AQUEOUS 1H NMR RELAXATION BY PARAMAGNETIC COMPLEXES

拟议研究的目的是研究这种影响 非交换配体，如水溶液上的大环配体 顺磁性金属离子对质子核磁共振弛豫的增强作用。这个 选择金属离子Mn(II)、Cu(II)和Gd(III)作为研究对象 因为它们具有最佳的性质(长电子自旋弛豫 水相质子核磁共振的时间和快速水相交换速率) 松弛和也是最有可能申请的金属 医学诊断核磁共振成像造影剂。大环 选择配体是因为它们形成了高度稳定的络合物， 在溶液中以动力学惰性交换，并提供一种或 为水中配体交换留下了更多的配位。在……里面 此外，大环配体具有合成灵活性，并且可以 被用来系统地改变配位几何， 配位数和不饱和度。所有这些都是 要素在确定两者之间的关系时非常重要 给定金属离子的弛豫增强能力(弛豫度) 每个交换水协调点和其他的性质 非交换配体。非交换配体的影响有 以前没有被研究过的。初步证据概述在我们的 实验室研究表明，对于Mn(II)，大环中的不饱和 配基可以引起每个水分子的弛豫度的变化 因数为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 顺磁作用下水相质子核磁共振弛豫机理 复合体。研究结果将在建筑结构设计中得到应用。 改进的医用核磁共振成像造影剂和 水相质子核磁共振弛豫增强的解释 金属蛋白与其活性部位配体的关系及 结构。

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.