Structure Determinations of Conformations by NMR

有了这个奖项，有机和高分子化学计划支持博士约翰D。罗伯茨在加州帕萨迪纳的加州理工学院。 这项工作将建立在早期的PI上的取代基对1，2-二取代乙烷的构象平衡的影响。 这些平衡将通过NMR使用质子-质子邻位耦合常数进行研究，该常数取决于由C-C键和从这些中心碳原子到其取代基的键定义的平面之间的平均二面角。 最初的重点是重复和重新解释卡拉布里亚大学Chidichimo教授报告的琥珀酸（HOCOCH 2CH 2CO 2 H）及其盐的测量结果。 扩展将包括其他溶剂系统，包括溶致介质，和其他分子，如氨基酸。拟议的研究涉及有机化学中的一个基本问题：是什么决定了有机分子中碳-碳单键的旋转角，其中许多含有C-C键，可以被视为1，2-二取代乙烷。 这些角度决定了许多有机分子的3D结构和许多性质，包括那些参与生物系统的分子。 除了阐明一个重要的主题，这项工作预计将提供优秀的培训博士后和本科生参与。

With this award the Organic and Macromolecular Chemistry Program supports the work of Dr. John D. Roberts at the California Institute of Technology in Pasadena, California. The work will build on earlier work of the PI on substituent effects on conformational equilibria of 1,2-disubstituted ethanes. These equilibria will be studied by NMR using proton-proton vicinal coupling constants, which depend on the average dihedral angle between the planes defined by the C-C bond and the bonds from these central carbon atoms to their substituents. The initial emphasis will be on repeating and reinterpreting measurements on succinic acid (HOCOCH2CH2CO2H) and its salts reported by Prof. Chidichimo at the University of Calabria. Extensions will include other solvent systems, including lyotropic media, and other molecules, such as aminoacids.The proposed research involves a fundamental question in organic chemistry: What determines the angle of rotation about carbon-carbon single bonds in organic molecules, many of which contain C-C bonds that can be regarded as 1,2-disubstituted ethanes. These angles determine the 3D structures, and many of the properties, of many organic molecules, including those involved in biological systems. In addition to shedding light on an important subject, the work is expected to provide excellent training for the postdoctoral and undergraduate students involved.