Synthesis and reactivity of cationic lanthanide metallocene complexes. Hexabromocarborane and tetraphenylborate as counter ions
Synthesis and reactivity of cationic lanthanide metallocene complexes. Hexabromocarborane and tetraphenylborate as counter ions
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阳离子镧系金属茂配合物的合成和反应性。
DOI：
10.1039/a804311f
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发表时间：
1998
期刊：
影响因子：
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通讯作者：
T. Mak
中科院分区：
文献类型：
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作者：
Zuowei Xie;Zhixian Liu;Zhongyuan Zhou;T. Mak
未溶剂化的Cp“2Ln(II)[Cp”=1，3-(Me3Si)2C5H3]与1当量的Ag(I)Y反应，或[Cp“2LnI]2与2摩尔当量的Ag(CB11Br6H6)在纯甲苯中于室温反应，得到了高产率的无Lewis碱的阳离子稀土茂金属配合物[Cp”2LN]Y(Y=1BPh4-，Ln=Sm1，Yb 2；Y=1C11Br6H6-，Ln=1Sm3，Er 4)。它们在室温下缓慢地发生分解反应。这些“刘易斯无碱”阳离子络合物的反应活性高度依赖于反离子的配位性质。由1，2-二甲氧基乙烷(DME)和四氢呋喃(THF)重结晶得到[Cp“2Sm(DME)][BPh4]5和[Cp”2Yb(THF)2][BPh4]6。而四氢呋喃的重结晶导致了四氢呋喃的开环聚合。从含有少量四氢呋喃的甲苯中通过重结晶得到了四氢呋喃配位化合物[Cp“2LN(THF)2][CB11Br6H6](Ln=3Sm7，Er8)。“Lewis无碱”阳离子“Cp”2Er+可从反离子CB11Br6H6-中抽出一个溴原子，或从CH2Cl2中抽出一个氯原子，分别生成[Cp“2ErBr2]2或[Cp”2ErCl2]2。不幸的是，这些阳离子在室温下对1-己烯没有反应活性。5，7，8和[Cp“2ErBr2]2的分子结构已通过单晶X射线分析得到确证。
Treatment of unsolvated Cp″2Ln(II) [Cp″ = 1,3-(Me3Si)2C5H3] with 1 equivalent of Ag(I)Y, or reaction of [Cp″2LnI]2 with 2 molar equivalents of Ag(CB11Br6H6) in pure toluene at room temperature gave “Lewis base-free” cationic lanthanide metallocene complexes [Cp″2Ln]Y (Y = BPh4–, Ln = Sm 1, Yb 2; Y = CB11Br6H6–, Ln = Sm 3, Er 4) in good yield. They slowly undergo decomposition reaction at room temperature. The reactivity of these “Lewis base-free” cationic complexes is highly dependent upon the coordinating nature of the counter ions. Complexes 3 and 4 are much more reactive than 1 and 2. Recrystallization of 1 and 2 from 1,2-dimethoxyethane (DME) and THF yielded [Cp″2Sm(DME)][BPh4] 5 and [Cp″2Yb(THF)2][BPh4] 6, respectively. However, recrystallization of 3 and 4 from THF resulted in the ring-opening polymerization of THF. The THF coordinated complexes [Cp″2Ln(THF)2][CB11Br6H6] (Ln = Sm 7, Er 8) were isolated via recrystallization of 3 and 4 from toluene containing a small amount of THF. The “Lewis base-free” cation “Cp″2Er+” can abstract one bromine atom from the counter ion CB11Br6H6– or one chlorine atom from CH2Cl2 to form [Cp″2ErBr]2 or [Cp″2ErCl]2, respectively. Unfortunately, these cations do not exhibit reactivity towards 1-hexene at room temperature. Molecular structures of 5, 7, 8 and [Cp″2ErBr]2 have been confirmed by single-crystal X-ray analyses.