Sterically Encumbered, Charge-Compensated Metallacarboranes. Synthesis and Structures of Ruthenium Pentamethylcyclopentadienyl Derivatives

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• 作者：Georgina M. Rosair ; Alan J. Welch ; and Andrew S. Weller
• 刊名：Organometallics
• 出版年：1998
• 出版时间：July 20, 1998
• 年：1998
• 卷：17
• 期：15
• 页码：3227 - 3235
• 全文大小：129K
• 年卷期：v.17,no.15(July 20, 1998)
• ISSN：1520-6041

文摘

The reactions of [RuCl(Cp*)]₄ with monoanionic, charge-compensated carborane anionshave been studied and products characterized by NMR spectroscopy (¹H and ¹¹B) and single-crystal X-ray diffraction. With [9-SMe₂-7,8-nido-C₂B₉H₁₀]^-, the product is the expectedspecies 3-(Cp*)-4-SMe₂-3,1,2-closo-RuC₂B₉H₁₀, the structure of which reveals some evidencefor steric congestion between the Cp* and SMe₂ substituents, which is characteristic of allof the compounds studied. Use of the carborane anion [7-Ph-9-SMe₂-7,8-nido-C₂B₉H₉]^-affords 1-Ph-3-(Cp*)-7-SMe₂-3,1,2-closo-RuC₂B₉H₉, in which the Ph and SMe₂ cage substituents are separated by a {BH} unit. ¹H NMR spectroscopy of this compound revealsrestricted rotation of the phenyl group at room temperature. Moreover, the compoundisomerizes, slowly at room temperature but rapidly if warmed, to the C_cage-separated isomer3-(Cp*)-4-SMe₂-11-Ph-3,1,2-closo-RuC₂B₉H₉. In contrast, and somewhat surprisingly, theanalogous compound 1-Ph-3-(Cp*)-4-SMe₂-3,1,2-closo-RuC₂B₉H₉ (prepared from [RuCl(Cp*)]₄and [7-Ph-11-SMe₂-7,8-nido-C₂B₉H₉]^-), which has adjacent Ph and SMe₂ substituents, doesnot isomerize, even when heated. The reaction between [RuCl(Cp*)]₄ and [7,8-Ph₂-9-SMe₂-7,8-nido-C₂B₉H₈]^- affords 1,2-Ph₂-3-(Cp*)-4-SMe₂-3,1,2-pseudocloso-RuC₂B₉H₈, the firstexample of a charge-compensated pseudocloso metallacarborane.