A General Pathway to Heterobimetallic Triple‐Decker Complexes

A systematic study on the reactivity of the triple‐decker complex [(Cp’’’Co)(2)(μ,η(4):η(4)‐C(7)H(8))] (A) (Cp’’’=1,2,4‐tritertbutyl‐cyclopentadienyl) towards sandwich complexes containing cyclo‐P(3), cyclo‐P(4), and cyclo‐P(5) ligands under mild conditions is presented. The heterobimetallic triple‐decker sandwich complexes [(Cp*Fe)(Cp’’’Co)(μ,η(5):η(4)‐P(5))] (1) and [(Cp’’’Co)(Cp’’’Ni)(μ,η(3):η(3)‐P(3))] (3) (Cp*=1,2,3,4,5‐pentamethylcyclopentadienyl) were synthesized and fully characterized. In solution, these complexes exhibit a unique fluxional behavior, which was investigated by variable temperature NMR spectroscopy. The dynamic processes can be blocked by coordination to {W(CO)(5)} fragments, leading to the complexes [(Cp*Fe)(Cp’’’Co)(μ(3),η(5):η(4):η(1)‐P(5)){W(CO)(5)}] (2 a), [(Cp*Fe)(Cp’’’Co)(μ(4),η(5):η(4):η(1):η(1)‐P(5)){(W(CO)(5))(2)}] (2 b), and [(Cp’’’Co)(Cp’’’Ni)(μ(3),η(3):η(2):η(1)‐P(3)){W(CO)(5)}] (4), respectively. The thermolysis of 3 leads to the tetrahedrane complex [(Cp’’’Ni)(2)(μ,η(2):η(2)‐P(2))] (5). All compounds were fully characterized using single‐crystal X‐ray structure analysis, NMR spectroscopy, mass spectrometry, and elemental analysis.