scholarly journals Surface Compositional Change of Iron Oxide Porous Nanorods: A Route for Tuning their Magnetic Properties

Molecules ◽  
2020 ◽  
Vol 25 (5) ◽  
pp. 1234 ◽  
Author(s):  
Alberto Casu ◽  
Danilo Loche ◽  
Sergio Lentijo-Mozo ◽  
Andrea Falqui
Keyword(s):  
Magnetocrystalline Anisotropy ◽  
Shape Anisotropy ◽  
Colloidal Synthesis ◽  
Oxide Shell ◽  
Synthetic Approach ◽  
Magnetic Response ◽  
Compositional Change ◽  
The Core ◽  
Magnetic Hardening ◽  
Magnetic Features

The capability of synthesizing specific nanoparticles (NPs) by varying their shape, size and composition in a controlled fashion represents a typical set of engineering tools that tune the NPs magnetic response via their anisotropy. In particular, variations in NP composition mainly affect the magnetocrystalline anisotropy component, while the different magnetic responses of NPs with isotropic (i.e., spherical) or elongated shapes are mainly caused by changes in their shape anisotropy. In this context, we propose a novel route to obtain monodispersed, partially hollow magnetite nanorods (NRs) by colloidal synthesis, in order to exploit their shape anisotropy to increase the related coercivity; we then modify their composition via a cation exchange (CE) approach. The combination of a synthetic and post-synthetic approach on NRs gave rise to dramatic variations in their magnetic features, with the pores causing an initial magnetic hardening that was further enhanced by the post-synthetic introduction of a manganese oxide shell. Indeed, the coupling of the core and shell ferrimagnetic phases led to even harder magnetic NRs.

Phosphatidylcholine-mediated regulation of growth kinetics for colloidal synthesis of cesium tin halide nanocrystals

Nanoscale ◽  
2021 ◽  
Vol 13 (39) ◽  
pp. 16726-16733
Author(s):  
Lu-Ming Wang ◽  
Jia-Kai Chen ◽  
Bin-Bin Zhang ◽  
Qi Liu ◽  
Yang Zhou ◽  
...  
Keyword(s):  
Growth Kinetics ◽  
Low Cost ◽  
Colloidal Synthesis ◽  
Synthetic Approach ◽  
Regulation Of Growth

A general and low-cost synthetic approach has been developed for producing colloidal CsSnX3 perovskite NCs.

Photoluminescence of Hybrid Structure Base in ZnO@SiO2 Core-Shell Nanoparticles inside Porous Silicon

2019 ◽  
Vol 286 ◽  
pp. 40-48
Author(s):  
Xairo Leon ◽  
Edith Osorio ◽  
Rene Pérez-Cuapio ◽  
Carlos Bueno ◽  
Mauricio Pacio ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Luminescent Properties ◽  
Electrolyte Solutions ◽  
Hybrid Structure ◽  
Colloidal Synthesis ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Sem Images ◽  
Mesoporous Silicon ◽  
The Core

In this work, core-shell ZnO@SiO2nanoparticles (NPs) were infiltrated into a macro/meso-porous silicon (PS) structure, to study its luminescent properties. The core-shell ZnO@SiO2NPs were obtained by colloidal synthesis. The core-shell ZnO@SiO2NP was 5 nm in diameter. The macro/meso-PS structure was made in two steps: we obtained the macroporous silicon (macro-PS) layer fist and the mesoporous silicon (meso-PS) layer second. This process was conducted using different electrolyte solutions, and the change of electrolyte led to a decrease in the special charge region over the wall macro-PS layer; this allowed the building of the meso-PS layers on the walls and the bottom of the macro-PS layer. The SEM results show the cross-section of the macro/meso-PS structure with and without core-shell ZnO@SiO2NPs. These SEM images show that the core-shell ZnO@SiO2NPs that infiltrated into macro/meso-PS structure were more efficiently bonded over all the porous walls. The core-shell ZnO@SiO2PL interacted with the macro/meso-PS structure, modifying its PL intensity and controlling a shift toward a lower wavelength.

A heterotrimetallic synthetic approach in versatile functionalization of nanosized {MxCu13–xW7}3+ and {M1Cu8W6} (M = Co, Ni, Mn, Fe) metal–cyanide magnetic clusters

2019 ◽  
Vol 6 (11) ◽  
pp. 3104-3118 ◽  
Author(s):  
Michal Liberka ◽  
Jedrzej Kobylarczyk ◽  
Tadeusz M. Muziol ◽  
Shin-ichi Ohkoshi ◽  
Szymon Chorazy ◽  
...  
Keyword(s):  
Cluster System ◽  
Synthetic Approach ◽  
Magnetic Clusters ◽  
Metal Cyanide ◽  
Magnetic Features

The addition of 3d metal heteroatom into CuII(Me3tacn)[W(CN)8]n− cluster system governs its structural and magnetic features.

Post-synthetic methods for functionalization of imidazole-fused porphyrins

2018 ◽  
Vol 22 (08) ◽  
pp. 619-631 ◽  
Author(s):  
Inna A. Abdulaeva ◽  
Kirill P. Birin ◽  
Yulia G. Gorbunova ◽  
Aslan Yu. Tsivadze ◽  
Alla Bessmertnykh-Lemeune
Keyword(s):  
Aromatic Aldehyde ◽  
Synthetic Methods ◽  
Synthetic Approach ◽  
Synthetic Route ◽  
Bond Forming ◽  
The Core ◽  
Material Chemistry ◽  
Bond Forming Reactions ◽  
Palladium Catalyzed

Several methods for the post-synthetic modification of imidazo[4,5-[Formula: see text]]porphyrins are reported. First, a synthetic approach to the isomeric difunctionalized porphyrins, containing two [Formula: see text]-fused 2-aryl-1[Formula: see text]-imidazole cycles at adjacent or opposite pyrrole rings of the macrocycle is developed. The core chemistry of this synthetic route is the transformation of 2-aryl-1[Formula: see text]-imidazo[4,5-[Formula: see text]]porphyrins into corresponding imidazodioxochlorins followed by Debus–Radziszewski condensation with aromatic aldehyde. Next, 2-(4-bromophenyl)-1[Formula: see text]-imidazo[4,5-[Formula: see text]]-5,10,15,20-tetramesitylporphyrin was transformed into useful carboxy- and phosphonato-substituted precursors for material chemistry according to palladium-catalyzed C–C and C–P bond forming reactions.

