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In this study, a new ligand, 5-(4-pyrimidinecarboxamido)-1H-tetrazol (4-H2pat), was synthesized by connecting the pyrimidine group and tetrazole group through an amide bond for the first time, aiming to construct new POM-based metal–organic complexes (POMOCs). By using the ligand 4-H2pat, two new POMOCs, [Cu4(4-pat)2(μ2-OH)(CrMo6(OH)6O18)(H2O)3]·2H2O (1) and [Cu2(4-pat)(β-Mo8O26)0.5(H2O)3] (2), were successfully synthesized under solvothermal and hydrothermal conditions, respectively. The structures were characterized by single crystal X-ray diffraction analysis, IR spectroscopy and powder X-ray diffraction (PXRD). In complex 1, the 1D [Cu4(μ2-OH)(4-pat)2]n3n+ metal–organic chains were connected by μ2-bridging [CrMo6(OH)6O18]3− (CrMo6) anions to construct a 2D layered structure. In complex 2, the 2D [Cu2(4-pat)]n2n+ metal–organic grid framework was consolidated by the μ4-bridging [β-Mo8O26]4− (Mo8) anions. The use of two different POM anion clusters results in the formation of two diverse 2D framework structures. Complexes 1 and 2 can effectively catalyze the oxidation of methyl phenyl sulfide as non-homogeneous catalysts with 97% and 95% conversions, respectively. They can also be used as electrocatalysts to prepare bulk-modified electrodes for detecting Cr(VI) and Fe(III) ions with low detection limits. In addition, the effects of different POMs on the structures and catalytic/electrocatalytic performances of the title complexes were discussed. [ABSTRACT FROM AUTHOR]

By designing and using a new flexible bis(pyrimidine)‐bis(amide) ligand H2L [H2L=N,N′‐bis(4‐pyrimidinecarboxamido)‐1,3‐propane], two new polyoxometalate (POM)‐based metal‐organic complexes (MOCs), H3[Cu2(L)2(PMo12O40)] (1) and [Cu2(H2L)2(β‐Mo8O26)] (2), were synthesized under solvothermal and hydrothermal conditions, respectively. In complexes 1 and 2, metal‐organic units and POM anions are linked together to form two distinct 2D structures. The [PMo12O40]3− (PMo12) anions were used as μ4‐bridging ligands in complex 1 and linked the 1D [Cu(L)]n metal‐organic chains to form a 2D layered structure. The [β‐Mo8O26]4− (Mo8) anions adopted two diverse coordination modes in complex 2 and connected the 1D [Cu(H2L)]n2n+ metal‐organic chains to generate a 2D grid structure. Complexes 1–2 can serve as electrode materials of supercapacitor and show large specific capacitances, up to 1065 and 956 F g−1 at current density of 2 A g−1, respectively, which surpass the parent POM and most of the previous reported POM‐based electrode materials, thus demonstrating the important role of introducing metal‐organic units in improving capacitive performances. Besides, the electrocatalytic redox activities of complexes 1–2 were also studied, both of them can be used as electrochemical sensors to detect Cr(VI) ions. They possess high sensitivity of 0.537 and 0.455 μA μM−1 and low detection limits of 0.16 and 0.33 μM, which are below the maximum content of Cr(VI) in groundwater required by the WHO. [ABSTRACT FROM AUTHOR]

Four new isostructural POM-based metal–organic complexes, [H2X2(L)2(TeMo6O24)(H2O)6]·4H2O [X = Cu (1), Co (2), Ni (3) and Zn (4); L = N,N′-bis(4-pyrimidinecarboxamido)-1,4-benzene], were synthesized with a new rigid bis(pyrimidine)-bis(amide) ligand by varying the central metal under hydrothermal conditions, and characterized by means of single crystal X-ray diffraction, IR spectra and powder X-ray diffraction (PXRD). Complexes 1–4 exhibit similar 2D supramolecular structures based on the [H2X2(L)2(TeMo6O24)(H2O)6] dinuclear units linked through hydrogen bonds. Complexes 1–4 not only show good electrochemical sensing properties for BrO3−, NO2−, hydrogen peroxide and ascorbic acid, but can also be used as adsorbents for the removal of organic dyes such as gentian violet and methylene blue. Among them, complex 4 has the lowest detection limit and best dye adsorption capacity. Alternatively, the effect of central metals on the properties of the title complexes was discussed. [ABSTRACT FROM AUTHOR]

In the presence of the ligand N,N-bis(3-pyrazolamide)-1,2-hexahydrobenzene (H2dpyh), three diverse fascinating structures were constructed from different polyoxometalate (POM) anions and CuII/CoII ions: {Cu8(μ2-OH)2(dpyh)4[CrMo6(OH)5O19](H2O)8}·2[CrMo6(OH)6O18]·4H2O (1), {Co(H2dpyh)[β-Mo8O26]0.5(H2O)} (2) and {Co3(H2dpyh)2[TeMo6O24](H2O)6} (3). Complexes 1–3 were characterized through single crystal X-ray diffraction, IR spectra and powder X-ray diffraction. Single-crystal analysis shows that complexes 1–3 contain internal flexible metal–pyrazole loops and different POMs, which exhibit 1D chain or 2D layer networks, respectively. Directed by the coordination modes of the POM anions and central metals, the shape and size of these metal–pyrazole loops can be tuned, which further influence the final structures and catalytic properties of complexes 1–3. The catalytic activity of these POM-based complexes toward the oxidation of thioether derivatives has been investigated, which proved the effect of metal–pyrazole loops and their final structures on the catalysis of the title complexes as heterogeneous catalysts. [ABSTRACT FROM AUTHOR]

Discovering and engineering herbicide-resistant genes is a crucial challenge in crop breeding. This study focuses on the 4-hydroxyphenylpyruvate dioxygenase Inhibitor Sensitive 1-Like (HSL) protein, prevalent in higher plants and exhibiting weak catalytic activity against many β-triketone herbicides (β-THs). The crystal structures of maize HSL1A complexed with β-THs were elucidated, identifying four essential herbicide-binding residues and explaining the weak activity of HSL1A against the herbicides. Utilizing an artificial evolution approach, we developed a series of rice HSL1 mutants targeting the four residues. Then, these mutants were systematically evaluated, identifying the M10 variant as the most effective in modifying β-THs. The initial active conformation of substrate binding in HSL1 was also revealed from these mutants. Furthermore, overexpression of M10 in rice significantly enhanced resistance to β-THs, resulting in a notable 32-fold increase in resistance to methyl-benquitrione. In conclusion, the artificially evolved M10 gene shows great potential for the development of herbicide-resistant crops., Competing Interests: Competing interests statement:The authors declare no competing interest.