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Adjusting the bandgap of polyoxo-titanium clusters (PTCs) to enhance their visible light catalytic performance is one of the effective strategies. Herein, three PTCs modified by organic carboxylic acid ligands with different conjugated systems were synthesized in one-step, [Ti6(O3P-Phen)2(OiPr)10(L)2] (OiPr = isopropyl alcohol; L = benzimidazole dicarboxylic acid, Ti6-BIDC; 4-chloromethyl benzoic acid = CMBA, Ti6-CMBA; malonic acid = MA, Ti6-MA), and were used as photocatalysts in the visible light catalytic degradation of tetracycline (50 mL, 50 mg L−1). Ti6-BIDC showed excellent catalytic activity and cycling stability in the degradation of tetracycline. Importantly, the degradation efficiency under real sunlight was 92.4%. The modification of carboxylic acid ligands significantly changed the photoelectric properties and specific surface area of the compounds. In addition, the results of active species trapping experiments demonstrated that the superoxide anion (˙O2−) radical and hole (h+) played dominant roles in TC degradation. The intermediates and possible pathways of TC degradation were analyzed by LC-MS, and the toxicity of the degradation intermediates was evaluated by the Mung bean planting experiment and toxicity estimation software tool (T.E.S.T.). This is the first report on the application of PTCs in photocatalytic degradation of tetracycline, providing new ideas for the degradation of tetracycline. [ABSTRACT FROM AUTHOR]

The "visible" proton‐conducting pathway offers a distinct advantage for researching the mechanism of proton conducting materials at the molecular level and developing new materials. To achieve this, three crystalline materials are constructed via acid–base chemistry based on phosphomolybdic acid and diversfied guanidine, namely, (CN3H6)6(PMo12O40)2·H2O (GH–PMo12), (CN4H7)3(PMo12O40)·H2O (AGH–PMo12), and (CN5H8)3(PMo12O40)·3.5H2O (DAGH–PMo12). Proton conductivity of GH–PMo12 in the [001] direction reaches up to 0.19 S cm−1 at 85 °C and 98% RH, as elucidated by impedance studies of single crystals. The clear proton transport path is proposed through the analysis of single crystal structure. Moreover, impedance studies of powder crystals reveal that the proton conductivity of GH–PMo12 is higher than that of the other two compounds. The underlying reasons for this result are clarified through the analysis of the pKa, proton density, and spatial structure. Additionally, GH–PMo12 is fabricated into composite membrane with a peak proton conductivity of 5.31 × 10−2 S cm−1, which exhibits promising potential for real‐world applications. [ABSTRACT FROM AUTHOR]

Two three-dimensional frameworks based on the {P4Mo6} unit, H(4,4′-bipy)2[Fe4(PO4)(H2O)4Na6][Fe6(H2O)4][(Mo6O12)(HPO4)3(PO4)(OH)3]4·5H2O (4,4′-bipy = 4,4′-bipyridine) (1) and H3(C12H14N2)4[Fe4(PO4)(H2O)4Na4][Fe2(Mo6O12(HPO4)3(PO4)(OH)3)4]·6H2O (2) were successfully synthesized by varying the solvent. The extended structures of the two compounds were formed by transition metal Fe(II) ions bridging the {P4Mo6}-based tetrameric clusters around [NaXFe4(PO4)] (X = 6 (1), or X = 4 (2)) core. The 4,4′-bipy molecules and in situ generated methyl viologen cations as templates induce the formation of two three-dimensional structures, an 8-connected bcu topology framework for 1 and a 4-connected 2-fold interpenetrating diamond-like topological network for 2, respectively. Additionally, multiform hydrogen bonds are found in the framework and also play an important role in stabilizing the structure. The proton conduction mechanism of the two compounds can be mainly classified as the Grotthuss mechanism; the proton conductivity values are 1.06 × 10−3 S cm−1 for 1 and 3.13 × 10−3 S cm−1 for 2 at 75 °C under 98% relative humidity. The visible-light photocatalytic activity was evaluated by photocatalytic decomposition of Cr(VI) and MB dye, and the removal ratios can reach 95.6% (1) and 82% (2) for Cr(VI), and 98% (1) and 99% (2) for MB. [ABSTRACT FROM AUTHOR]