CAREER: Functionalized Bent para-Phenylenes: New Strategies and Tools for the Synthesis of Carbon Nanotubes

职业：功能化弯曲对亚苯基：合成碳纳米管的新策略和工具

• 批准号: 1654691
• 负责人: Bradley Merner
• 金额: $ 70万
• 依托单位: Auburn University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-05-01 至 2023-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1654691&HistoricalAwards=false
• 关键词: CAREER; Functionalized; Bent; para; Phenylenes

With this CAREER Award, the Chemical Synthesis Program of the Chemistry Division supports the research of Professor Bradley L. Merner at Auburn University. The main objective of Professor Merner's research is to develop new strategies for the controlled synthesis of carbon nanotubes. At the present, one of the chief problems interfering with the synthesis of carbon nanotubes is our inability to make them in a uniform manner. Modern carbon nanotube syntheses lead to mixtures that complicate correlations between nanotube structure and physical properties. To address this gap, the Merner group is developing the synthetic tools needed to build smaller sections of a carbon nanotube that can then be assembled into larger nanotubes in a systematic way. By controlling the size of the smaller pieces, the size of the larger nanotube can be intentionally controlled. Since carbon nanotubes are made of a series of benzene rings that are stitched together, the synthesis initially targets larger cyclic systems that contain both multiple benzene rings and the functionality needed to bind the them together and build the targeted nanotubes. The lynchpin of this approach is the use of an unstrained benzene surrogate during the construction of the larger rings. Once those rings are assembled, then strained, bent benzene rings are released so they are trapped with in the larger ring structure. The route offers many opportunities to access carbon nanotube building blocks that were previously unavailable. The educational component of the program involves the development of chemical synthesis-teaching modules that are offered to rising junior and senior-level high school students in the Southeast region as part of the Auburn University Summer Science Institute. Underrepresented undergraduate students wishing to pursue graduate-level training in STEM-related fields participate in a chemical synthesis summer research program. Furthermore, in order to expose more undergraduate students to graduate-level research experiences, students enrolled in honors organic chemistry at Auburn University synthesize important starting materials that are used in future synthetic method development by graduate students in Professor Merner's laboratory. Carbon nanotubes are of great interest in the fields of materials science, engineering and biological sensing. However their use in these areas is hampered by the inability to access carbon nanotubes that are of a defined, homogenous structure. In this research project, Professor Merner and his group are tackling this challenge with new synthetic strategies that imbed the nonplanar benzene rings that comprise carbon nanotubes within functionalized polycyclic building blocks. This is an important step in the construction of uniform carbon nanotubes because if the size and shape of the building blocks can be controlled, then the size and shape of the nanotube assembled from the building blocks can be controlled. In this project, the molecular complexity of the building blocks are increased systematically so that they can better understand the reactivity of strained molecules, possible releases of this strain energy to afford undesired by-products, and the reaction mechanisms by which these processes occur. This information guides the synthesis of the more complex systems eventually culminating in the construction of the carbon nanotubes themselves. The initial strategy being pursued uses a non-cross-coupling-based approach to prepare macrocyclic, functionalized carbon nanotube substructures. These functionalized systems are employed in programmed, late-stage carbon-carbon bond forming reactions to build larger structures. Several annulation strategies to join adjacent arenes are investigated and the reactions afford pi-extended macrocyclic segments that are representative of carbon nanotube sidewall structures. The target structures not only lead to development of new chemical tools for accessing these complex organic molecules, but also provide first-rate training in chemical synthesis to undergraduate and graduate students, and deepen the understanding of chemical reactivity in strained, complex hydrocarbons.

