Actinide Metallocene Hydride Chemistry: C鈥揌 Activation in Tetramethylcyclopentadienyl Ligands to Form [渭-畏5-C5Me3H(CH2)-魏C]2鈥?/sup> Tuck-over Li

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• 作者：Nathan A. Siladke ; Christopher L. Webster ; Justin R. Walensky ; Michael K. Takase ; Joseph W. Ziller ; Daniel J. Grant ; Laura Gagliardi ; William J. Evans
• 刊名：Organometallics
• 出版年：2013
• 出版时间：November 11, 2013
• 年：2013
• 卷：32
• 期：21
• 页码：6522-6531
• 全文大小：521K
• 年卷期：v.32,no.21(November 11, 2013)
• ISSN：1520-6041

文摘

Hydrogenolysis of the dimethyl actinide metallocenes (C₅Me₄SiMe₃)₂UMe₂ and (C₅Me₄H)₂AnMe₂ (An = Th, U) was examined for comparison with the hydrogenolysis of (C₅Me₅)₂AnMe₂ that forms the hydrides [(C₅Me₅)₂ThH₂]₂, [(C₅Me₅)₂UH₂]₂, and [(C₅Me₅)₂UH]₂. Parallel reactivity is not found with the (C₅Me₄SiMe₃)^{鈭?/sup> and (C₅Me₄H)鈭?/sup> complexes. Instead, this study led to the first example of a 鈥渢uck-over鈥?[渭-畏5-C₅Me₃H(CH₂)-魏C]2鈥?/sup> dianion derived from (C₅Me₄H)鈭?/sup> ligands by C鈥揌 bond activation and rare examples of a polymetallic thorium polyhydride compound and an organometallic Th3+ complex. (C₅Me₄SiMe₃)₂UMe₂ reacts with H₂ to form the bis(tethered alkyl) complex (畏5-C₅Me₄SiMe₂CH₂-魏C)₂U, a product of C鈥揌 bond activation of the silylmethyl groups. The only identifiable product of hydrogenolysis of (C₅Me₄H)₂UMe₂ is (C₅Me₄H)₃U. The first thorium complex of (C₅Me₄H)鈭?/sup> was synthesized by reaction of 2 equiv of (C₅Me₄H)MgCl(THF) with ThBr₄(THF)₄ to produce (C₅Me₄H)₂ThBr₂. This complex reacts with MeLi to make (C₅Me₄H)₂ThMe₂. The latter complex reacts with H₂ to form the ligand redistribution product (C₅Me₄H)₃ThMe and the tetrametallic octahydride tuck-over complex (C₅Me₄H)₄[渭-畏5-C₅Me₃H(CH₂)-魏C]₂Th₄(渭-H)₄(渭₃-H)₄. For comparison with the (C₅Me₄H)₃U product, the thorium analogue, (C₅Me₄H)₃Th, was synthesized by potassium reduction of a [(C₅Me₄H)₃Th][BPh₄] intermediate obtained in situ from (C₅Me₄H)₃ThMe and [HNEt₃][BPh₄]. (C₅Me₄H)₃Th can also be prepared from KC₈ and (C₅Me₄H)₃ThBr, obtained from KC₅Me₄H and ThBr₄(THF)₄.}