Effects of the Co-Presence of Conflicting Magnetic Anisotropy in Ba Ferrite Particles

2010 ◽  
Vol 67 ◽  
pp. 108-112
Author(s):  
Giancarlo Bottoni
Keyword(s):  
Thermal Stability ◽  
Magnetic Properties ◽  
Magnetic Anisotropy ◽  
Low Temperatures ◽  
Magnetocrystalline Anisotropy ◽  
Shape Anisotropy ◽  
Recording Media ◽  
Magnetization Switching ◽  
Crystalline Anisotropy ◽  
Thermal Stability Of

In Ba ferrite particles magnetocrystalline and shape anisotropies are contemporarily present and conflicting. The strength and evolution of the two anisotropies are studied, through the dependence of the anisotropy constants on temperature. While in pure Ba ferrite particles the anisotropy is uniaxial at all temperatures, since the magnetocrystalline anisotropy clearly prevails on shape anisotropy, in particles modified for employment in recording media the two anisotropies are comparable and at low temperatures the shape anisotropy result stronger than the crystalline anisotropy. Besides the irregular shape of the particles introduces further preferred directions for the magnetization. The Co/Ti-doped particles show a multiple axes anisotropy. The macroscopic magnetic properties are found in relationship with the evolution of the anisotropy. Also the influence that the presence of such multiple anisotropy has on the magnetization switching and on the thermal stability of the magnetization of the Ba ferrite particles is analyzed.

Effect of Particle Size on the Oxidation Behavior of Nanophase Tin Synthesized by Inert Gas Condensation

2007 ◽  
Vol 119 ◽  
pp. 9-12
Author(s):  
J.S. Kim ◽  
Moo Young Huh ◽  
Jae Pyong Ahn
Keyword(s):  
Particle Size ◽  
Tin Oxide ◽  
Inert Gas ◽  
Oxide Shell ◽  
Gas Condensation ◽  
Size Dependent ◽  
The Core ◽  
Inert Gas Condensation ◽  
Effect Of Particle Size ◽  
Higher Temperature

Nanophase tin powder having sizes ranging from 6 to 40 nm was synthesized by the inert gas condensation method using helium as the convection gas. As-synthesized particles smaller than 8 nm were the amorphous tin oxide. As-synthesized particles larger than 10 nm can be characterized by the core-shell structure comprising inner crystalline tin core and outer amorphous tin oxide shell having a thickness of about 4 nm. Upon annealing in air, the oxidation of nanophase tin particles strongly depended on particle size. With increasing particle size, the transformation into the crystalline phases took places at a higher temperature. Calculation of the size dependent melting temperature of tin particles indicates that melting of the tin encapsulated with the amorphous tin oxide took place prior to the oxidation.

scholarly journals A Model for Late-Stage Modification of Polyurethane Dendrimers Using Thiol-Ene Click Chemistry

2021 ◽  
Author(s):  
Dhruba Poudel ◽  
Richard Taylor
Keyword(s):  
Click Chemistry ◽  
Late Stage ◽  
Click Reaction ◽  
Synthetic Approach ◽  
Protecting Group ◽  
One Pot ◽  
The Core ◽  
Curtius Reaction

Protecting group free, one-pot multicomponent Curtius reaction was utilized to afford diurethane G-1 dendron. In our synthetic approach, G-1 dendron can undergo late-stage modification using thiol-ene click reaction, which was then attached to the core to furnish a dendrimer. In another approach, the G-1 dendron was attached to the core and so formed dendrimer was surface functionalized using thiol-ene click chemistry. Either way, we can synthesize the dendrimer.

scholarly journals Nickel platinum (NixPt1−x) nanoalloy monodisperse particles without the core–shell structure by colloidal synthesis

2020 ◽  
Vol 2 (9) ◽  
pp. 3882-3889
Author(s):  
Cora Moreira Da Silva ◽  
Armelle Girard ◽  
Maxime Dufond ◽  
Frédéric Fossard ◽  
Amandine Andrieux-Ledier ◽  
...  
Keyword(s):  
Reduction Potential ◽  
Synthesis Temperature ◽  
Colloidal Synthesis ◽  
Core Shell ◽  
Monodisperse Particles ◽  
The Core ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
Core Shell Structure ◽  
Nickel Platinum

Versatile colloidal route towards the synthesis of nanoalloys with controlled size and chemical composition, based on the correlation between the oxidation–reduction potential of metal cations in the precursors and the synthesis temperature.

scholarly journals Dual chiral silver catalyst in the synthetic approach to the core of hepatitis C virus inhibitor GSK 625433 using enantioselective 1,3-dipolar cycloaddition of azomethine ylides and electrophilic alkenes

2017 ◽  
Vol 28 (10) ◽  
pp. 1423-1429 ◽  
Author(s):  
Ihssene Chabour ◽  
Luis M. Castelló ◽  
Juan Mancebo-Aracil ◽  
María Martín-Rodríguez ◽  
María de Gracia Retamosa ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Azomethine Ylides ◽  
Dipolar Cycloaddition ◽  
Synthetic Approach ◽  
Silver Catalyst ