Search

By targeted introduction of 6-nitrobenzimidazole into polymolybdate, two new polymolybdate-based copper-organic complexes were successfully synthesized, namely {Cu2(6-nbm)4[β-Mo8O26](H2O)2}·(6-nbm)2·4H2O (1) and H2{Cu2(6-nbm)4[TeMo6O24](H2O)4}·(6-nbm)2·4H2O (2) (6-nbm = 6-nitrobenzimidazole), and structurally characterized by single-crystal X-ray diffraction, IR spectroscopy and powder X-ray diffraction (PXRD). Complexes 1 and 2 are both one-dimensional (1D) chain structures, in which 6-nbm hangs on the 1D chain in a monodentate coordination mode, appearing with a butterfly-like configuration. Complexes 1 and 2 both display bifunctional electrocatalytic activity toward the reduction of KNO2, as well as the oxidation of ascorbic acid (AA). The title complexes, used to prepare bulk-modified carbon paste electrodes (1–CPE and 2–CPE), can be used as electrochemical sensors, which show lower detection limit, good selectivity and anti-interference ability. In addition, the carbon cloth-based electrode modified with complex 1 (1–CC) exhibits ideal capacitance and long-term cycle stability, indicating that complex 1 can be a potential candidate for a pseudocapacitive material. In addition, complexes 1 and 2 show catalytic activity for the CO2 reduction reaction. [ABSTRACT FROM AUTHOR]

Poplars are widely distributed in the northern hemisphere and have good adaptability to different living environments. The accumulation of genome and transcriptome data provides a chance to conduct comparative genomics and transcriptomics analyses to elucidate the evolutionary patterns of Populus phylogeny. Transcript sequences of eight Salicaceae species were downloaded from public databases. All of the pairwise orthologues were identified by comparative transcriptome analysis in these species, from which we constructed a phylogenetic tree and estimated the rate of divergence. The divergence times of the phylogenetic clades were mainly estimated during the Middle Miocene Climate Transition (MMCT) to Quaternary Ice Age. We also identified all of the fast-evolving sequences of positive selection and found some resistance genes that were related to environmental factors. Our results suggest that drought-, H2O2- and cold-stress genes are involved in positive selection along with the paleoclimate change. These data are useful in elucidating the evolutionary patterns and causes of speciation in the Populus lineage.

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]

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]

A new Anderson‐type polyoxometalate(POM)‐based one‐dimensional metal‐organic complex, namely, H2[Cu2[AlMo6(OH)6O18]2(3‐bpah)4(H2O)4] ⋅ 6H2O (1) (3‐bpah=N−N′‐bis(3‐pyridinecarboxamide)‐1,2‐cyclohexane) was synthesized by hydrothermal method. Implement basic characterization operations of single crystal X‐ray diffraction, IR spectroscopy, X‐ray powder diffraction and thermogravimetric analysis were performed. Complex 1 possesses not only the typical electrochemical behavior of the Anderson‐type polyoxoanion, but also excellent electrochemical stability. The carbon paste electrode bulk modified by complex 1(1‐CPE) can be used as an ampere sensor to detect potassium nitrite. The carbon cloth‐based electrode fabricated by complex 1(1‐CC)was capable of being used as electrocatalyst for hydrogen evolution reaction, the overpotential is 480 mV at the current density of 10 mA cm−2. 1‐CC can also be used as capacitor electrode, which shows an area capacitance of 293 mF cm−2 in 0.1 M H2SO4 solution and up to 10 hours of life stability. It can maintain 89.7 % of the capacitance after 1000 cycles of constant current charge/discharge. [ABSTRACT FROM AUTHOR]

Nitrofurans are important synthetic broad-spectrum antibacterial drugs with the basic structure of 5-nitrofuran. Due to their toxicity, it is essential to develop a sensitive sensor with strong anti-interference capabilities for their detection. In this work, two {P 4 Mo 6 O 31 } 12- -based compounds, [H 4 (HPTTP)] 2 {Cu I [Mo 12 O 24 (OH) 6 (PO 4 ) 3 (HPO 4 )(H 2 PO 4 ) 4 ]}· x H 2 O ( x = 13 for ( 1 ), 7 for ( 2 ); HPTTP = 4,4',4″,4‴-(1 H -pyrrole-2,3,4,5-tetrayl)tetrapyridine), exhibiting similar coordination but distinct stacking modes. Both compounds were synthesized and used for the electrochemical detection of nitrofuran antibiotics. The tetrapyridine-based ligand was generated in situ during assembly, and its potential mechanism was discussed. Composite electrode materials, formed by mixing graphite powder with compounds 1 - 2 and physically grinding them, proved to be highly effective in the electrochemical trace detection of furazolidone (FZD) and furaltadone hydrochloride (FTD·HCl) under optimal conditions. Besides, the possible electrochemical detection mechanisms of two nitro-antibiotics were studied.

In this work, a new α-γ-type [Mo 8 O 26 ] 4- anion was first synthesized and characterized by single-crystal X-ray diffraction analysis and was obtained by introducing molybdate to the synthesis of metal-organic complex (MOC) under hydrothermal conditions. An octamolybdate-based MOC, namely, {[Cu 8 (H 2 O) 6 ](dpyh) 4 (α-γ-Mo 8 O 26 ) }·(β-Mo 8 O 26 )·8.5H 2 O (H 2 dpyh = N , N -bis(3-pyrazolamide)-1,2-hexahydrobenzene), was obtained. The α-γ-type [Mo 8 O 26 ] 4- anion was composed of four MoO 6 octahedra and four MoO 5 trigonal bipyramids by sharing their edges and corners. The title complex exhibited a 1D structure in which an α-γ-type [Mo 8 O 26 ] 4- anion was connected with [Cu 4 (dpyh) 2 ] units in a staggered manner. Under optimized conditions, complex 1 as the catalyst can achieve a highly efficient conversion (more than 99%) of thioanisole within 30 min and above 99% selectivity toward sulfoxide. Furthermore, efficient catalytic oxidation of thioether derivatives was also performed with 1 as the catalyst. In addition, the stable electrochemical sensing performance and adsorption capacity toward organic dyes were tested.