Transformations and Agostic Interactions of Hydrocarbyl Ligands Bonded to the Sulfur-Rich Dimolybdenum Site {Mo2Cp2(acs.org/images/entities/mgr.gif" border=

详细信息    查看全文

• 作者：Nolwenn Cabon ; Alan Le Goff ; Christine Le Roy ; Franç ; ois Y. P&eacute ; tillon ; Philippe Schollhammer ; Jean Talarmin ; John E. McGrady ; and Kenneth W. Muir
• 刊名：Organometallics
• 出版年：2005
• 出版时间：December 5, 2005
• 年：2005
• 卷：24
• 期：25
• 页码：6268 - 6278
• 全文大小：869K
• 年卷期：v.24,no.25(December 5, 2005)
• ISSN：1520-6041

文摘

A series of chemical and electrochemical transformations of systems in which a {Mo₂Cp₂(ages/entities/mgr.gif">-SMe)₃} core is bridged by a ages/entities/mgr.gif">-C₂H_nR ligand (n = 0-4) are described in this paper. Thereaction of the alkylidene complex [Mo₂Cp₂(ages/entities/mgr.gif">-SMe)₃(ages/entities/mgr.gif">-ages/gifchars/eta.gif" BORDER=0 >¹:ages/gifchars/eta.gif" BORDER=0 >²-CHCH₂Tol)](BF₄) (1) with LiBuⁿat 0 ages/entities/deg.gif">C produces the ages/entities/mgr.gif">-ages/gifchars/sigma.gif" BORDER=0 >,ages/gifchars/pi.gif" BORDER=0 >-vinyl complex [Mo₂Cp₂(ages/entities/mgr.gif">-SMe)₃((ages/entities/mgr.gif">-ages/gifchars/eta.gif" BORDER=0 >¹:ages/gifchars/eta.gif" BORDER=0 >²-CH=CHTol] (2) in goodyield. The molecular structure of 2 has been confirmed by X-ray analysis. Upon treatmentwith NaBH₄ 1 is readily converted into the semibridging alkyl species [Mo₂Cp₂(ages/entities/mgr.gif">-SMe)₃(ages/entities/mgr.gif">-CH₂CH₂Tol)] (3), which is also formed by electrochemical reduction of 1 in acidic medium.NMR and X-ray diffraction studies of 3 are consistent with, but do not definitively establish,the presence of a ages/gifchars/eta.gif" BORDER=0 >¹ ages/gifchars/alpha.gif" BORDER=0>-agostic interaction. Density functional theory has been used to confirmthe presence of agostic interactions in both 1 and 3 and also to explore the exchange pathwaysfor these hydrocarbyl dimolybdenum systems. Electrochemical transformation of theages/entities/mgr.gif">-alkylidene complex 1 gives 3 as the major product when acid is present and a mixture of2 and 3 when acid is absent, production of 2 being favored by low initial concentrations of1. Theoretical, spectroscopic, and diffraction data are used to explain the formation andstructures of closely related [Mo₂Cp₂(ages/entities/mgr.gif">-SMe)₃(ages/entities/mgr.gif">-C₂H_nR]^z+ complexes (n = 0-4 and z = 0, 1),including 1-3.