Synthetic utility of [(C5Me5)2Ln][(μ-Ph)2BPh2] in accessing [(C5Me5)2LnR]x unsolvated alkyl lanthanide metallocenes, complexes with high C-H activation reactivity

The loosely ligated [BPh4](1-) ion in [(C5Me5)(2)Ln][(μ-Ph)(2)BPh2] can be readily displaced by alkyllithium or potassium reagents to provide access to unsolvated alkyl lanthanide metallocenes, [(C-5-Me-5)(2)LnR](x), which display high C-H activation reactivity. [(C5Me5)(2)SmMe](3), [(C5Me5)(2)LuMe](2), [(C5Me5)(2)-LaMe](x), (C5Me5)(2)Sm(CH2Ph), [(C5Me5)(2)Sm(CH2SiMe3)](x), and [(C5Me5)(2)SmPh](2) were prepared in this way. [(C5Me5)(2)SmMe](3) metalates toluene, benzene, SiMe4, and (C5Me5)(1-) ligands to make (C5Me5)(2)Sm(CH2-Ph), [(C5Me5)(2)SmPh](2), [(C5Me5)(2)Sm(CH2SiMe3)](x), and (C5Me5)(6)Sm-4[C5Me3(CH2)(2)](2), respectively. These C-H activation reactions can be done using an in situ synthesis of [(C5Me5)(2)LnMe](x) such that the [(C5Me5)(2)Ln][(μ-Ph)(2)BPh2]/LiMe/RH combination provides a facile route to a variety of unsolvated [(CsMe5)(2)LnR], products.