Reactivity of [Ge9{Si(SiMe3)3}3]− Towards Transition‐Metal M2+ Cations: Coordination and Redox Chemistry

Recently the metalloid cluster compound Ge₉Hyp₃]^? ( 1 ; Hyp=Si(SiMe₃)₃) was oxidatively coupled by an iron(II) salt to give the largest metalloid Group 14 cluster Ge₁₈Hyp₆]. Such redox chemistry is also possible with different transition metal (TM) salts TM²⁺ (TM=Fe, Co, Ni) to give the TM⁺ complexes Fe(dppe)₂]Ge₉Hyp₃] ( 3 ; dppe=1,2‐bis(diphenylphosphino)ethane), Co(dppe)₂]Ge₉Hyp₃] ( 4 ), Ni(dppe)(Ge₉Hyp₃)] ( 5 ) and Ni(dppe)₂(Ge₉Hyp₃)]⁺ ( 6 ). Such a redox reaction does not proceed for Mn, for which a salt metathesis gives the first open shell Hyp₃Ge₉‐M‐Ge₉Hyp₃] cluster ( 2 ; M=Mn). The bonding of the transition metal atom to 1 is also possible for Ni (e.g., compound 6 ), in which one or even two nickel atoms can bind to 1 . In contrast to this in case of the Fe and Co compounds 3 and 4 , respectively, the transition‐metal atom is not bound to the Ge₉ core of 1 . The synthesis and the experimentally determined structures of 2 – 6 are presented. Additionally the bonding within 2 – 6 is analyzed and discussed with the aid of EPR measurements and quantum chemical calculations.