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

Abstract

ABSTRACT The heterobimetallic M 14 cluster [Co 3 Ga 2 ]H(μ 2 ‐GaTMP) 9 ( 1 , TMP = 2,2,6,6‐tetramethylpiperidinyl) was obtained by treating CoCl 2 with GaTMP in the presence of Mg and H 2 as reduction additives. 1 features a trigonal bipyramidal Co 3 Ga 2 kernel with one substituent‐free Ga atom and one exposed GaH moiety inside a metallo‐environment of nine edge‐bridging GaTMP ligands. The resulting Co 3 Ga 11 cluster core mimics a packing motif of the structurally related intermetallic phase Co 2 Al 5 . The GaTMP ligands not only donate their lone pairs to the Co, but also to the exposed, bare Ga of the Co 3 Ga 2 kernel, thus contributing to the increase in delocalization over the M 14 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/H 2 ‐induced Ga deprotection and TMP‐trapping in the Hauser ‐base complex [Mg(TMP)(THF)μ 2 Cl] 2 . The method bears potential for generalization, and first results were obtained for related Fe/Ga clusters.