Combination of Spectroscopic Methods: In Situ NMR and UV/Vis Measurements To Understand the Formation of Group 4 Metallacyclopentanes from the Corresponding Metallacyclopropenes
Combination of Spectroscopic Methods: In Situ NMR and UV/Vis Measurements To Understand the Formation of Group 4 Metallacyclopentanes from the Corresponding Metallacyclopropenes
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DOI：
10.1021/ja809368s
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发表时间：
2009-04-01
影响因子：
15
通讯作者：
Rosenthal, Uwe
中科院分区：
文献类型：
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作者：
Beweries, Torsten;Fischer, Christian;Rosenthal, Uwe
二氯化物外消旋(ebthi)HfCl2[ebthi = 1,2-乙烯-1,1'-双(eta(5)-四氢茚基)]与锂在双(三甲基甲硅烷基)乙炔存在下反应，得到铪环丙烯外消旋(ebthi)Hf(eta(2)-Me3SiC2SiMe3)(1-Hf)。蓝绿色配合物1-Hf与过量乙烯在室温下反应，导致烯烃插入到黄绿色的环戊烯2-Hf上，后者仅在溶液中稳定，并在100℃乙烯作用下消除炔烃，形成相应的黄色环戊烷3-Hf，并通过X射线晶体结构分析对其进行了表征。详细研究了 1-Hf 通过 2-Hf 逐步生成络合物 3-Hf 的反应，并与相应的环丙烯锆 1-Zr、环戊烯锆 2-Zr 和环戊烷锆 3-Zr 的形成和稳定性进行了比较。此外，还研究了二茂钛炔配合物1-Ti与乙烯的反应。为了研究炔配合物 1-M 的反应行为，使用了 NMR 光谱，并将结果与紫外/可见光谱进行了比较，表明在铪环戊烯 2-Hf 形成之前存在双-π-配合物。
By reaction of the dichloride rac-(ebthi)HfCl2[ebthi = 1,2-ethylene-1,1'-bis(eta(5)-tetrahydroindenyl)] with lithium in the presence of bis(trimethylsilyl)acetylene, the hafnacyclopropene rac-(ebthi)Hf(eta(2)- Me3SiC2SiMe3) (1-Hf) was obtained. The reaction of the blue-green complex 1-Hf with an excess of ethylene at room temperature leads by insertion of the olefin to the yellow-green hafnacyclopentene 2-Hf which is only stable in solution and eliminates the alkyne at 100 degrees C under ethylene to form the corresponding yellow hafnacyclopentane 3-Hf, which was characterized by X-ray crystal structure analysis. The reaction of 1-Hf to give stepwise via 2-Hf the complex 3-Hf was investigated in detail and compared to the formation and stability of the corresponding zirconacyclopropene 1-Zr, zirconacyclopentene 2-Zr, and zirconacyclopentane 3-Zr. Moreover, the reaction of the titanocene alkyne complex 1-Ti with ethylene was studied. For investigating the reaction behavior of the alkyne complexes 1-M, NMR spectroscopy was used and the results were compared with UV/vis spectroscopy, suggesting the existence of a bis-pi-complex prior to the formation of the hafnacyclopentene 2-Hf.