Synthesis, Structural Characterization, and Reactivity of Lanthanide Complexes Containing a New Methylene-Bridged Indenyl−Pyrrolyl Dianionic Ligand

A new methylene-bridged ligand incorporating both indenyl and pyrrolyl moieties, (C9H7)CH2(α-C4H3NH) (1), was prepared. Reaction of LnI2 with 1 equiv of [(C9H6)CH2(α-C4H3N)]Li2(THF)x in THF,
followed by recrystallization in DME, gave the organolanthanide(II) complexes {(η5-C9H6)CH2[μ-η1:η5-(α-C4H3N)]Ln(DME)}2 (Ln = Sm (2), Yb (3)) in mederate yields. Treatment of SmCl3 with 1 equiv
of [(C9H6)CH2(α-C4H3N)]Li2(THF)x in THF gave the trivalent organosamarium chloride {(η5-C9H6)CH2[μ-η1:η5-(α-C4H3N)]Sm(μ-Cl)2Li(THF)2}2 (4) in 73% yield, while reaction of ErCl3 with [(C9H6)CH2(α-C4H3N)]Li2(THF)x under the same conditions generated [(η5-C9H6)CH2(μ-η1:η3-C4H3N)Er(μ3-Cl)(μ-Cl)Li(THF)2]2 (5). Reaction of 4 with 2 equiv of n-butyllithium (nBuLi) and subsequently with N,N‘-dicyclohexylcarbodiimide (CyNCNCy) gave the carbodiimide insertion into the Sm−C bond product
{(η5-C9H6)CH2[μ-η1:η5-(α-C4H3N)]Sm[CyNC(nBu)NCy]}2 (6), while treatment of 4 with 2 equiv of NaN(SiMe3)2 in THF followed by reacting with CyNCNCy gave the carbodiimide insertion into the Sm−N
bond product [(η5-C9H7)CH2[μ-η1:η5-(α-C4H3N)]Sm{CyNC[N(SiMe3)2]NCy}]2 (7). These complexes were
characterized by IR and 1H NMR spectra and elemental analyses. Furthermore, the structures of all these
compounds were also confirmed by X-ray diffraction analyses.