Santner Silke, Yogendra Sivathmeehan, Weigand Jan J, Dehnen Stefanie
Fachbereich Chemie und Wissenschaftliches Zentrum für Materialwissenschaften, Philipps-Universität Marburg, Hans-Meerwein-Strasse, 35032, Marburg, Germany.
Professur für Anorganische Molekülchemie, TU Dresden, Mommsenstrasse 4, 01062, Dresden, Germany.
Chemistry. 2017 Feb 10;23(9):1999-2004. doi: 10.1002/chem.201605988. Epub 2017 Jan 23.
The synthesis of anionic chalcogenidometalate superspheres can be achieved from [Ge Se ] salts and SnCl in ionic liquids with 1-alkyl-(2,)3-(di)methylimidazolium cations, denoted as (C (C )C Im) (alkyl = butyl for n=4, hexyl for n=6, octyl for n=8). Their formation is apparently independent from the lengths of the C chain, and the presence or absence of a second methyl group at the ionic liquid cation (that are exchanged for alkali metal cations in precursor compounds during the reactions), although this may appear counterintuitive. In contrast, and equally counterintuitive, the ionic liquid anion was found to play a crucial role for both the general observability as well as the crystal yield and quality of the products, although they are not part of the product: a minimum content of chloride is needed, while ionic liquids with [BF ] anions alone do not support the product formation/crystallization. The observation suggests a subtle equilibrium of SnCl with according halidostannate anions that decreases the reactivity of the tin source. The finding is of particular interest, as chloride anions were shown to have been major impurities of former "chloride-free" ionic liquid charges, which potentially led to irreproducible synthesis protocols in the literature.
在含有1-烷基-（2,3-）（二）甲基咪唑阳离子（表示为（Cₙ（Cₘ）C Im），其中n = 4时烷基为丁基，n = 6时为己基，n = 8时为辛基）的离子液体中，由[GeSe]盐和SnCl₂可以实现阴离子硫属元素金属酸盐超球的合成。它们的形成显然与碳链长度以及离子液体阳离子上第二个甲基的存在与否无关（在反应过程中，这些甲基在 precursor 化合物中会被碱金属阳离子取代），尽管这可能看起来违反直觉。相反，同样违反直觉的是，发现离子液体阴离子对于产物的总体可观察性以及晶体产率和质量都起着关键作用，尽管它们不是产物的一部分：需要最低含量的氯离子，而仅含有[BF₄]阴离子的离子液体不支持产物的形成/结晶。这一观察结果表明SnCl₂与相应的卤化锡酸根阴离子之间存在微妙的平衡，这降低了锡源的反应性。这一发现特别有趣，因为氯离子已被证明是以前“无氯”离子液体批次中的主要杂质，这可能导致文献中合成方案的不可重复性。
