银(I)配位聚合物修饰Preyssler型多金属氧酸盐的高维、高连接结构的组装及性质

以AgNO3、K12.5Na1.5[Na P5W30O110]·15H2O及柔性配体1,1′-双(3,5-二甲基-1H-吡唑)甲烷(H2bdpm)为原料,利用水热合成方法合成了1个新的基于单核银为中心的Preyssler多酸阴离子的有机-无机杂化化合物:[Ag13(H2bdpm)8(H2O)5(HAg P5W30O110)]·2H2O(1),并通过元素分析、红外光谱、热重分析和X-射线单晶衍射等分析手段对化合物1进行了表征.X-射线单晶结构分析表明,该化合物属于三斜晶系,P1空间群,晶胞参数:a=19.135(5),b=20.313(5),c=28.400(5),Z=2,R1=0.0550,w R2=0.1542.化合物1包含罕见的以单核银为中心的Preyssler型多酸阴离子,该阴离子通过金属银连接形成二维无机层.相连的二维层之间通过多种Ag-H2bdpm金属有机亚单元进一步连接形成三维框架.该化合物最大的结构特点在于Preyssler型多酸阴离子的高连接(十八连接)以及Ag(I)离子多样的配位模式.     

Luminescent Nanofibers Fabricated from Phenanthroimidazole Derivatives by Organogelation: Fluorescence Response towards Acid with High Performance

Nanofibers based on phenanthroimidazole derivatives PCC , PDC , and PSC were fabricated by organogelation processes, and their fluorescence sensory properties towards acid were investigated. It was found that the emission of PCC in the nanofiber‐based film could be quenched significantly upon exposure to gaseous TFA due to the formation of protonated PCC , in which ICT (intramolecular charge transfer) would occur. On the other hand, TFA vapor led to the emitting colors of PDC and PSC in the nanofiber‐based films to turn to yellow and green from sky blue and blue, respectively. Additionally, we found that the decay times of PCC were 0.1 s and 1.9 s in probing the saturated vapor of TFA in nanofiber‐based film and in spin‐coated film, respectively. The results suggested that the high surface‐to‐volume ratio and large interspace in the nanofiber‐based networks favored the enhanced adsorption, accumulation, and diffusion of gaseous molecules, resulting in such a high performance.     

Rogue waves in baroclinic flows

We investigate an AB system, which can be used to describe marginally unstable baroclinic wave packets in a geophysical fluid. Using the generalized Darboux transformation, we obtain higher-order rogue wave solutions and analyze rogue wave propagation and interaction. We obtain bright rogue waves with one and two peaks. For the wave packet amplitude and the mean-flow correction resulting from the self-rectification of the nonlinear wave, the positions and values of the wave crests and troughs are expressed in terms of a parameter describing the state of the basic flow, in terms of a parameter responsible for the interaction of the wave packet and the mean flow, and in terms of the group velocity. We show that the interaction of the wave packet and mean flow and also the group velocity affect the propagation and interaction of the amplitude of the wave packet and the self-rectification of the nonlinear wave.     

Novel Bi2MoO6 Nanosheets/Vertical TiO2 Nanorods Arrays Heterojunction with Enhanced Photoelectrochemical Performance under Visible Light Irradiation

Novel Bi₂MoO₆/TiO₂ heterojunction was fabricated by growing Bi₂MoO₆ nanosheets arrays on the vertically aligned TiO₂ nanorods arrays via a two-step solvothermal method. The obtained Bi₂MoO₆/TiO₂ hierarchical heterojunction showed excellent visible light photoelectrochemical performance. Compared with the pure TiO₂ and Bi₂MoO₆, the photocurrent density of the heterojunction was increased 57 and 29 times, respectively. Furthermore, the hydrogen generation rate of the Bi₂MoO₆/TiO₂ for photoelectrocatalytic water-splitting was about 6 times higher than that of the pure Bi₂MoO₆. The improved performance can be attributed to the synergistic effects of enhanced absorption of visible light, increase of migration rate and separation efficiency of photo-induced carriers.     

