ROTATIONAL BARRIERS, MOLECULAR MODELS & STEREOSELECTION

旋转势垒，分子模型

• 批准号: 3293103
• 负责人: KENNETH B WIBERG
• 金额: $ 11.74万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1986
• 资助国家: 美国
• 起止时间: 1986-12-01 至 1994-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3293103
• 关键词: X ray crystallography; acetaldehyde; chemical models; chemical structure function; chemical synthesis; electrical potential; epoxides; intermolecular interaction; lactones; mathematical model; molecular dynamics; optical rotation

Problems of conformation, stereoselection and intermolecular interactions are key elements in both the understanding of the role of biologically important compounds, and in the design of their synthesis. The long term goal is to gain enough information concerning these problems so that more effective procedures for molecular modeling may be developed, and that non-covalent interactions between molecules may be better understood. The plan is to carry out both experimental and theoretical studies, and to relate the results of the two approaches in as detailed a fashion as possible. The problem of the factors determining stereo- and regioselection also will be examined. Specifically, it is proposed to determine the heats of formation of the C4-Cl2 monocyclic lactones vis calorimetric measurements and to study their conformations. These data will provide the first real test of current molecular mechanics force fields for lactones, and should allow better force fields to be developed. The acidity and basicity of lactones as a function of ring size also will be studied. In addition, non-covalent interactions will be studied making use of electrostatic potentials and related quantities. This is a commonly used model in a semiempirical sense. Detailed calculations of three dimensional electrostatic potential maps using large basis sets will be carried out, and will be related to models containing point charges, dipole and quadrupoles. The latter will be obtained from the wave functions. Other proposed studies include a study of regioselection in the ring opening of spirocyclic epoxides, and of epoxides having internal nucleophiles. Conformational studies will be continued for systems such as vinylacetaldehyde and phenylacetaldehyde.

构象、立体选择和分子间相互作用问题 是理解生物学作用的关键要素 重要的化合物，及其合成的设计。 长期来看 目标是获得有关这些问题的足够信息，以便更多 可以开发有效的分子建模程序，并且 分子之间的非共价相互作用可能会得到更好的理解。 这 计划开展实验和理论研究， 以尽可能详细的方式将两种方法的结果联系起来 可能的。 决定立体感的因素问题 区域选择也将受到审查。 具体来说，建议确定形成热 C4-Cl2 单环内酯的量热测量并研究其 构象。 这些数据将为当前的测试提供第一次真正的测试 内酯的分子力学力场，并且应该允许更好的 力场待开发。 内酯的酸度和碱度 戒指尺寸的函数也将被研究。 此外，非共价 将利用静电势来研究相互作用 相关数量。 这是半经验模型中常用的模型 感觉。 三维静电势的详细计算 将进行使用大基组的地图，并将与 包含点电荷、偶极子和四极子的模型。 后者将 由波函数获得。 其他拟议的研究包括环区域选择的研究 螺环环氧化物和具有内部结构的环氧化物的开环 亲核试剂。 将继续对以下系统进行构象研究： 乙烯基乙醛和苯乙醛。