Sharif Digital Repository

A new plasmonic Ag hybridized CuWO4/WO3 heterostructure was successfully synthesized via a ligand-assisted sol gel method. The as-prepared plasmonic nanohybrid was thoroughly characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-visible spectroscopy, photoluminescence (PL) spectrometry, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, Brunauer-Emmett-Teller (BET) surface area analysis and electrochemical impedance spectroscopy (EIS). Moreover, the photocatalytic activity was evaluated by photo-degradation of methylene blue (MB) under visible light irradiation. The results indicate that the as-prepared plasmonic Ag-CuWO4/WO3 nanohybrid (compared to pure... 

Graphene-based materials are revealing the leading edge of advanced technology for their exceptional physical and chemical properties. Chemical manipulation on graphene surface to tailor its unique properties and modify atomic structures is being actively pursued. Therefore, the discovery of robust and general protocols to anchor active functionality on graphene basal plane is still of great interest. Multicomponent reactions promise an enormous level of interest due to addressing both diversity and complexity in combinatorial synthesis, in which more than two starting compounds react to form a product derived from entire inputs. In this article, we present the first covalent... 

Dinuclear cis-dioxomolybdenum(VI) complex [{MoO 2(Bz 2Benzenediyldtc)} 2] coordinated by a quadradentate dithiocarbamate (Bz 2Benzenediyldtc 2- = 1,4-benzenediylbis(benzyldithiocarbamate)(2-)) has been prepared and characterized by elemental analysis, 13C NMR, IR and UV-vis spectroscopy. The kinetics of the oxygen atom transfer between [{MoO 2(Bz 2Benzenediyldtc)} 2] and PPh 3 was studied spectrophotometrically in CH 2Cl 2 medium at 520 nm and four different temperatures, 288, 293, 298 and 303 K, respectively. The reaction follows second order kinetics with the rate constant k = 0.163(2) M -1 S -1 and its increasingly strong absorption at 520 nm clearly indicate the formation of a μ-oxo... 

The interaction of [60]fullerene with a series of 15-19-membered macrocycles containing an O 2N 2-donor set has been investigated by UV-visible spectroscopy. The formation constants arising from the complexation of [60]fullerene with these azacrown macrocycles, having various ring size, were determined in CHCl 3 media applying Benesi-Hildebrand equation. The stoichiometry has been found by the Job method in each case. The thermodynamic parameters, for example, formation enthalpies (δH o) and entropies (δS o), for these complexation were also determined. Experimentally, it was found that macroring size of the azacrown has a prominent effect on azacrown complexation with [60]fullerene in terms... 

The morphological manipulation, structural characterization, and optical properties of different CdSe nanocrystals were reported. Several different CdSe nanostructures, including nanowires, tetrapod crystals, and nanoparticles were grown by varying the volume ratio of triethylenetetraamine (TETA) and water (WA) in their mixed solution. By manipulating the growth driving force (i.e., the degree of supersaturation) and kinetics of the process (i.e., growth rate), the morphology and crystal structure of CdSe nanocrystals can be tailored. Growth driving force changed their morphology from nanowires to tetrapod structures and from the latter structure to nanoparticles. Moreover, kinetics of the... 

This research reports the preparation and examination of Cadmium Telluride (CdTe) Quantum Dots and doping CdTe QDs with Europium (Eu), Gadolinium (Gd), and Manganese (Mn) prepared in aqueous solution using TGA as a capping agent. Magnetic QDs (MQDs) are important agents for fluorescence (FL) /magnetic resonance (MR) dual-modal imaging due to their excellent optical and magnetic properties. Herein, the chemical bonds, structural, fluorescence, and magnetized properties of CdTe QDs and effect of Mn, Eu, and Gd ions doping on their properties were examined by X-ray powder diffraction (XRD), high-resolution transmission electron microscopy (HRTM), Energy-dispersive X-ray spectroscopy (EDX),... 

Magnetic nanocomposite hydrogels containing different amounts of graphene oxide were synthesized and characterized by FTIR, XRD, TGA, SEM, TEM, VSM and UV-vis spectroscopy. The prepared hydrogels were used as adsorbents for removal of a cationic dye, crystal violet, from water. The kinetics and isotherm of adsorption and the effect of different experimental conditions such as graphene oxide content, pH of the solution, contact time, adsorbent dosage and initial dye concentration on adsorption capacity were then investigated. Parameters related to kinetics and isotherm models were calculated and discussed. It was found that adsorption is well-described by pseudo-second-order kinetics and... 

