NMR STUDY OF METAL-ION COMPLEXATION

这个项目将涉及核磁共振的应用 (NMR)金属离子络合物的研究 离子载体，拉沙洛西A和莫能菌素。 的 长期目标是定量评价化学计量 以及复合物的净电荷; 离子载体和复合物的几何形状;特异性结合位点 在离子载体和复合物的几何形状中，即，是否 金属离子仅在外部位点被包围或结合; 金属离子的大小和配位倾向对形成的络合物类型的影响; 以及阴离子络合能力的影响。 要使用的金属离子 是三价镧、镥和钇，都是强络合物 大小、电子和磁性不同的试剂。 一 多核方法使用氢-1，碳-13，氮-14，氯- 35，钇-89和镧-139 NMR光谱将在此应用。 结构研究 实验将涉及直接观察 结合和游离离子载体的单独的共振信号组， 通过其复合物的分解和随后的 配体交换在NMR时间尺度上足够慢。 的目的 项目将通过氢-1化学位移，弛豫时间， 信号面积测定，沿着化学位移和弛豫时间 计划研究的其他核的实验。

This project will involve the application of nuclear magnetic resonance (NMR) spectroscopy to the study of metal-ion complexes of the carboxylic ionophores, lasalocid A and monensin, in aqueous solvent mixtures. The long-range objective are the quantitative evaluation of the stoichiometry and the resultant net charge of the complex; the specific binding sites in the ionophore and the geometry of the complex; the specific binding sites in the ionophore and the geometry of the complex, that is, whether the metal-ion is surrounded or binds at an outer site only; the effect of metal-ion size and coordinating propensity on the type of complex formed; and the influence of anion complexing ability. The metal-ions to be used are trivalent lanthanum, lutetium, and yttrium, all strong complexing agents varying in size, and electronic and magnetic properties. A multinuclear approach using hydrogen-1, carbon-13, nitrogen-14, chlorine- 35, yttrium-89, and lanthanum-139 NMR spectroscopy will be applied in this structural study. The experiments will involve the direct observation of separate sets of resonance signals for bound and free ionophore, a condition made possible by the dissociation of its complex and subsequent ligand exchange slow enough on the NMR time scale. The objective of the project will be attained by hydrogen-1 chemical shift, relaxation time, and signal area determinations, along with chemical shift and relaxation time experiments for the other nuclei planned for study.