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981.
N-Amido imidazolium salt was employed as a ligand in the palladium-catalyzed cross-coupling reaction of aryl halides and thiols, and showed good activity in the formation of thioether. The best combination for the coupling with aryl bromides was N-amido imidazolium salt 2 and NaHMDS, and that for the coupling with aryl iodides was N-amido imidazolium salt 1 and KOtBu. The coupling reactions were conducted in the presence of Pd(OAc)2 (1 mol %) in DMSO at 80 °C for 12 h. 相似文献
982.
Xiao‐Ying Cheng Ming‐Fang Wang Zheng‐Yin Yang Yong Li Zeng‐Chen Liu Qiao‐Xia Zhou 《无机化学与普通化学杂志》2013,639(5):832-841
The Schiff base ligand, 1‐phenyl‐3‐methyl‐5‐hydroxypyrazole‐4‐methylene‐8′‐quinolineimine, and its CuII, ZnII, and NiII complexes were synthesized and characterized. The crystal structure of the ZnII complex was determined by single‐crystal X‐ray diffraction, indicating that the metal ions and Schiff base ligand can form mononuclear six‐coordination complexes with 1:1 metal‐to‐ligand stoichiometry at the metal ions as centers. The binding mechanism and affinity of the ligand and its metal complexes to calf thymus DNA (CT DNA) were investigated by UV/Vis spectroscopy, fluorescence titration spectroscopy, EB displacement experiments, and viscosity measurements, indicating that the free ligand and its metal complexes can bind to DNA via an intercalation mode with the binding constants at the order of magnitude of 105–106 M –1, and the metal complexes can bind to DNA more strongly than the free ligand alone. In addition, antioxidant activities of the ligand and its metal complexes were investigated through scavenging effects for hydroxyl radical in vitro, indicating that the compounds show stronger antioxidant activities than some standard antioxidants, such as mannitol. The ligand and its metal complexes were subjected to cytotoxic tests, and experimental results indicated that the metal complexes show significant cytotoxic activity against lung cancer A 549 cells. 相似文献
983.
A series of heterometallic LnIII–SbIII edta‐containing compounds with the formulas [Sb2(edta)2Ln]NO3 · nH2O [edta = ethylenediaminetetraacetate; Ln = Eu, n = 7 ( 1 ); Gd, n = 7.5 ( 2 ) and Tb, n = 8 ( 3 )] were synthesized and characterized by elemental analyses (EA), powder X‐ray diffraction (PXDP), Fourier transform infrared spectroscopy (FT‐IR), and thermogravimetric analyses (TGA). Their fluorescence and magnetic properties were also studied. The thermal analysis demonstrates the compounds formation of the antimony, lanthanide ions, and edta4– ligands. FT‐IR spectra reveal that the antimony and lanthanide ions are connected through the carboxylate bridges. The studies of luminescence properties show that compounds 1 and 3 exhibit typical luminescence in the visible region. Furthermore, magnetic properties reveal compounds 2 and 3 have weak ferromagnetic behavior. 相似文献
984.
Jong Min Lee Ji‐eun Kim Jayant Borana Bong Hyun Chung Bong Geun Chung 《Electrophoresis》2013,34(13):1931-1938
We developed the dual‐micropillar‐based microfluidic platform to direct embryonic stem (ES) cell fate. 4 × 4 dual‐micropillar‐based microfluidic platform consisted of 16 circular‐shaped outer micropillars and 8 saddle‐shaped inner micropillars in which single ES cells were cultured. We hypothesized that dual‐micropillar arrays would play an important role in controlling the shear stress and cell docking. Circular‐shaped outer micropillars minimized the shear stress, whereas saddle‐shaped inner micropillars allowed for docking of individual ES cells. We observed the effect of saddle‐shaped inner micropillars on cell docking in response to hydrodynamic resistance. We also demonstrated that ES cells cultured for 6 days within the dual‐micropillar‐based microfluidic platform differentiated into neural‐like cells. Therefore, this dual‐micropillar‐based microfluidic platform could be a potentially powerful method for screening of lineage commitments of single ES cells. 相似文献
985.
Dongmei Wang Xiaojiao Song Yin Duan Liang Xu Jing Zhou Hongquan Duan 《Electrophoresis》2013,34(9-10):1339-1342
Polystyrene (PS) nanoparticles coated by BSA, hereafter denoted as PS/BSA, were prepared and chemically immobilized for the first time onto a capillary inner wall for open‐tubular CEC (OTCEC). EOF and scanning electron micrography were used to characterize the prepared nanoparticle‐coated capillaries. To investigate the performance of the prepared columns in OTCEC, chiral separation of d ,l ‐tryptophan (dl ‐Trp) was performed in monolayer BSA‐modified capillary and PS/BSA nanoparticle‐coated columns. The results indicated that the nanoparticle‐modified column afforded a higher resolution compared with the monolayer type. Rapid enantioseparation of dl ‐Trp (within 3 min) was achieved with the PS/BSA‐immobilized column using an electroosmotic pump‐assisted CEC. Enantiomer separations of other compounds like dl ‐tyrosine and warfarin were also achieved with the column. Besides, run‐to‐run and column‐to‐column repeatabilities of the PS/BSA‐coated column in the chiral separation were systematically introduced. 相似文献
986.
