Synthesis and Reactivities of Guanidinate Dianion Complexes of Heterobimetallic Lanthanide−Lithium Cp2Ln[(CyN)2CNPh]Li(THF)3

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• 作者：Pengzhi Zheng ; Jianquan Hong ; Ruiting Liu ; Zhengxing Zhang ; Zhen Pang ; Linhong Weng ; Xigeng Zhou
• 刊名：Organometallics
• 出版年：2010
• 出版时间：March 8, 2010
• 年：2010
• 卷：29
• 期：5
• 页码：1284-1289
• 全文大小：867K
• 年卷期：v.29,no.5(March 8, 2010)
• ISSN：1520-6041

文摘

The treatment of Cp₃Ln with 1 equiv of N,N′-dicyclohexyl-N′′-phenylguanidine followed by reacting with butyllithium yields a series of novel guanidinate dianion complexes of heterobimetallic lanthanide−lithium with formula Cp₂Ln[(CyN)₂CNPh]Li(THF)₃ (Ln = Yb (1a), Er (1b), Y (1c), Dy (1d)). Reactivities of these dianionic guanidinate complexes toward various electrophiles have been investigated. Reaction of 1 with Me₂RSiCl produced tetrasubstituted guanidinate monoanion complexes Cp₂Ln[(CyN)₂CN(Ph)SiRMe₂] ((R = Me, Ln = Yb (2a), Er (2b), Y (2c); R = ^tBu, Ln = Yb (3a), Er (3b)), indicating that the Li−N bond is preferred to couple with chlorosilanes. In contrast, the regioselective functionalization of the NCy group bonded to the lanthanide ion was achieved by reaction of 1a with Me₂SiCl₂ to produce Me₂Si(CyN)₂C═NPh (4) and Cp₂YbCl(THF) (5). Significantly, treatment of 1d with PhCOCl leads to the cleavage of one C−N bond of the dianionic guanidinate, giving the acylamino complex [Cp₂Dy(OC(Ph)NCy)]₂ (6). These results have shown that the active site of the dianionic guanidinate ligand is tunable due to the delocalization of the two negative charges on the three N atoms. All the compounds were characterized by elemental analysis and spectroscopic methods. The structures of compounds 1−6 are also determined through X-ray single-crystal diffraction analysis.