Mixed Si/Ge Nine-Atom Zintl Clusters: ESI Mass Spectrometric Investigations and Single-Crystal Structure Determination of Paramagnetic [Si9鈥?i>xGex]3鈥?/sup>

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• 作者：Markus Waibel ; Thomas F. F盲ssler
• 刊名：Inorganic Chemistry
• 出版年：2013
• 出版时间：May 20, 2013
• 年：2013
• 卷：52
• 期：10
• 页码：5861-5866
• 全文大小：308K
• 年卷期：v.52,no.10(May 20, 2013)
• ISSN：1520-510X

文摘

Mixed Si/Ge compounds are of special interest as potential materials for photovoltaic applications. In order to evaluate the usage of soluble precursor compounds, we investigated the synthesis of heteroatomic nine-atom clusters that consist of Si and Ge atoms through dissolution of the ternary Zintl phases K₁₂Si_17鈥?i>xGe_x (x = 9, 12) and Rb₁₂Si_17鈥?i>xGe_x (x = 9). Electrospray ionization (ESI) mass spectrometry demonstrates the presence of mixed Si_9鈥?i>xGe_x clusters in acetonitrile solution. From ammonia solutions of the ternary phases, four compounds that contain 3-fold negatively charged [Si_9鈥?i>xGe_x]^{3鈥?/sup> clusters are obtained. The paramagnetic behavior is confirmed by EPR spectroscopy. [E₉]3鈥?/sup> Zintl clusters are considered as intermediate structures in the stepwise oxidation of [E₉]4鈥?/sup> clusters to novel element allotropes (E = Si鈥揚b). The structure of Rb[Rb-crypt]₂[Si_2.3(1)Ge_6.7(1)](NH₃)₇ and the isostructural structures of [Rb-crypt]₃[Si_2.2(1)Ge_6.8(1)](NH₃)₈, [K-crypt]₃[Si_2.4(1)Ge_6.6(1)](NH₃)_8.5, and [K-crypt]₃[Si_4.6(1)Ge_4.4(1)](NH₃)_8.5 are investigated by single-crystal X-ray diffraction (crypt = 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]-hexacosane). The Si/Ge ratio of the products correlates with the composition of the ternary precursor phases.}