Reactivity of Lanthanocene Hydroxides toward Ketene, Isocyanate, Lanthanocene Alkyl, and Triscyclopentadienyllanthanide Complexes

The reactivity of [Cp2Ln(μ-OH)(THF)]2 (Ln = Y (1), Er (2), Yb (3)) toward PhEtCCO, PhNCO, Cp3Ln, [Cp2Ln(μ-CH3)]2, and the LiCl adduct of Cp2LnnBu(THF)x was examined. In all cases, OH-centered reactivity is observed: 
complexes 1−3 react with PhEtCCO to form the O−H addition products [Cp2Ln(μ-η1:η2-O2CCHEtPh)]2 (Ln = Yb
(5), Er (6), Y (7), respectively, for 1−3), whereas treatment of 1 with PhNCO affords the addition/CpH-elimination/rearrangement product [{Cp2Y(THF)}2(μ-η2:η2-O2CNPh)] (8), which contains an unusual PhNCO2 dianionic ligand.
Analogous compound [Cp2Ln(THF)]2(μ-η2:η2-O2CNPh) (Ln = Yb (9), Er (10)) and 8 can be obtained in a higher
yield by treatment of [Cp2Ln(μ-OH)(THF)]2 with PhNCO followed by reaction with the corresponding Cp3Ln. However,
attempts to prepare the corresponding heterobimetallic complex by reacting stoichiometric amounts of [Cp2Y(μ-OH)(THF)]2 with PhNCO followed by treating it with Cp3Yb are unsuccessful. Instead, only rearrangement products
8 and 9 are obtained. Furthermore, the reaction of 3 with [Cp2Yb(μ-CH3)]2 or Cp3Yb forms oxo-bridged compound
[Cp2Yb(THF)]2(μ-O) (11), whereas the reaction of [Cp2ErCl]2 with LinBu followed by treatment with 2 affords unexpected
μ-oxo lanthanocene cluster (Cp2Er)3(μ-OH)(μ3-O)(μ-Cl)Li(THF)4 (12). In contrast to 1 and 2, 3 shows a strong
tendency to undergo the intermolecular elimination of CpH at room temperature, giving trinuclear species [Cp2Yb(μ-OH)]2[CpYb(THF)](μ3-O) (4). The single-crystal X-ray diffraction structures of 1, 2, and 4−12 are described.
All the results offer an interesting contrast to transition- and main-metal hydroxide complexes.