On the Mechanism of Connecting Deltahedral Zintl Clusters via Conjugated Buta‐1,3‐dien‐1,4‐diyl Functionalities: Synthesis and Structure of [Ge 9 −CH=CH−CH=CH−Ge 9 ] 6−

We report on the synthesis and structure, as well as on the mechanism of formation of the [Ge 9 −CH=CH−CH=CH−Ge 9 ] 6− unit. As shown by in situ NMR spectroscopy ( 1 H, COSY, HSQC, HMBC), both (1 Z ,3 Z )‐ and (1 E ,3 Z )‐[Ge 9 −CH=CH−CH=CH−Ge 9 ] 6− are formed during the reaction of a mixture of 1,4‐bis(trimethylsilyl)butadiyne and A 4 Ge 9 (A=K, Rb) with ethylenediamine. However, upon layering of the obtained solution with 222‐crypt/toluene (222‐crypt=4,7,13,16,21,24‐hexaoxa‐1,10‐diazabicyclo‐[8.8.8]hexacosan) only the (1 Z ,3 Z )‐isomer crystallizes as {[A(222‐crypt)] 6 [(1 Z ,3 Z )‐(Ge 9 −CH=CH−CH=CH−Ge 9 )]}(tol) 2 (en) 2 (A=K, Rb) salts. Single crystals of these salts were characterized by X‐ray structure analysis and Raman spectroscopy, indicating the presence of three superimposed conformers of (1 Z ,3 Z )‐[Ge 9 −CH=CH−CH=CH−Ge 9 ] 6− , which show different orientations of the cluster units with respect to the planar (1 Z ,3 Z )‐buta‐1,3‐dien‐1,4‐diyl linker unit.