Oxidation Potentials and Chemical Reactivities

氧化电位和化学反应性

• 批准号: 8800299
• 负责人: Frederick Bordwell
• 金额: $ 19.91万
• 依托单位: Northwestern University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-12-15 至 1991-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8800299&HistoricalAwards=false
• 关键词: Oxidation; Potentials; Chemical; Reactivities

This grant in the Organic Dynamics Program provides support for the research of Dr. Fred Bordwell of Northwestern University. This work is divided into four areas: (1) the measurement of the acid strength of neutral and positively charged organic compounds, (2) the estimation of the energy required for the homolytic breakage of C-H, N-H and S-H bonds, (3) the effect of substituent groups on this latter, bond breaking process, and (4) organic reaction mechanisms involving the transfer of an electron. This work will provide insight into the pathway of organic reactions, especially those involving negatively charged species. The ease with which a molecule H-A can be cleaved thermally into two radical fragments, i.e., H-A giving H atom and A atom, provides an important insight into its reactivity. The Bordwell group has recently devised a method of estimating the size of such bond dissociation energies (BDE's) by combining the oxidation potential of the anion and the acidity constant of its conjugate acid, both measured in dimethyl sulfoxide solution. This method will be used to estimate BDE's for a large number of important weak acids for which BDE's have hitherto been inaccessible. By combining the oxidation potentials of the acid and the anion, and the acidity constant of the acid, the acidities of radical cations have been estimated. No previous information of this type has been available despite the importance of radical cations as intermediates. Finally, redox potentials combined with rate studies are expected to reveal significant new details concerning the role of single electron transfer in reactions of anions with electrophiles.

有机动力学计划的这笔赠款为以下方面提供支持： 美国西北大学的弗雷德·博德维尔博士的研究。 这项工作分为四个方面：（1）测量 中性和带正电荷有机物的酸强度 （2）计算所需的能量， C-H、N-H和S-H键的均裂断裂; 后者上的取代基，键断裂过程，和 (4)有机反应机理涉及转移的一个 这项工作将提供深入了解的途径， 有机反应，特别是那些涉及负 带电物种 分子H-A能被热裂解的容易程度 分成两个自由基片段，即，H-A给出H原子和A原子， 提供了对其反应性的重要见解。 的 Bordwell集团最近设计了一种方法， 这种键离解能（BDE）的大小， 阴离子的氧化电位和酸度常数 其共轭酸，均在二甲基亚砜中测量 溶液 该方法将用于估算一个国家的溴化二苯醚 大量重要的弱酸， 迄今为止无法访问。 通过结合氧化作用 酸和阴离子的电势，以及酸度常数 在酸中，自由基阳离子的酸度已经被 估算 以前没有此类信息， 尽管自由基阳离子作为 中间体的 最后，氧化还原电位结合速率 研究有望揭示重要的新细节， 关于单电子转移在反应中的作用， 阴离子与亲电体。