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The design of efficient catalysts for photocatalytic CO2 conversion is of great importance for the sustainable development of society. Herein, three polyoxometalate (POM)-based crystalline materials were formulated prepared by substituting transition metals and adjusting solvent acidity with 2-(2-pyridyl) benzimidazole (pyim) as the light-trapping ligand, namely {[SiW12O40][Co(pyim)2]2}·2C2H5OH (SiW12Co2), {[SiW12O40][Ni(pyim)2]2}·2C2H5OH (SiW12Ni2), and {[SiW12O40][Mn(pyim)2]2}·2C2H5OH (SiW12Mn2). X-ray crystallography diffraction analysis indicates that the three complexes exhibit isostructural properties, and form a stable one-dimensional chain structure stabilized by two [M(pyim)2]22+ (M = Co, Ni, and Mn) fragments serving as dual-nodes to the adjacent SiW12 units. A comprehensive analysis of the structural characterization and photocatalytic CO2 reduction properties is presented. Under light irradiation, SiW12Co2 exhibited a remarkable CO generation rate of 10 733 μmol g−1 h−1 with a turnover number of 328, outperforming most of the reported heterogeneous POM-based photocatalysts. Besides, cycling tests revealed that SiW12Co2 is an efficient and stable photocatalyst with great recyclability for at least four successive runs. This study proves that the successful incorporation of diverse transition metals into the POM anion could facilitate the development of highly efficient photocatalysts for the CO2RR. [ABSTRACT FROM AUTHOR]

This paper introduces a numerical approach for the fractional-order Rössler chaotic systems and gives error analysis. The effectiveness of the present method is determined by comparing the numerical results of the high-precision difference scheme and predictor-correctors scheme. Some complex dynamical behaviors for the fractional-order Rössler chaotic systems are shown. [ABSTRACT FROM AUTHOR]

The anionic template method is an effective strategy for synthesizing high-nuclearity transition-lanthanide (3d–4f) heterometallic clusters. Herein, two lanthanide clusters with formulas [Gd20Ni21(μ3-OH)21(CO3)6(IDA)21(C2H4NO2)6(C2O4)3(MoO4)1.5(μ2-OH)1.5(H2O)9]Cl10.5·79H2O (1) and [Tb20Ni21(μ3-OH)21(CO3)6(IDA)21(C2H4NO2)6(C2O4)3(MoO4)(μ2-OH)2(H2O)10]Cl11·32H2O (2) were synthesized by introducing MoO42− anions as templates. Structural analysis indicates that compounds 1 and 2 are isomorphic, featuring a fascinating triangular-shaped metal framework. Magnetic property investigations illuminate the fact that compound 1 exhibits a large −ΔSm of 37.83 J kg−1 K−1 at 3 K for ΔH = 7 T. In particular, it is worth mentioning that compound 1 has an excellent low-field magnetic entropy (−ΔSm = 23.85 J kg−1 K−1 at 2 K, 2 T). [ABSTRACT FROM AUTHOR]

Two polyoxometalate (POM)-based hybrid compounds have been successfully designed and constructed by the hydrothermal method with molecular formulas [K(H2O)2Fe II0.33 Co0.67(H2O)2(DAPSC)]2{[Fe II0.33 Co0.67(H2O)(DAPSC)]2[Fe II0.33 Co0.67(H2O)4]2[Na2Fe III4 P4W32O120]}·21.5H2O (1), and [Na(H2O)2Fe II0.33 Mn0.67(H2O)2(DAPSC)]2{[Fe II0.33 Mn0.67(H2O)(DAPSC)]2[Fe II0.33 Mn0.67(H2O)4]2[Na2Fe III4 P4W32O120(H2O)2]}·24H2O (2) (DAPSC = 2,6-diacetylpyridine bis-(semicarbazone)), respectively. Structural analysis revealed that 1 and 2 consisted of metal–organic complexes containing DAPSC ligands with dumbbell-type inorganic clusters, iron–cobalt (iron–manganese) and some other ions. By utilizing a combination of strongly reducing {P2W12} units and bimetal-doped centres the CO2 photoreduction catalytic capacity of 1 and 2 was improved. Notably, the photocatalytic performance of 1 was much better than that of 2. In CO2 photoreduction, 1 exhibited CO selectivity as high as 90.8%. Furthermore, for 1, the CO generation rate reached 6885.1 μmol g−1 h−1 at 8 h with 3 mg, and its better photocatalytic performance was presumably due to the introduction of cobalt and iron elements to give 1 a more appropriate energy band structure. Further recycling experiments indicated that 1 was a highly efficient CO2 photoreduction catalyst, which could still possess catalytic activity after several cycles. [ABSTRACT FROM AUTHOR]

