Stability and Conversion of Tin Zintl Anions in Liquid Ammonia Investigated by NMR spectroscopy.

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.

Elusive transmetalation intermediate in copper-catalyzed conjugate additions: direct NMR detection of an ethyl group attached to a binuclear phosphoramidite copper complex.

Copper-catalyzed asymmetric conjugate addition reactions are a very powerful and widely applied method for enantioselective carbon-carbon bond formation. However, structural and mechanistic insight into these famous reactions has been very limited so far. In this article, the first direct experimental detection of transmetalation intermediates in copper-catalyzed reactions is presented.

Reaction of Sn4(4-) in liquid ammonia: the formation of Rb6[(η2-Sn4)Zn(η3-Sn4)]·5NH3.

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.

Synthesis of heteroatomic Zintl anions in liquid ammonia--the new highly charged [Sn4Bi4]4- and fully ordered [Sn2Bi2]2-.

The new Zintl anion [Sn(4)Bi(4)](4-), synthesized by dissolving CsSnBi in liquid ammonia, forms a monocapped nortricyclane-like cage. Its electron localization function (ELF) analysis shows evidence for 3-centre bonding. The analogous reaction with KSnBi results in a crystallographically fully ordered tetrahedral [Sn(2)Bi(2)](2-) ion.