Isotope Effects and Mechanisms in Eliminations and Other Proton Transfer Reactions

消除和其他质子转移反应中的同位素效应和机制

• 批准号: 8818894
• 负责人: William Saunders
• 金额: $ 27.42万
• 依托单位: University of Rochester
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-01-01 至 1992-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8818894&HistoricalAwards=false
• 关键词: Isotope; Effects; Mechanisms; Eliminations; Other

With support from the Organic Dynamics Program, Professor William H. Saunders, Jr. of The University of Rochester will study the effect on chemical behavior caused by replacing one or more atoms in a molecule with an isotope (an atom with the same qualitative chemical behavior but a different atomic weight). The difference in reaction rates caused by such replacements will lead to conclusions about the detailed pathways (mechanisms) of the particular chemical reactions in question. Such knowledge facilitates the use of the reactions to synthesize compounds of industrial and pharmaceutical interest. Major emphasis will be placed on exploring the influence of quantum mechanical tunneling on rates and isotope effects in proton transfer reactions. In order to obtain such information, isotope effects and their temperature dependencies will be determined for bimolecular eliminations and deprotonation of aliphatic nitro compounds. Another characteristic of tunneling that will be explored is noncumulative behavior of isotope effects in multiply labeled species (isotope effects on isotope effects). Kinetic enolate formation and other reactions showing attenuated temperature dependencies will be studied. Dr. Saunders will test the hypothesis that such abnormal temperature dependence can in many instances be attributed to reaction via more than one base species. Isotope effect calculations will be performed as they are needed to interpret experimental results.

在有机动力学项目的支持下，罗彻斯特大学的小威廉·h·桑德斯教授将研究用同位素（具有相同定性化学行为但原子量不同的原子）取代分子中的一个或多个原子对化学行为的影响。由这种替换引起的反应速率的差异将导致有关特定化学反应的详细途径（机制）的结论。这些知识有助于利用这些反应来合成具有工业和药学意义的化合物。主要的重点将放在探索量子力学隧道对质子转移反应速率和同位素效应的影响。为了获得这些信息，同位素效应及其温度依赖性将被确定为双分子消除和去质子化的脂肪族硝基化合物。隧道效应的另一个特征是同位素效应在多重标记物种中的非累积行为（同位素效应对同位素效应的影响）。动力学烯酸酯形成和其他反应显示减弱的温度依赖性将被研究。桑德斯博士将验证这样一种假设，即在许多情况下，这种异常的温度依赖性可以归因于通过不止一种碱基进行的反应。当需要解释实验结果时，将进行同位素效应计算。