一种新的NMR法测定溶液中碱土金属混合物的方法原理(英文)

本文研究了碱土金属离子-锶、钡及钙可以形成在NMR标尺上是稳定配合物的条件。找到了最适合得到这样的配合物的配体-C222穴醚。研究并归属了碱土金属离子以及碱金属-钠、钾及锂配合物在氯仿中的~(13)C NMR谱。检测出了可用于分析自由配体及其与碱土金属配合物的~(13)C NMR信号,还研究了不同比例混合物的碱土金属及碱金属在氯仿中的~(13)C NMR谱,得到了当自由配体过量时在钡、钙及锶每种金属浓度为1×10~(-3)M的谱中可观测到相当于自由配体及每种离子配合的配体的分立信号。这些信号的积分值的精度可以定量地表征金属离子的浓度,所得结果为首次观测到的。它可以作为用~(13)C NMR波谱建立新的无机分析方法。文中并阐明了作溶液中碱土金属混合物NMR测定方法的具体条件,并讨论了将这一方法扩展到包括一系列碱金属在内的更复杂的混合物的可能性。试验在VARIAN XL-200波谱仪上进行。

THE PRINCIPLES OF NOVEL NMR METHOD FOR THE DETERMINATION OF ALKALINE EARTH METAL MIXTURES IN SOLUTIONS

The conditions of forming complexes stable in the NMR time scale, for alkali-earth metals -strontium, barium and calcium were investigated. Most suitable ligand for forming such complexes-cryptand C222 was found ~(13)C NMR spectra of akali -earth metal and alkali metal ?sodium, potassium and lithium complexes in deuterochloroform were studied and interpreted. ~(13)C NMR signals of free ligand and its complexes with alkali earth metals which should be used for analytical purposes were assigned. ~(13)C NMR spectra of different mixtures of alkali-earth and alkali metals in chloroform were studied. It was shown that in the spectrum of a mixture of barium, calcium and strontium in concentration of 0.001M for each metal under excess amount of free ligand, individual signals corresponding to free ligand and each of the ions were observed. These signals could be integrated with sufficient accuracy and each characterizes concentration of one of the metal ions correspondingly. These observed for the first time results allow to develop, in principle, a new method of inorganic analysis by ~(13)C NMR spectroscopy. Suggestions of analytical methods for the NMR-determination of alkali-earth metals in their mixture were discussed in detail. The method could be extended to the analysis of more complicated mixtures including alkali metal series. Spectra were run on Varian XL-200 spectrometer.