Icosahedral Ga‐Centred Nickel Carbonyl Clusters: Synthesis and Characterization of [H 3– n Ni 12 (μ 12 ‐Ga)(CO) 22 ] n– ( n = 2, 3) and [Ni 14.3 (μ 12 ‐Ga)(CO) 24.3 ] 3– Anions

Abstract

The reaction of [Ni 5 (CO) 12 ] 2- or [Ni 6 (CO) 12 ] 2- with GaCl 3 in dichloromethane under a nitrogen atmosphere affords a mixture of [Ni 12+x (μ 12 -Ga)(CO) 22+x ] 3- (x = 0-3) clusters. Short exposure of the above mixture to a carbon monoxide atmosphere leads to the green icosahedral [Ni 12 (μ 12 -Ga)(CO) 22 ] 3- trianion, which was isolated and characterized as its [NnBu 4 ] + salt. In contrast, crystallization of the above mixture in the presence of Ni(CO) 4 enabled isolation of a cocrystallized mixture of [Ni 14 (μ 12 -Ga)(CO) 24 ] 3- (70%) and [Ni 15 (μ 12 -Ga)(CO) 25 ] 3- (30 %). As inferable from its structure, the additional three Ni(CO) moieties condense onto interlayer faces of the icosahedron. Protonation of [Ni 12 (μ 12 -Ga)-(CO) 22 ] 3- affords the corresponding [HNi 12 (μ 12 -Ga)(CO) 22 ] 2- hydride derivative, which was isolated in a pure state and fully characterized. All of the above compounds conform to the cluster-borane analogy, by the inclusion principle, and none exhibits relevant redox behaviour.