Chemical fixation of carbon dioxide (CO2) is an energy-saving method for alleviating the greenhouse gas emissions, whereas it persists a challenge posed by the demand for efficient catalysts. Herein, four unprecedented examples of tetradecanuclear vanadium clusters, namely, [(C2H8N2)6(CH3O)8(CH3OH)2VIV10VV4O26] (V14−1), [(C3H10N2)6(CH3O)8(CH3OH)2VIV10VV4O26](V14−2), [(C6H14N2)6(CH3O)8(CH3OH)2VIV10VV4O26]·5H2O (V14−3) and [(C4H12N2O)4(C4H11N2O)2(CH3O)2VIV10VV4O28]·6H2O (V14−4), have been triumphantly designed and constructed under solvothermal conditions. Among them, compounds V14−1–4 are the first cases of tetradecanuclear vanadium clusters without the introduction of inorganic acid radical ions. Two main units [VIV10VV4O26]8+ and [VIV10VV4O28]4+ represent brand-new configurations of tetradecanuclear vanadium clusters. Given the fact that the presence of VIV/VV can potentially facilitate electron transfer and consequently expedite catalytic reactions, we explored the catalytic activities of these compounds. Remarkably, V14−1 was further used as a heterogeneous catalyst in the CO2 fixation into cyclic carbonates under milder conditions (60 °C, 0.5 MPa) and exhibited higher catalytic activity. Also, the experimental results indicated that V14−1 could efficiently catalyze the sulfoxidation, which could fully convert most sulfides within 40 min at room temperature. Moreover, as a stable heterogeneous catalyst employed in CO2 fixation with epoxides and oxidation of sulfides, V14−1 could be consecutively used multiple cycles without losing its catalytic activity. [ABSTRACT FROM AUTHOR]

It is a meaningful and challenging work for structural and synthetic chemists to isolate nano-sized high-nuclearity cluster-molecules. In this work, two largest hetero-metallic nano-clusters Gd158Co38 were obtained via the "multi-anions-template" method. Different from the reported giant hollow-nano-clusters, the Ln158 core in Gd158Co38 (the protein-sized nano-clusters, ca. 4.3 nm × 3.6 nm × 3.5 nm) has the highest Ln nuclear number, which is integrated by twelve halide ions (with the form of icosahedron) as key templates, while Co ions (as 3d metals) are located in its periphery. This emergence indicates a novel structure form of non-open Ln-containing high-nuclearity clusters, and affords a consummate pattern to analyse and assemble the complex cluster-molecules. In addition, Gd158Co38@Cl12 breaks the record magnetic entropy change of 3d–4f clusters with −ΔSmmax = 46.95 J kg−1 K−1 at 7.0 T, 2.0 K. [ABSTRACT FROM AUTHOR]

Carbon dioxide (CO2) and the combustion of sulfide in gasoline are the main causes of air pollution. A great deal of attention has been paid to solving the problem and the catalytic reaction seems to be a decent choice. Due to the high-density of Lewis acidic active sites, polyoxometalates are undoubtedly an ideal choice for the sulfur oxidation reaction. With the reasons foregoing, two novel Zn-capped polyoxometalate-based organic–inorganic hybrids, {[α-PMo V2 Mo VI10 O39(OH)Zn2][bbbm]3}·0.5C2H5OH (1) and TBA2{[ε-PMo V8 Mo VI4 O37(OH)3Zn4][phim]3} (2) ((where bbbm = 1-(4-imidazol-1-ylbutyl) imidazole) and phim = 2-phenylimidazole) were successfully obtained by hydrothermal synthesis. In the two compounds, the N-donor ligands in a monodentate or bidentate coordination mode are directly connected to the Keggin anions by Zn-capped atoms, forming an extended one-dimensional chain. It is noteworthy that compound 2 ends up with an interesting spiral infinite chain possibly thanks to the TBA+ cations residing in gaps as structure-directing agents. Simultaneously, the catalytic properties indicate that compounds 1 and2 as efficient heterogeneous catalysts display a decent catalytic activity in the sulfur removal process. Especially, 2 enabled satisfying catalytic oxidation of dibenzothiophene (DBT) to produce more valuable dibenzothiophene sulfone (DBTO2) at 55 °C, and the conversion almost reached 99%. Besides, compound 2 also shows satisfactory catalytic effectiveness in the oxidation of various epoxides in the CO2 cycloaddition reaction, which suggests that compound 2 has the potential to function as a dual functional material with tremendous prospects in sulfur oxidation and carbon dioxide cycloaddition for the first time. [ABSTRACT FROM AUTHOR]

