RUI-Benzannulated antiaromatic dications and dianions: using antiaromaticity to probe delocalization

RUI-苯扎环反芳香双键和双阴离子：利用反芳香性探测离域

• 批准号: 1265545
• 负责人: Nancy Mills
• 金额: $ 26.02万
• 依托单位: Trinity University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-01 至 2015-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1265545&HistoricalAwards=false
• 关键词: RUI; Benzannulated; antiaromatic; dications; dianions

Through this award, funded by the Chemical Structure, Dynamics, and Mechanisms-B Program of the Division of Chemistry, Dr. Nancy Mills of Trinity University will examine the factors that affect delocalization by modification of antiaromatic dications and dianions. Antiaromatic species have been shown to be more sensitive to factors affecting delocalization because of their inherent tendency to avoid delocalization which results in an increase in antiaromaticity. For example, by annulation of a variety of polycyclic aromatic compounds to a cyclopentadienyl cation, the tension between the energetic advantages of delocalization of positive charge versus the stability from the intact polycyclic aromatic compound can be probed. Antiaromatic dianions are also accessible experimentally. Initial studies suggest that they are more antiaromatic than corresponding dications. Varying the position of benzannulation of a cycloheptatrienyl anionic system can again result in differences in antiaromaticity through differences in patterns of delocalization.Stability is one of the most important concepts in chemistry because all chemical reactions result in making the most stable molecules possible. There is a class of compounds, called antiaromatic, which have been suggested by theory to be particularly unstable. Needless to say, these compounds have not been carefully studied because of the anticipated difficulty in making them. However, a suite of these compounds was discovered in an attempt to make something else and have proven to be much easier to make and study than anticipated. Because they are still relatively unstable, they turn out to be very sensitive to changes in their structure. Just as some changes in a physical structure, like a house or an automobile, might be hard to see in the dim light of dusk, but be very visible in daylight, changes that are hard to understand in a molecular structure that is stable, become very visible in a less stable, antiaromatic compound. These studies will be carried out by undergraduate students, with an emphasis on students just beginning their study of chemistry. By engaging these students in research early in their academic career, they are in a better position to learn what aspects of science interest them the most, and to make choices in coursework to support that interest. They will be aided by post-doctoral researchers who are interested in teaching undergraduate students as a career. The workforce development inherent in training undergraduates and prospective faculty is the primary broader impact of the grant.

通过这项由化学系化学结构、动力学和机制b项目资助的奖项，三一大学的Nancy Mills博士将研究通过修饰反芳香指示物和碘离子来影响离域的因素。研究表明，抗芳香族植物对离域的影响更为敏感，因为它们固有的避免离域的倾向导致其抗芳香族性的增加。例如，通过将多种多环芳香族化合物环接成环戊二烯基阳离子，可以探索正电荷离域的能量优势与完整多环芳香族化合物的稳定性之间的张力。反芳离子也可以通过实验得到。初步研究表明，它们比相应的指示物更具有抗芳香性。改变环庚三烯基阴离子体系的苯并环的位置可以通过不同的离域模式再次导致抗芳性的差异。稳定性是化学中最重要的概念之一，因为所有的化学反应都会产生最稳定的分子。有一类化合物叫做反芳香族化合物，理论上认为它特别不稳定。不用说，这些化合物还没有被仔细研究过，因为预计制造它们会有困难。然而，在试图制造其他东西时发现了一组这些化合物，并且证明比预期的更容易制造和研究。因为它们仍然相对不稳定，所以它们对结构的变化非常敏感。就像物理结构的一些变化，比如房子或汽车，在昏暗的暮色中可能很难看到，但在白天却很明显，在稳定的分子结构中难以理解的变化，在不太稳定的反芳香族化合物中变得非常明显。这些研究将由本科生进行，重点是刚开始学习化学的学生。通过让这些学生在学术生涯的早期参与研究，他们可以更好地了解自己对科学的哪些方面最感兴趣，并在课程作业中做出选择来支持这种兴趣。他们将得到博士后研究人员的帮助，这些博士后研究人员有兴趣以教授本科生为职业。培训本科生和未来教师的内在劳动力发展是该资助的主要影响。