Rare-earth metal complexes stabilized by amino-phosphineligand. Reaction with mesityl azide and catalysis of the cycloaddition of organic azides and aromatic alkynes
作者:Bo Liu、Dongmei Cui
DOI:10.1039/b811363g
日期:——
Stoichiometric reactions between mesityl azide (MesN3, Mes = 2,4,6-C6H2Me3) and amino-phosphine ligated rare-earth metal alkyl, LLn(CH2SiMe3)2(THF) (L = (2,6-C6H3Me2)NCH2C6H4P(C6H5)2; Ln = Lu (1a), Sc (1b)), amide, LLu(NH(2,6-C6H3iPr2))2(THF) (2) and acetylide at room temperature gave the amino-phosphazide ligated rare-earth metal bis(triazenyl) complexes, [L(MesN3)]Ln[(MesN3)(CH2SiMe3)]2 (Ln = Lu (3a); Sc (3b)), bis(amido) complex [L(MesN3)]Lu[NH(2,6-C6H3iPr2)]2 (4), and bis(alkynyl) complex (5) (L(MesN3)Lu (CCPh)2)2, respectively. The triazenyl group in 3 coordinates to the metal ion in a rare η2-mode viaNβ and Nγ atoms, generating a triangular metallocycle. The amino-phosphazide ligand, L(MesN3), in 3, 4 and 5 chelates to the metal ion in a η3-mode viaNα and Nγ atoms. In the presence of excess phenylacetylene, complex 3a isomerized to 3′, where the triazenyl group coordinates to the metal ion in a η3 mode viaNα and Nγ atoms. Complexes 1, 2, 3 and 4 have shown an unprecedented catalytic activity towards the cycloaddition of organic azides and aromatic alkynes to afford 1,5-disubstituted 1,2,3-triazoles selectively.
异亚丙基叠氮化物 (MesN3, Mes = 2,4,6-C6H2Me3) 与氨基膦连接的稀土金属烷基 LLn(CH2SiMe3)2(THF) (L = (2,6-C6H3Me2)NCH2C6H4P(C6H5) 之间的化学计量反应)2; Ln = Lu (1a), Sc (1b)), 酰胺, LLu(NH(2,6-C6H3iPr2))2(THF) (2) 和乙炔在室温下得到氨基磷酰肼连接的稀土金属双(三氮烯基)络合物,[L(MesN3)]Ln[(MesN3)(CH2SiMe3)]2 (Ln = Lu (3a); Sc (3b)),双(酰胺基)络合物[L(MesN3)]Lu[分别为 NH(2,6-C6H3iPr2)]2 (4) 和双(炔基)络合物 (5) (L(MesN3)Lu (CCPh)2)2。 3中的三氮烯基通过Nβ和Nγ原子以稀有的η2-模式与金属离子配位,生成三角形金属环。 3、4和5中的氨基磷酰肼配体L(MesN3)通过Nα和Nγ原子以η3模式与金属离子螯合。在过量苯乙炔存在下,络合物 3a 异构化为 3',其中三氮烯基通过 Nα 和 Nγ 原子以 η3 模式与金属离子配位。配合物 1、2、3 和 4 对有机叠氮化物和芳香族炔烃的环加成选择性地产生 1,5-二取代的 1,2,3-三唑表现出前所未有的催化活性。