Synthesis and Crystal Structure of a Salt Containing ∞ 1 {Zn[ trans ‐μ 2 (η 3 :η 3 ‐Ge 9 )]} 2– Anions: A Polymer with Ge 9 Zintl Clusters Bridged by Zn Atoms

The reaction of an ethylenediamine (en) solution of K 4 Ge 9 with Zn 2 (Mesnacnac) 2 {Mesnacnac = [(2,4,6‐Me 3 C 6 H 2 )NC(Me)] 2 CH} in the presence of 18‐crown‐6 (18‐crown‐6 = 1,4,7,10,13,16‐hexaoxacyclooctadecane) leads to the formation of the new compound [K(18‐crown‐6)] 2 {Zn[ trans ‐μ 2 (η 3 :η 3 ‐Ge 9 )]}(en). A crystallographic structure determination revealed that the salt contains ∞ 1 [Zn(Ge 9 )] 2– polyanions in which each Zn atom bridges two Ge 9 clusters by coordinating to opposite triangular faces of the Ge 9 deltahedra. The polymeric chain can be formally described as consisting of a trans Zn II complex with two [η 3 :η 3 ‐Ge 9 ] 4– ligands. 1 H NMR spectroscopic investigations indicated that the protonation of the Mesnacnac – ligand by the solvent ethylenediamine plays a crucial role in the disproportionation of the Zn I starting material and thus in the formation of the polymeric Zn II complex. In contrast, the reaction of ZnPh 2 instead of Zn 2 (Mesnacnac) 2 under the same conditions leads to the known complex [PhZn(η 4 ‐Ge 9 )] 3– .