Ni-Metalated Ge₉ Zintl Clusters as Single-Site Homogeneous Catalysts

Homogeneous catalytic reactions performed without or with highly abundant transition metals is an increasing field of research due to cost-effectiveness and sustainability. Therefore, using main group element Zintl cluster as support material for transition metals via synthesizing single site homogeneous catalysts (SSHoC) could be a way to make such metals feasible for catalysis, without the risk of metal loss or agglomeration like in classical single site catalysts. A synthetic protocol for four cluster compounds K[Hyp₃Ge₉Ni(PR₃)] (Hyp = Si{SiMe₃}₃; R = Ph, ^ptolyl, ⁱPr, Me, 1–4) is presented, in which the nickel atom is embedded into the cluster core. The products were characterized by NMR spectroscopy, ESI/MS as well as for 1 and 3 by single crystal X-ray structure determination comprising a closo-[Ge₉Ni] core. The cleavage of the triphenylphosphine ligand in 1 in THF, with and without 2.2.2-crypt, and acetonitrile as well as the isomerization of 1-hexene in the same solvents have been investigated via NMR spectroscopy.