Utility of the 1,3,4,6,7,8-Hexahydro-2H-pyrimido[1,2-a]pyrimidinato Ligand, (hpp)−, in Stabilizing Uranium Metallocene Mono-Alkyl and “Tuck-in” Complexes

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• 作者：Elizabeth Montalvo ; Joseph W. Ziller ; Antonio G. DiPasquale ; Arnold L. Rheingold ; William J. Evans
• 刊名：Organometallics
• 出版年：2010
• 出版时间：May 10, 2010
• 年：2010
• 卷：29
• 期：9
• 页码：2104-2110
• 全文大小：868K
• 年卷期：v.29,no.9(May 10, 2010)
• ISSN：1520-6041

文摘

Monoalkyl uranium chemistry has been probed by reacting the metallocene chloride complex (C₅Me₅)₂(hpp)UCl, 1, (hpp)⁻ = 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidinato, with alkyl lithium reagents. Complex 1 reacts with LiMe, LiC≡CPh, LiPh, and LiEt to generate (C₅Me₅)₂(hpp)UMe, 2, (C₅Me₅)₂(hpp)U(C≡CPh), 3, (C₅Me₅)₂(hpp)UPh, 4, and (C₅Me₅)₂(hpp)UEt, 5, respectively. Complexes 2−5 react with CuI to form the iodide complex (C₅Me₅)₂(hpp)UI, 6, and methane, phenylacetylene, benzene, and ethane, respectively. Attempts to make a neopentyl analogue of 2−5 from the reaction of 1 with neopentyllithium yielded the “tuck-in” complex (C₅Me₅)(η⁵:η¹-C₅Me₄CH₂)(hpp)U, 7. Complex 7 can also be synthesized by heating 5 to 70 °C in a reaction that forms ethane as a byproduct.