Lithium Carbenoids and Related Species: Structure and Reactions

锂类胡萝卜素和相关物质：结构和反应

• 批准号: 1258670
• 负责人: Lawrence Pratt
• 金额: $ 22.35万
• 依托单位: CUNY Medgar Evers College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-01 至 2015-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1258670&HistoricalAwards=false
• 关键词: Lithium; Carbenoids; Related; Species; Structure

The Chemical Structure, Dynamics and Mechanisms Program supports Professors Lawrence M. Pratt, at Fisk University in Nashville TN, and Marcus A. Tius at the University of Hawaii who will continue their efforts to better understand the structures and reaction mechanisms of lithium carbenoids. The project will use a combination of computational quantum chemistry and NMR spectroscopy to determine the structure of lithium carbenoids in solution, and their tendency to form mixed aggregates with other lithium compounds. Mixed aggregates are well known in organolithium chemistry, and they sometimes have dramatic effects on reactivity and selectivity. The reaction mechanisms studied to date have often been quite complex, and would be very difficult to elucidate without the use of computational chemistry. Preliminary work completed during the initial grant period has shown which computational methods are most appropriate for the problems in this study. The predictions of the reaction products, obtained from the calculated mechanisms, will be tested in the laboratory of the Tius synthetic group. Frequently, two or more reaction mechanisms are operating concurrently, and changing the reaction conditions may enhance or suppress one mechanism. This sometimes results in improved reaction selectivity, purer products, and reductions in the production of toxic wastes. It may also show that the reagents being investigated are not ideal for a particular reaction, and may spur the search for alternate synthetic methods.With the support of the Chemical Structure, Dynamics and Mechanisms Program in the Chemistry Division at the National Science Foundation, Professors Lawrence M. Pratt, at Fisk University in Nashville TN, and Marcus A. Tius at the University of Hawaii will contribute to further understanding of lithium carbenoid reactions that can lead to a wider application in synthetic organic reactions. Organolithium reagents are ubiquitous in modern synthesis but little is known about the factors affecting their structure and reactivity. Broader impacts are in student education and training, with the largest impact on minority students. Fisk University is a Historically Black College/University (HBCU), with about 98% African-American and about 70% female students. The University of Hawaii is a collaborating institution, and is also committed to the inclusion of minorities in science. Louisiana Tech University is also a collaborating institution, with a large African-American student population and some joint faculty appointments with Grambling State University, another HBCU. A major impact of this research will be to revitalize the graduate (MS) program at Fisk, which had been hurt by economic conditions in recent years. A goal of this project is to help those students bridge into a program of their choice, possibly at one of the several research universities collaborating with Professor Pratt on this and other projects.

化学结构，动力学和机制计划支持田纳西州纳什维尔大学Fisk University的Lawrence M. Pratt教授，以及夏威夷大学的Marcus A. Tius，他们将继续他们的努力，以更好地了解锂类carbenoids的结构和反应机制。该项目将使用计算量子化学和NMR光谱的组合来确定溶液中锂类carbenoids的结构，以及它们与其他锂化合物形成混合聚集体的趋势。混合骨料在化学中是众所周知的，有时对反应性和选择性产生巨大影响。迄今为止研究的反应机制通常非常复杂，如果不使用计算化学，很难阐明。在初始赠款期间完成的初步工作表明，哪些计算方法最适合本研究中的问题。从计算的机制获得的反应产物的预测将在Tius合成组的实验室中进行测试。 通常，两个或多个反应机制同时运行，改变反应条件可能会增强或抑制一种机制。有时，这会提高反应选择性，纯净产物以及有毒废物产生的降低。 It may also show that the reagents being investigated are not ideal for a particular reaction, and may spur the search for alternate synthetic methods.With the support of the Chemical Structure, Dynamics and Mechanisms Program in the Chemistry Division at the National Science Foundation, Professors Lawrence M. Pratt, at Fisk University in Nashville TN, and Marcus A. Tius at the University of Hawaii will contribute to further understanding of lithium carbenoid reactions that can lead to a wider在合成有机反应中应用。有机石试剂在现代合成中无处不在，但对影响其结构和反应性的因素知之甚少。对学生的教育和培训的影响更大，对少数族裔学生的影响最大。 Fisk University是一所历史悠久的黑人学院/大学（HBCU），约有98％的非裔美国人和约70％的女学生。夏威夷大学是一家合作机构，也致力于将少数民族纳入科学。路易斯安那理工大学也是一家合作机构，拥有大量的非裔美国学生人数，并与另一家HBCU的Grambling州立大学联合任命。这项研究的主要影响是振兴菲斯克的研究生（MS）计划，近年来经济状况受到了伤害。该项目的一个目的是帮助这些学生桥接他们选择的计划，这可能是在与普拉特教授合作的几所研究型大学和其他项目中合作的一所研究。