CARBON-13 MAGNETIC RESONANCE--METHODS AND THEORY

碳 13 磁共振——方法和理论

• 批准号: 6384985
• 负责人: David Morris Grant
• 金额: $ 20.76万
• 依托单位: UNIVERSITY OF UTAH
• 依托单位国家: 美国
• 财政年份: 1978
• 资助国家: 美国
• 起止时间: 1978-06-01 至 2003-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6384985
• 关键词: bioengineering /biomedical engineering; biomedical equipment development; biophysics; carbon; chemical models; chemical structure; computer program /software; conformation; hydrogen bond; intermolecular interaction; liquid crystal; method development; molecular dynamics; monoterpenes; nitrogen; nitrogenous heterocyclic compound; nuclear magnetic resonance spectroscopy; nucleobase; peptide structure; quantum chemistry; stable isotope; structural biology; tannins

DESCRIPTION (Adapted from applicant's abstract): This research project involves the development of experimental methods for detecting less receptive nuclei with special emphasis placed on 13C and 15N. The application of such methods to biologically important system and their theoretical consequences are stressed. The value of chemical shifts in structural correlations of liquid samples has been very well documented and these concepts are now being developed in the shielding tensor. The 3D aspects of shielding tensors becomes one of the significant aspects of this proposal. Solid state work on either powders or single crystals is required to obtain shielding tensors and their principal orientations in the molecular frame. Use of tensor data along with theory is advancing our understanding of the origins of chemical shielding and its use in shift structure correlations. The expansion from a isotropic shift to six tensor parameters in solids provides details unavailable in liquids. Thus, work will be directed towards the development of single crystal methods for biomolecules of a size not here-to-fore possible. Recent advances of a 2D magic angle turning (MAT) experiment now provides a method for obtaining solid power patterns for compounds with 2-3 dozen different carbons. Several new modifications have been developed to better address structural problems. These include two 3-D PHORMAT experiments. One is a separated local field and also a CS-CS-CS 3D PHORMAT spectrum. A new technique for importing greater evaluation resolution, TIGER, is reducing the time necessary for acquiring PHORMAT data on any complex molecules. A combination of these methods is providing shift tensor information on a variety of biomolecules important in biomedical applications. Use of Dynamic Nuclear Polarization (DNP) from unpaired electrons with 15N detection indicates that enhancement factors of about 2 orders of magnitude may be possible for a large number of compounds. As 15N shifts exhibit even greater dependence upon structural effects than 13C, this enhancement portends well for 15N chemical shifts of biomolecules. Thus, the extension to use both 14N and 13C offers a significant opportunity to expand our long term 13C program.

描述（改编自申请人的摘要）：该研究项目 涉及开发实验方法，以较少检测 接受核具有特殊重点，放在13C和15N上。这 将这种方法应用于生物学重要的系统及其 强调理论后果。化学位移的价值 液体样品的结构相关性已被充分记录 这些概念现在正在屏蔽张量中开发。 3D 屏蔽张量的各个方面成为 这个建议。粉末或单晶上的固态工作是 需要在 分子框架。使用张量数据以及理论正在推进我们的 理解化学屏蔽的起源及其在转移中的使用 结构相关。从各向同性转移到六个张量的扩展 固体中的参数可提供液体中无法使用的详细信息。 因此，工作将针对单晶的发展 不可能的大小生物分子的方法。最近的 2D魔术角转（MAT）实验的进步现在提供了 获得2-3二个化合物的固体功率模式的方法 不同的碳。已经开发了一些新的修改以更好 解决结构问题。这些包括两个3-D Phormat实验。 一个是一个分离的局部场，也是CS-CS-CS 3D Phormat光谱。 进口更多评估解决方案的新技术是Tiger 减少在任何复合物上获取Phormat数据所需的时间 分子。这些方法的组合是提供换档张量 有关生物医学重要的多种生物分子的信息 申请。使用不成对的动态核极化（DNP） 检测15N的电子表明增强因子大约 对于大量化合物，可能有2个数量级。作为 15n转移比对结构效应的依赖性比 13c，这种增强对15N的化学移位预示 生物分子。因此，使用14N和13C的扩展名提供了 扩大我们长期13C计划的重要机会。