Synthesis and Optical Properties of Fe@Au,Ni@Au Bimetallic Core–Shell Nanoparticles

Fe@Au and Ni@Au core–shell nanoparticles (NPs) were synthesized by liquid-phase reduction of iron and nickel compounds by sodium borohydride in an aqueous medium. Transmission electron microscopy, X-ray powder diffraction, and spectrophotometry were used to confirm the structure of the NPs and to determine their shape and the average core and shell size.     

One-Step Photochemical Green Synthesis of Water-Dispersible Ag,Au, and Au@Ag Core–Shell Nanoparticles

A simple and green synthetic protocol for the rapid and effective preparation of Ag, Au and Au@Ag core–shell nanoparticles (NPs) is reported based on the light irradiation of a biocompatible, water-soluble dextran functionalized with benzophenone (BP) in the presence of AgNO₃, HAuCl₄, or both. Photoactivation of the BP moiety produces the highly reducing ketyl radicals through fast (<50 ns) intramolecular H-abstraction from the dextran scaffold, which, in turn, ensures excellent dispersibility of the obtained metal NPs in water. The antibacterial activity of the AgNPs and the photothermal action of the Au@Ag core–shell are also shown.     

Synthesis and Fluorescence Properties of Eu^2＋-Doped KMgF3 Nanoparticles

Introduction Nanomaterialsusuallyshowsomenoveloptical,electronic,magneticandchemicalpropertiessignifi cantlydifferentfromthoseofthebulkmaterialsbecause oftheirextremelysmallsize,largespecificsurfaceare asandpeculiarquantumsize.Thepotentialoftheirap plicat…     

Synthesis of Cu@Ag Nanoparticles with a Core–Shell Structure Stabilized with Oxyethylated Carboxylic Acid

Russian Journal of General Chemistry - Bimetallic Cu@Ag nanoparticles with a core–shell structure were synthesized by reduction of copper 2-[2-(2-methoxyethoxy)ethoxy]acetate with hydrazine...     

Photoinduced Electron Transfer from the Inorganic Core to the Organic Shell of Hybrid Core–Shell Nanoparticles: Impedance Spectroscopy

In hybrid core–shell nanoparticles with inorganic nanocrystals in the core and organic molecules in the shell, photoinduced electron transfer occurs from the core to the shell. This leads to exciton dissociation through an ultrafast electron-transfer process that results in charge separation and finally photocurrent in the external circuit in devices based on such core–shell nanoparticles. In this work, we have fabricated and characterized sandwiched devices based on a series of core–shell systems. From impedance spectroscopy, we have observed that photoinduced charge separation in core–shell systems is associated with a decrease in the device resistance and an increase in the dielectric constant of the active material. In the series of core–shell systems, we have observed a one-to-one correlation between the photoinduced electron-transfer process and the changes in resistive and dielectric parameters upon illumination.     

Synthesis of CuInS2@CdS Core‐Shell Nanocrystals

CuInS₂@CdS core‐shell nanocrystals were prepared in a wet chemical process. Transmission electron microscope (TEM), x‐ray energy dispersive spectroscopy (EDAX), x‐ray diffraction (XRD), absorption, and photoluminescence (PL) spectra were used to confirm the formation of the CuInS₂@CdS core‐shell structure. The growth of CdS shell not only increased the PL intensity, but also restrained the transformation of CuInS₂ from nanoparticles to nanorods after annealing, which was attributed to an effective chemical passivation of the CuInS₂ core by the CdS shell.     

Synthesis of Hollow SiO2 Nanoparticles from Dy2O3@SiO2 Core–Shell Nanocomposites via a Recyclable Sonochemical Method

Hollow silica nanoparticles were prepared from Dy₂O₃@SiO₂ core–shell nanocomposites, for the first time, by a simple ultrasonic assisted sol–gel method. The Dy₂O₃@SiO₂ core–shell nanocomposites were prepared by the deposition of a SiO₂ layer onto the surface of Dy₂O₃ nanoparticles using a three-step coating process. The hollow SiO₂ nanostructures were obtained by selective removal of the Dy₂O₃ cores. The structure, morphology and composition of the products were determined by the techniques of X-ray diffraction, Fourier transfom infrared spectroscopy, scanning electron microscopy, and transmission electron microscopy. The results indicated that hollow SiO₂ nanostructures were sphere-like shape with the average size of 20?nm and had an amorphous crystal structure. The important advantage of this process is the recyclability of the Dy₂O₃ nanoparticles as the starting material of the reaction.     

