Synthesis, Characterization, Selective Catalytic Activity, and Reactivity of Rare Earth Metal Amides with Different Metal−Nitrogen Bonds
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- 作者：Xiancui Zhu ; Jiaxi Fan ; Yunjun Wu ; Shaowu Wang ; Lijun Zhang ; Gaosheng Yang ; Yun Wei ; Chengwei Yin ; Hong Zhu ; Shihong Wu ; Hongtao Zhang
- 刊名：Organometallics
- 出版年：2009
- 出版时间：July 13, 2009
- 年：2009
- 卷：28
- 期：13
- 页码：3882-3888
- 全文大小：768K
- 年卷期：v.28,no.13(July 13, 2009)
- ISSN：1520-6041
文摘
A series of neutral rare earth metal amides with different metal−nitrogen bonds were synthesized and characterized. The selective catalytic activity and reactivity of the complexes incorporating different metal−nitrogen (Ln−N, Ln = rare earth metal) bonds were studied. Treatment of (Me2Si)[(2,6-R12-4-R2-C6H2)NH]2 with [(Me3Si)2N]3LnIII(μ-Cl)Li(THF)3 in toluene produced the neutral rare earth metal complexes {(Me2Si)[(2,6-R12-4-R2-C6H2)N]2}LnN(SiMe3)2(THF) (R1 = iPr, R2 = H, Ln = Yb (1), Y (2), Eu (3), Sm (4), Nd (5); R1 = R2 = H, Ln = Yb (6), Sm (7)) incorporating different Ln−N bonds in good yields. Reaction of 6 or 7 with grease (Me2SiO)3 in toluene produced the selective insertion products [C6H5N(Me2Si)N(C6H5)(Me2SiO)LnN(SiMe3)2]2 (Ln = Yb (8), Sm (9)). The structures of complexes 1, 2, 4, 5, 8, and 9 were additionally determined by single-crystal X-ray analyses. Investigation of catalytic activity of the complexes indicated that the complexes displayed a high selectivity on cyclotrimerization or cyclodimerization toward isocyanates depending on the nature of the isocyanates. These catalysts have the advantages of a high reactivity and good selectivity toward isocyanates, easy preparation, low catalyst loading, and high conversion, as well as mild reaction conditions.