From the magnetization measurements at 1.6 K we observe that the DyNi compound exhibits narrow domain walls frozen by the anisotropy. The non-colinear magnetic structure of this compound has been studied by neutron diffraction techniques. Its magnetic structure is isomorphous to that of HoNi belonging to the space group Pnm′a′. 相似文献
Environmentally benign synthesis of novel pegylated polyphenolics, by combining the extraordinary selectivities of a lipase and an oxidase to develop polymeric electrolytes for applications in dye sensitised solar cells. 相似文献
Self‐doped sulfonated polyaniline (PSA) has been synthesized on the surface of micellar nanoparticles made from positively charged surfactants by biocatalysis. The conformation forced by the electrostatic charge interactions between the positively charged micelle and the negatively charged PSA increases the conductivity of the PSA by three orders of magnitude. The pure PSA recovered from ion exchange, however, shows quite similar electrical properties compared with sulfonated polyanilines reported earlier. The increased conductivity of PSA complexes is as a result of the increased charge carrier concentration caused by a certain conformational locking.
A series of novel dispiropyrrolidine-linked 1,2,3-triazole derivatives have been prepared by one-pot, four-component protocol that employed 5-arylidene-3-(prop-2-ynyl)thiazolidine-2,4-dione, isatin, sarcosine and substituted azides using Cu(I) generated in situ as catalyst in PEG-400 as a highly efficient and green media. This is the first report of a four-component reaction involving a classical Huisgen reaction, in which the two dipolar moieties (substituted azides and in situ generated azomethine ylides) react with acetylenic and olefinic dipolarophiles, respectively. The 1,3-dipolar cycloaddition proceeds in a highly regio- and stereo-selective manner. This methodology can be an ideal tool for the preparation of biologically important five-membered heterocyclic compounds in one pot. 相似文献
In situ topochemical polymerization of two diacetylene monomers within nanoporous TiO2 thin films was carried out under visible light irradiation. One of the monomers used contains a carboxylic acid group, which could help to link the monomer onto the TiO2 surface covalently. UV-Vis absorption and Raman studies showed that both monomers were successfully photopolymerized. These results suggest that the covalent linkage of the diacetylene to the nanoparticle through the carboxylic acid group is not needed. Since photopolymerization of diacetylene is typically induced by excitation of the monomer at λ< 300 nm, the observed red shift of the photopolymerization wavelength is attributed to the photosensitization effect of TiO2. The morphological study of the polydiacetylene/TiO2 nanocomposite revealed that the diacetylene monomers were polymerized in the vicinity of the TiO2 nanoparticles. This is attributed to the fact that the electron-transfer process occurs at the interface of nanocrystalline TiO2 (nc-TiO2) and the diacetylene monomer and the polymerization is expected to be initiated near the nc-TiO2 surface. Photopolymerization of the carboxylated diacetylene monomer with other oxides nanoparticles, such as ZnO and SiO2 was also investigated.相似文献
A study of the slow hydrolysis of labile acetal groups by low concentrations of lactic acid to release the active molecules is reported. A prototype molecule containing cyclic acetal groups, dimethyl‐2,3‐O‐benzylidene‐L‐tartrate (DMTAc) and the same molecule incorporated as a pendant group in a polyamide were studied for their hydrolysis by low concentrations of lactic acid. The release of benzaldehyde during slow hydrolysis is monitored by UV‐vis and 1H‐NMR spectroscopy. This study is very useful to ultimately design and synthesize a polymer with covalently bound insecticidal/anti‐microbial/anti‐fungal materials for the development of controlled release formulations. 相似文献
We have used the formation of surface relief gratings (SRG) on azobenzene polymers to manipulate TiO2 nanoparticles and to fabricate TiO2 nanoparticle gratings. Suspensions of an azobenzene polymer (PDO3) and TiO2 were used to spin coat thin films on glass slide substrates. By interfering coherent light from an Argon laser on the surface of the PDO3‐TiO2 composite films, SRGs were fabricated. Atomic force microscopic images of the SRGs show TiO2 nanoparticles dispersed throughout the sample, and in particular, at the peaks of the SRG after oxygen plasma treatment. The lateral forces acting on the azobenzene polymer during the SRG fabrication drag the TiO2 nanoparticles. These results indicated that it is feasible to create TiO2 nanoparticle gratings with the composites. 相似文献
One-pot, three-component synthesis of spiro[diindenopyridine-indoline]triones has been reported via the reaction of 1,3-indandione, aromatic amines, and isatins with (PEG-OSO3H) as an efficient, polymeric acid surfactant–based catalyst in water and also in presence of acidic ionic liquid [NMP]H2PO4, which acts both as a medium and catalyst under conventional heating and ultrasonic irradiation. The reactions were complete in short reaction times with excellent yield of products. Surfactant-based PEG-OSO3H could be recycled and reused several times without any significant loss of activity. The compounds exhibit fluorescence in methanol with large Stokes shift. 相似文献