Nonagermanide Zintl Clusters with Mg2+ Counter Ions

Abstract

AbstractIon exchange processes are rarely investigated with respect to tetrel element Zintl clusters. We now discovered that the addition of Mg complexes to nonagermanide anions comprising K+ counter cations results in an exchange of the alkali ions by alkaline earth cations. Upon stirring K[Ge9{Si(TMS)3}3] (TMS=trimethylsilyl) and Mg(NacNacMes)I (NacNacMes=N,N’‐bis(2,4,6‐trimethylphenyl)‐β‐diketiminate) in MeCN the product [Mg(NacNacMes)(MeCN)4][Ge9{Si(TMS)3}3]⋅ MeCN is formed. Reactions of Mg(NacNacMes)I with K4Ge9 in liquid ammonia as a solvent yielded [K[2.2.2]crypt]4[Mg(NacNacMes)(NH3)4]2[Ge9−Ge9] ⋅ 32.58 NH3 featuring a mixed alkali/alkaline earth metal cationic sphere and an oxidative coupling of the [Ge9]4− clusters. From comparable reactions of [Mg(NacNacMes)]2 with K4Ge9 or K12Ge17 in liquid ammonia crystals of [K[2.2.2]crypt][NacNacMes] ⋅ NH3 and [K(18‐crown‐6)][NacNacMes] ⋅ 3 NH3, respectively, were isolated. All compounds were characterized by means of single crystal structure determination.