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991.
Nanoscaled coordination polymers based on biologically prevalent ions have potential applications in drug delivery and biomedical imaging. Herein, coordination polymer nanoparticles of anionic porphyrins, including meso‐tetra(4‐carboxyphenyl)‐porphyrin (H2TCPP4?) and meso‐tetra(4‐sulfonatophenyl)‐porphyrin (H2TPPS4?), and alkaline or alkaline earth metal cations, such as K+ and Ca2+, were constructed in aqueous solution in the presence of cucurbit[7]uril (CB7) or cucurbit[8]uril (CB8). UV/Vis absorption and fluorescence spectroscopy, dynamic light scattering (DLS), scanning electron spectroscopy (SEM), and atomic force microscopy (AFM) were applied to explore the assembly and particle formation of porphyrin anions and metal cations mediated by CBn. The particle size depends on the kinds of CBn and metal cations and their concentrations. The uptake of H2TPPS4? particles by tumor cells (A549 cells) was found to be more efficient than H2TPPS4? at 37 °C, showing the application potential of such assembled particles in biology and medicine.  相似文献   
992.
Concise and efficient three‐component domino [4+1+1] carbocyclization to highly substituted fluoren‐9‐one derivatives promoted by K2CO3 has been developed under microwave irradiation conditions. The direct bis‐cyanation and aryl amination residing in fluoren‐9‐one framework were achieved in a one‐pot operation. The reaction proceeds at fast rates and can be finished within 30 min, which makes workup convenient to give good to excellent chemical yields.  相似文献   
993.
A series of tri-substituted chiral pyrrolidin-2-one derivatives have been designed and synthesized as CC chemokine receptor 4 (CCR4) antagonists. The structure of CCR4 was built by homology modeling. Asymmetric synthesis was applied to synthesize the R,R configuration chiral pyrrolidin-2-one scaffold. The stereoisomeric con- figurations of the compounds were identified by 2D I H-~H COSY spectroscopy and 1D NOESY spectroscopy. This method was more economical and convenient than traditional X-ray single crystal diffraction. In addition, the inter- actions between these compounds and the N-terminal extracellular tail of CCR4 were studied using capillary zone electrophoresis. The CCR4 chemotaxis inhibition effect was tested in CCR4-transfected HEK293 cells. Several compounds showed potent activities as CCR4 antagonists. Among these compounds, lc is the most active one. Its apparent binding constant of CZE experiment result is (1.569±0.11)× 10s L·mol ^-1, and its percentage inhibition of the HEK293/CCR4 cells migration with the concentration of I gmol·L ^-1 in DMSO is 59%. And compound If has slightly higher affinity to N-terminal of CCR4 according to its apparent binding constant than lb because of the in- troduced ester linkage. Further studies on the mechanism of these compounds are in progress.  相似文献   
994.
A new copper and silver‐mediated cyanation of aryl iodides with DDQ as a cyanide source is achieved, providing nitriles with good yields. This new approach represents a safe method leading to aryl nitriles.  相似文献   
995.
The title complex l-[Cu4(Hvap)2(vap)2(MeOH)2](CIO42 1 has been synthesized and characterized by EA. IR,TGA,solid-state CD spectra and X-ray single-crystal analyses(l-H2vap’.a Schiff base ligand derived from the condensation of o-vanillin and l-2-amino-3-phenyl-l-propanol).Complex 1 crystallizes in monoclinic system,chiral space group P21 with a =10.4257(18).b = 21.695(4),c = 15.721(3)A,β= 94.443(3).V= 3545.1(11) 3,Z=2,Cu4C70H78N4O22Cl2.Mr= 1652.42,Dc= 1.548 g/cm3, F(000)= 1704 andμ(MoKα) = 1.338 mm-1.The final R = 0.0682 and wR = 0.1420 for 6170 observed reflections with I > 2σ(I) and R = 0.1775 and wR = 0.1830 for all data.The structure of complex 1 contains a boat-shaped(Cu4O4} motif.The solid-state CD spectra confirm the chiral nature of complex 1.  相似文献   
996.
