Alkali metal cations, nuclear properties

A review of nuclear magnetic properties of alkali metal nuclei is followed by a brief survey of solvation of alkali metal cations, their hydration especially. The chemistry of alkali metal anions is then evoked. Chemical shifts and relaxation rates will be described with emphasis on the predominant factors contributing to these observables. A brief history of alkali metal NMR will be followed by selected applications to ion pairing phenomena, inclusion complexes, preferential solvation, the chelate effect, and polyelectrolytes. 

All the M2+ ions are smaller and considerably less polarizable than the iso-electronic M+ ions, as the higher effective nuclear charge binds the remaining electrons tightly. Thus the effect of polarization of cations on the properties of their salts are less important. Ca, Sr, Ba, and Ra form a closely allied series in which the properties of the elements and their compounds vary systematically with increasing size in much the same manner as in the alkali metals. 

Hetero-multi-nuclear complexes are obtained easily due to this coordination ability. Lanthanide ions and alkali and alkaline earth metal ions can interact with these oxygen atoms. Metallohosts containing salen analogues for cations are designed and constructed on the basis of these binding properties. 

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