Molecular Alloys, Linking Organometallics with Intermetallic Hume−Rothery Phases: The Highly Coordinated Transition Metal Compounds [M(ZnR)n] (n ≥ 8) Containing Or

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• 作者：Thomas Cadenbach ; Timo Bollermann ; Christian Gemel ; Mustafa Tombul ; Israel Fernandez ; Moritz von Hopffgarten ; Gernot Frenking ; Roland A. Fischer
• 刊名：Journal of the American Chemical Society
• 出版年：2009
• 出版时间：November 11, 2009
• 年：2009
• 卷：131
• 期：44
• 页码：16063-16077
• 全文大小：522K
• 年卷期：v.131,no.44(November 11, 2009)
• ISSN：1520-5126

文摘

This paper presents the preparation, characterization and bonding analyses of the closed shell 18 electron compounds [M(ZnR)_n] (M = Mo, Ru, Rh, Ni, Pd, Pt, n = 8−12), which feature covalent bonds between n one-electron organo-zinc ligands ZnR (R = Me, Et, η⁵-C₅(CH₃)₅ = Cp*) and the central metal M. The compounds were obtained in high isolated yields (>80%) by treatment of appropriate GaCp* containing transition metal precursors 13-18, namely [Mo(GaCp*)₆], [Ru₂(Ga)(GaCp*)₇(H)₃] or [Ru(GaCp*)₆(Cl)₂], [(Cp*Ga)₄RhGa(η¹-Cp*)Me] and [M(GaCp*)₄] (M = Ni, Pd, Pt) with ZnMe₂ or ZnEt₂ in toluene solution at elevated temperatures of 80−110 °C within a few hours of reaction time. Analytical characterization was done by elemental analyses (C, H, Zn, Ga), ¹H and ¹³C NMR spectroscopy. The molecular structures were determined by single crystal X-ray diffraction. The coordination environment of the central metal M and the M−Zn and Zn−Zn distances mimic the situation in known solid state M/Zn Hume−Rothery phases. DFT calculations at the RI-BP86/def2-TZVPP and BP86/TZ2P+ levels of theory, AIM and EDA analyses were done with [M(ZnH)_n] (M = Mo, Ru, Rh, Pd; n = 12, 10, 9, 8) as models of the homologous series. The results reveal that the molecules can be compared to 18 electron gold clusters of the type M@Au_n, that is, W@Au₁₂, but are neither genuine coordination compounds nor interstitial cage clusters. The molecules are held together by strong radial M−Zn bonds. The tangential Zn−Zn interactions are generally very weak and the (ZnH)_n cages are not stable without the central metal M.