Synthetic Aspects of (C5H4SiMe3)3Ln Rare-Earth Chemistry: Formation of (C5H4SiMe3)3Lu via [(C5H4SiMe3)2Ln]+ Metallocene Precursors
摘要:
New analogues of Cp'(3)Ln (Cp' = C5H4SiMe3, Ln = rare earth) complexes have been synthesized with the largest and smallest lanthanides, La and Lu. Due to the smaller size of Lu, the reaction of LuCl3 with 3 equiv of KCp' produced only traces of Cp'Lu-3, yielding [Cp'Lu-2(mu-Cl)](2) as the major product. An alternative route was developed in which [Cp'Lu-2(mu-Cl)](2) reacts with (C3H5)MgCl to form the tetrameric allyl complex [Cp'Lu-2(mu-eta(1):eta(1)-C3H5)](4). The allyl complex reacts with [HNEt3][BPh4] to generate [Cp'Lu-2(THF)(2)][BPh4], which reacts with KCp' to produce Cp'Lu-3 in good yield. The reaction of LaCl3 with 3 equiv of KCp' in Et2O gave the unsolvated Cp'La-3, while the same reaction in rigorously dry THF gave solvated Cp'La-3(THF). The reaction of LaCl3 and KCp' in improperly dried THF gave the mixed-ligand complex Cp'2CpLa(THF) (Cp = C5H5), rather than the expected hydrolysis product, [Cp'La-2(mu-OH)](2).