A General Pathway to Heterobimetallic Triple‐Decker Complexes

Abstract

A systematic study on the reactivity of the triple‐decker complex [(Cp’’’Co)2(μ,η4:η4‐C7H8)] (A) (Cp’’’=1,2,4‐tritertbutyl‐cyclopentadienyl) towards sandwich complexes containing cyclo‐P3, cyclo‐P4, and cyclo‐P5 ligands under mild conditions is presented. The heterobimetallic triple‐decker sandwich complexes [(Cp*Fe)(Cp’’’Co)(μ,η5:η4‐P5)] (1) and [(Cp’’’Co)(Cp’’’Ni)(μ,η3:η3‐P3)] (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)(μ3,η5:η4:η1‐P5){W(CO)5}] (2 a), [(Cp*Fe)(Cp’’’Co)(μ4,η5:η4:η1:η1‐P5){(W(CO)5)2}] (2 b), and [(Cp’’’Co)(Cp’’’Ni)(μ3,η3:η2:η1‐P3){W(CO)5}] (4), respectively. The thermolysis of 3 leads to the tetrahedrane complex [(Cp’’’Ni)2(μ,η2:η2‐P2)] (5). All compounds were fully characterized using single‐crystal X‐ray structure analysis, NMR spectroscopy, mass spectrometry, and elemental analysis.