ROTATIONAL BARRIERS, MOLECULAR MODELS & STEREOSELECTION

旋转势垒，分子模型

• 批准号: 3293107
• 负责人: KENNETH B WIBERG
• 金额: $ 13.59万
• 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/3293107
• 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的问题 是对生物学作用的理解的关键要素 重要的化合物及其合成的设计。 长期 目标是获得有关这些问题的足够信息，以便更多 可以开发出有效的分子建模程序，并且 可以更好地理解分子之间的非共价相互作用。 这 计划将同时进行实验和理论研究，以及 将两种方法的结果详细介绍 可能的。 确定立体和立体的因素的问题 还将检查区域选择。 具体而言，建议确定形成的热量 C4-CL2单核酸内酯进行量热测量并研究其 构象。 这些数据将提供当前的第一个真实测试 内酯的分子力学力场，应允许更好 要开发的力场。 内酯的酸度和碱性作为 还将研究环大小的功能。 另外，非共价 使用静电电位，将研究相互作用 相关数量。 这是半经验中的常用模型 感觉。 三维静电电势的详细计算 使用大型基集的地图将进行，并将与 包含点电荷，偶极子和四倍的模型。 后者会 可以从波函数中获得。 其他提出的研究包括对环中的区域选择的研究 开放螺旋环氧化物和具有内部的环氧化物 亲核者。 诸如等系统将继续进行构象研究 乙烯基甲醛和苯基乙醛。