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ABSTRACT: A new silsesquioxane molecule was synthesized, in which triphenyl benzene was connected with three Si(OC2H5)3 groups using three urea groups as the bridge. The molecule could self-assemble through the intermolecular H-bonding among urea groups and pi-pi interaction of triphenyl benzene core in the solution and it could also be transferred into hybrid silicas by hydrolysis. When the non-preorganized silsesquioxane was hydrolyzed, isolated spherical hybrid silica was gained. However, when the silsesquioxane was preorganized before the hydrolyzation uniform interconnected spherical hybrid silica and intertwined nanofibrous one could be generated under acidic and basic conditions, respectively. The photoluminescence (PL) spectra of the obtained hybrid silicas showed that they still kept the emission properties of their precursor silsesquioxane, and the shift of the emission bands was due to the pi-pi interaction of triphenyl benzene in the course of polycondensation.
Journal of Nanoscience and Nanotechnology 09/2006; 6(8):2560-5. · 1.56 Impact Factor
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ABSTRACT: We report the synthesis and self-assembly of a new pi-conjugated dichalcone substituted carbazole-based low molecular mass organogelator. It could form stable gels in most halogen-aromatic solvents. The transmission electron microscopy (TEM) images revealed that the gel formed fibrous structures with diameter of 50-100 nm, which consisted of several thinner fibers. The FT-IR, UV-vis and XRD results suggested that the H-bonds and pi-pi interactions were the main driving forces for the formation of the self-assembled gel, in which the U-shaped molecules were stacked into lamellar structures. The fluorescent spectra showed that the emission of the xerogel red-shifted markedly compared with the sol state, which resulted from the aggregation of the molecules.
Organic & Biomolecular Chemistry 08/2006; 4(13):2591-4. · 3.70 Impact Factor
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ABSTRACT: We report on the synthesis and self-assembly of a new series of discotic molecules containing triphenylbenzene as the core and alkoxy side chain with varying length. It was found that compounds 3 a-c, 4 b and 5 b could form stable gels in several apolar solvents. Transmission electron microscopy (TEM) images revealed that their morphologies were very different for the different alkoxy-substituted organogels. In toluene or hexane, 3 b and 3 c resulted in both left- and right-handed helical fibers, whereas 3 a resulted in straight rigid fibers; 4 b and 5 b resulted in most straight fibers with a few twisted fibers. The results from FT-IR and UV/Vis absorption spectroscopy indicated that the hydrogen bonding and pi-pi interactions were the main driving forces for the formation of the self-assembled gels. Further detailed analysis of their aggregation modes were conducted by UV-visible absorption spectra and X-ray diffraction (XRD) measurements. Based on these findings, the influence of these peripheral alkoxy substituents on the gel formation and the aggregation mode were discussed. The special enhanced fluorescent emissions, which resulted from aggregation, were also found in the gel phase.
Chemistry 04/2006; 12(12):3287-94. · 5.93 Impact Factor
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ABSTRACT: A new hydrogel based on glucose-appended Schiff base derivative has been employed as the template to synthesize CdS and NiS nanostructures with different morphologies. The FT-IR and UV-vis results revealed that H-bonding and pi-pi interaction played important roles in the formation of original hydrogel fibers. The study of mineralization mechanism suggested that the inorganic ions were firstly adsorbed at the surface of the hydrogel fibers due to the hydrophilic affinity with the hydrophilic glucose groups. With the penetration of H2S gas, the preformed CdS or NiS nanoparticles on the surface of the fibers acted as the growing points for the continuous growth. And the different adsorption abilities of the metal ions at the hydrogel fibers resulted in the formation of CdS nano-necklaces and NiS nanotubes.
Journal of Nanoscience and Nanotechnology 04/2006; 6(3):807-12. · 1.56 Impact Factor
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ABSTRACT: A new series of binary organogels, which showed good gelated capability and strongly enhanced fluorescence emission, were designed and prepared by simply mixing two components of L-tartaric acid and alkoxyl substituted stilbazoles. It was found that L-tartaric acid could not only introduce stilbazole with fluorescent property into the gel system, but also provided a main motif for the formation of the gel-phase via multiple hydrogen bonds. Meanwhile, pi-pi interactions between the complexes also played a key role in the gel formation. The decreased nonradiative process, suggested by the longer fluorescent lifetime of aggregates than that of monomers and the presence of the J-aggregation for the aggregated state, favored the enhanced fluorescence emission.
Organic & Biomolecular Chemistry 08/2005; 3(14):2508-12. · 3.70 Impact Factor
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ABSTRACT: A new cholesterol organogelator 1 was synthesized, which was confirmed as an effective gelator for various organic solvents and could self-assemble into network fibers in some organic solvents. Moreover, gelator 1 could act as templates for the synthesis of various CuS nanofibers with different helical pitches. For example, when H(2)S was used as the sulfur source, straight and bending helical CuS nanofibers with a pitch of 100-200 nm could be fabricated in butyl acetate and benzene-butanol gel systems, respectively, while bending CuS nanofibers with a similar helical pitch (ca. 50 nm) could be obtained when thioacetamide was used as the sulfur source in both gel systems. It was first found that the morphologies of inorganic nanofibers could be controlled by the binding sites between the inorganic precursor and the organogel.
