Physicochemical implications of surface alkylation of high-valent, Lindqvist-type polyoxovanadate-alkoxide clusters
Physicochemical implications of surface alkylation of high-valent, Lindqvist-type polyoxovanadate-alkoxide clusters
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DOI：
10.1039/d0nr09201k
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发表时间：
2021-03-28
期刊：
影响因子：
6.7
通讯作者：
Matson, Ellen M.
中科院分区：
文献类型：
--
作者：
Fertig, Alex A.;Rabbani, S. M. Gulam;Matson, Ellen M.
我们报告了一个罕见的例子，直接烷基化的表面的全体聚氧乙烯簇，利用增加的亲核性的钒氧化物组件。将三氟甲基磺酸甲酯（MeOTf）加成到母体多氧钒酸盐簇[V6 O 13（TRIOL（R））（2）]（2-）（TRIOL =三（羟甲基）甲烷; R = Me，NO2）导致簇核的一个或两个桥接氧化物配体官能化，生成[V6 O 12（OMe）（TRIOL（R））（2）]（1-）和[V6 O 11（OMe）（2）（TRIOL（R））（2）]（2-），分别官能化和未官能化衍生物的电子吸收光谱的比较表明，络合物的总电荷减少导致发生配体至金属电荷转移事件所需的能量减少，同时减轻由封端TRIOL配体施加的诱导效应。有机官能化的多钒酸盐簇的家庭的电化学分析揭示了配体环境和簇核心的氧化还原性质的关系：增加的有机官能化的钒氧化物组装体的表面转化为阳极转移的Lindqvist离子的还原事件。总的来说，这项工作提供了深入了解原子精确修改后的表面结构的纳米级，氧化还原活性的金属氧化物组件的电子效应。
We report a rare example of the direct alkylation of the surface of a plenary polyoxometalate cluster by leveraging the increased nucleophilicity of vanadium oxide assemblies. Addition of methyl trifluoromethylsulfonate (MeOTf) to the parent polyoxovanadate cluster, [V6O13(TRIOL(R))(2)](2-) (TRIOL = tris(hydroxymethyl)methane; R = Me, NO2) results in functionalisation of one or two bridging oxide ligands of the cluster core to generate [V6O12(OMe)(TRIOL(R))(2)](1-) and [V6O11(OMe)(2)(TRIOL(R))(2)](2-), respectively. Comparison of the electronic absorption spectra of the functionalised and unfunctionalised derivatives indicates the decreased overall charge of the complex results in a decrease in the energy required for ligand to metal charge transfer events to occur, while simultaneously mitigating the inductive effects imposed by the capping TRIOL ligand. Electrochemical analysis of the family of organofunctionalised polyoxovanadate clusters reveals the relationship of ligand environment and the redox properties of the cluster core: increased organofunctionalisation of the surface of the vanadium oxide assembly translates to anodic shifts in the reduction events of the Lindqvist ion. Overall, this work provides insight into the electronic effects induced upon atomically precise modifications to the surface structure of nanoscopic, redox-active metal oxide assemblies.