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⁻

Abstract

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.

On the Reactivity of Silylated Ge9 Clusters: Synthesis and Characterization of [ZnCp*(Ge9{Si(SiMe3)3}3)], [CuPiPr3(Ge9{Si(SiMe3)3}3)], and [(CuPiPr3)4{Ge9(SiPh3)2}2]

“…It comprises oxidative coupling reactions under formation of dimers, [2] oligomers, [3] or polymers; [4] the insertion of metal ions into cluster compounds leading to endohedrallyf illed clusters like [(Pd 2 )@Ge 18 ] 4À , [5] [Pt@Pb 12 ] 2À [6] or [Cu@E 9 ] 3À (E = Sn, Pb); [7] or fragmentation of clusters thereby creatingn ew polymetallic structures, such as [(Sn 15 )Ti(Cp 2 Ti) 2 (CpTi)] + [8] as ar ecent example among many others. [14] Furthermore, the functionalization of Ge 9 clusters increases their solubility in more common organic solvents, so that the vinylated Ge 9 clusters are soluble in acetonitrile( ACN), and functionalization with SiR 3 Cl organosilane reagents leads to products that are soluble even in tetrahydrofuran (THF), hexane, or toluene. [11] Ad iminution of the relativelyh igh charge of the Zintl anionsb yt he addition of organic groups gives access to an even more versatile chemistry.T he first organo-Zintl cluster was obtained by the reaction of K 4 Ge 9 with bis(trimethylsilyl)acetylene (btmsa) in ethylenediamine resulting in the bis-vinylated Ge 9 cluster species [ Ge 9 (CH=CH 2 ) 2 ] 2À .…”

Bisvinylated [R–Ge9–Ge9–R]4– Cluster Dimers

“…After the addition of 18crown‐6 and KC 5 H 5 to the reaction mixture, the compounds [K(18crown‐6)] 2 {(η 5 ‐C 5 H 5 )[K(18crown‐6)] 2 }[Ge 9 (CHCH 2 )]·en and [K(18crown‐6)]{(η 5 ‐C 5 H 5 )[K(18crown‐6)] 2 } [Ge 9 (CHCH 2 ) 2 ]·en with mono‐ and divinylated Ge 9 clusters, respectively, have been found to crystallize depending on the relative amounts of K 4 Ge 9 and BTMSA 17. Most intriguing results also include the coupling of two Ge 9 units by a conjugated electronic π system with formation of the Zintl triad [ R ‐Ge 9 ‐CH=CH‐CH=CH‐Ge 9 ‐ R ] 4– 21…”

On the Mechanism of Connecting Deltahedral Zintl Clusters via Conjugated Buta‐1,3‐dien‐1,4‐diyl Functionalities: Synthesis and Structure of [Ge9−CH=CH−CH=CH−Ge9]6−

“…As reported previously, 1‐trimethylsilyl‐7‐amino‐5‐aza‐hepta‐3‐en‐1‐yne ( 3 ) is formed quantitatively in the reaction of en with 2 (Scheme ) . Thus, the absence of 3 in the reaction mixtures prepared by dissolving pre‐mixtures of A 4 Ge 9 and 2 in en demonstrates that the nucleophilic addition of [Ge 9 ] 4− to 2 is favored over an en‐addition, and the formation of 3 does not take place under such conditions.…”

“…The Zintl triads 1 a and 1 b were synthesized by stirring pre‐mixtures of the solids A 4 Ge 9 (1 equiv) and 1,4‐bis(trimethylsilyl)butadiyne ( 2 ) (0.25–0.5 equiv) with water‐free en solvent for 20 h (Scheme and Equation . In former experiments leading to the Zintl triads with Z R side chains in C , suspensions of 2 in en were treated with solid A 4 Ge 9 . By contrast, the method presented herein avoids a pre‐mixing of 2 with en, and focuses on the direct addition of en to a mixture of 2 with A 4 Ge 9 .…”

“…Recently, we reported the first representatives of such Zintl triads, [CH 2 =CH−(Ge 9 )−( ZE B )−(Ge 9 )−CH=CH 2 ] 4− [ ZE B =(1 Z ,3 E )‐buta‐1,3‐dien‐1,4‐diyl)] and [( Z R )−(Ge 9 )−( ZZ B )−(Ge 9 )−( Z R )] 4− [ ZZ B =(1 Z ,3 Z )‐buta‐1,3‐dien‐1,4‐diyl; Z R =(2 Z ,4 E )‐7‐amino‐5‐aza‐hepta‐2,4‐dien‐2‐yl] ( C ) (Scheme ). C was obtained by the reaction of K 4 Ge 9 with a mixture of 1,4‐bis(trimethylsilyl)butadiyne and 1‐trimethylsilyl‐7‐amino‐5‐aza‐hepta‐3‐en‐1‐yne in en solvent . Besides the linkage of the two cluster units by a diene, the reaction of 1,4‐bis(trimethylsilyl)butadiyne with the solvent en led to the formation of the functional group Z R as part of the Zintl triad C .…”