Langmuir 01/2005; 20(25):11234-9. · 4.19 Impact Factor
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ABSTRACT: Hydrogels based on beta-D-glucopyranoside-substituent thiosemicarbazide derivatives were synthesized and used as template to fabricate netlike CdS nanofibers. The self-assembling properties of the hydrogels and their effect on the synthesis of CdS nanostructure were studied. Fourier transform infrared spectra, UV-visible absorption spectra and X-ray diffraction revealed that pi-pi stacking, hydrogen bonds and interdigitated interactions between hydrophobic chains had influence on the formation of self-assembled lamellar hydrogel. Transmission electron microscopic and electron diffraction observation showed the formation of hexagonal stacking nanofiber-based CdS semiconductor materials. The transmission electron microscopic pictures of the CdS nanostructure in difference growth stages revealed the growth mechanism of CdS nanofibers templated by hydrogel.
Journal of Nanoscience and Nanotechnology 12/2004; 4(8):1045-51. · 1.56 Impact Factor
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ABSTRACT: A new cholesterol organogelator 4 was synthesized and its gelation property was evaluated. It was confirmed that 4 was an effective gelator for various organic solvents and could self-assemble into network fibers with a bilayer of folded conformation in some organic solvents. Moreover, organogelator 4 could act as a template for the synthesis of novel pearl-necklace porous CdS nanofibers. The transcription process of organogel fibers into CdS nanofibers was investigated, and it was found that Cd2+ ions were coated on the organogel fibers by the interaction with ester groups of 4, which might lead to the change of the arrangement of the organogelator and seemed to serve as nucleation sites for metalization. The further growth of CdS began with these nucleation sites along the organogel fibers. Meanwhile, parts of 4 free from organogel fibers have an effect on the formation of the CdS nanofibers consisting of the network and wormlike CdS particles.
Langmuir 08/2004; 20(15):6470-5. · 4.19 Impact Factor
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ABSTRACT: A new hydrogel based on a substituted phenyl glucoside with a Schiff base in the aglycon was synthesized, and the self-assembling characteristics was studied. FTIR spectra, UV-vis absorption spectra and X-ray diffraction (XRD) revealed that pi-pi interactions between the Schiff base moieties, hydrogen bonds, and the interdigitated interactions between hydrophobic chains had effects on the formation of the self-assembling hydrogel. Scanning electron microscopic (SEM) and transmission electron microscopic (TEM) observation showed that the three-dimensional hydrogel network was constructed from nanotubes with inner diameters of ca. 75 nm and wall of ca. 20 nm.
Carbohydrate Research 06/2004; 339(7):1311-6. · 2.33 Impact Factor
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ABSTRACT: The synthesis of Au and Ag metal nanoparticles stabilized by G4, G5, and G6 hyperbranched poly(amine–ester) (HPAE) is reported. The reduction of hydrogen tetrachloroaurate and silver nitrate in the presence of HPAE resulted in the formation of stable, uniform, water-soluble nanoparticles. The average particle sizes are (2.4 ±0.5)–(4.1 ±0.4) nm for Au and (2.5 ±4.9)–(10.3 ±1.7) nm for Ag, depending on the generation of HPAE and metal ion-to-end tertiary amine of HPAE (M:N) used. All of the obtained colloidal solutions are stable for a long period of time. The results from ultraviolet–visible absorption spectra and Fourier transform infrared absorption spectroscopic investigations confirm the interactions between metal and HPAE.
Journal of Materials Research. 05/2003; 18(06):1392 - 1398.
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ABSTRACT: This paper presents novel organogelators based on long chain substituted benzoic acid hydrazine which can form stable gels in bulk organic solvents and self-assemble into various microstructures in organogel phases. It is found that hydrogen bonding and van der Waals interaction play an important role on the formation of organogel.
Journal of Molecular Liquids.
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ABSTRACT: Copper sulfides were synthesized by using the low-molecular-mass hydrogel nanofibers self-assembled from a L-glutamic acid derivative. The as-prepared copper sulfides showed a nanoribbon structure with diameter of 30–70 nm and lengths of 1–10 μm. The investigation of FT-IR absorption spectra and XRD pattern for the neat hydrogel and composite gel suggested that H-bonding was the main driving force to help the formation of ordered nanofibers of the hydrogel and the composite gel. The resulted mineralization indicated that the inorganic ions (Cu2+) were firstly coordinated to the carboxylate anions (COO−). With the penetration of H2S, the preformed CuS nanoparticles on the surface of the fibers acted as the growing points for the continuous growth.
Materials Chemistry and Physics 112(2):500-503. · 2.23 Impact Factor
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ABSTRACT: This paper presents a novel method for the preparation of copper sulfide (CuS) nanotubes using hydrogel based on N-lauroylalanine as template under mild condition. The resulting samples are examined by transmission electron microscopy (TEM) FT-IR spectroscopy, X-ray powder diffraction (XRD), UV–vis absorption spectroscopy. It is found that the intermolecular hydrogen bonds play an important role on the formation of the hydrogel and the Cu2+ coordination gel. The formation process of CuS nanotube is also discussed.
Materials Chemistry and Physics 91(1):44-47. · 2.23 Impact Factor
