Insertion, Isomerization, and Cascade Reactivity of the Tethered Silylalkyl Uranium Metallocene (畏5-C5Me4SiMe2CH2-魏C)2U

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• 作者：Nathan A. Siladke ; Joseph W. Ziller ; William J. Evans
• 刊名：Journal of the American Chemical Society
• 出版年：2011
• 出版时间：March 16, 2011
• 年：2011
• 卷：133
• 期：10
• 页码：3507-3516
• 全文大小：1195K
• 年卷期：v.133,no.10(March 16, 2011)
• ISSN：1520-5126

文摘

Investigation of the insertion reactivity of the tethered silylalkyl complex (畏⁵-C₅Me₄SiMe₂CH₂-魏C)₂U (1) has led to a series of new reactions for U鈭扖 bonds. Elemental sulfur reacts with 1 by inserting two sulfur atoms into each of the U鈭扖 bonds to form the bis(tethered alkyl disulfide) complex (畏⁵:畏²-C₅Me₄SiMe₂CH₂S₂)₂U (2). The bulky substrate N,N鈥?diisopropylcarbodiimide, ⁱPrN鈺怌鈺怤ⁱPr, inserts into only one of the U鈭扖 bonds of 1 to produce the mixed-tether complex (畏⁵-C₅Me₄SiMe₂CH₂-魏C)U[畏⁵-C₅Me₄SiMe₂CH₂C(ⁱPrN)₂-魏²N,N鈥瞉 (3). Carbon monoxide did not exclusively undergo a simple insertion into the U鈭扖 bond of 3 but instead formed {渭-[畏⁵-C₅Me₄SiMe₂CH₂C(鈺怤ⁱPr)O-魏²O,N]U[OC(C₅Me₄SiMe₂CH₂)CN(ⁱPr)-魏²O,N]₂ (4) in a cascade of reactions that formally includes U鈭扖 bond cleavage, C鈭扤 bond cleavage of the amidinate ligand, alkyl or silyl migration, U鈭扥, C鈭扖, and C鈭扤 bond formations, and CO insertion. The reaction of 3 with isoelectronic tert-butyl isocyanide led to insertion of the substrate into the U鈭扖 bond, but with a rearrangement of the amidinate ligand binding mode from 魏² to 魏¹ to form [畏⁵:畏²-C₅Me₄SiMe₂CH₂C(鈺怤^tBu)]U[畏⁵-C₅Me₄SiMe₂CH₂C(鈺怤ⁱPr)N(ⁱPr)-魏N] (5). The product of double insertion of ^tBuN鈮 into the U鈭扖 bonds of 1, namely [畏⁵:畏²-C₅Me₄SiMe₂CH₂C(鈺怤^tBu)]₂U (6), was found to undergo an unusual thermal rearrangement that formally involves C鈭扝 bond activation, C鈭扖 bond cleavage, and C鈭扖 bond coupling to form the first formimidoyl actinide complex, [畏⁵:畏⁵:畏³-^tBuNC(CH₂SiMe₂C₅Me₄)(CHSiMe₂C₅Me₄)]U(畏²-HC鈺怤^tBu) (7).