomplishment Based Renewal

在这个由化学部大分子、超分子和纳米化学项目资助的项目中，加州大学戴维斯分校的Alan L. Balch和Marilyn M. Olmstead将探索一组有前途的内嵌富勒烯的结构和化学反应性。内嵌富勒烯是碳原子的笼子，包裹着各种原子、离子或小分子。利用x射线衍射对大型富勒烯笼和手性富勒烯笼进行结构表征的工作涉及到在较小的、接近球形的富勒烯（如Bucky球、C60和碳纳米管）之间提供桥梁的分子。内嵌富勒烯在光收集和其他光电和电化学装置中的应用涉及到这些分子的还原和氧化，但对这些外部功能化的内嵌富勒烯的结构和化学反应性以及这些内嵌富勒烯氧化和还原形成的阳离子和阴离子知之甚少。研究人员打算制备各种内嵌富勒烯的结晶盐，以确定氧化和还原行为如何改变它们的结构，内容物在笼中的位置，以及笼内原子之间相互作用的性质。他们已经发现了几个新的富勒烯家族，其组成为M3C106-124、M4C122-154、M3C107-125，并将探索这些非凡分子的化学反应性和结构。该项目将为研究生和本科生提供最先进的实验室经验，他们将学习化学合成技术，电弧中富勒烯的形成，富勒烯分离和纯化的色谱方法，晶体和共晶体生长，以及单晶x射线衍射方法，包括传统的内部源和同步辐射。学生们还将学习如何在小组内以及与全球各地的科学家合作。富勒烯的原型C60曾经是一种罕见的化学物质，现在可以大量获得。鲍尔奇和奥姆斯特德教授预计，内嵌富勒烯的可用性也会有类似的增加。内嵌富勒烯是一种多用途的材料，它的特性可以反映被困在里面的原子的性质。因此，含钆内嵌体是磁共振成像的有效造影剂，并且具有将有毒的钆原子安全地捕获在不反应的碳笼中的优势。含镥内膜在x射线对比成像中很有用。富勒烯是设计新型塑料太阳能电池的首选分子，内嵌式富勒烯代表了一组有前途的新分子，可以改善和增强这些电池的工作特性。

In this project, funded by the Macromolecular, Supramolecular and Nanochemistry Program of the Chemistry Division, Alan L. Balch and Marilyn M. Olmstead of the University of California, Davis will explore the structures and chemical reactivity of a promising group of endohedral fullerenes, cages of carbon atoms that encapsulate a variety of atoms, ions or small molecules. Work on the structural characterization of large fullerene cages and chiral fullerene cages by X-ray diffraction involves molecules that provide a bridge between smaller, nearly spherical fullerenes like the Bucky ball, C60, and carbon nanotubes. The use of endohedral fullerenes in light harvesting and other electro-optical and electrochemical devices involves reduction and oxidation of these molecules, yet little is known about the structures and chemical reactivities of externally functionalized endohedral fullerenes and of the cations and anions formed by oxidation and reduction of these endohedral fullerenes. The researchers intend to prepare crystalline salts of a variety of endohedral fullerenes to determine how oxidation and reduction behavior alters their structure, the location of the contents with regard to the cage, and the nature of interactions between atoms inside cages. They have discovered several new families of fullerenes with compositions M3C106-124, M4C122-154, M3C107-125 and will explore the chemical reactivity and structures of these remarkable molecules.This project will provide state of the art laboratory experiences for graduate and undergraduate students who will be learning the techniques of chemical synthesis, fullerene formation in an electric arc, chromatographic methods of fullerene separation and purification, crystal and cocrystal growth, and single crystal X-ray diffraction methods including both conventional in-house sources and synchrotron radiation. The students will also learn how to collaborate within the group and also with scientists in varied locations globally. Once a rare chemical, the prototypical fullerene, C60, is now available in ton quantities. Professors Balch and Olmstead anticipate a similar increase in the availability of endohedral fullerenes. Endohedral fullerenes are versatile materials that have properties that reflect the nature of the atoms trapped inside. Thus, gadolinium-containing endohedrals are effective contrast agents for magnetic resonance imaging and have the advantage of safely trapping the toxic gadolinium atoms inside an unreactive carbon cage. Lutetium-containing endohedrals are useful in X-ray contrast imaging. Fullerenes are the molecules of choice in the design of new plastic solar cells, and endohedral fullerenes represent a promising new set of molecules to improve and enhance the operational characteristics of these cells.