The photocatalytic reduction of CO2 to chemical fuels is attractive for addressing both the greenhouse effect and the energy crisis, but the key challenge is the design and synthesis of photocatalysts with remarkable performance under visible-light irradiation. Herein, we present two novel polyoxometalate-based organo–metallophosphate frameworks (POMPOs), formulated as [Zn4(PO4)(C7H8N4)6][BW12O40]·2H2O (1) and [Co4(PO4)(C7H8N4)6][BW12O40]·1.5H2O (2). According to the single crystal analysis, both compounds possess host organo–metallophosphate (OMPO) frameworks constructed with PO43− anions, with the Keggin-type polyoxometalate H5BW12O40 (BW12) as a guest encapsulated in these size-matched frameworks. Due to the synergistic combination of the POMs and OMPO frameworks in the system of photocatalytic CO2 reduction, compound 2 could act as a highly efficient cocatalyst in combination with the [Ru(bpy)3]Cl2 complex. The CO generation rate over compound 2 is 10 852 μmol g−1 h−1 with a high selectivity of 93.4%, which is superior to that of most reported POM-based or MOF-based catalysts for CO2 photoreduction. To our knowledge, this is the first report of OMPO frameworks functionally combined with Keggin-type POMs being extended for the photoreduction of CO2 and this affords a new pathway for the efficient photoconversion of CO2 to CO. [ABSTRACT FROM AUTHOR]

Designing and synthesizing lanthanide clusters have always been a research hotspot. Herein, three lanthanide clusters with the formula [Ln8(IN)14(μ3-OH)8(μ2-OH)2(H2O)8]·xH2O (Ln = 1-Gd and x = 11; Ln = 2-Dy and x = 8; Ln = 3-Eu and x = 8) have been isolated in the presence of isonicotinic acid under solvothermal conditions. Structural analysis indicates that those three compounds are isostructural, featuring boat-shaped {Ln8} metal frameworks. Magnetic measurements reveal that 1-Gd exhibits a larger MCE with the maximum −ΔSm value of 31.77 J kg−1 K−1 at 2 K for ΔH = 7 T, while 2-Dy displays slow magnetization relaxation. Besides, the photoluminescence properties of 3-Eu were investigated. [ABSTRACT FROM AUTHOR]

Two captivating {P4Mo6}-based compounds, formulated as (H2bbi)2{[Co2(bbi)][Co2.33(H2O)4][H9.33CoP8Mo12O62]}·4H2O (1) and (H2bbi){[Zn(Hbbi)]2[Zn0.75(bbi)][K2Zn(H2O)4][H8.5ZnP8Mo12O62]} (2) [bbi = 1,1′-(1,4-butanediyl)bis(imidazole)], were successfully synthesized under hydrothermal conditions. Structural analysis demonstrates that compounds 1 and 2 are constructed from hourglass-shaped structures [M(P4Mo6O31)2]n− (M = Co, Zn), which are all made up of molybdophosphates and one transition metal ion as the central connecting node. Compounds 1 and 2 feature three-dimensional (3D) frameworks, which are all connected to form a 3D structure by metal ions and bbi ligands. More interestingly, compound 1 exhibits higher catalytic activity than 2 in CO2 photoreduction due to the suitable energy band structure of Co species in {P4Mo6} clusters. The CO yield was 3261 μmol g−1 with high selectivity in 8 h for compound 1 in photocatalytic CO2 reduction, which is highly promising in the photocatalytic field. Additionally, the photoluminescence properties of 2 were investigated. [ABSTRACT FROM AUTHOR]