Hebei Key Laboratory of Organic Functional Molecules, National Demonstration Center for Experimental Chemistry Education, Testing and Analysis Center, Hebei Key Laboratory of Inorganic Nanomaterials, College of Chemistry and Materials Science, Hebei Normal University, Shijiazhuang 050024, Hebei, P. R. China.
Inorg Chem. 2022 Dec 19;61(50):20596-20607. doi: 10.1021/acs.inorgchem.2c03472. Epub 2022 Dec 2.
Photocatalytic organic transformation derived by functionalized polyoxometalate (POM)-based metal-organic frameworks provides a feasible route for fine chemical synthesis. Herein, three kinds of photoactive three-dimensional silver-containing polyoxotungstate frameworks are synthesized with the formulas [AgL(OH)][Na(HO)][PWO]·HO (), [AgL][SiWO] (), and [Ag(HO)][AgL][BWO]·9HO () (L = 1,4-di(4H-1,2,4-triazol-4-yl)benzene). In compounds -, the cationic Ag-triazole clusters with diverse nuclei serve as nodes to assemble with rigid bridging ligands (L) and polyoxoanions to extend into stable three-dimensional frameworks, in which Keggin-type anions act as guests or pendants. When using them as heterogeneous photocatalysts, compounds - show high catalytic activity and selectivity for the photocatalytic aerobic oxidation of benzyl alcohol to benzoic acid under 10 W 365 nm light irradiation. Among them, compound exhibits the highest performance with ca. 99% benzyl alcohol conversion and 99% selectivity of benzoic acid in 9 h. Compounds and show ca. 79 and 88% conversions of benzyl alcohol, respectively, which are higher than those of the individual Keggin-type precursors. Moreover, mechanism investigation suggests that the synergistic cooperation occurring between cationic Ag-triazole clusters and Keggin-type polyoxoanions modulates the energy band structures of compounds -, resulting in the efficient separation of photogenerated carriers and accelerating the aerobic oxidation of benzyl alcohol. This work provides some important guidance for the design and development of efficient POM-based photocatalysts for practical organic transformation.
功能化多金属氧酸盐（POM）基金属有机骨架的光催化有机转化为精细化学品合成提供了可行的途径。本文合成了三种具有化学式[AgL(OH)][Na(HO)][PWO]·HO ()、[AgL][SiWO] ()和[Ag(HO)][AgL][BWO]·9HO ()（L=1,4-二(4H-1,2,4-三唑-4-基)苯）的光活性三维含银多钨酸盐骨架。在化合物-中，具有不同核的阳离子 Ag-三唑簇作为节点与刚性桥联配体（L）和多氧阴离子组装，扩展成稳定的三维骨架，其中 Keggin 型阴离子作为客体或悬垂基。当它们用作多相光催化剂时，化合物-在 10 W 365nm 光照射下对苄醇的光催化有氧氧化具有高催化活性和选择性，生成苯甲酸。其中，化合物在 9 小时内表现出约 99%的苄醇转化率和 99%的苯甲酸选择性，表现出最高的性能。化合物和分别显示出约 79%和 88%的苄醇转化率，高于单个 Keggin 型前体的转化率。此外，机理研究表明，阳离子 Ag-三唑簇和 Keggin 型多氧阴离子之间发生的协同合作调节了化合物-的能带结构，导致光生载流子的有效分离并加速苄醇的有氧氧化。这项工作为设计和开发用于实际有机转化的高效 POM 基光催化剂提供了一些重要的指导。
