A controllable synthesis of multi-armed CdTe nanorods

A simple, productive and low-cost route has been developed to synthesize multi-armed CdTe nanorods using myristic acid (MA) as a complex agent. The yield of this approach can reach 75%. The dimension of the multi-armed nanorods can be controlled by tuning the molar ratios of Cd/Te and Cd/MA; the diameter can be changed from 2 to 7 nm while the length from 15 to 60 nm. The hexagonal structure was confirmed in x-ray diffraction analysis. However, it was assumed that one crystal is composed of the dominant hexagonal structure along with a cubic structure in the core.

Room-temperature strategy for networked nonspherical gold nanostructures from Au(III)-[G-2]-CO2H dendrimer complex

The present work describes a convenient approach to fabricate networked nonspherical gold nanostructures by using [G-2]-CO2H dendrimer and toluene as capping and bridging agents in a CH2Cl2 and H2O biphasic system. A controlled linear assembly is achieved without the use of any catalyst at room temperature. UV-vis spectrum, transmission electron microscopy (TEM), selected area electron diffraction (SAED), and X-ray diffraction (XRD) analysis show that the product is well networked nanostructures with diameter of 4-10 nm and consists of coalesced face-centered cubic gold nanocrystals. Extended experiments reveal that both benzene and dimethylbenzene can also inhabit the gold ions to make them crosslinked, prolong the nucleation points and eventually facilitate the formation of the networks.

Mercaptoethane sulfonate protected, water-soluble gold and silver nanoparticles: Syntheses, characterization and their building, multilayer films with polyaniline via ion-dipole interactions

Mercaptoethane sulfonate protected, water-soluble gold and silver nanoparticles (Au-MES and Ag-MES) are synthesized by one-phase method and characterized by TEM, TGA and XPS techniques, UV-vis and FTIR spectra. Both Au-MES and Ag-MES nanoparticles are soluble in the water up to 2.0 mg/ml and the stability of AU-MES is much better than that of Ag-MES. When dissolved in the water. they behave like a polyanion and can be used to build multilayer films with polyaniline (PANI) by way of layer-by-layer. A new approach is presented to fabricate the Multilayer films of Au-MES/PANI and Ag-MES/PAN]. The assembly mechanism of these multilayer films is also discussed. We anticipate highly conducting PANI films can be obtained by doping with these nanoparticles.

Rapid synthesis of cubic Pt nanoparticies and their use for the preparation of Pt nanoagglomerates

We report the synthesis of hexadecyltrimethylammonium bromide (CTAB)-stabilized cubic Pt nanoparticles by NaBH4 reduction of H2PtCl6 in aqueous CTAB solution. These Pt nanoparticles (average size of 7 nm) were well dispersed in aqueous solution and stable at least for 2 months. Addition of a trace amount of AgNO3 can alter the morphology of these Pt nanoparticles. More interestingly, the as-prepared uniform Pt nanoparticles were further developed into bigger Pt nanoagglomerates (similar to 20 to 47 nm) by a seed-mediate growth process. Dentritic and spherical Pt nanoagglomerates can be synthesized by altering the incubation time and their size can be tuned by controlling the amount of the seeds added.

Synthesis of neodymium hydroxide nanotubes and nanorods by soft chemical process

A facile soft chemical approach using cetyltrimethylammoniurn bromide (CTAB) as template is successfully designed for synthesis of neodymium hydroxide nanotubes. These nanotubes have an average outer diameter around 20 nm, inner diameter around 2 nm, and length ranging from 100 to 120 nm, high BET surface area of 495.71 m(2) g(-1). We also find that neodymium hydroxide nanorods would be obtained when CTAB absented in reaction system. The Nd(OH)(3) nanorods might act as precursors that are converted into Nd2O3 nanorods through dehydration at 550 degrees C. The nanorods could exhibit upconversion emission characteristic under excitation of 591 nm at room temperature.

