Wolf Silke, Liebertseder Mareike, Feldmann Claus
Institut für Anorganische Chemie, Karlsruhe Institute of Technology (KIT), Engesserstrasse 15, D-76131 Karlsruhe, Germany.
Dalton Trans. 2021 Jun 22;50(24):8549-8557. doi: 10.1039/d0dt03766d.
[BMIm][Sn(AlCl4)3] (1) ([BMIm]: 1-butyl-3-methylimidazolium), [BMPyr][Sn(AlCl4)3] (2) ([BMPyr]: 1-butyl-1-methyl-pyrrolidinium), and [BMIm][Pb(AlCl4)3] (3) are obtained by reaction of SnCl2/PbCl2 in [BMIm]Cl/[BMPyr]Cl/AlCl3-based ionic liquids. The colourless crystals of the title compounds contain infinite 1∞[M(AlCl4)3]n- chains (M: Sn, Pb) that are separated by the voluminous [BMIm]+/[BMPyr]+ cations. The central Sn2+/Pb2+ is coordinated by chlorine in the form of distorted squared anti-prismatic polyhedra. Each Cl atom, in turn, is part of an [AlCl4]- tetrahedron that interlinks Sn2+/Pb2+ to the chain-like building unit. In addition to the novel structural arrangement, all title compounds surprisingly show intense white-light emission. Although Sn2+ and Pb2+ are well-known as dopants in conventional phosphors, efficient luminescence via s-p-transitions of compounds containing Sn2+/Pb2+ in molar quantities and as regular lattice constituents is rare. The emission of [BMIm][Sn(AlCl4)3] and [BMPyr][Sn(AlCl4)3] is very efficient with quantum yields of 51 and 76%, which belong to the highest values known for s-p-based luminescence of Sn2+.
通过在基于[BMIm]Cl/[BMPyr]Cl/AlCl₃的离子液体中使SnCl₂/PbCl₂反应，得到了[BMIm][Sn(AlCl₄)₃]（1）（[BMIm]：1-丁基-3-甲基咪唑鎓）、[BMPyr][Sn(AlCl₄)₃]（2）（[BMPyr]：1-丁基-1-甲基吡咯烷鎓）和[BMIm][Pb(AlCl₄)₃]（3）。标题化合物的无色晶体包含由大量的[BMIm]⁺/[BMPyr]⁺阳离子分隔的无限长的1∞[M(AlCl₄)₃]ⁿ⁻链（M：Sn，Pb）。中心的Sn²⁺/Pb²⁺以扭曲的四方反棱柱体形式由氯配位。每个Cl原子依次是一个[AlCl₄]⁻四面体的一部分，该四面体将Sn²⁺/Pb²⁺连接成链状结构单元。除了新颖的结构排列外，所有标题化合物令人惊讶地都表现出强烈的白光发射。尽管Sn²⁺和Pb²⁺在传统磷光体中作为掺杂剂是众所周知的，但通过含有摩尔量的Sn²⁺/Pb²⁺且作为规则晶格成分的化合物的s-p跃迁实现高效发光是罕见的。[BMIm][Sn(AlCl₄)₃]和[BMPyr][Sn(AlCl₄)₃]的发射非常高效，量子产率分别为51%和76%，这属于已知的基于Sn²⁺的s-p发光的最高值。