Microwave-Assisted Synthesis of ZnO–rGO Core–Shell Nanorod Hybrids with Photo- and Electro-Catalytic Activity

The unique two-dimensional structure and surface chemistry of reduced graphene oxide (rGO) along with its high electrical conductivity can be exploited to modify the electrochemical properties of ZnO nanoparticles (NPs). ZnO–rGO nanohybrids can be engineered in a simple new two-step synthesis, which is both fast and energy-efficient. The resulting hybrid materials show excellent electrocatalytic and photocatalytic activity. The structure and composition of the as-prepared bare ZnO nanorods (NRs) and the ZnO–rGO hybrids have been extensively characterised and the optical properties subsequently studied by UV/Vis spectroscopy and photoluminescence (PL) spectroscopy (including decay lifetime measurements). The photocatalytic degradation of Rhodamine B (RhB) dye is enhanced using the ZnO–rGO hybrids as compared to bare ZnO NRs. Furthermore, potentiometry comparing ZnO and ZnO–rGO electrodes reveals a featureless capacitive background for an Ar-saturated solution whereas for an O₂-saturated solution a well-defined redox peak was observed using both electrodes. The change in reduction potential and significant increase in current density demonstrates that the hybrid core–shell NRs possess remarkable electrocatalytic activity for the oxygen reduction reaction (ORR) as compared to NRs of ZnO alone.     

Selective Acceptorless Dehydrogenation of Primary Amines to Imines by Core–Shell Cobalt Nanoparticles

Core–shell nanocatalysts are attractive due to their versatility and stability. Here, we describe cobalt nanoparticles encapsulated within graphitic shells prepared via the pyrolysis of a cationic poly-ionic liquid (PIL) with a cobalt(II) chloride anion. The resulting material has a core–shell structure that displays excellent activity and selectivity in the self-dehydrogenation and hetero-dehydrogenation of primary amines to their corresponding imines. Furthermore, the catalyst exhibits excellent activity in the synthesis of secondary imines from substrates with various reducible functional groups (C=C, C≡C and C≡N) and amino acid derivatives.     

Preparation and Characterization of Polymer‐Protected Pt@Pt/Au Core‐Shell Nanoparticles

Poly(N‐vinyl‐2‐pyrolidone) protected Pt‐core bimetallic Pt/Au‐shell (Pt@Pt/Au) nanoparticles were prepared by multi‐step reduction of HAuCl₄ and H₂PtCl₆ alternately by hydrogen adsorbed on platinum atom. Transmission electronic microscopy (TEM) and x‐ray diffraction (XRD) were used to characterize Pt@Pt/Au nanoparticles. The structure of the shell of the nanoparticles seems to be the Au‐Pt solid solution.     

Core–Shell Composites Based on Partially Oxidized Blend of Detonation Synthesis Nanodiamonds

Russian Journal of Applied Chemistry - The results of a study on the production of graphite–diamond nanocompositions by partial oxidation of a detonation synthesis blend in aqueous solutions...     

Synthesis and Structure of a Novel Cluster with Trigonal-bipyramidal Ge_2Ru_3 Core

ＩｎｔｒｏｄｕｃｔｉｏｎＷｅｒｅｃｅｎｔｌｙｒｅｐｏｒｔｅｄａｎｉｎｔｒａｍｏｌｅｃｕｌａｒｔｈｅｒｍａｌｒｅａｒ ｒａｎｇｅｍｅｎｔｂｅｔｗｅｅｎＳｉ—ＳｉａｎｄＦｅ—Ｆｅｂｏｎｄｓｉｎｔｈｅｄｉｎｕ ｃｌｅａｒｉｒｏｎｃｏｍｐｌｅｘ { (Ｍｅ2 ＳｉＳｉＭｅ2 ) [(η5 Ｃ5Ｈ4 )Ｆｅ(ＣＯ) ]2 (μ ＣＯ) 2 } (Ｓｃｈｅｍｅ 1) .1 5Ｔｈｅｔｈｅｒｍａｌｒｅａｒｒａｎｇｅｍｅｎｔｗａｓｌａｔｅｒｅｘｔｅｎｄｅｄｔｏｇｅｒｍａｎｉｕｍ ｉｒｏｎａｎｄｓｉｌｉｃｏｎ ｒｕｔｈｅｎｉ ｕｍａｎａｌｏｇｕｅｓ .6 8Ｔｈ…     