A novel supramolecular graft copolymer(SGP) composed of viologen-containing copolymer(P(DMA-co-diEV)) as the main chain and Np ended PNIPAM(Np-PN1PAm) as the grafts is prepared(DMA:N,N- dimethylacryamide,diEV:ethylviologen dimer,Np:naphthalene,PNIPAM:poly(N-isopropylacrylamide)). The grafting is based on the triple complexation among a host of cucurbit[8]uril(CB[8])and two guests of diEV and Np,which is characterized by UV-vis spectra and ITC.Temperature sensitive property of PNIPAm moiety allows SGP to self-assemble into non-covalently connected micelle(NCCM) at high temperature. The micelles are sensitive to reducing agents,for example Na2S2O3,which breaks the current inclusion complex pair and induces aggregation.  相似文献   
997.
用基于第一性原理的密度泛函理论方法,对Cs3Bi2X9(X=Cl、Br、I)的光电特性进行理论计算,并系统阐述这3种晶体的表面效应对光电性能的影响。结果表明,3种材料的光学特性由铋原子和卤素原子最外层p轨道上的价电子主导。在可见光区中,材料的吸收峰会随卤素原子序数的增加呈现红移,其中一维结构的Cs3Bi2Cl9表面结构在光吸收能力上尤为特别且敏感;二维结构的Cs3Bi2Br9光吸收能力会受厚度影响;零维结构的Cs3Bi2I9非常稳定,且几乎不受表面特性和晶体厚度的影响。  相似文献   
998.
熊兴泉  江云兵 《化学进展》2013,(6):999-1011
通过高效的反应精确合成功能分子已成为现代化学发展的趋势之一。基于呋喃/马来酰亚胺(MI)之间的Diels-Alder(D-A)反应作为一种高效的和高选择性的点击反应,克服了铜催化的叠氮/炔之间的1,3-偶极环化加成(CuAAC)反应中引起的金属污染等缺点,为生物医药载体、功能性材料的制备提供更可行的途径。同时,呋喃/MI之间的D-A反应具备原料易得、反应条件温和及易发生retro D-A(rD-A)反应等优点,在制备响应性材料领域备受关注。本文综述了近年基于呋喃/MI的可逆D-A反应在响应性聚合物合成、智能材料、生物分子及表面修饰等方面的应用,并展望了D-A反应的发展前景。  相似文献   
999.
建立液相色谱–串联质谱(LC–MS/MS)法检测动物性食品中万古霉素药物残留的方法。用磷酸盐缓冲溶液对动物性食品中的万古霉素进行提取,经HLB固相萃取柱净化,采用电喷雾离子源,以正离子检测方式进行质谱分析。实验结果表明,万古霉素质量浓度在1~500μg/L范围内与色谱峰面积呈良好的线性,相关系数r=0.998。低、中、高3个质量浓度添加水平的回收率为84.8%~118.2%,相对标准偏差为2.2%~7.2%(n=5),检出限为2μg/kg。  相似文献   
1000.
A modified glassy carbon (GC) electrode was developed for the amperometric detection of biogenic amines, particularly histamine. The electrode was modified with the co‐enzyme pyrroloquinoline quinone (PQQ) by entrapment during electropolymerziation of pyrrole to form polypyrrole (PPy). This method formed a thin film on the electrode surface possessing very good stability with a shelf‐life exceeding one month without loss of signal. Optimal conditions for the PQQ/PPy electrode were determined and a linear response was found for histamine in phosphate buffer (pH 6) at +550 mV from 40 to 170 mg L?1 with a limit of detection (S/N≥3) of 38 mg L?1. The practical linear range offered by this method suggests ideal use for spoilage detection in fermented foods.  相似文献   
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