Inorg. Chem. 2010, 49, 2793–2798 2793
DOI: 10.1021/ic902296d
γ-Deprotonation of Anionic Bis(trimethylsilyl)amidolanthanide Complexes with a
Countered [(TpMe2)2Ln]þ Cation
Fuyan Han,† Jie Zhang,*,† Weiyin Yi,† Zhengxing Zhang,† Jingyi Yu,† Linhong Weng,† and Xigeng Zhou*,†,‡
†Shanghai Key Laboratory of Molecular Catalysis and Innovative Material, Department of Chemistry, Fudan
University, Shanghai 200433, People’s Republic of China, and ‡State Key Laboratory of Organometallic
Chemistry, Shanghai 200032, People’s Republic of China
Received November 19, 2009
TpMe2LnCl2 (1) reacts with 2 equiv of KN(SiMe3)2 in tetrahydrofuran at room temperature to yield the ligand
redistribution/γ-deprotonation products [(TpMe2)2Ln]þ[((Me3Si)2N)2Ln(CH2)SiMe2N(SiMe3)]- [Ln = Er (2), Y (3)].
Complex 2 can also be obtained by reacting [(Me3Si)2N]2ErCl with KTpMe2. However, 1 reacts with 1.5 and 1 equiv of
KN(SiMe3)2 to yield [(TpMe2)2Er]þ[((Me3Si)2N)3ErCl]- (4) and [(TpMe2)2Er]þ{[(Me3Si)2N)TpMe2ErCl]2(μ-Cl)2K}-
(5), respectively. Furthermore, it is found that 2 reacts with 2 equiv of CyNdCdNCy (Cy = cyclohexyl) to give the
tandem HN(SiMe3)2 elimination and Ln-C insertion product (TpMe2)Er[(CyN)2CCH2SiMe2N(SiMe3)] (6) in 71%
isolated yield. The results reveal that the γ-deprotonation degree of advancement increases with an increase of the
steric hindrance around the central metal ion. All new complexes have been characterized by elemental analysis and
spectroscopic properties, and their solid-state structures have also been determined through single-crystal X-ray
diffraction analysis.
Introduction
contrast to the ever-growing literature on poly-
(pyrazolyl)borate complexes of transition metals,1,2 examples
of lanthanide species incorporating these functionalities
remain scarce.3-5 There does not appear to be a large effort
to expand upon this class of compounds, which is probably
due to the lack of viable synthetic methodologies to access
these complexes. For example, replacement of the halide
(X-) of TpMe2LnX2 or (TpMe2)2LnX by other anionic
ligands, such as alkyl and amido, remains a significant
challenge,3a,6 even though it has been established in the past
as a very powerful and efficient method for the synthesis of
various lanthanocene derivatives.7 Most of the
(TpMe2)2LnIIIL derivatives were prepared by the oxidation
of (TpMe2)2LnII with organic reagents. Recently, Sella and
co-workers reported the synthesis of the first lanthanide(III)
amide with the Tp* ligand (TpMe2)2NdNPh2 by prudential
control of the reaction conditions of (TpMe2)2NdCl with
NaNPh2.8
Poly(pyrazolyl)borate anion ligands are currently attract-
ing considerable attention because of both their potential as
an alternative to cyclopentadienyl ligands and their out-
standing performances in conferring organometallic com-
plexes higher reactivity and new reaction patterns.1-4 In
*To whom correspondence should be addressed. E-mail: xgzhou@
fudan.edu.cn (X.Z.), zhangjie@fudan.edu.cn (J.Z.).
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2010 American Chemical Society
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