Formation of Mixed‐Valence Luminescent Silver Clusters via Cation‐Coupled Electron‐Transfer in a Redox‐Active Ionic Crystal Based on a Dawson‐type Polyoxometalate with Closed Pores
Formation of Mixed‐Valence Luminescent Silver Clusters via Cation‐Coupled Electron‐Transfer in a Redox‐Active Ionic Crystal Based on a Dawson‐type Polyoxometalate with Closed Pores
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DOI：
10.1002/ejic.202100101
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发表时间：
2021-03
影响因子：
2.3
通讯作者：
Naoya Haraguchi;Tomoki Okunaga;Y. Shimoyama;Naoki Ogiwara;Soichi Kikkawa;S. Yamazoe;M. Inada;T. Tachikawa;S. Uchida
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文献类型：
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作者：
Naoya Haraguchi;Tomoki Okunaga;Y. Shimoyama;Naoki Ogiwara;Soichi Kikkawa;S. Yamazoe;M. Inada;T. Tachikawa;S. Uchida
基于Dawson型聚氧乙烯酸盐（POM）[α-P2 WVI 18 O 62]6-的氧化还原活性离子晶体用于在室温下形成和稳定小的混合价发光银簇，而无需保护配体的帮助。Cs3 H5 [Cr 3 O（OOCH）6（etpy）3]3[α-P2 WV 5 WVI 13 O 62]·5 H2O（etpy=4-乙基吡啶）的还原离子晶体通过与作为还原剂的抗坏血酸钠的阳离子耦合电子转移（CET）反应形成，以提供电子和Cs+作为POM的抗衡阳离子。然后，通过Cs+和Ag+之间的离子交换以及CET反应引入银：X射线光电子能谱和元素分析表明，离子晶体通过电子转移从POM（W5+）氧化为Ag+，并形成[Ag01.5AgI1.5]H4.5[Cr 3 O（OOCH）6（etpy）3]3[α-P2 WV 3 WVI 15 O 62]·7 H2O。光致发光和X射线吸收精细结构表明，银物种以混合价发光团簇形式存在，其平均分子式为[Ag 4]2+，可能呈四面体几何构型。
A redox‐active ionic crystal based on a Dawson‐type polyoxometalate (POM) [α‐P2WVI18O62]6−is utilized to form and stabilize small mixed‐valence luminescent silver clusters without the aid of protecting ligands at room temperature. A reduced ionic crystal of Cs3H5[Cr3O(OOCH)6(etpy)3]3[α‐P2WV5WVI13O62] ⋅ 5H2O (etpy=4‐ethylpyridine) is formed by a cation‐coupled electron‐transfer (CCET) reaction with sodium ascorbate as a reducing reagent to provide electrons and Cs+as counter cations of POM. Then, silver is introduced via ion‐exchange between Cs+and Ag+jointly with CCET reaction: X‐ray photoelectron spectroscopy and elemental analysis show that the ionic crystal is oxidized via electron‐transfer from the POM (W5+) to Ag+, and [Ag01.5AgI1.5]H4.5[Cr3O(OOCH)6(etpy)3]3[α‐P2WV3WVI15O62] ⋅ 7H2O is formed. Photoluminescence and X‐ray absorption fine structure suggest that the silver species exist as mixed‐valence luminescent clusters with an average formula of [Ag4]2+probably in a tetrahedral geometry.