Effect of furan π-bridge on the photovoltaic performance of D-A copolymers based on bi(alkylthio-thienyl)benzodithiophene and fluorobenzotriazole

The medium band gap donor-acceptor(D-A) copolymer J61 based on bi(alkylthio-thienyl)benzodithiophene as donor unit and fluorobenzotriazole as acceptor unit and thiophene as π-bridge has demonstrated excellent photovoltaic performance as donor material in nonfullerene polymer solar cells(PSCs) with narrow bandgap n-type organic semiconductor ITIC as acceptor.For studying the effect of π-bridges on the photovoltaic performance of the D-A copolymers,here we synthesized a new D-A copolymer J61-F based on the same donor and acceptor units as J61 but with furan π-bridges instead of thiophene.J61-F possesses a deeper the highest occupied molecular orbital(HOMO) level at-5.45 eV in comparison with that(-5.32 eV) of J61.The non-fullerene PSCs based on J61-F:ITIC exhibited a maximum power conversion efficiency(PCE) of 8.24%with a higher open-circuit voltage(V_(oc)) of 0.95 V,which is benefitted from the lower-lying HOMO energy level of J61-F donor material.The results indicate that main chain engineering by changing π-bridges is another effective way to tune the electronic energy levels of the conjugated D-A copolymers for the application as donor materials in non-fullerene PSCs.     

<Emphasis Type="Italic">Tetra</Emphasis>-armed conjugated microporous polymers for gas adsorption and photocatalytic hydrogen evolution

Two novel tetra-armed conjugated microporous polymers with different geometries have been designed and synthesized via Suzuki-Miyaura cross coupling polycondensation. Both polymers are stable in various organic solvents tested and are thermally stable. The pyrene-containing polymer of PrPy with the rigid pyrene unit shows a higher Brunauer-Emmet-Teller specific surface area of 1219 m² g^?1 than the tetraphenylethylene-containing polymer of PrTPE (770 m² g^?1), which leads to a high CO₂ uptake ability of 3.89 mmol g^?1 at 1.13 bar/273 K and a H₂ uptake ability of 1.69 wt% at 1.13 bar/77 K. The photocatalytic hydrogen production experiments revealed that PrPy also shows a better photocatalytic performance than PrTPE due to the higher conjugation degree and planar structure, the broader UV-visible (UV-Vis) absorption, the lower photoluminescence lifetime, and the higher specific surface area.     

关于泰勒公式及其应用的再认识

本文首先给出了在欧氏空间下泰勒公式及余项的不同表示,之后把泰勒公式进一步推广到巴拿赫空间,给出了多维与无限维空间上算子形式的泰勒公式;最后,阐述了泰勒公式在数学学科和其它学科广泛而深刻的应用,从而揭示了泰勒公式的核心与灵魂.     

The fourth power mean of the general 2-dimensional Kloostermann sums mod <Emphasis Type="Italic">p</Emphasis>

The main purpose of this paper is using the analytic methods and the properties of Gauss sums to study the computational problem of one kind fourth power mean of the general 2-dimensional Kloostermann sums mod p, and give an exact computational formula for it.     

Turn-on Circularly Polarized Luminescence in Chiral Indium Chlorides by 5s2 Metal Centers

Introducing chirality into the metal-halide hybrids has enabled many emerging properties including chiroptical activity, spin-dependent transport, and ferroelectricity. However, most of the chiral metal-halide hybrids to date are non-emissive, and the underlying mechanism remains elusive. Here, we show a new strategy to turn on the circularly polarized luminescence (CPL) in chiral metal-halide hybrids. We demonstrate that alloying Sb³⁺ into chiral indium-chloride hybrids dramatically increases the photoluminescence quantum yield in two new series of chiral indium-antimony chlorides. These materials exhibit strong CPL signals with tunable energy and a high dissymmetry factor up to 1.5×10⁻². Mechanistic studies reveal that the emission originates from the self-trapped excitons centered in 5s² Sb³⁺. Moreover, near-ultraviolet pumped white light is demonstrated with a polarization up to 6.0 %. Our work demonstrates new strategies towards highly luminescent chiral metal-halide hybrids.     

Enhanced Four-Electron Oxygen Reduction Selectivity of Clamp-Shaped Cobalt(II) Porphyrin(2.1.2.1) Complexes

The molecular structure, electrochemistry, spectroelectrochemistry and electrocatalytic oxygen reduction reaction (ORR) features of two Co^II porphyrin(2.1.2.1) complexes bearing Ph or F₅Ph groups at the two meso-positions of the macrocycle are examined. Single crystal X-ray analysis reveal a highly bent, nonplanar macrocyclic conformation of the complex resulting in clamp-shaped molecular structures. Cyclic voltammetry paired with UV/Vis spectroelectrochemistry in PhCN/0.1 M TBAP suggest that the first electron addition corresponds to a macrocyclic-centered reduction while spectral changes observed during the first oxidation are consistent with a metal-centered Co^II/Co^III process. The activity of the clamp-shaped complexes towards heterogeneous ORR in 0.1 M KOH show selectivity towards the 4e⁻ ORR pathway giving H₂O. DFT first-principle calculations on the porphyrin catalyst indicates a lower overpotential for 4e⁻ ORR as compared to the 2e⁻ pathway, consistent with experimental data.