Synthesis, Structure and Thermal Behavior of a New Coordination Polymer Based on Mixed Pyrazine-2-carboxylate and Oxalate Ligands

Abstract  

A new 4d–4f coordination polymer, [AgGd(pyzc)₂(ox)·H₂O)] (1) [pyzc = Pyrazine-2-carboxylate, ox = oxalate] has been successfully synthesized under hydrothermal conditions and structurally determined by single-crystal X-ray diffraction, and characterized by elemental analysis, infrared spectroscopy, thermogravimetric analysis and power X-ray diffraction. Single-crystal X-ray analysis reveals that it crystallizes in the monoclinic space group P2 ₁ /c with a = 10.0746(1) ?, b = 18.642(1) ?, c = 8.0525(2) ?, β = 112.470(1)°, Mr = 617.34, Z = 4, V = 1505.6(2) ?³, μ = 5.732, F(000) = 1164. The Gd(III) ion is nine-coordinated by two O-donors and two N-donors of two different chelating pyzc ligands, four O-donors of two different chelating oxalate ligands, and one O-donor of another carboxylate group of one pyzc ligand. The compound represents a 3D microporous polymeric network constructed by gadolinium–oxalate chains and Ag-pyzc subunits.     

（FeCp2）0．65FNi（C3S7）2]的合成及表征

合成了一种新型的导电配位型化合物（FeCp2）0．65FNi（C3S7）2].通过元素分析（EA），电感耦合等离子体原子发射光谱（ICP—AES），核磁共振（^1HNMR），紫外光谱（UV）对该化合物进行了表征。     

Recent advances in theoretical models of respiratory mechanics

As an important branch of biomedical engineering, respiratory mechanics helps to understand the physiology of the respiratory system and provides fundamental data for developing such clinical technologies as ventilators. To solve different clinical problems, researchers have developed numerous models at various scales that describe biological and mechanical properties of the respiratory system. During the past decade, benefiting from the continuous accumulation of clinical data and the dramatic progress of biomedical technologies (e.g. biomedical imaging), the theoretical modeling of respiratory mechanics has made remarkable progress regarding the macroscopic properties of the respiratory process, complexities of the respiratory system, gas exchange within the lungs, and the coupling interaction between lung and heart. The present paper reviews the advances in the above fields and proposes potential future projects.     

Synthesis and Photophysics of Novel Soluble Polymeric Zn Metal Complex Based on Bis(8-hydroxyquinoline) Groups with Benzene Unit

A novel ligand: 2,2′‐(1,3‐phenylenedivinylene)bis‐8‐hydroxyquinoline (m‐B8QPH) ( 4 ) and the corresponding polymeric metal complex Zn ( m‐B8QPH ) ( 5 ) were designed and synthesized in a convenient way. The luminescence properties of the compounds Zn ( m‐B8QPH ) ( 5 ) and Zn(p‐B8QPH) ( 9 ) were investigated by UV‐vis and fluorescence spectra in DMF at room temperature. The experimental results showed that the polymeric complexes 5 and 9 emitted yellow luminescence at 578 and 554 nm in DMF solution. The polymeric complex 5 has demonstrated good solubility in common organic solvents and good thermal stability with high T_g: 261°C. Furthermore, the molecular interactions of 5 with fullerene (C₆₀) and fulleropyrrolidine containing 3,5‐bis(trifluoromethyl)benzene ( 11 ) were also investigated, which indicated the metal dye 5 can be used as new fluorescent probe.     

The factors of spontaneous parametric down conversion process in BiB3O6 crystal with a broadband pump

We investigate the spontaneous parametric down-conversion (SPDC) process in biaxial nonlinear crystal BiB₃O₆ (BIBO) with a broadband pump. Under the type I and type II phase-matching conditions, we numerically calculate the influencing factors on SPDC process in BIBO crystal, such as temporal and spatial walk-off, the acceptance angles, and spectral acceptance bandwidth. Comparing the two types of phase-matching, we could conclude that the type II phase-matching in BIBO crystal is better for the SPDC because of zero dispersion and bigger acceptance parameters. These results can be used to construct a system to generate ultra-fast entangled photon pairs.     

Radical cation salt induced Povarov reaction between iminoethyl glyoxylate and N-vinylamides: synthesis of quinoline-2-carboxylate derivatives

A domino process between iminoethyl glyoxylate and N-vinylamides was achieved under the catalytic radical cation salt induced conditions, producing a series of quinoline-2-carboxylates. N-Vinylamides were involved as an acetylene equivalent. A possible mechanism was proposed to rationalize the formation of the products.     

Cation radical induced cycloaddition reaction between aryl imines and ethyl diazoacetate

The reaction of ethyl diazoacetate with aryl imines can be initiated by persistent cation radical salt tris(4-bromophenyl)aminium hexachloroantimonate, giving exclusively cis-aziridine carboxylates.     

图的k部划分的一个注记

设k≥2是一个整数。本文证明了任意有m条边的图都存在一个顶点的划分V_1,V_2…,V_k,使得e(V_1,V_2…,V_k)≥k-1/k m+k-1/2k((2m+1/4)~1/2-1/2)-(k-2)~2/8k,且max{e(V_i):1≤i≤k}≤m/k~2+(k-1)/2k~2((2m+1/4)~1/2-1/2+3/8-7k-4/8k~2.我们的结果改进了[Fan G.,Hou J.,Zeng Q.,A bound for judicious k-partitions of graphs,Discrete Appl.Math.,2014,179:86—99]的主要结论.     

Molecularly imprinted polymers on the surface of silica microspheres via sol‐gel method for the selective extraction of streptomycin in aqueous samples

Streptomycin‐imprinted silica microspheres were prepared by combining a surface molecular‐imprinting technique with the sol‐gel method. A mixture of tetrahydrofuran, ethanol, and water (6:1:1, v/v/v) was selected as dispersing solvent while 3‐aminopropyltriethoxysilane and triethoxyphenylsilane acted as functional monomers, and tetraethyl orthosilicate as a cross‐linker. Characterization of the molecularly imprinted polymers was conducted using scanning electron microscope and dynamic binding experiments. As compared to the nonimprinted polymers, the imprinted polymers exhibited a higher degree of saturated adsorption volume up to 26.3 mg/g, and better selectivity even in an aqueous solution with interfering compounds, including dihydrostreptomycin, neomycin, and tetracycline. The adsorption ability and selectivity were observed to be influenced by the mole ratio of 3‐aminopropyltriethoxysilane and triethoxyphenylsilane. Feasibility of the polymers to be used for actual application was also evaluated with spiked samples, indicating great potential for large‐scale applications. Moreover, the streptomycin‐imprinted polymers can be repeatedly used for 12 cycles without losing original performance, which is beneficial for commercial use.