Dong‐Jun Yu Jun Hu Yan Huang Hong‐Bin Shen Yong Qi Zhen‐Min Tang Jing‐Yu Yang 《Journal of computational chemistry》2013,34(11):974-985
Understanding the interactions between proteins and ligands is critical for protein function annotations and drug discovery. We report a new sequence‐based template‐free predictor (TargetATPsite) to identify the Adenosine‐5′‐triphosphate (ATP) binding sites with machine‐learning approaches. Two steps are implemented in TargetATPsite: binding residues and pockets predictions, respectively. To predict the binding residues, a novel image sparse representation technique is proposed to encode residue evolution information treated as the input features. An ensemble classifier constructed based on support vector machines (SVM) from multiple random under‐samplings is used as the prediction model, which is effective for dealing with imbalance phenomenon between the positive and negative training samples. Compared with the existing ATP‐specific sequence‐based predictors, TargetATPsite is featured by the second step of possessing the capability of further identifying the binding pockets from the predicted binding residues through a spatial clustering algorithm. Experimental results on three benchmark datasets demonstrate the efficacy of TargetATPsite. © 2013 Wiley Periodicals, Inc. 相似文献
987.
Fu-Qiang Jin Jian-Chun Zhang Min Li Xin-Min Hao Hua Zhang 《Journal of Dispersion Science and Technology》2013,34(8):1148-1151
NaOH/poly(sodium acrylate) composites were prepared by in situ polymerization of acrylic acid with an overneutralization level by adding excess NaOH. The composites were studied by XRD, IR and 23Na MAS NMR spectroscopy. The results showed that the high neutralization degree (>100%) may lead to a complete polymerization. Both XRD and 23Na MAS NMR spectra did not show any peaks of phase-separated NaOH or Na2CO3 until the neutralization degree was up to 217.5%. It can be presumed that the aggregates of Na+ ions can contain approximately two Na+ units for every carboxyl group before the phase separation. 相似文献
988.
Shi‐Zhou Fu Bao‐Lin Yin De‐zhi Sun 《Journal of Dispersion Science and Technology》2013,34(7):1112-1116
The foam performances of 3‐dodecoxy‐2‐hydroxypropyl trimethylammonium chloride (C12TAC) have been determined in the existence of different relative amount of polymer. The experimental results show that the foaming ability of the mixture systems of the C12TAC/PEG and C12TAC/PVP is stronger than that of the surfactant solutions in the absence of polymer, and with the increase of relative amount of polymer both foaming efficiency and foam stability of the surfactant solutions are evidently enhanced. For the aqueous solution of the surfactant, effect of temperature on foaming properties has also been examined. The results show that both the foaming ability and stability of the foams of the surfactant solutions are highest (or strongest) at 30°C. 相似文献
989.
以制得的纳米Fe3O4颗粒作为载体,用还原法将还原出的Au与Pt分别负载到Fe3O4颗粒表面,制得纳米Pt/Au/Fe3O4复合材料。对Pt/Au/Fe3O4进行紫外可见光吸收光谱、透射电子显微镜、X射线衍射及光电子能谱等物理表征,结果表明,Au与Pt均匀地沉积到了Fe3O4纳米颗粒表面。对纳米Pt/Au/Fe3O4复合材料进行循环伏安扫描,当H2PtCl6的加入量达到8 mL时,Pt/Au/Fe3O4催化性能最佳;正扫电流峰ip与扫描速率的平方根v1/2线性相关,Pt/Au/Fe3O4催化氧化甲醇的过程受扩散控制;对催化剂进行201次循环伏安扫描,催化剂仍然能保持较好的催化性能且稳定性良好。因此,所合成催化剂Pt/Au/Fe3O4是一种具有良好化学稳定性的阳极催化剂材料。 相似文献
990.
Two kinds of aliphatic alternating polyesteramide prepolymers were prepared through melt polycondensation from N,N’-bis(2-hydroxyethyl)-adipamide and adipic acid or sebacic acid. Chain extension of them was conducted with 2,2′-(1,4-phenylene)-bis(2-oxazoline) and adipoyl biscaprolactamate as combined chain extenders. The chain extended polyesteramides (ExtPEAs) were characterized by IR, 1 H-NMR, differential scanning calorimetry, thermogravimetric analysis, wide angle X-ray scattering, tensile test and enzymatic degradation. The results showed that the ExtPEA(4,m)s were mainly constituted with the diester adipamide alternating units. ExtPEA(4,4) and ExtPEA(4,8) had Tm of 83.8℃ and 85.8℃ and initial decomposition temperature above 310.0℃. They crystallized similarly as Nylon-66 did and were flexible thermoplastic materials with tensile strength up to 25.64 MPa and strain at break up to 737%. 相似文献