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.