Structural regularity and diversity in hybrids of aromatic thioethers and BiBr3: from discrete complexes to layers and 3D nets
作者:Guo Huang、Yan-Qiong Sun、Zhengtao Xu、Matthias Zeller、Allen D. Hunter
DOI:10.1039/b902490p
日期:——
This paper aims to explore the regular structural patterns and the associated electronic properties of a group of hybrid networks based on BiBr3 and aromatic thioethers, with emphasis on structurally correlating the organic molecules with the BiBr3 aggregates as well as the overall hybrid networks. It was found that extended BiBr3 chains tend to be associated with the slender 4-methylthiophenylalkynyl units, whereas biaryl-based molecules with 4-MeSPh groups directly linked to aromatic cores form hybrids with discrete BiBr3 clusters of variable nuclearities and connectivities. By using multidentate ligands with open geometries, this exploratory study also achieves hybrid BiBr3-aromatic thioether networks with open framework and higher dimensional (e.g., 3D) features, which are potentially amenable to further study on guest exchange experiments. Diffuse reflectance measurements on the powder samples of the hybrids and the organic molecules reveal significant electronic interactions between the inorganic and organic components, with the absorption edges of the hybrids uniformly shifted to lower energies relative to the organic samples. In systems with similar network connectivity and local bonding features, the shifts appear to be proportional to the absorption energy of the organic molecules, suggesting that, in a first order approximation, the absorption edge in the hybrids involves substantially the electronic transitions from the HOMOs of the organic molecules to the LUMOs (or conduction bands) of the inorganic components.
本文旨在探索一组基于 BiBr3 和芳香硫醚的杂化网络的规则结构模式和相关电子特性,重点是从结构上将有机分子与 BiBr3 聚合体以及整个杂化网络联系起来。研究发现,延伸的 BiBr3 链往往与细长的 4-甲硫基炔基单元相关联,而 4-甲硫基炔基直接与芳香族核心相连的双芳基分子则与核度和连接度可变的离散 BiBr3 簇形成杂交。通过使用具有开放几何结构的多叉配体,这项探索性研究还实现了具有开放框架和更高维度(如三维)特征的 BiBr3-芳香族硫醚杂化网络,这有可能促进客体交换实验的进一步研究。对混合物和有机分子粉末样品进行的漫反射测量显示,无机成分和有机成分之间存在显著的电子相互作用,相对于有机样品,混合物的吸收边缘均匀地偏移到更低的能量。在具有类似网络连通性和局部成键特征的体系中,这种偏移似乎与有机分子的吸收能量成正比,这表明,在一阶近似中,杂化物的吸收边缘在很大程度上涉及从有机分子的 HOMO 到无机成分的 LUMO(或导带)的电子跃迁。