Effect of Aromaticity and Anti-Aromaticity on Transition States and Intrinsic Barriers of Reactions

芳香性和反芳香性对过渡态和反应本征势垒的影响

• 批准号: 0446622
• 负责人: Claude Bernasconi
• 金额: --
• 依托单位: University of California-Santa Cruz
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-01-01 至 2009-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0446622&HistoricalAwards=false
• 关键词: Effect; Aromaticity; Anti; Transition; States

With the support of the Organic and Macromolecular Chemistry Program, Professor Claude F. Bernasconi, of the Department of Chemistry and Biochemistry at the University of California, Santa Cruz, will continue experimental and computational studies of the effect of aromaticity and anti-aromaticity on the intrinsic barriers to a number of fundamental chemical reactions. Investigations of intrinsic barriers, that is the barriers in the absence of a thermodynamic driving force, allow critical evaluation of the factors affecting transition state energies and contribute to our basic understanding of the rates of chemical reactions. Both experimental and computational approaches will be used in these investigations. The experimental approach will involve kinetic and equilibrium measurements of proton transfers, nucleophilic additions to highly electrophilic systems, and hydride ion transfers. Reactions will be chosen which allow modulation of the degree of aromaticity or anti-aromaticity in products or reactants and intrinsic barriers will be determined experimentally. The computational approach will focus on gas phase proton, hydride ion, hydrogen atom, halonium ion, and halide ion transfers involving aromatic and anti-aromatic species. Intrinsic barriers will be calculated and compared to the respective barriers of corresponding model reactions that do not involve aromatic or anti-aromatic species. The broader impacts of this research will be two-fold. At the scientific level, the project addresses fundamental questions about chemical reactions and our understanding of how structure affects chemical reactivity, a central theme of physical organic chemistry. At the level of human resource development, the proposed work provides students with a broad educational experience, ranging from synthesis and spectroscopic characterization to kinetics, data analysis, and computational chemistry.

在有机和高分子化学项目的支持下，克劳德·F·位于圣克鲁斯的加州大学化学和生物化学系的Bernasconi将继续进行芳香性和反芳香性对一些基本化学反应的内在障碍的影响的实验和计算研究。调查的内在障碍，即障碍的热力学驱动力的情况下，允许关键的评估影响过渡态能量的因素，并有助于我们的基本理解的化学反应的速率。实验和计算方法将用于这些调查。 实验方法将涉及质子转移，亲核加成高度亲电系统，和氢化物离子转移的动力学和平衡测量。将选择允许调节产物或反应物中的芳香性或反芳香性程度的反应，并且将通过实验确定固有势垒。计算方法将集中在气相质子，氢化物离子，氢原子，卤离子，卤离子转移涉及芳香族和反芳香族物种。将计算固有势垒，并将其与不涉及芳族或反芳族物质的相应模型反应的相应势垒进行比较。 这项研究的广泛影响将是双重的。在科学层面，该项目解决了有关化学反应的基本问题，以及我们对结构如何影响化学反应性的理解，这是物理有机化学的中心主题。 在人力资源开发层面，拟议的工作为学生提供了广泛的教育经验，从合成和光谱表征到动力学，数据分析和计算化学。