Alkylyttrium Complexes Supported by N,N'-Dicyclohexyl-N' '-bis(trimethylsilyl)guanidinate Ligands
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- 作者：Alexander A. Trifonov ; Dmitrii M. Lyubov ; Georgy K. Fukin ; Evgenii V. Baranov ; Yu. A. Kurskii
- 刊名：Organometallics
- 出版年：2006
- 出版时间：July 31, 2006
- 年：2006
- 卷：25
- 期：16
- 页码：3935 - 3942
- 全文大小：172K
- 年卷期：v.25,no.16(July 31, 2006)
- ISSN：1520-6041
文摘
The reaction of anhydrous YCl3 with an equimolar amount of lithium N,N'-dicyclohexyl-N' '-bis(trimethylsilyl)guanidinate, Li[(Me3Si)2NC(NCy)2], in THF afforded the monoguanidinate dichloro complex[{(Me3Si)2NC(NCy)2}Y{(
-Cl)2Li(THF)2}(-Cl)]2 (1). X-ray diffraction study showed that complex 1has a bimetallic tetranuclear dimeric core with six 2-bridging chloro ligands. Treatment of complex 1with 4 molar equiv of LiCH2SiMe3 in hexane at 0 
C yielded the monomeric salt-free dialkyl complex{(Me3Si)2NC(NCy)2}Y(CH2SiMe3)2(THF)2 (2). The monoguanidinate tetramethyl ate-complex {(Me3Si)2NC(NCy)2}Y[(-Me)2Li(TMEDA)]2 (3) was prepared by the reaction of complex 1 with 8 equiv ofMeLi in the presence of excess TMEDA in toluene at 20 C. The complexes 2 and 3 were structurallycharacterized. Alkylation of complex 1 with t-BuLi (1:4 molar ratio) in hexane resulted in the formationof the bis(guanidinate) alkyl yttrium complex {(Me3Si)2NC(NCy)2}2Y(t-Bu) (4) in 42% yield. Theguanidinate ligand redistribution was also observed in the reaction of the mono(guanidinate) dichloroyttrium complex {(Me3Si)2NC(NCy)2}YCl2(Et2O) (5) with 2 molar equiv of LiCH2SiMe3 in hexane at 0C. This reaction afforded ate-complex {(Me3Si)2NC(NCy)2}2Y(-CH2SiMe3)2Li (6) in 34% yield. TheX-ray diffraction study has revealed a low formal coordination number of the lithium atom in 6 and itsagostic interaction with two methyl carbon atoms of SiMe3 groups.
-Cl)2Li(THF)2}(-Cl)]2 (1). X-ray diffraction study showed that complex 1has a bimetallic tetranuclear dimeric core with six 2-bridging chloro ligands. Treatment of complex 1with 4 molar equiv of LiCH2SiMe3 in hexane at 0 C yielded the monomeric salt-free dialkyl complex{(Me3Si)2NC(NCy)2}Y(CH2SiMe3)2(THF)2 (2). The monoguanidinate tetramethyl ate-complex {(Me3Si)2NC(NCy)2}Y[(-Me)2Li(TMEDA)]2 (3) was prepared by the reaction of complex 1 with 8 equiv ofMeLi in the presence of excess TMEDA in toluene at 20 C. The complexes 2 and 3 were structurallycharacterized. Alkylation of complex 1 with t-BuLi (1:4 molar ratio) in hexane resulted in the formationof the bis(guanidinate) alkyl yttrium complex {(Me3Si)2NC(NCy)2}2Y(t-Bu) (4) in 42% yield. Theguanidinate ligand redistribution was also observed in the reaction of the mono(guanidinate) dichloroyttrium complex {(Me3Si)2NC(NCy)2}YCl2(Et2O) (5) with 2 molar equiv of LiCH2SiMe3 in hexane at 0C. This reaction afforded ate-complex {(Me3Si)2NC(NCy)2}2Y(-CH2SiMe3)2Li (6) in 34% yield. TheX-ray diffraction study has revealed a low formal coordination number of the lithium atom in 6 and itsagostic interaction with two methyl carbon atoms of SiMe3 groups.