A General Pathway to Heterobimetallic Triple-Decker Complexes.

A systematic study on the reactivity of the triple-decker complex [(Cp'''Co) (μ,η :η -C H )] (A) (Cp'''=1,2,4-tritertbutyl-cyclopentadienyl) towards sandwich complexes containing cyclo-P , cyclo-P , and cyclo-P ligands under mild conditions is presented. The heterobimetallic triple-decker sandwich complexes [(CpFe)(Cp'''Co)(μ,η :η -P )] (1) and [(Cp'''Co)(Cp'''Ni)(μ,η :η -P )] (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) } fragments, leading to the complexes [(CpFe)(Cp'''Co)(μ ,η :η :η -P ){W(CO) }] (2 a), [(CpFe)(Cp'''Co)(μ ,η :η :η :η -P ){(W(CO) ) }] (2 b), and [(Cp'''Co)(Cp'''Ni)(μ ,η :η :η -P ){W(CO) }] (4), respectively. The thermolysis of 3 leads to the tetrahedrane complex [(Cp'''Ni) (μ,η :η -P )] (5). All compounds were fully characterized using single-crystal X-ray structure analysis, NMR spectroscopy, mass spectrometry, and elemental analysis.