A stable Schrock-type hafnium-silylene complex
A stable Schrock-type hafnium-silylene complex
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DOI：
10.1021/ja067251d
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发表时间：
2006-12-20
影响因子：
15
通讯作者：
Sekiguchi, Akira
中科院分区：
文献类型：
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作者：
Nakata, Norio;Fujita, Toshiyuki;Sekiguchi, Akira
第一个稳定的铪-亚甲硅烷基络合物，（η-C5 H4 Et）2（PMe 3）HfSi（SiMetBu 2）2（6），以膦加合物的形式，通过1，1-二硫代硅烷（1）与0.9当量的（η-C5 H4 Et）2 HfCl 2在干甲苯中在−50 °C下的偶联反应，然后在− 50 ° C下用过量的PMe 3处理，以红色晶体的形式获得。在6的29 Si NMR谱中，来自亚甲硅烷基配体的信号在295.4ppm处大幅向低场移动，JSiP耦合常数为15.0Hz。6的X射线晶体学分析显示，Si-Hf键长（2.6515（9）Å）比典型的Si-Hf单键短约5%，明显表明硅和铪原子之间的双键特征。发现化合物6是Schrock型硅烯络合物，这一结论得到了模型络合物（η-C5 H4 Et）2（PMe 3）HfSi（SiMe 3）2（8）的自然布居分析（NPA）电荷分布的支持，显示硅原子上带负电荷（−0.34）。
The first stable hafnium−silylene complex, (η-C5H4Et)2(PMe3)HfSi(SiMetBu2)2(6) was obtained in the form of the phosphine adduct as red crystals by the coupling reaction of 1,1-dilithiosilane (1) with 0.9 equiv of (η-C5H4Et)2HfCl2in dry toluene at −50 °C, followed by treatment with an excess of PMe3at −50 °C. In the29Si NMR spectrum of6, the signal from the silylene ligand is shifted greatly downfield at 295.4 ppm, with aJSiPcoupling constant of 15.0 Hz. X-ray crystallographic analysis of6revealed that the Si−Hf bond length (2.6515(9) Å) is about 5% shorter than typical Si−Hf single bonds, obviously indicating the double-bond character between the silicon and hafnium atoms. The compound6was found to be a Schrock-type silylene complex, a conclusion that was supported by the natural population analysis (NPA) charge distribution for the model complex, (η-C5H4Et)2(PMe3)HfSi(SiMe3)2(8), showing a negative charge on the silicon atom (−0.34).