Aggregation-Mode-Dependent Optical Properties of Cationic Gold Clusters: Formation of Ordered Assemblies in Solution and Unique Optical Responses
Aggregation-Mode-Dependent Optical Properties of Cationic Gold Clusters: Formation of Ordered Assemblies in Solution and Unique Optical Responses
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DOI：
10.1021/acs.jpcc.0c05220
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发表时间：
2020-07
影响因子：
3.7
通讯作者：
Mizuho Sugiuchi;Mingzhe Zhang;Yusaku Hakoishi;Yukatsu Shichibu;N. Horimoto;Y. Yamauchi;Y. Ishida;K. Konishi
中科院分区：
文献类型：
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作者：
Mizuho Sugiuchi;Mingzhe Zhang;Yusaku Hakoishi;Yukatsu Shichibu;N. Horimoto;Y. Yamauchi;Y. Ishida;K. Konishi
在这篇文章中，我们报道了双膦配体的[Au6]2+团簇在有机溶剂中聚集的研究结果，并强调了有序团簇的形成与J聚集体的吸收响应和光致发光增强有关。硝酸盐在甲醇/水(10/90v/v)中聚集后，可见吸收带较单体形式有一定的红移。聚集体在溶液中的X射线衍射图给出了尖锐的信号，揭示了具有特定取向的有序团簇的形成。从衍射结果估计的短的簇间距离意味着配位层的穿透堆积，这可能有助于团簇跃迁偶极子的激子耦合。在富水条件下的聚集也导致了近红外光致发光的增强，这可以归因于团簇分子在聚集体中的紧密堆积对分子运动/振动的限制。对水含量和反阴离子影响的详细考察表明，存在几种不同光学性质的聚集模式。这项工作展示了“团簇”的独特性质，并展示了配位金属团簇在基于聚集的功能材料设计中的潜在用途。
In this Article, we report the results of studies on the aggregation of a diphosphine-ligated [Au6]2+ cluster in aqueous organic solvents, and we highlight the formation of ordered cluster assemblies associated with the J-aggregate-like absorption response and photoluminescence enhancement. Upon aggregation in methanol/water (10/90 v/v), the nitrate salt exhibited a definite red shift of the visible absorption band from the monomeric form. X-ray diffraction profiles of the aggregate in solution gave sharp signals, which revealed the formation of ordered cluster assemblies with particular orientation. The short intercluster distances, as estimated from the diffraction results, imply the interpenetrative packing of the ligand layers, which may contribute to the excitonic coupling of the cluster transition dipoles. The aggregation at the water-rich conditions also caused the enhancement of the near-IR photoluminescence emission, which can be ascribed to the restriction of molecular motion/vibration resulting from the close packing of the cluster molecules in the aggregates. The detailed inspections on the effects of the water contents and counteranions indicated that there are several aggregation modes with different optical features. This work showcases the unique properties of “cluster of clusters” and shows the potential utility of coordinated metal clusters in the design of aggregation-based functional materials.