Tetramethylcyclopentadienyl Ligands Allow Isolation of Ln(II) Ions across the Lanthanide Series in [K(2.2.2-cryptand)][(C5Me4H)3Ln] Complexes

@article{Jenkins2018TetramethylcyclopentadienylLA,
  title={Tetramethylcyclopentadienyl Ligands Allow Isolation of Ln(II) Ions across the Lanthanide Series in [K(2.2.2-cryptand)][(C5Me4H)3Ln] Complexes},
  author={Tener F. Jenkins and David H. Woen and Luke N. Mohanam and Joseph W. Ziller and Filipp Furche and William J. Evans},
  journal={Organometallics},
  year={2018}
}
Although previous studies of the stabilization of Ln(II) ions across the lanthanide series have relied on Me3Si-substituted cyclopentadienyl ligands, we now find surprisingly that these ions can also exist surrounded by three tetramethylcyclopentadienyl ligands. Reduction of the 4fn Ln(III) complexes, Cptet3Ln (Cptet = C5Me4H) using potassium graphite in the presence of 2.2.2-cryptand (crypt) produces the Ln(II) complexes, [K(crypt)][Cptet3Ln] for Ln = La, Ce, Pr, Nd, Sm, Gd, Tb, and Dy, all of… 
34 Citations
Reactivity of Ln(II) Complexes Supported by (C5H4Me)1– Ligands with THF and PhSiH3: Isolation of Ring-Opened, Bridging Alkoxyalkyl, Hydride, and Silyl Products
Reduction of CpMe3Ln(THF), 1-Ln (Ln = La and Gd; CpMe = C5H4Me), with KC8 in the presence of 2.2.2-cryptand (crypt) generates dark solutions, 2-Ln, with EPR spectra consistent with Ln(II) complexes:
Reductive Reactivity of the 4f75d1 Gd(II) Ion in {GdII[N(SiMe3)2]3}-: Structural Characterization of Products of Coupling, Bond Cleavage, Insertion, and Radical Reactions.
The reductive reactivity of a Ln(II) ion with a nontraditional 4fn5d1 electron configuration has been investigated by studying reactions of the {GdII(N(SiMe3)2)3]}- anion with a variety of reagents
Isolation of reactive Ln(ii) complexes with C5H4Me ligands (CpMe) using inverse sandwich countercations: synthesis and structure of [(18-crown-6)K(μ-CpMe)K(18-crown-6)][CpMe3LnII] (Ln = Tb, Ho).
TLDR
It is reported that crystallographically-characterizable Ln(ii) complexes of Tb and Ho can be isolated by reducing CpMe3Ln(THF) with KC8 in THF in the presence of 18-crown-6 (18-c-6).
The importance of the counter-cation in reductive rare-earth metal chemistry: 18-crown-6 instead of 2,2,2-cryptand allows isolation of [YII(NR2)3]1− and ynediolate and enediolate complexes from CO reactions†
TLDR
By changing the potassium chelator from crypt to 18-crown-6 (18-c-6), the [Ln(NR2)3]1− anions can be isolated not only for Ln = Gd, Tb, Dy, and Tm, but also for Ho, Er, and Y.
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The capacity of X-ray photoelectron spectroscopy (XPS) to provide information on the electronic structure of molecular organometallic complexes of Ln(II) ions (Ln = lanthanide) has been examined for
Evaluating electrochemical accessibility of 4fn5d1 and 4fn+1 Ln(II) ions in (C5H4SiMe3)3Ln and (C5Me4H)3Ln complexes.
The reduction potentials (reported vs. Fc+/Fc) for a series of Cp'3Ln complexes (Cp' = C5H4SiMe3, Ln = lanthanide) were determined via electrochemistry in THF with [nBu4N][BPh4] as the supporting
Structural variations in cyclopentadienyl uranium(III) iodide complexes
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KC8 reduction of Y(OArAd,Ad,t-Bu)3 in THF in the presence of 2.2-cryptand (crypt) produces the room-temperature stable, crystallographically characterizable Y(II) aryloxide.
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Heteroleptic U(III) complexes supported by bis(cyclopentadienyl) frameworks have been synthesized to examine their suitability as precursors to U(II) complexes. The newly synthesized
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Reduction of CpMe3Ln(THF), 1-Ln (Ln = La and Gd; CpMe = C5H4Me), with KC8 in the presence of 2.2.2-cryptand (crypt) generates dark solutions, 2-Ln, with EPR spectra consistent with Ln(II) complexes:
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