Structure and Dynamic Behavior of Selected Organolithium Compounds

选定有机锂化合物的结构和动态行为

• 批准号: 8817746
• 负责人: Gideon Fraenkel
• 金额: --
• 依托单位: Ohio State University Research Foundation -DO NOT USE
• 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 1994-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8817746&HistoricalAwards=false
• 关键词: Structure; Dynamic; Behavior; Selected; Organolithium

This project in the Organic Dynamics Program by Professor Gideon Fraenkel of the Ohio State University is aimed at the elucidation of the structure of organolithium compounds by Nuclear Magnetic Resonance Spectroscopy. In addition, the Ohio State group will investigate the way that organolithium compounds group together in solution (aggregation). This work is highly significant in that organolithiums are widely used by organic chemists as intermediates in the synthesis of new and important compounds. A variety of NMR techniques including line-shape analysis and NOE experiments will be applied to the study of structure and dynamic behavior of model solvated organolithium compounds enriched in Li-6, and if necessary C-13 at the alpha carbon, selected to reveal specific effects and interactions. Use of very low temperature, down to 120 degrees K, and low concentrations to ensure that C-Li bond exchange processes do not perturb the spectra, will allow observation of specific structural features. These include a) possible interactions of (RLi)n species with isolated double bonds; b) nature of ligand solvation and accompanying thermodynamics; c) the degree of non-planarity of allyllithiums; and d) structure of theoretically interesting dilithium compounds. Cisoid diamines and triamines, some chiral, will be synthesized to see if they stabilize different (RLi)n aggregates, and also to ensure slow lithium ligand exchange. The architecture of ion pairs will be studied via NOE experiments including ion pairs in liquid crystal media making use of the structural dependence of the dipolar couplings. Exchange averaging in the latter spectra will allow measurement of very fast rates of exchange of ion among ion pairs. The signal averaging of C-13/Li-6 couplings and shifts among species seen in NMR data for RLi compounds will be analyzed to determine exchange rates, and via kinetics and structural information, to learn about exchange mechanisms at equilibrium.

这个项目在有机动力学计划由教授 俄亥俄州州立大学的吉迪恩·弗伦克尔的研究目标是 有机锂化合物的结构解析 核磁共振光谱。 此外，俄亥俄州 国家小组将调查有机锂 化合物在溶液中聚集在一起（聚集）。 这项工作 是非常重要的，因为有机锂被广泛用于 有机化学家作为中间体在合成新的和 重要的化合物。 各种核磁共振技术，包括线形分析和 NOE实验将应用于结构和 溶剂化有机锂模型化合物的动力学行为 富含Li-6，并且如果需要，在α碳处富含C-13， 以揭示特定的影响和相互作用。 使用 非常低的温度，低至120 K， 浓度，以确保C-Li键交换过程 不干扰光谱，将允许观察特定的 结构特征 这些因素包括：a）可能的相互作用 具有孤立双键的（RLi）n物质; B）配体的性质 溶剂化和伴随的热力学; c） 烯丙基锂的非平面性;和d） 理论上有趣的二锂化合物。 顺式二胺 和三胺，一些手性，将被合成，看看他们是否 稳定不同的（RLi）n聚集体，并且还确保缓慢的 锂配体交换 离子对的结构将通过NOE进行研究 实验包括液晶介质制作中的离子对 利用偶极耦合的结构依赖性。 在后一光谱中的交换平均将允许测量 离子对之间的离子交换速度非常快。 C-13/Li-6耦合的信号平均和 将分析在RLi化合物的NMR数据中看到的物质， 确定汇率，并通过动力学和结构 信息，以了解平衡状态下的交换机制。