From M(BH4)3 (M = La, Ce) Borohydride Frameworks to Controllable Synthesis of Porous Hydrides and Ion Conductors.
From M(BH4)3 (M = La, Ce) Borohydride Frameworks to Controllable Synthesis of Porous Hydrides and Ion Conductors.
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从 M(BH4)3 (M = La, Ce) 硼氢化物框架到多孔氢化物和离子导体的可控合成。
DOI：
10.1021/acs.inorgchem.6b01526
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发表时间：
2016
影响因子：
4.6
通讯作者：
T. Jensen
中科院分区：
文献类型：
--
作者：
M. Ley;Mathias Jørgensen;R. Černý;Y. Filinchuk;T. Jensen
稀土金属硼氢化物具有许多有趣的性质，如锂离子电导和发光等，这一系列材料得到了很好的开发。然而，以前通过MCl3和LiBH4反应得到M(BH4)3(M=La，Ce)的尝试得到了Lim(BH4)3CL。本文提出了一种合成M(BH4)3(M=La，Ce)的合成方法，通过与二甲基硫形成中间体络合物来分离M(BH4)3。立方C-Ce(BH_4)_3(Fm_3·̅_c)是A(BH_4)_3(A=Y，Sm，Er，Yb)的高温晶型。Ce3+离子的较大尺寸使得开放的REO3型框架结构中的空白可能被像H2这样的小客体分子访问。另一种新的菱面体多晶型r-M(BH4)3(M=La，Ce)是一种封闭形式的骨架，容易产生层错。新化合物M(BH4)3(M=La，Ce)可与LiCl发生加成反应生成LiM(BH4)3CL，又称Li4[M4(BH4)12Cl4]，后者含有独特的四核簇合物[M4(BH4)12Cl4]4-，具有较高的锂离子导电性。这一反应途径为合成具有不同阴离子(X)和金属离子(A)的A4[M4(BH4)12X4](M=La，Ce)化合物和潜在的高离子电导率开辟了一条途径。
Rare earth metal borohydrides show a number of interesting properties, e.g., Li ion conductivity and luminescence, and the series of materials is well explored. However, previous attempts to obtain M(BH4)3 (M = La, Ce) by reacting MCl3 and LiBH4 yielded LiM(BH4)3Cl. Here, a synthetic approach is presented, which allows the isolation of M(BH4)3 (M = La, Ce) via formation of intermediate complexes with dimethyl sulfide. The cubic c-Ce(BH4)3 (Fm3̅c) is isostructural to high-temperature polymorphs of A(BH4)3 (A = Y, Sm, Er, Yb) borohydrides. The larger size of the Ce3+ ion makes the empty void in the open ReO3-type framework structure potentially accessible to small guest molecules like H2. Another new rhombohedral polymorph, r-M(BH4)3 (M = La, Ce), is a closed form of the framework, prone to stacking faults. The new compounds M(BH4)3 (M = La, Ce) can be combined with LiCl in an addition reaction to form LiM(BH4)3Cl also known as Li4[M4(BH4)12Cl4]; the latter contains the unique tetranuclear cluster [M4(BH4)12Cl4]4- and shows high Li-ion conductivity. This reaction pathway opens a way to synthesize a series of A4[M4(BH4)12X4] (M = La, Ce) compounds with different anions (X) and metal ions (A) and potentially high ion conductivity.