Detection of the Elusive Highly Charged Zintl Ions Si4~(4-) and Sn4~(4-) in Liquid Ammonia by NMR Spectroscopy

摘要

The appeal of Zintl anions originates from the fact that they are molecular building blocks of main-group elements that may be manipulated in solution. Apart from their intrinsic significance for the chemistry of the elements, they are promising starting materials for the development of new hybride materials containing transition metals and main-group elements. The solution chemistry of the bare clusters also offers the possibility to find new elemental modifications by oxidative coupling, as was shown for germanium, or to create potential semiconducting amorphous or crystalline films by anodical deposition. The dominant characterization method for nearly all of the reported compounds and materials has so far been single-crystal X-ray structure analysis. In contrast, much less is known about the species that actually occur in solution. To better understand the complicated processes which take place when Zintl anions react with reagents, the behavior of the bare polyanions in pure solutions must first be investigated. The long-range goal of these investigations would be a better understanding of Zintl anion solutions, thus facilitating an increasingly rational approach to their use in chemical transformations.