RUI-Antiaromaticity of Indenylidene Dications and the Aromaticity/Antiaromaticity Continuum

RUI-茚亚基双阳离子的反芳香性和芳香性/反芳香性连续体

• 批准号: 0242227
• 负责人: Nancy Mills
• 金额: $ 25.3万
• 依托单位: Trinity University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-05-15 至 2007-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0242227&HistoricalAwards=false
• 关键词: RUI; Antiaromaticity; Indenylidene; Dications; Aromaticity

The concepts of aromaticity and antiaromaticity play central roles in organic chemistry. Although somewhat elusive concepts, a combination of experimental and calculational tools may be used to assess aromacity and antiaromaticity through analysis of magnetic, structural, and energetic criteria. Indenylidene dications allow the assessment of magnetic properties through the paratropicity of protons on both the five- and six-membered rings, allowing evaluation of the antiaromaticity suggested by the nucleus independent chemical shift values. Because the cyclopentadienyl ring of the indenylidene cation can respond to increased antiaromaticity through deformation, structural properties can be assessed. Energetic properties can be assessed by electrochemical oxidation and comparison of redox potentials with those of non-antiaromatic model systems. By playing the various criteria against each other in aromatic and antiaromatic systems, the criteria that most effectively define aromatic/antiaromatic systems will be exposed.Ever since the initial realization that benzene and related "aromatic" hydrocarbons display unusually high stability, the factors responsible for this stability have been of great interest. "Aromaticity" and its counterpoint, antiaromaticity, in which compounds display lower than anticipated stability, play central roles in defining organic chemical structure and reactivity. With the support of a Research at Undergraduate Institutions (RUI) grant from the Organic and Macromolecular Chemistry Program, Professor Nancy S. Mills, of the Department of Chemistry at Trinity University, is exploring new molecular systems expected to display antiaromaticity. Through the rational design and synthesis of appropriate organic molecules and analysis of their magnetic, structural, and energetic properties, Professor Mills is defining the criteria that most effectively define aromaticity and antiaromaticity. A large number of undergraduate research assistants will participate in these studies, providing them with valuable research experience and education in a variety of experimental, instrumental, and theoretical techniques.

芳香性和反芳香性的概念在有机化学中起着核心作用。尽管概念有些难以捉摸，但实验和计算工具的结合可用于通过分析磁性、结构和能量标准来评估芳香性和反芳香性。茚叉二甲基可以通过五元环和六元环上质子的顺向性来评估磁性，从而可以评估与核无关的化学位移值所暗示的反芳香性。由于茚叉基阳离子的环戊二烯基环可以通过变形来响应增加的反芳香性，因此可以评估结构特性。能量特性可以通过电化学氧化以及氧化还原电位与非反芳香模型系统的比较来评估。通过在芳香族和反芳香族体系中相互比较各种标准，将暴露出最有效地定义芳香族/反芳香族体系的标准。自从最初认识到苯和相关的“芳香族”碳氢化合物表现出异常高的稳定性以来，导致这种稳定性的因素一直引起人们的极大兴趣。 “芳香性”及其对应的反芳香性（其中化合物表现出低于预期的稳定性）在定义有机化学结构和反应性方面发挥着核心作用。在有机和高分子化学项目本科院校研究 (RUI) 资助的支持下，三一大学化学系的 Nancy S. Mills 教授正在探索有望表现出反芳香性的新分子系统。通过合理设计和合成适当的有机分子并分析其磁性、结构和能量特性，米尔斯教授正在定义最有效定义芳香性和反芳香性的标准。大量本科生研究助理将参与这些研究，为他们提供宝贵的研究经验和各种实验、仪器和理论技术方面的教育。