Core–Shell Structured Chitosan-Polyethylenimine Nanoparticles for Gene Delivery: Improved Stability,Cellular Uptake,and Transfection Efficiency

The delivery of nucleic acids relies on vectors that condense and encapsulate their cargo. Especially nonviral gene delivery systems are of increasing interest. However, low transgene expression levels and limited tolerability of these systems remain a challenge. The improvement of nucleic acid delivery using depolymerized chitosan–polyethylenimine DNA complexes (dCS-PEI/DNA) is investigated. The secore complexes are further combined with chitosan-based shells and functionalized with polyethylene glycol (PEG) and cell penetrating peptides. This modular approach allows to evaluate the effect of functional shell components on physicochemical particle characteristics and biological effects. The optimized ternary complex combines a core-dCS-linear PEI/DNA complex with a shell consisting of dCS-PEG-COOH, which results in improved nucleic acid encapsulation, cellular uptake and transfection potency in human hepatoma HuH-7cells and murine primary hepatocytes. Effects on transgene expression are confirmed in wild-type mice following retrograde intrabiliary infusion. After administration of only 100 ng complexed DNA, ternary complexes induced a high reporter gene signal for three days. It is concluded that ternary coreshell structured nanoparticles comprising functionalized chitosan can be used for in vitro andin vivo gene delivery.     

Preparation and Chromatographic Features of Fibrous Core–Shell HPLC Packing Material

In this study, fibrous core–shell silica particles were successfully synthesized via a one-step oil–water biphase stratification coating strategy. The core–shell silica particles were composed of 3-µm non-pore silica cores and thin shells (50–100 nm), which have radial-like direct channels and a large pore size (19.89 nm). The fibrous core–shell silica particles were further modified by n-octadecyltrichlorosilane and used as stationary-phase media in high-performance liquid chromatography (HPLC). The chromatographic properties of the particles were systematically studied in small-molecule and protein separation processes. The results showed that the back pressure was as low as 8.5 MPa under the 1.0-mL min^?1 flow velocity. Furthermore, fibrous core–shell silica particles with an 80-nm shell were used for separating seven small molecules within 10 min and six proteins within 6 min. This work demonstrates that the fibrous core–shell silica particles could be used as an HPLC stationary phase with good performance and low back pressure, and that they have great potential for application to HPLC separation in the future.     

A General Catalyst Based on Cobalt Core–Shell Nanoparticles for the Hydrogenation of N-Heteroarenes Including Pyridines

Herein, we report the synthesis of specific silica-supported Co/Co₃O₄ core–shell based nanoparticles prepared by template synthesis of cobalt-pyromellitic acid on silica and subsequent pyrolysis. The optimal catalyst material allows for general and selective hydrogenation of pyridines, quinolines, and other heteroarenes including acridine, phenanthroline, naphthyridine, quinoxaline, imidazo[1,2-a]pyridine, and indole under comparably mild reaction conditions. In addition, recycling of these Co nanoparticles and their ability for dehydrogenation catalysis are showcased.     

Different Reactivity of Rutile and Anatase TiO2 Nanoparticles: Synthesis and Surface States of Nanoparticles of Mixed-Valence Magnéli Oxides

Magnéli phases Ti_nO_2n−1 (3<n≤10) are mixed Ti⁴⁺/Ti³⁺ oxides with high electrical conductivity. When used for water remediation or electrochemical energy storage and conversion, they are nanostructured and exposed to various environments. Therefore, understanding their surface reactivity is of prime importance. Such studies have been hindered by carbon contamination from syntheses. Herein, this synthetic and characterization challenge is addressed through a new approach to 50 nm carbon-free Ti₄O₇ and Ti₆O₁₁ nanoparticles. It takes advantage of the different reactivities of rutile and anatase TiO₂ nanoparticles towards H₂, to use the former as precursor of Ti_nO_2n−1 and the latter as a diluting agent. This approach is combined with silica templating to restrain particle growth. The surface reactivity of the Magnéli nanoparticles under different atmospheres was then evaluated quantitatively by synchrotron-radiation-based X-ray photoelectron spectroscopy, which revealed oxidized surfaces with lower conductivity than the core. This finding sheds a new light on the charge transfer occurring in these materials.     

