Sb@Ni12@Sb20–/+ and Sb@Pd12@Sb20n Cluster Anions, Where n = +1, −1, −3, −4: Multi-Oxidation-State Clusters of Interpenetrating Platonic Solids

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• 作者：Yi WangMelanie Moses-DeBusk ; Lauren StevensJunkai Hu ; Peter Zavalij ; Kit BowenBrett I. Dunlap ; Evan R. Glaser ; Bryan Eichhorn
• 刊名：Journal of the American Chemical Society
• 出版年：2017
• 出版时间：January 18, 2017
• 年：2017
• 卷：139
• 期：2
• 页码：619-622
• 全文大小：354K
• ISSN：1520-5126

文摘

K<sub>5sub>Sb<sub>4sub> and K<sub>3sub>Sb<sub>7sub> Zintl ion precursors react with Pd(PPh<sub>3sub>)<sub>4sub> in ethylenediamine/toluene/PBu<sub>4sub><sup>+sup> solutions to give crystals of Sb@Pd<sub>12sub>@Sb<sub>20sub><sup>n–sup>/PBu<sub>4sub><sup>+sup> salts, where n = 3, 4. The clusters are structurally identical in the two charge states, with nearly perfect I<sub>hsub> point symmetry, and can be viewed as an Sb@Pd<sub>12sub> icosahedron centered inside of an Sb<sub>20sub> dodecahedron. The metric parameters suggest very weak Sb–Sb and Pd–Pd interactions with strong radial Sb–Pd bonds between the Sb<sub>20sub> and Pd<sub>12sub> shells. All-electron DFT analysis shows the 3– ion to be diamagnetic with I<sub>hsub> symmetry and a 1.33 eV HOMO–LUMO gap, whereas the 4– ion undergoes a Jahn–Teller distortion to an S = 1/2 D<sub>3dsub> structure with a small 0.1 eV gap. The distortion is predicted to be small and is not discernible by crystallography. Laser desorption–ionization time-of-flight mass spectrometry (LDI-TOF MS) studies of the crystalline samples show intense parent Sb@Pd<sub>12sub>@Sb<sub>20sub><sup>–sup> ions (negative ion mode) and Sb@Pd<sub>12sub>@Sb<sub>20sub><sup>+sup> (positive ion mode) along with series of Sb@Pd<sub>12-ysub>@Sb<sub>20-xsub><sup>–/+sup> ions. Ni(cyclooctadiene)<sub>2sub> reacts with K<sub>3sub>Sb<sub>7sub> in en/tol/Bu<sub>4sub>PBr solvent mixtures to give black precipitates of Sb@Ni<sub>12sub>@Sb<sub>20sub><sup>n–sup> salts that give similar Sb@Ni<sub>12sub>@Sb<sub>20sub><sup>–/+sup> parent ions and Sb@Ni<sub>12-ysub>@Sb<sub>20-xsub><sup>–/+sup> degradation series in the respective LDI-TOF MS studies. The solid-state and gas-phase studies of the icosahedral Sb@M<sub>12sub>@Sb<sub>20sub><sup>n–/n+sup> ions show that the clusters can exist in the −4, −3, −1, +1 (M = Pd) and +1, −1 (M = Ni) oxidation states. These multiple-charge-state clusters are reminiscent of redox-active fullerenes (e.g., C<sub>60sub><sup>nsup>, where n = +1, 0, −1, −2, −3, −4, −5, −6).