{BW12O40} Hybrids Modified by in Situ Synthesized Rigid Ligand with Supercapacitance and Photocatalytic Properties.

Organic rigid ligand-modified polyoxometalate-based materials possess complex and diverse structures, promising electrochemical energy storage properties and outstanding photocatalytic capabilities. Hence, two new [BW12O40]5-(abbreviated as {BW12O40})-based inorganic-organic hybrids [{Cu(en)2(H2O)}][{Cu(pdc)(en)}{Cu(en)2}(BW12O40)]·2H2O (1) and [{CuI5(pz)6(H2O)4}(BW12O40)] (2) (pdc = 2-picolinate, en = ethylenediamine, pz = pyrazine) were successfully synthesized through a hydrothermal method. Among them, pdc and pz were obtained by in situ transformation from 2,6-pyridinedicarboxylic acid (H2 pydc) and 2,3-pyrazinedicarboxylic acid (H2pzdc), respectively. In compound 1, the {BW12O40} clusters as an intermediate junction connect with {Cu(pdc)(en)}{Cu(en)2} and {Cu(en)2(H2O)} to form monomers, which in turn form supramolecular chains, sheets, and space network via hydrogen bonding. The {BW12O40} clusters are packed into copper-pyrazine frameworks in compound 2, and a unique polyoxometalate-based metal organic frameworks (POMOFs) structure with a new topology of {12}2{6.123.142}2{62.12.142.18}{62.123.16}{6}6 is formed via covalent bonds. When used as electrode materials for supercapacitors, the values of specific capacitance are 651.56 F g-1 for 1-GCE and 584.43 F g-1 for 2-GCE at a current density of 2.16 A g-1 and good cycling stability (90.94%, 94.81% of the initial capacity after 5000 cycles at 15.12 A g-1, respectively). The kinetic analysis reveals that surface capacitance plays a major role. Furthermore, both compounds can effectively degrade Rhodamine B (RhB) and Methylene blue (MB), showing the outstanding photocatalytic performance.

{BiW8 O30 } Exerts Antitumor Effect by Triggering Pyroptosis and Upregulating Reactive Oxygen Species.

We successfully synthesized {BiW8 }, a 10-nuclear heteroatom cluster modified {BiW8 O30 }. At 24 h post-incubation, the IC50 values of {BiW8 } against HUVEC, MG63, RD, Hep3B, HepG2, and MCF7 cells were 895.8, 127.3, 344.3, 455.0, 781.3, and 206.3 µM, respectively. The IC50 value of {BiW8 } on the MG63 cells was more than 2-fold lower than that of the other raw materials. Through morphological and functional features, we demonstrated pyroptosis as a newly identified mechanism of cell death induced by {BiW8 }. {BiW8 } increased 2-fold reactive oxygen species (ROS) levels in MG63 cells at 24 h post-incubation. Compared with 0 h, the glutathione (GSH) content decreased by 59, 65, 75, 94, and 97 % at 6, 12, 24, 36 and 48 h post-incubation, respectively. Furthermore, multiple antitumor mechanisms of {BiW8 } were identified via transcriptome analysis and chemical simulation, including activation of pyroptosis, suppression of GSH generation, depletion of GSH, and inhibition of DNA repair.

Inhibition of Mitochondrial ATP Synthesis and Regulation of Oxidative Stress Based on {SbW8 O30 } Determined by Single-Cell Proteomics Analysis.

The 10-nuclear heteroatom cluster modified {SbW8 O30 } was successfully synthesized and exhibited inhibitory activity (IC50 =0.29 µM). Based on proteomics analysis, Na4 Ni2 Sb2 W2 -SbW8 inhibited ATP production by affecting the expression of 16 related proteins, hindering metabolic functions in vivo and cell proliferation due to reactive oxygen species (ROS) stress. In particular, the low expression of FAD/FMN-binding redox enzymes (relative expression ratio of the experimental group to the control=0.43843) could be attributed to the redox mechanism of Na4 Ni2 Sb2 W2 -SbW8 , which was consistent with the effect of polyoxometalates (POMs) and FMN-binding proteins on ATP formation. An electrochemical study showed that Na4 Ni2 Sb2 W2 -SbW8 combined with FMN to form Na4 Ni2 Sb2 W2 -SbW8 -2FMN complex through a one-electron process of the W atoms. Na4 Ni2 Sb2 W2 -SbW8 acted as catalase and glutathione peroxidase to protect the cell from ROS stress, and the inhibition rates were 63.3 % at 1.77 µM of NADPH and 86.06 % at 10.62 µM of 2-hydroxyterephthalic acid. Overall, our results showed that POMs can be specific oxidative/antioxidant regulatory agents.

A Facile Grinding Method for the Synthesis of 3D Ag Metal-Organic Frameworks (MOFs) Containing Ag6 Mo7 O24 for High-Performance Supercapacitors.

Successful synthesis of three kinds of dynamically stable compounds by a simple grinding method is reported, giving Ag6 Mo7 O24 , Ag-BTC (Ag-MOF, BTC=benzene-1,3,5-tricarboxylic acid), and {Ag6 Mo7 O24 }@Ag-MOF metal-organic frameworks (MOFs). According to the electrochemical dynamic analysis, these materials have pseudocapacitor behavior and high capacitance. The unique nanorod structure of {Ag6 Mo7 O24 }@Ag-MOF provides more active sites, faster ion/electron transfer, and electrolyte diffusion pathways, resulting in excellent specific capacitance (971 F g-1 ) higher than the other compounds. {Ag6 Mo7 O24 }@Ag-MOF (glassy carbon electrode) also has an excellent rate ability (60.1 %) and long cycle stability (98 % retention after 5000 cycles). In addition, the fully symmetrical button battery (with nickel foam as the current collector) fabricated with {Ag6 Mo7 O24 }@Ag-MOF delivers an energy density of 11.1 Wh kg-1 at 600.1 Wh kg-1 coupled with excellent cycling stability (86.4 %) at 1.2 V. These results demonstrate a new simple grinding method to prepare polyoxometalate-based metal-organic frameworks (POMOFs) for high-performance materials.

Efficient visible light-driven water oxidation catalysts based on B-ß-{BiW8O30} and unique 14-nuclear hetero-metal sandwich unit.

A sandwich tungstobismuthate with new topology based on {B-ß-BiW8O30}-cluster and unique 14-nuclear sandwich unit is reported as a high-efficiency visible light-driven water oxidation catalyst containing extended hetero-metal oxygen layer. At optimal conditions, the turn-over number (TON) of the title compound can reach 205.5 with O2 yield of 32.88%.