In the present study, bubble-driven magnesium-based micromotors were fabricated through a shading method, and the potential of magnetic guidance of magnesium-based Janus micro/nanomotors through functionalization with superparamagnetic iron oxide nanoparticles (SPIONs) was investigated for the first time. SPIONs had physical electrostatic attraction with the positively charged magnesium spheres due to negative charges on their surfaces. It was also found that upon applying a field gradient, the micromotors’ velocity increased by 13% unlike other magnetically navigated spherical magnesium-based micromotors which only show a change in direction. In this work the cytotoxicity of the moving... 

The present investigation introduces a new series of cycloplatinated(II) complexes, with the general formula Pt(O-bpy)(Me)(CN-R)] (R = benzyl, 2-naphtyl and tert-butyl), which are able to generate the stable trans-Pt(IV) product in the solution after the reaction with iodomethane. In fact, the trans product is both the kinetic and thermodynamic product of the reaction; this observation was supported by DFT calculations. These Pt(II) complexes are supported by 2,2'-bipyridine N-oxide (O-bpy) and one of several isocyanides as the cyclometalated and ancillary ligands, respectively. These new Pt(II) complexes undergo oxidative addition with MeI to give the corresponding trans-Pt(IV) complexes.... 

A recyclable optical nanosensor was developed by immobilizing L-tyrosine functionalized silver nanoparticles (AgNPs) on the polyethylene terephthalate (PET) substrate for rapid determination of Pb2+ ions. At first, the L-tyrosine functionalized AgNPs were assessed in the solution phase; the response time was lower than 15 s, and a limit of detection lower than 9 nM was obtained in the dynamic range of 1–1000 nM. For fabrication of the optical assay kit, the design of experiment (DOE) was used to optimize the immobilization efficiency of the nanoparticles on PET films by studying AgNO3 concentration and pH as two crucial parameters. The assay kit in optimal conditions showed a sharp localized... 

A series of new ternary zinc(II) complexes [Zn(L1-10)(phen)], where phen is 1,10-phenanthroline and H2L1-10 = tridentate Schiff base ligands derived from the condensation of amino acids (glycine, l-phenylalanine, l-valine, l-alanine, and l-leucine) and salicylaldehyde-5-sulfonates (sodium salicylaldehyde-5-sulfonate and sodium 3-methoxy-salicylaldehyde-5-sulfonate), have been synthesized. The complexes were characterized by elemental analysis, IR, UV-vis, 1H NMR, and 13C NMR spectra. The IR spectra of the complexes showed large differences between νas(COO) and νs(COO), Δν (νas(COO) - νs(COO)) of 191-225 cm-1, indicating a monodentate coordination of the carboxylate group. Spectral data... 

Colloidal copper nanoparticles were prepared by pulsed Nd:YAG laser ablation in water and acetone. Size and optical properties of the nanoparticles were characterized by transmission electron microscopy and UV-visible spectrophotometry, respectively. The copper particles were rather spherical and their mean diameter in water was 30 nm, whereas in acetone much smaller particles were produced with an average diameter of 3 nm. Optical extinction immediately after the ablation showed surface plasmon resonance peaks at 626 and 575 nm for the colloidal copper in water and acetone, respectively. Time evaluation showed a blue shift of the optical extinction maximum, which is related to the change of... 

Synthesis of colloidal metal oxides with controllable size and morphology is burgeoning field of research in nanoscience. Low band gap gray Zn/ZnO colloidal nanoparticles were fabricated by plasma-liquid interaction of DC arc discharge in water. Scanning electron microscopy, X-ray diffraction and UV–vis spectroscopy were employed for morphology, crystal structure and optical characterizations respectively. Optical emission spectroscopy was used to investigate the plasma properties during the synthesis and formation mechanism of nanoparticles. Nanoparticles with different size and shape were fabricated only by adjusting discharge current during synthesis without introducing any chemical... 

