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961.
Bing Yang Zengqi Xie Houyu Zhang Hai Xu Muddasir Hanif Xin Gu Feng He Jingsheng Yu Yuguang Ma Jiacong Shen Xiaodong Liu Jikang Feng 《Chemical physics》2008
2,5-Diphenyl-1,4-distyrylbenzene (DPDSB), a model compound of PPV, have been synthesized with two isomers: cis- and trans-DPDSB in our lab. We have found three distinguishing features of photophysical properties between these two isomers. To explain these three special spectral behaviors, the quantum-chemical computations were performed to investigate the ground-state and excited-state molecular geometries, electronic structure, absorption and emission properties, potential–energy curve of the ground-state and excited-state, and so on. According to our calculated results, the nature causing above distinguishing photophysical properties is larger configuration displacement of cis-DPDSB than trans-DPDSB from the ground-state to the excited-state, especially for the changes in torsion angle along vinyl double bonds in cis-DPDSB. 相似文献
962.
Junbo Li Weidong Zhou Yuliang Li Huibiao Liu Xiaodong Yin Haiyan Zheng Zicheng Zuo 《Tetrahedron letters》2008,49(33):4857-4861
A series of axles containing the tetraethyl ester calix[4]arene derivative unit and 1,5-dioxynaphthalene (DNP) unit, with different lengths of ether chains, have been synthesized. Complexation of the axles and the cyclobis(paraquat-p-phenylene) (CBPQT4+) has been investigated by UV-vis and 1H NMR spectra. The effect of the length of ether chain on the threading/dethreading processes has also been demonstrated, which indicated that the efficiency of threading/dethreading process decreases with the extension of ether chain. 相似文献
963.
Chen Z Xie S Shen L Du Y He S Li Q Liang Z Meng X Li B Xu X Ma H Huang Y Shao Y 《The Analyst》2008,133(9):1221-1228
The interactions between Hela cells and silver nanoparticles (AgNPs) have been studied by scanning electrochemical microscopy (SECM) with both IrCl(6)(2-/3-) and Fe(CN)(6)(3-/4-) as the dual mediators. IrCl(6)(2-), which can be produced in situ and react with AgNPs, is used as the mediator between the AgNPs on the cells and the SECM tip. Another redox couple, Fe(CN)(6)(3-/4-), which has a similar hydrophilicity to IrCl(6)(2-/3-), but cannot react with AgNPs, is also employed for the contrast experiments. The cell array is cultured successfully onto a Petri dish by microcontact printing (muCP) technique, which can provide a basic platform for studying of single cells. The approach curve and line scan are the two methods of SECM employed here to study the Hela cells. The former can provide the information about the interaction between Hela cells and AgNPs whereas the later gives the cell imaging. The permeability of cell membranes and morphology are two main factors which have effects on the feedback mode signals when K(3)Fe(CN)(6) is used as the mediator. The permeability of the cell membranes can be ignored after interaction with high concentration of AgNP solution and the height of the Hela cells is slightly decreased in this process. The kinetic rate constants (k(0)) between IrCl(6)(2-) and Ag on the Hela cell can be evaluated using K(3)IrCl(6) as the mediator, and they are increased with the higher concentrations of the AgNP solutions. The k(0) is changed about 10 times from 0.43 +/- 0.04 x 10(-4) to 1.25 +/- 0.07 x 10(-4) and to 3.93 +/- 1.9 x 10(-4) cm s(-1) corresponding to 0, 1 and 5 mM of AgNO(3) solution. The experimental results demonstrate that the AgNPs can be adsorbed on the cell surface and detected by SECM. Thus, the amount of AgNPs adsorbed on cell membranes and the permeability or morphology changes can be investigated simultaneously using this approach. The dual mediator system and cell array fabricated by muCP technique can provide better reproducibility because they can simplify experiments, and provide a platform for further single cell detection. 相似文献
964.
Morphology transition and aggregation-induced emission of an intramolecular charge-transfer compound
Xu J Liu X Lv J Zhu M Huang C Zhou W Yin X Liu H Li Y Ye J 《Langmuir : the ACS journal of surfaces and colloids》2008,24(8):4231-4237
An intramolecular charge-transfer (ICT) compound, (TCBD)2OPV3, has been synthesized and fabricated into one-dimensional nanotubes by a reprecipitation method. The observation of SEM and TEM showed the nanotubes were formed from their zero-dimensional precursors of hollow nanospheres. Reconstruction was found to happen during the morphology transition progress. The morphology transition and reconstruction are proposed to be a "curvature strain releasing" process driven by donor-acceptor dipole-dipole interactions. An aggregation-induced emission (AIE) effect was observed for (TCBD)2OPV3. Both aggregates of vesicles and nanotubes were observed to be good red emitters with near-infrared end emission of 750-850 nm, which endows the material with potential applications in the fields of optical devices, biosensors, and biolabels. 相似文献
965.
Xuehong Ren Lei Kou Jie Liang S. D. Worley Ywh-Min Tzou T. S. Huang 《Cellulose (London, England)》2008,15(4):593-598
N-halamine silane syntheses and coatings of cotton fabrics as siloxanes were addressed for a series of silanes. The coated fabrics were chlorinated by exposure to dilute sodium hypochlorite with a range of chlorine loadings from 0.20% to 0.26%. Two types of N–Cl moieties were involved in the N-halamine siloxanes, amine and amide. The siloxane-coated cotton swatches were very effective in inactivating Escherichia coli O157:H7 and Staphylococcus aureus, each in 10 min contact time. The N–Cl bond and compound stabilities under UV irradiation and ambient light exposure were also investigated. Both UV and laboratory light stability tests show that most of the chlorine on cotton coated with 3-(3-triethoxysilylpropyl)-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decane-2,4-dione could be regenerated after irradiation, while most of the lost chlorine from 5,5-dimethyl-3-(3′-triethoxysilylpropyl)hydantoin and 4-[3-triethoxysilylpropoxyl]-2,2,6,6-tetramethylpiperidine could not be recovered upon rechlorination. 相似文献
966.
967.
Li Z Xu Y Ma X Dervishi E Saini V Biris AR Lupu D Biris AS 《Chemical communications (Cambridge, England)》2008,(28):3260-3262
We report on the role of CO(2) in improving carbon nanotube yield and crystallinity from catalytic chemical vapor deposition of hydrocarbons. 相似文献
968.
969.
Reaction of CoCl(2).4H(2)O with Ag(3)[Cr(ox)(3)] (3 : 2 mol/mol) in methanol gives rise to an oxalate-bridged complex [Co(MeOH)(2)](3)[Cr(ox)(3)](2).6MeOH that consists of a rare cloverleaf-like layered structure (12,3-net). Ferromagnetic coupling is operative between the adjacent metal ions through the oxalate bridges. 相似文献
970.
A catalytic cascade synthesis of isoxazoline-N-oxide was developed through proline-catalyzed nitroalkene activation. A large substrate scope was obtained with good to excellent yields. Mechanistic studies revealed intramolecular cyclization as the rate-determining step, giving only trans isomers in all cases. 相似文献