Capping [H8−nNi42C8(CO)44]n− (n = 6, 7, 8) Octa-carbide Carbonyl Nanoclusters with [Ni(CO)] and [CuCl] Fragments

The reactions of [Ni16(C2)2(CO)23]4− and [Ni38C6(CO)42]6− with CuCl afforded mixtures of the previously reported [HNi42C8(CO)44(CuCl)]7− bimetallic octa-carbide cluster and the new [HNi43C8(CO)45]7− and [HNi44C8(CO)46]7− homo-metallic octa-carbides. The three species have very similar properties resulting always in co-crystals such as [NMe4]7[HNi42+2xC8(CO)44+2x(CuCl)1−x]·6.5MeCN (x = 0.14) (86% [HNi42C8(CO)44(CuCl)]7−, 14%[HNi43C8(CO)45]7−/[HNi44C8(CO)46]7−) and [NMe4]7[HNi42+2xC8(CO)44+2x(CuCl)1−x]·5.5MeCN (x = 0.30) (70% [HNi42C8(CO)44(CuCl)]7−, 30% [HNi43C8(CO)45]7−/[HNi44C8(CO)46]7−). The new homo-metallic octa-carbides can be obtained free from the Ni–Cu octa-carbido cluster by reacting [Ni10(C2)(CO)16]2− in thf with a stoichiometric amount of CuCl, and crystals of [NMe4]6[H2Ni43+xC8(CO)45+x]·6MeCN (x = 0.72), which contain [H2Ni44C8(CO)46]6− (72%) and [H2Ni43C8(CO)45]6− (28%), have been obtained. Despite the different charges and compositions, these anions display almost identical structures, which are also closely related to those previously reported for the bimetallic Ni–Cd octa-carbido clusters [Ni42+xC8(CO)44+x(CdCl)]7− and [HNi42+xC8(CO)44+x(CdBr)]6−. Indeed, all these clusters are based on the same Ni42C8 cage decorated by miscellaneous [CdX]+ (X = Cl, Br), [CuCl] and [Ni(CO)] fragments.