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991.
A novel hyperbranched conjugated chemosensor with bipyridyl groups as periphery groups(BPY-HPV) was synthesized.BPY-HPV was highly sensitive to metal ions(Cu2+,Ni2+) for the strong coordination interaction(Ksv at the order of 107 mol-1 L) monitored by fluorescence spectroscopy.Moreover,by hydrogen bonds and charge transfer interaction,BPY-HPV shows strong interaction with 1,1,2,2-tetrachloroethane whatever in CH2Cl2(Ksv~106 mol-1 L) or film. 相似文献
992.
Lead nanotapes were synthesized in liquid ammonia solvent in the presence of sodium metal at low temperature.The process was template free.Transmission electron microscopy(TEM) observations and X-ray diffraction(XRD) characterizations revealed that the as-prepared Pb nanotapes have average diameters in the range of 40-50 nm.and lengths up to several hundred nanometers, and exhibit cubic crystal structures. 相似文献
993.
A series of naphthopyrans with hydrazone unit ( 8a – 8m ), were synthesized and characterized by 1H NMR, 13C NMR, IR and HRMS. The photochromic properties were investigated under continuous irradiation, in particular regard to the fatigue resistance and the lifetime of the colored open form in solution and polymers. The results showed that these compounds had both good photochromic properties and high fatigue resistance. Detailed studies showed that representative compound 8d (3,3‐di‐4‐methoxybenzoic acid methylenehydrazino‐[3H]‐naphtho [2,1‐b]pyran) had good photochromic properties in THF solution, in solid state, and in polymers, and exhibited a significant bathochromic shift in the spectra of the open forms compared to known naphthopyrans 9 (3,3‐diphenyl‐[3H]‐naphtho[2,1‐b]pyran). On the other hand, the higher melting points of target compounds are promising for the polymer film preparation through hot‐melt method. 相似文献
994.
Chiral N, N'-dialkylated cyclohexanediamine derived ligands have been synthesized and used in the asymmetric hydrogenation of aryl ketones. Optically active alcohols with up to 90% enantiomeric excess were obtained in high yields. 相似文献
995.
996.
The novel Bi2WO6 nanomaterials, which consist of nanosheets and nanoparticles, were successfully synthesized by a combination of electrospinning
and calcining processes. The Bi2WO6 with different morphologies and microstructures had been obtained in the same experimental conditions. The growth mechanism
of such special nanostructures was investigated, and citric acid played an important role in the formation of Bi2WO6 nanostructures. The Bi2WO6 nanomaterials exhibited excellent photocatalytic property in the photodegradation of the pulping and papermaking wastewater
under visible light irradiation. Besides, preparation of the photocatalyst using electrospinning was beneficial for separation
and recycling. So, the Bi2WO6 nanomaterials have a great potential in application for wastewater treatment in the future. 相似文献
997.
Meng X Qin C Wang XL Su ZM Li B Yang QH 《Dalton transactions (Cambridge, England : 2003)》2011,40(39):9964-9966
Immobilization of the chiral salen-metal complex [Mn(III)(salen)(H(2)O)(2)ClO(4)] on the Keggin-type polyoxometalate (POM) skeletons leads to the isolation of POM derivatives functionalized with chiral salen-metal complexes, which represent the first examples of introducing chiral salen-metal complexes into the POM systems. 相似文献
998.
Cheng X Lu Z Li Y Wang Q Lu C Meng Q 《Dalton transactions (Cambridge, England : 2003)》2011,40(44):11788-11794
A unique tubular molecular-assembly, constructed by β-cyclodextrin and Na[Ni(mnt)(2)], was identified by X-ray crystallography. Inclusion complex Na[Ni(mnt)(2)]@β-cyclodextrin (1) crystallized in space group P2(1)2(1)2 as hydrated head-to-head, tail-to-tail, and head-to-tail host pipelines with negatively charged [Ni(mnt)(2)](-) guests included, exhibiting a 3?:?1 (host?:?guest) stoichiometry. The hydrophilic transition-metal coordination compound (Na[Ni(mnt)(2)]) was embedded within a hydrophobic cyclodextrin cavity, which resulted in a β-cyclodextrin trimer motif and one-third "empty" host packing model in the crystal. Induced circular dichroism (ICD) spectra of inclusion complex 1 was investigated, which indicated the same penetration pattern of the guests in host cavities in solution phase as that discovered in the crystal structure. In addition, PM3 quantum chemistry calculations strongly supported the co-conformational alignments of inclusion complex 1 that was identified in the crystal as well as in the solution. 相似文献
999.
The existence and uniqueness of the global solution of stochastic differential equations with discrete variable delay is investigated
in this paper, and the pathwise estimation is also done by using Lyapunov function method and exponential martingale inequality.
The results can be used not only in the case of bounded delay but also in the case of unbounded delay. As the applications,
this paper considers the pathwise estimation of solutions of stochastic pantograph equations. 相似文献
1000.
Thresholds for extinction and persistence are important for assessing the risk of mortality in systems exposed to toxicant. In this paper, three single-species models with random perturbation in a polluted environment are proposed and investigated. One is the generalized logistic model and the other two are the stochastic resource–consumer models of Leslie and Gallopin. For each model, the survival threshold is obtained in some cases. In general, each threshold is determined by intensity of the random noise, the mean stress measure in organisms, the population intrinsic growth rate and the stress response rate. 相似文献