AQUEOUS 1H NMR RELAXATION BY PARAMAGNETIC COMPLEXES

顺磁性络合物的水相 1H NMR 弛豫

• 批准号: 3438718
• 负责人: SUSAN C JACKELS
• 金额: $ 10.51万
• 依托单位: WAKE FOREST UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-04-01 至 1992-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3438718
• 关键词: chemical synthesis; contrast media; copper; cyclic compound; gadolinium; ligands; magnetic resonance imaging; manganese; nuclear magnetic resonance spectroscopy; water solution

The objective of the proposed research is to study the influence of nonexchanging ligands such as macrocyclic ligands on the aqueous proton NMR relaxation enhancement by paramagnetic metal ions. The metal ions Mn(II), Cu(II) and Gd(III) are chosen for this study because they have optimal properties (long electron-spin relaxation time and rapid aqueous exchange rate) for aqueous proton NMR relaxation and also are the metals most likely to be applied for medical diagnostic NMR imaging contrast agents. Macrocyclic ligands are chosen because they form highly stable complexes which are kinetically inert to exchange in solution and provide one or more coordination sites remaining for aqueous ligand exchange. In addition, macrocyclic ligands are synthetically flexible and can be utilized to systematically vary coordination geometry, coordination number and degree of unsaturation. All of these features are important in determining the relationship between relaxation enhancement ability (relaxivity) of a given metal ion per exchanging water coordination site and the nature of other nonexchanging ligands. The influence of nonexchanging ligands has not previously been studied. Preliminary evidence outlined in our laboratory shows that for Mn(II), unsaturation in the macrocyclic ligand can cause variations in relaxivity per water molecule over a range of a factor of 2. These results will be extended to other metal ions and ligands and will provide valuable insights into the mechanism of aqueous proton NMR relaxation by paramagnetic complexes. The results will have applications for the design of improved medical NMR imaging contrast agents and for the interpretation of aqueous proton NMR relaxation enhancement by metalloproteins in relation to their active-site ligands and structure.

本研究的目的是研究 非交换配体如大环配体在水溶液中的 顺磁金属离子质子核磁共振弛豫增强。 的 金属离子Mn（II）、Cu（II）和Gd（III）被选择用于本研究 因为它们具有最佳性质（长电子自旋弛豫 时间和快速的水交换速率）进行水质子NMR 弛豫，也是最有可能被应用的金属 医用诊断核磁共振成像造影剂。 大环 选择配体是因为它们形成高度稳定的络合物， 是动力学惰性的，以在溶液中交换，并提供一种或 更多的配位位点保留用于水性配体交换。 在 此外，大环配体在合成上是灵活的， 用于系统地改变配位几何形状， 配位数和不饱和度。 所有这些 特征在确定 给定金属离子的弛豫增强能力（弛豫率） 根据交换水协调点和其他 非交换配体。 非交换配体的影响 以前没有研究过。 初步证据概述在我们的 实验表明，对于Mn（II），大环中的不饱和度 配体可以引起每个水分子的弛豫率的变化， 系数为2的范围。 这些结果将推广到其他 金属离子和配体，并将提供有价值的见解， 顺磁共振弛豫机理 配合物 研究结果可用于设计 改进的医用核磁共振成像造影剂和用于 水溶液质子核磁共振弛豫增强解释 金属蛋白与其活性位点配体的关系， 结构