Nano-Mg- [4-methoxy phenylsalicylaldiminemethylpyranopyrazole]Cl2 (nano-[Mg-4MSMP]Cl2) as a nano-Schiff base complex was prepared and fully characterized using some various techniques including fourier transform infrared spectroscopy (FT-IR), energy-dispersive x-ray spectroscopy (EDS), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), differential thermal gravimetric analysis (DTA), mass spectroscopy (MS) and scanning electron microscopy (SEM). Nano-[Mg-4MSMP]Cl2 was successfully used as an efficient catalyst for the preparation of some 1-(α-aminoalkyl) -2 -naphthols. 相似文献
A lanthanide-binding tag site-specifically attached to a protein presents a tool to probe the protein by multiple spectroscopic techniques, including nuclear magnetic resonance, electron paramagnetic resonance and time-resolved luminescence spectroscopy. Here a new stable chiral LnIII tag, referred to as C12 , is presented for spontaneous and quantitative reaction with a cysteine residue to generate a stable thioether bond. The synthetic protocol of the tag is relatively straightforward, and the tag is stable for storage and shipping. It displays greatly enhanced reactivity towards selenocysteine, opening a route towards selective tagging of selenocysteine in proteins containing cysteine residues. Loaded with TbIII or TmIII ions, the C12 tag readily generates pseudocontact shifts (PCS) in protein NMR spectra. It produces a relatively rigid tether between lanthanide and protein, which is beneficial for interpretation of the PCSs by single magnetic susceptibility anisotropy tensors, and it is suitable for measuring distance distributions in double electron–electron resonance experiments. Upon reaction with cysteine or other thiol compounds, the TbIII complex exhibits a 100-fold enhancement in luminescence quantum yield, affording a highly sensitive turn-on luminescence probe for time-resolved FRET assays and enzyme reaction monitoring. 相似文献
Fe3O4 magnetic nanoparticles (MNPs) were prepared by co-precipitation method. The nanoparticles were silica coated using TEOS, and then modified by the polymeric layers of polypropylene glycol (PPG) and polyethylene glycol (PEG). Finally, the core-shell samples were decorated with Ag, Au, and Cu nanoparticles. The products were characterized by vibrating sample magnetometry (VSM), TGA, SEM, XRD, and FTIR methods. The antibacterial activity of the prepared samples was evaluated in inactivation of E. coli and S. aureus microorganisms, representing the Gram-negative and Gram-positive species, respectively. The effect of solid dosage, bacteria concentration and type of polymeric modifier on the antibacterial activity was investigated. TEM images of the bacteria were recorded after the treatment time and according to the observed changes in the cell wall, the mechanism of antibacterial action was discussed. The prepared nanostructures showed high antibacterial activity against both Gram-negative and Gram-positive bacteria. This was due to the leaching of metal ions which subsequently led to the lysis of bacteria. A theoretical investigation was also done by studying the interaction of loaded metals with the nucleotide components of the microorganism DNA, and the obtained results were used to explain the experimental data. Finally, based on the observed inactivation curves, we explain the antibacterial behavior of the prepared nanostructures mathematically.
Azobenzene-based calamitic liquid crystals, 4-((4-(4-methoxymethyl-1,2,3-triazol-1-yl)phenyl)diazenyl)phenylalkanoates have been isolated and their structures were characterised. The structure–property correlation with respect to the different alkanoyloxy terminal chain (–COOCnH2n+1 where n adopts odd numbers ranging from 3 to 15) has also been given attention in the present study. In this series, all compounds exhibit smectogenic properties. The lower homologues shows enantiotropic SmA phase as well as monotropic SmC phase. The higher homologues exhibit homeotropic alignment of smectic phases. These compounds possess very high anisotropic inclination in which the mesomorphic region covers nearly 80°C. 相似文献
New bis(pyrazolylenaminones) were prepared in good yields. Their synthetic utilities as precursors for regioselective synthesis of novel bis(hetarylpyrazoles) were also investigated. The mechanisms and selectivities observed in the studied reactions were discussed. 相似文献
A mixed-ligand silver(I) complex of triphenylphosphine and N,N′-dibutylthiourea (Dbtu), [Ag(Ph3P)2(Dbtu)2]NO3, is prepared and its structure in the solid state is determined by X-ray crystallography. X-ray structure of this complex
shows that it is mononuclear with the silver atom coordinated by two PPh3 and two dibutylthiourea ligands adopting a distorted tetrahedral geometry. The crystal structure shows the formation of 1-D
chains through intermolecular hydrogen bonding interactions between N-H of Dbtu and nitrate ions. The new complex is also
characterized by IR and NMR (1H and 31P) spectroscopy. The spectroscopic data are discussed in terms of the nature of bonding. A similar mixedligand complex is
also prepared for tetramethylthiourea (Tmtu), but the structure of the resulting compound shows that it is a bis(phosphine)
complex, [Ag(PPh3)2NO3] rather than a mixed-ligand complex. 相似文献
Calculations [1] of rheological properties of polymeric solutions have usually been restricted to very dilute o r to very concentrated solutions. In either case, one starts with a model for the micro- structure. Between these two conceptual extremes lies the broad class of moderately concentrated solutions. To cover this region theoretically, two approaches have been used; 1) network theories focusing attention on entanglement junctions, and 2) single-molecule theories focusing attention on single molecules but including inter- molecular interactions. Williams, Wang, and Zimm introduced a double model; one for a particular macromolecule and another for solutions containing like molecules in which the chosen macro- molecule is suspended. This approach has turned out to be quite successful because spheres immersed in a suspension of like spheres behave as i f suspended in a Newtonian fluid, and the resulting ex- pression for viscosity is quite simple in form and qualitatively correct for moderate concentrations. 相似文献
Journal of Thermal Analysis and Calorimetry - The refined pitch (1#) and impregnating pitch (2#) were obtained under certain conditions with the modified pitch as the raw materials. The data of... 相似文献