Synthesis, Characterization and Properties of Novel Star-Shaped π-Conjugated Oligomers with Triphenylamine Core

Four new star‐shaped π‐conjugated oligomers ( TPA‐CZ3 , TPA‐TPA3 , TPA‐PTZ3 and TPA‐BT3 ) with triphenylamine as a core and different electron‐donating ability groups, carbazole, triphenylamine, phenothiazine and bithiophene, as peripheral units have been designed and synthesized via the Heck reaction. These oligomers show good solubility in common organic solvents. Their photophysical, electrochemical, electronic structure and charge transfer properties between these star‐shaped π‐conjugated oligomers and N,N′‐bis(1‐ethylpropyl)‐3,4:9,10‐perylene bis(tetracarboxyl diimide) (EP‐PDI) have been investigated by UV‐vis absorption spectra, photoluminescence (PL) spectra, cyclic voltammetry (CV) measurement, theoretical calculations and fluorescence quenching. The results show that the absorptions and fluorescences of TPA‐CZ3 , TPA‐TPA3 and TPA‐PTZ3 are red shifted with the electron‐donating ability of the peripheral unit increasing from carbazole to triphenylamine and phenothiazine. In addition, although the bithiophene group has a weaker electron‐donating ability than carbazole, triphenylamine and phenothiazine, the absorption and fluorescence of TPA‐BT3 have a red shift than those of TPA‐CZ3 , TPA‐TPA3 and TPA‐PTZ3 because TPA‐BT3 has a longer conjugation length than TPA‐CZ3 , TPA‐TPA3 and TPA‐PTZ3 . The triphenylamine core and the peripheral units can constitute a large conjugated structure. The fluorescence quenching properties indicate that efficient charge transfer can happen between the star‐shaped oligomers and EP‐PDI.     

Synthesis and Crystal Structure of a Novel (2:2) Macrocyclic Thiocarbohydrazone

Thiocarbohydrazoneshavebeentestedasantindcrobialandantitumouragentsandwidelyusedinanalyticalchemistry'-'.Ontheotherhand,thechemistryofmacrocycliccompoundshasattTactedcontinuousinterestformanyyears.Thiocarbohydrazide,HZN'N'HC(S)NHN'Hz,anditsSchiffbasecomplexesconstitUteintersstingligandsystemsbecauseoftheavailbilityofseveralpotentialdonorsites,inwhichthioketo-thioenoltautomerismispossible.Significantly,theyareabletoformbothmono-andbinuclearcomplexesbydifferentmethods3-6.Withtheaimofdesign…     

Core–Shell Structured NaYF4:Yb,Er Nanoparticles with Excellent Upconversion Luminescent for Targeted Drug Delivery

Journal of Cluster Science - A core–shell-structured composite by combining mesoporous silica with upconversion luminescence (UCL) property had considerable application potentials in the...     

Radioluminescence of Europium(III) in POCl3–SnCl4–235UO2+ 2–Eu3+, and D2O–235UO2+ 2–Eu3+ Solutions

Results of studying the spectral and luminescent properties of Eu³⁺ ions upon homogeneous excitation of POCl₃–SnCl₄–^-UO²⁺ ₂–Eu³⁺ and D₂O–²³⁵UO²⁺ ₂–Eu³⁺ solutions by -particles are presented. It was found that the radioluminescence intensity of Eu³⁺ ions in both solvents increases proportionally to the energy input by -particles. The yield of radioluminescence photons from europium ions in the POCl₃–SnCl₄–UO²⁺ ₂–Eu³⁺ solutions is more than nine times as high as that in D₂O–UO²⁺ ₂–Eu³⁺. The radiation-chemical yields of excited ⁵ D ₀ states of Eu³⁺ ions are 0.74 ± 0.07 and 0.18 ± 0.02 ions/100 eV in POCl₃–SnCl₄–UO²⁺ ₂–Eu³⁺ and D₂O–UO²⁺ ₂–Eu³⁺ solutions, respectively.