Molecular Mimics of Intermetallic Phases: Selective Alkylamide‐Ligand Deprotection Drives Co/Ga Cluster Formation

The heterobimetallic M₁₄ cluster [Co₃Ga₂]H(μ²-GaTMP)₉ (1, TMP = 2,2,6,6-tetramethylpiperidinyl) was obtained by treating CoCl₂ with GaTMP in the presence of Mg and H₂ as reduction additives. 1 features a trigonal bipyramidal Co₃Ga₂ kernel with one substituent-free Ga atom and one exposed GaH moiety inside a metallo-environment of nine edge-bridging GaTMP ligands. The resulting Co₃Ga₁₁ cluster core mimics a packing motif of the structurally related intermetallic phase Co₂Al₅. The GaTMP ligands not only donate their lone pairs to the Co, but also to the exposed, bare Ga of the Co₃Ga₂ kernel, thus contributing to the increase in delocalization over the M₁₄ core, according to bonding analysis. The synthesis of 1 represents proof-of-concept to steer the coordination of GaTMP to transition metal centers toward a kernel-alloyed Co/Ga cluster formation. This is rationalized by Mg/H₂-induced Ga deprotection and TMP-trapping in the Hauser-base complex [Mg(TMP)(THF)μ²Cl]₂. The method bears potential for generalization, and first results were obtained for related Fe/Ga clusters.