Computational Study of Reaction Mechanisms for Lithium Carbenoids and Related Species

有机和高分子化学项目支持菲斯克大学的劳伦斯·普拉特教授的工作，他的研究将调查碳化锂类化合物的反应，这是一类重要的合成试剂。研究模式将主要是计算量子化学，必要时辅之以实验方法。计算方法对于这类化合物的研究很重要，因为实验研究存在许多困难。碳化锂类化合物对空气敏感，活性高，通常只能在低温下进行研究。光谱测量提供了线索，但单独使用时不能阐明这类反应物的详细机理。计算量子化学将用于确定可能存在于溶液中的物种，并估计每个假设反应步骤的活化能。现代量子方法可以用化学方法精确地估计这些势垒，例如，在1或2千卡/摩尔以内。通过这种方式，普拉特教授将收集大量的数据，这些数据将使他能够确定哪些物种发生反应，如果有活性中间体，以及反应发生的速度有多快。这项工作将导致对有机反应机理的更好理解。由有机和高分子化学计划资助的这项工作将导致更有效的有机合成方法，包括难以合成制药业使用的天然产品。此外，这项工作还将加强对现有计算方法及其局限性的理解。更广泛的影响包括在多文化和多国背景下培养本科生和硕士研究生。国际和平协会目前参与了几个国家和国际合作，并正在扩大这些合作，将波多黎各的大学包括在内。菲斯克大学是HBCU的一所机构，招收约70%的女性。该协会致力于将其他代表性不足的少数族裔纳入研究项目。这一研究项目产生的培训将帮助学生为在全球市场取得成功做好准备，并将提供培训，为学生为就业市场和最好的博士项目和专业学校做好准备。

The Organic and Macromolecular Chemistry Program supports the work of Professor Lawrence Pratt of Fisk University whose research will investigate the reactions of lithium carbenoids, an important class of synthetic reagents. The mode of investigation will be primarily computational quantum chemistry, augmented by experimental methods when necessary. Computational methods are important for research on this class of compounds because experimental studies present many difficulties. Lithium carbenoids are air sensitive and highly reactive, and can often be studied only at low temperatures. Spectroscopic measurements provide clues but cannot, when used alone, elucidate the detailed mechanisms of this class of reactants. Computational quantum chemistry will be used to determine the species that are likely to be present in solution, and to estimate the activation energies of each hypothetical reaction step. Modern quantum methods can estimate these barriers with chemical accuracy, e.g., within one or two kcal/mol. In this way, Professor Pratt will gather a large quantity of data that will allow him to determine which species react, what the reactive intermediates are, if any, and how fast the reactions are likely to occur.This work will result in a better understanding of organic reaction mechanisms. The funding of this work by the Organic and Macromolecular Chemistry Program will result in more efficient methods for organic synthesis, including hard to synthesize natural products that are used by the pharmaceutical industry. Also, an enhanced understanding of the available computational methods and their limitations will result from this work. Broader impacts include the training of undergraduate and masters graduate students in a multicultural and multinational setting. The PI is currently involved in several national and international collaborations, and is expanding these to include universities in Puerto Rico. Fisk University is an HBCU institution with an enrollment of about 70% women. The PI is committed to include other underrepresented minorities in the research projects. The training resulting from this research project will help prepare students to succeed in the global marketplace, and will provide training to prepare students for the job market and the best Ph. D. programs and professional schools.