Computational Study of Reaction Mechanisms for Lithium Carbenoids and Related Species

有机和大分子化学计划支持菲斯克大学的劳伦斯·普拉特教授的工作，他的研究将调查碳酸锂的反应，碳酸锂是一类重要的合成试剂。研究模式将主要是计算量子化学，必要时辅以实验方法。计算方法对这类化合物的研究很重要，因为实验研究存在许多困难。锂类碳化合物对空气敏感，反应性强，通常只能在低温下进行研究。光谱测量提供了线索，但当单独使用时，不能阐明这类反应物的详细机制。计算量子化学将用于确定溶液中可能存在的物质，并估计每个假设反应步骤的活化能。现代量子方法可以以化学精度估计这些势垒，例如在1或2千卡/摩尔范围内。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质会发生反应，如果有的话，反应的中间产物是什么，以及反应可能发生的速度。这项工作将有助于更好地理解有机反应机理。有机和大分子化学计划对这项工作的资助将导致更有效的有机合成方法，包括制药工业使用的难以合成的天然产物。此外，对可用计算方法及其局限性的更好理解将从这项工作中产生。更广泛的影响包括在多元文化和跨国环境中培养本科生和硕士研究生。PI目前参与了若干国家和国际合作，并正在将这些合作扩大到包括波多黎各的大学。菲斯克大学是一所HBCU机构，女性入学率约为70%。PI致力于将其他代表性不足的少数民族纳入研究项目。这项研究项目所产生的培训将帮助学生在全球市场上取得成功，并将为学生就业市场和最好的博士课程和专业学校提供培训。

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.