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Updated: Jun 13, 2026

Isolating Free Carbenes, their Mixed Dimers and Organic Radicals
Published on: April 19, 2019
1,7-Digallatetracarborane: Between Nucleophilic closo-Cluster and "Inverse Sandwich" Digallylene
Julijan Sarcevic1, Tobias Heitkemper1, Niklas Mehner1
1Institut für Anorganische Chemie, Universität Stuttgart, Stuttgart, Germany.
Abstract:
This manuscript describes the synthesis and chemistry of an unprecedented carborane cluster of low-valent main-group elements with a unique structural motif. On the basis of a dianionic borole π-ligand platform (L = [R5(C4B)]2-) an "inverse sandwich", Janus-type digallylene complex L(Ga+I)2 featuring two nucleophilic Ga(I) ions was accessed. This compound can also be described as a closo-type 1,7-digallatetracarborane cluster. Preliminary reactivity studies on this new compound class have been conducted. Assessment of Lewis-basicity in coordination chemistry with transition metals and main group Lewis-acids indicate electronic communication between the Ga-atoms. Oxidation with free borole (L) gives rise to bent digallocene L(Ga+II)-(Ga+II)L, the first group 13 element-based dimetallocene-type compound. Examples demonstrate that L(Ga+I)2 can behave as both a discrete digallacarborane cluster and a bis-gallylene π-complex capable of releasing Ga+.
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