Synthesis and Isolation of Di-n-butylhafnocene and Its Application as a Versatile Starting Material for the Synthesis of New Hafnacycles

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• 作者：Vladimir V. Burlakov ; Torsten Beweries ; Vyacheslav S. Bogdanov ; Perdita Arndt ; Wolfgang Baumann ; Pavel V. Petrovskii ; Anke Spannenberg ; Konstantin A. Lyssenko ; Vladimir B. Shur ; Uwe Rosenthal
• 刊名：Organometallics
• 出版年：2009
• 出版时间：May 11, 2009
• 年：2009
• 卷：28
• 期：9
• 页码：2864-2870
• 全文大小：174K
• 年卷期：v.28,no.9(May 11, 2009)
• ISSN：1520-6041

文摘

The previously described hafnocene alkyne complexes are of limited applicability for the generation of the hafnocene fragment in stoichiometric and catalytic reactions. For this reason di-n-butylhafnocene (1-Hf) was fully characterized and used as a hafnocene source in reactions with alkynes and diynes. With bis(trimethylsilyl)acetylene and pyridine the alkyne complex Cp₂Hf(py)(η²-Me₃SiC₂SiMe₃) (2-Hf) was obtained and coordination of di-tert-butylbutadiyne yielded the first structurally characterized hafnacyclocumulene, Cp₂Hf(η⁴-t-BuC₄-t-Bu) (4-Hf). By the coupling of 2 equiv of the 1,3-butadiyne RC₄R at the hafnocene center, hafnacyclopentadienes were formed regioselectively (R = t-Bu, 5-t-Bu-Hf; R = SiMe₃, 5-SiMe₃-Hf). In the case of 1,4-diphenylbutadiyne the hafnocene-substituted [4]radialene 6-Hf was formed. Treatment of the latter with acid gave the free [4]radialene 7. In the reaction of 4-Hf with diphenylacetylene, the alkyne inserted into the Hf−C_α bond to give the hafnacyclopentadiene 8.