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 -C₇ H₈ )] (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.