Catalytic properties of silica/silver nanocomposites

The catalytic properties of silver nanoparticles supported on silica and the relation between catalytic activity of silver particles and the support (silica) size are investigated in the present article. The silver nanoparticles with 4 nm diameters were synthesized and were attached to silica spheres with sizes of 40, 78, 105 nm, respectively. The reduction of Rhodamine 6G (R6G) by NaBH4 was designed by using the SiO2/Ag core-shell nanocomposites as catalysts. The experimental results demonstrated that the catalytic activity of silica/silver nanoparticles depends on not only the concentration of catalysts (silver) but also the support silica size. Silver particles supported on small SiO2 spheres (similar to 40 nm) show high catalytic activity. Moreover, by making a comparison between the UV-vis spectra of the catalyst before and after the catalytic reaction, we found that the position of surface plasma resonance (SPR) peak of Ag nanoparticles changes little. The above results suggested that the size and morphology of silver particles were probably kept unchanged after the reduction of R6G and also implied that the catalytic activity of silver particles was hardly lost during the catalytic reaction.

Biodegradable electrospun poly(L-lactide) fibers containing antibacterial silver nanoparticles

Biodegradable poly(L-lactide) (PLA) ultrafine fibers containing nanosilver particles were prepared via electrospinning. Morphology of the Ag/PLA fibers and distribution of the silver nanoparticles were characterized. The release of silver ions from the Ag/PLA fibers and their antibacterial activities were investigated. These fibers showed antibacterial activities (microorganism reduction) of 98.5% and 94.2% against Staphylococcus aureus and Escherichia coli, respectively, because of the presence of the silver nanoparticles.

Syntheses, structures and luminescence of silver(I) sulfonate complexes with PPh3 ligand

In this paper, four new luminescent silver(I) sulfonate complexes with PPh3, namely Ag(L1)(PPh3)(2) (1), Ag(L2)(PPh3)(3) (2), [Ag-2(L3)(PPh3)(4) (H2O)center dot 1.5CH(3)CN center dot 0.5H(2)O (3) and [Ag-4(L4)(PPh3)(10)]center dot 8H(2)O (4), where L1=p-toluenesulfonate, L2=1-naphthalenesulfonate, L3=3-carboxylate-4-hydroxybenzenesulfonate, L4=1, 3, 6, 8-pyrenetetrasulfonatc and PPh3=triphenylphosphine, have been synthesized and characterized. The crystal structures were determined by single-crystal X-ray diffraction method. Compounds 1, 2, 3 and 4 adopt discrete structures rather than polymeric structures. Compounds I and 2 show mononuclear structures while 3 and 4 are dinuclear and tetranuclear molecules, respectively. Moreover the numbers of PPh3 molecules coordinating to one silver center are two or three. The photoluminescent properties of 1, 2 and 3 are discussed.

Fabrication of silver nanoparticles ring templated by plasmid DNA

Silver nanoparticles ring was successfully fabricated by electrostatic assembling 4-aminothiophenol (4-ATP) capped silver nanoparticles on predefined extended circular plasmid pBR322 DNA. The silver nanoparticles ring which was about 1.5 mu m in length, and about 2.2 nm in height can be obtained by adjusting the reaction time. The normal Raman scattering spectra reveal that the 4-ATP has contacted with the silver nanoparticles by forming a strong Ag-S bond. The AFM data show that the assembly of 4-ATP capped silver nanoparticles on DNA is ordered.

Fabrication of arrays of silver nanoparticle aggregates by microcontact printing and block copolymer nanoreactors

A combination of microcontact printing and block copolymer nanoreactors succeeded in fabricating arrays of silver nanoparticle aggregates. A complex solution of polystyrene-block-poly(4-vinylpyridine) micelles and silver salt was used as an ink to form thin films or droplets on polydimethylsiloxane stamp protrusions. After these complex aggregates were printed onto silicon substrates under controlled conditions, highly ordered arrays of disklike, dishlike, and dotlike complex aggregates were obtained. A Subsequent oxygen reactive ion etching treatment yielded arrays of silver nanoparticle aggregates.