Titanium does not react well with the human tissues and due to its bio-inert nature the surface modification has yet to be well-studied. In this study, the sonoelectrochemical process has been carried out to generate TiO2 nanotube arrays on implantable Ti 6–4. All the prepared nanotubes fill with the vancomycin by immersion and electrophoresis method. Drug-releasing properties, antibacterial behavior, protein adsorption and cell attachment of drug-modified nanotubes are examined by UV–vis, flow cytometry, modified disc diffusion, BSA adsorption, and FESEM, respectively. The most uniform morphology, appropriate drug release, cell viability behavior and antibacterial properties can be achieved... 

The present work was aimed to account a green and eco-friendly synthesis of palladium nanoparticles using Rosmarinus officinalis leaves extracts for the first time, therefore, that can be an acceptable replacement for chemical media to improve potential biological properties. The synthesized palladium nanoparticles were fully characterized using FT-IR, XRD, FESEM, TEM and UV/Vis spectroscopy techniques. Catalytic activity was investigated by Mizoroki-Heck reaction, and optimized based on solvent, temperature and time of the reaction, and the best results were found in water as a green media without any additional reagents. Biological activity of the synthesized nanoparticles were evaluated... 

Herein, MIL-101(Fe), CoFe2O4, novel binary (MIL-101(Fe)/CoFe2O4, MIL-101(Fe)/GO and CoFe2O4/GO), and ternary (MIL-101(Fe)/CoFe2O4/(3%)GO and MIL-101(Fe)/CoFe2O4/(7%)GO) magnetic composites based upon the MIL-101(Fe) were synthesized. The XRD, FESEM, TEM, EDX, BET-BJH, FTIR, VSM, DRS, PL, EIS and other electrochemical analyses were applied to characterize samples. The MIL/CoFe2O4/(3%)GO demonstrated the best performance compared to other samples for visible light photocatalytic and photo-Fenton-like degradation of Direct Red 23 (DtR-23), Reactive Red 198 (ReR-198) dyes as well as Tetracycline Hydrochloride (TC-H) antibiotic. Degradation of dyes using the ternary composite after 70 min of... 

Photocatalytic membrane reactors (PMRs), coupling photocatalysts and membranes in a single system, have shown a considerable potential to reduce membrane fouling, which is one of the major drawbacks of using membranes to treat water and wastewater. In this study, the visible light-activated photocatalysts were incorporated into the polyacrylonitrile (PAN) casting solution to synthesize the photocatalytic composite membranes. The physicochemical properties and the morphology of the membranes and photocatalysts were characterized by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), X-ray diffraction analysis (XRD), ultraviolet–visible diffuse reflectance... 

Tungsten oxide nanoparticles were fabricated by a pulsed laser ablation method in deionized water using the first harmonic of a Nd:YAG laser (λ = 1064 nm) at three different laser pulse energies (E1 = 160, E2 = 370 and E3 = 500 mJ/pulse), respectively. The aim is to investigate the effect of laser pulse energy on the size distribution and gasochromic property of colloidal nanoparticles. The products were characterized by dynamic light scattering (DLS), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and UV-Vis spectroscopy. The results indicated that WO 3 nanoparticles were formed. After ablation, a 0.2 g/l PdCl 2 solution was added to activate the solution against... 

A manganese porphyrin, meso-tetrakis(pentafluorophenyl)porphyrinato manganese(iii) acetate, Mn(TPFPP)OAc, was immobilized on silica-coated magnetic Fe3O4 nanoparticles functionalized with 3-aminopropyltriethoxysilane (APTS) through the amino propyl linkage using a grafting process in toluene solvent. This enabled the covalent immobilization of Mn(iii) porphyrin via an aromatic nucleophilic substitution reaction, to afford the Fe3O4@SiO2-NH2@MnPor catalyst. The resulting nanoparticles were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), FT-IR spectroscopy, UV-Vis spectroscopy, elemental analysis (CHN), atomic absorption spectroscopy (AAS), and vibrating... 

In recent years, the importance of capturing CO2 has increased due to the necessity of minimizing climate change and the detrimental effects of CO2 emissions from industrial processes. CO2 absorption, as one of the most mature carbon capture technologies, has been improved by introducing nanosized particles into liquid absorbents. Nanofluids have been the subject of interest in many studies recently due to their tremendous impact on absorption. This review comprehensively examines the CO2 absorption behavior for nanofluids through the investigation of different absorption systems. Potential mechanisms for improving the absorption/regeneration performance of nanoabsorbents as well as the...