On the Oxidation of [Ge9]4− – Crystal Structures and Raman Spectroscopic Investigation of Linked Ge9 Clusters

Abstract

AbstractOxidation of Ge9 Zintl clusters can afford condensed cluster species in the form of dimers, oligomers and polymers. In this work, we present a new route for the synthesis of Ge9 tetramers present in the compound [K(18‐crown‐6)]8[Ge9=Ge9=Ge9=Ge9] ⋅ 4 pyr. The reaction of a pyridine solution of K4Ge9 with 18‐crown‐6 first leads to the formation of green needles of yet unknown composition, which convert into the reported tetramer over time. In this reaction pyridine acts as oxidation reagent. Raman studies on the green needles as well as on tetrameric and polymeric Ge9 feature complex vibrational patterns. Furthermore, we present the crystal structure of a new type of Ge9 dimer in the compound K4[K(2.2.2‐crypt)]2[Ge9−Ge9] ⋅ 4 en ⋅ 2 thf, which represents an intermediate between the two established conformers.