RESUMEN
Homoatomic polyanions of post-transition main-group metals, namely, Zintl anions, are precast in analogous Zintl phases and can react in solution to form new materials. Despite comprehensible reaction approaches, the formed products cannot be planned in advance, as hitherto undetected and therefore disregarded side reactions take place. The outcomes and interpretations of the reactions of Zintl anions are so far based mainly on crystal structures, which only allow characterization of the product that has the lowest solubility. Here we present the results of our investigation of the stability of highly charged tin Zintl anions in liquid ammonia, which is not exclusively based on solution effects but also on the oxidative influence of the solvent. This allows for a deeper understanding of the ongoing processes in solution and opens doors to the directed synthesis of transition metal complexes of Sn4 (4-) , here shown by its reactivity towards MesCu.
RESUMEN
The reaction of Rb4Sn4 with ZnPh2 in liquid ammonia in the presence of [2.2.2]-cryptand yielded crystals of Rb6[(η(2)-Sn4)Zn(η(3)-Sn4)]·5NH3, which could be characterized by single crystal X-ray diffraction. This is the first example of a successful solution reaction of the highly charged tetrahedral Sn4(4-) anions. The homoleptic [E4ZnE4](6-) complex (E = tetrel element) was previously known only for E=Ge and Si/Ge.