通过这个职业奖，化学部的化学合成项目支持了奥本大学Bradley L. Merner教授的研究。Merner教授研究的主要目标是开发碳纳米管受控合成的新策略。目前，干扰碳纳米管合成的主要问题之一是我们无法以统一的方式制造它们。现代碳纳米管合成导致混合物，使纳米管结构和物理性质之间的关系复杂化。为了弥补这一缺陷，默纳小组正在开发合成工具，以构建碳纳米管的小部分，然后以系统的方式组装成更大的纳米管。通过控制小片的尺寸，可以有意地控制大纳米管的尺寸。由于碳纳米管是由一系列苯环拼接而成的，因此合成最初的目标是包含多个苯环以及将它们结合在一起并构建目标纳米管所需的功能的更大的循环系统。这种方法的关键是在构建较大的环时使用非张力苯替代物。一旦这些环组装好，绷紧的、弯曲的苯环就会释放出来，这样它们就会被困在更大的环结构中。这条路线提供了许多机会来获取以前无法获得的碳纳米管构建块。该项目的教育部分包括化学合成教学模块的开发，作为奥本大学暑期科学研究所的一部分，该模块提供给东南地区初高中学生。希望在stem相关领域进行研究生水平培训的未被充分代表的本科生参加化学合成暑期研究计划。此外，为了让更多的本科生接触到研究生水平的研究经验，奥本大学荣誉有机化学专业的学生在Merner教授的实验室合成了重要的起始材料，这些材料将用于研究生未来的合成方法开发。碳纳米管在材料科学、工程和生物传感等领域受到广泛关注。然而，它们在这些领域的应用受到无法获得具有确定的、均匀结构的碳纳米管的阻碍。在这个研究项目中，Merner教授和他的团队正在用新的合成策略来解决这个挑战，他们将包含碳纳米管的非平面苯环嵌入到功能化的多环构建块中。这是构建均匀碳纳米管的重要一步，因为如果构建块的大小和形状可以控制，那么由构建块组装的纳米管的大小和形状就可以控制。在这个项目中，构建模块的分子复杂性系统地增加，以便他们可以更好地理解应变分子的反应性，这种应变能可能释放以提供不希望的副产物，以及这些过程发生的反应机制。这些信息指导更复杂系统的合成，最终形成碳纳米管本身。最初的策略是采用非交叉耦合的方法来制备大环、功能化的碳纳米管子结构。这些功能化系统被用于程序化的、后期碳-碳键形成反应，以构建更大的结构。研究了几种连接相邻芳烃的环化策略，并得到了代表碳纳米管侧壁结构的pi延伸大环段。这些目标结构不仅有助于开发新的化学工具来获取这些复杂的有机分子，而且还为本科生和研究生提供了一流的化学合成训练，并加深了对应变复杂碳氢化合物化学反应性的理解。

项目成果

A macrocycle directed total synthesis of di- O -methylendiandrin A

二-O-亚甲基二苯甲酮大环定向全合成

• DOI: 10.1039/d0cc03302b
• 发表时间: 2020
• 期刊: Chemical Communications
• 影响因子: 4.9
• 作者: Barnes, Timothy H.;Johnson, Kara F.;Gorden, John D.;Merner, Bradley L.
• 通讯作者: Merner, Bradley L.

Carbamoyl Functionalized Bent para -Phenylenes via an Unexpected Reaction of the Burgess Reagent with α-Ketols

通过 Burgess 试剂与 α-酮醇的意外反应生成氨基甲酰基官能化弯曲对亚苯基

• DOI: 10.1021/acs.joc.0c02979
• 发表时间: 2021
• 期刊: The Journal of Organic Chemistry
• 作者: Jackson, Sydney N.;Caskey, Andrew L.;Narayanan, Natasha K.;Merner, Bradley L.
• 通讯作者: Merner, Bradley L.

Highly Strained para-Phenylene-Bridged Macrocycles from Unstrained 1,4-Diketo Macrocycles

• DOI: 10.1055/s-0036-1589081
• 发表时间: 2017-08
• 期刊: Synlett
• 影响因子: 2
• 作者: Nirmal K Mitra;Caroline P. Merryman;B. Merner