Electrochemical detection of DNA immobilized on gold colloid particles modified self-assembled monolayer electrode with silver nanoparticle label

The target DNA was immobilized successfully on gold colloid particles associated with a cysteamine monolayer on gold electrode surface. Self-assembly of colloidal An onto a cysteamine modified gold electrode can enlarge the electrode surface area and enhance greatly the amount of immobilized single stranded DNA (ssDNA). The electrontransfer processes of [Fe(CN)(6)](4)-/[Fe(CN)(6)](3-) on the gold surface were blocked due to the procedures of the target DNA immobilization, which was investigated by impedance spectroscopy. Then single stranded target DNA immobilized on the gold electrode hybridized with the silver nanoparticle-oligonucleotide DNA probe, followed by the release of the silver metal atoms anchored on the hybrids by oxidative metal dissolution, and the indirect determination of the released solubilized Ag-1 ions by anodic stripping voltammetry (ASV) at a carbon fiber microelectrode. The results show that this method has good correlation for DNA detection in the range of 10-800 pmol/1 and allows the detection level as low as 5 pmol/1 of the target oligonucleotides.

A new alpha-Keggin type polyoxometalate coordinated to four silver complex moieties: {PW9V3O40[Ag(2,2 '-bipy)](2)[Ag-2(2,2 '-bipy)(3)](2)}

A new polyoxometalate derivative {PW9V3O40[Ag(2,2'-bipy)](2)[Ag-2(2,2'-bipy)(3)](2)} 1 has been hydrothermally synthesized and structurally characterized by the single crystal X-ray diffraction. X-Ray analysis showed that both [Ag(2,2'-bipy)](+) and [Ag-2(2,2'-bipy)(3)](2+) units are supported on the alpha-Keggin polyoxoanion [PW9V3O40](6-) via the surface bridging oxygen atoms. 1 represents the first alpha-Keggin type polyoxoanion coordinated with four transition metal complex moieties, which further acts as a neutral molecular units for the construction of an interesting three-dimensional supramolecular framework.

One-pot synthesis and characterization of novel silver-gold bimetallic nanostructures with hollow interiors and bearing nanospikes

One-pot preparation of shell-type silver-gold bimetallic nanostructures with hollow interiors and bearing nanospikes, based on colloid seed-engaged replacement reaction and colloid-mediated deposition reactions, has been reported. Heating-induced evolution of Ag-Au bimetallic nanoshells can lead to spontaneous production of nanospikes on the colloid surface. The hollow interior structure and bimetallic nature of the as-prepared colloids are characterized by transmission electron microscopy (TEM), UV-vis spectroscopy, and X-ray photoelectron spectroscopy (XPS).

Polyol-mediated synthesis of polyhedral silver clusters

Besides the spheres, polyhedral silver nanoclusters were prepared by the polyol process with 3-aminopropyl triethoxysilane (APTES). In the process, APTES acts as not only the stabilizer but also the template.

Surface-enhanced Raman spectroscopy of microperoxidase-11 on roughed silver electrodes

The conformation of microperoxidase-11 (MP-11) adsorbed on roughened silver electrodes was studied using surface-enhanced Fourier transform Raman spectroscopy. The results demonstrate that MP-11 was initially adsorbed via its polypeptide chain with a alpha-helix conformation, as indicated by the enhancement of the characteristic bands related to the amides I and III. The weak resonance effect of the porphyrin macrocycle in the near IR region contributes to the spectrum of the heme group. The presence of imidazole as the sixth ligand to the heme iron influences the conformation of the polypeptide chain of MP-11 on the electrode surface. Evaporation of solvent water results in an opened conformation of the adsorbed MP-11. which allows the heme group to contact the electrode surface directly.