Isolation and Structural Characterization of a Mackay 55-Metal-Atom Two-Shell Icosahedron of Pseudo-Ih Symmetry, Pd55L12(μ3-CO)20 (L = PR3, R = Isopropyl): Comparative Analysis with Interior Two-Shell

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• 作者：Jeremiah D. Erickson ; Evgueni G. Mednikov ; Sergei A. Ivanov ; Lawrence F. Dahl
• 刊名：Journal of the American Chemical Society
• 出版年：2016
• 出版时间：February 10, 2016
• 年：2016
• 卷：138
• 期：5
• 页码：1502-1505
• 全文大小：282K
• ISSN：1520-5126

文摘

We present the first successful isolation and crystallographic characterization of a Mackay 55-metal-atom two-shell icosahedron, Pd₅₅L₁₂(μ₃-CO)₂₀ (L = PPrⁱ₃) (1). Its two-shell icosahedron of pseudo-I_h symmetry (without isopropyl substituents) enables a structural/bonding comparison with interior 55-metal-atom two-shell icosahedral geometries observed within the multi-shell capped 145-metal-atom three-shell Pd₁₄₅(CO)₇₂(PEt₃)₃₀ and 165-metal-atom four-shell Pt-centered (μ₁₂-Pt)Pd_164-xPt_x(CO)₇₂(PPh₃)₂₀ (x ≈ 7) nanoclusters, and within the recently reported four-shell Au₁₃₃(SC₆H₄-p-Bu^t)₅₂ nanocluster. DFT calculations carried out on a Pd₅₅(CO)₂₀(PH₃)₁₂ model analogue, with triisopropyl phosphine substituents replaced by H atoms, revealed a positive +0.84 e charge for the entire Pd₅₅ core, with a highly positive second-shell Pd₄₂ surface of +1.93 e.