Organometallic Chemistry of Periodic pi-Electron Surfaces: Carbon Nanotubes and Graphene

技术摘要：该项目由固态和材料化学计划支持，涉及制备一类新的石墨化材料，其中表面用过渡金属功能化，从而允许在苯环系统之间形成由双六面体金属键组成的原子级互连；这种方法有望提供一种方法来增加一维碳纳米管和二维石墨烯片材的电子结构的维度。初步实验表明，铬络合物的制备方法很多，包括用羰基铬前驱体的溶液相功能化、以单六面体络合物为起始的加压固相热反应和电子束物理气相沉积(电子束)气相金属气相合成。所有这些材料都表明，在有机金属功能化过程中，起始石墨化结构的导电性发生了变化，这一提议的目的是扩大对金属与石墨烯表面相互作用的基本理解，并完善材料的合成和物理表征。基于对石墨烯在Dirac点的电子结构的前线分子轨道分析，石墨烯被认为是配位络合物中的一种很好的配体，显然可以制备各种各样的有机金属插层化合物。因此，本研究的目标是开发一类具有独特电子性质的新型过渡金属-石墨烯材料，并在原子水平上为石墨化表面之间的电子互连奠定基础。作为电子、光电子和自旋电子器件的活性成分，新材料可能会引起人们的兴趣。非技术总结：该项目将导致一类新的碳纳米管和石墨烯框架，它们通过共价而不是离子键连接在一起。所提出的材料有望具有新颖的催化、电子和磁性；一些已知的电荷转移石墨化合物表现出超导电性，这种可能性存在于所提出的有机金属化合物中。这个项目的更广泛的影响将在本科生和研究生的参与和培训中最为明显，这将发生在一个高度整合的、多学科的项目中，其工作旨在促进化学科学的基础和重要技术方面的进步。学生们将接触到一套广泛的现代研究工具，并将熟悉纳米科学与工程中心的纳米制造工具和分析技术。我们发现，对于寻求进入电子行业的学生来说，这种培训是一种无价的资产。将通过加州少数群体参与联盟(CAMP)、夏季桥梁研究计划和CNAS院长暑期实习，特别努力吸引妇女和少数族裔参与研究计划。该项目得到了固体和材料化学计划的支持。

TECHNICAL SUMMARY:This project, supported by the Solid State and Materials Chemistry Program, involves preparation of a new class of graphitic materials in which the surfaces are functionalized with transition metals, thereby allowing the formation of atomic scale interconnects that consist of bis-hexahapto-metal-bonds between the benzenoid ring systems; this approach is anticipated to provide a method to increase the dimensionality of the electronic structure of the 1-D carbon nanotubes and the 2-D graphene sheets. Preliminary experiments show that chromium complexes are accessible by a wide range of preparative methods, which include solution phase functionalization with chromium carbonyl precursors, solid state thermal reactions under pressure beginning with mono-hexahapto complexes and gas phase metal vapor synthesis using electron beam physical vapor deposition (e-beam). All of these materials show evidence of a change in the electrical conductivities of the starting graphitic structures on organometallic functionalization and it is the purpose of this proposal to broaden the fundamental understanding of the interaction between metals and graphene surfaces and to refine the synthesis and physical characterization of the materials. Based on a frontier molecular orbital analysis of the electronic structure of graphene at the Dirac point, graphene is identified as an excellent ligand in coordination complexes and it is apparent that a wide variety of organometallic intercalation compounds can be prepared. Thus the goal of the proposed research is to develop a class of novel transition metal-graphene materials that exhibit unique electronic properties and to lay the foundation for electronic interconnects between graphitic surfaces at the atomic level. The new materials may be of interest as the active constituent in electronic, opto-electronic and spintronic devices. NON-TECHNICAL SUMMARY:This project will lead to a new class of carbon nanotube and graphene frameworks that are held together by covalent, rather than ionic bonding. The proposed materials are expected to have novel catalytic, electronic and magnetic properties; a number of the known charge transfer graphite compounds exhibit superconductivity and such a possibility exists with the proposed organometallic compounds. The broader impact of this project will be most evident in the participation and training of students at the undergraduate and graduate level which will occur in a highly integrated, multidisciplinary program whose work is directed toward advancements in fundamental and technologically significant aspects of the chemical sciences. The students will be exposed to an extensive suite of modern research tools and will become familiar with the Center for Nanoscale Science and Engineering nanofabrication tools and analytical techniques. We have found that such training serves as an invaluable asset for students that are seeking entry into the electronics industry. Special effort will be devoted to attracting women and minorities into the research program through the California Alliance for Minority Participation (CAMP), the Summer Bridge Research Program and CNAS Dean Summer Internships. This project is supported by the Solid State and Materials Chemistry Program.