Linking deltahedral zintl clusters with conjugated organic building blocks: Synthesis and characterization of the zintl triad [R-Ge₉-CH-CH=CH-CH-Ge₉-R]^4-

The accessibility of triads with deltahedral Zintl clusters in analogy to fullerene-linker-fullerene triads is another example for the close relationship between fullerenes and Zintl clusters. The compound {[K(2.2.2-crypt)]₄[RGe₉-CH-CH=CH-CH-Ge₉R]}(toluene)₂ (R=(2Z,4E)-7-amino-5-aza-hepta-2,4-dien-2-yl), containing two deltahedral [Ge₉] clusters linked by a conjugated (1Z,3Z)-buta-1,3-dien-1,4-diyl bridge, was synthesized through the reaction of 1,4-bis(trimethylsilyl)butadiyne with K₄Ge₉ in ethylenediamine and crystallized after the addition of 2.2.2-cryptand and toluene. The compound was characterized by single-crystal structure analysis as well asNMR and IR spectroscopy. Zintl triads: The general possibility to synthesize electronically coupled Zintl clusters using conjugated electron π-systems as linkers in analogy to fullerene-linker-fullerene triads opens a new area of applications for Zintl clusters.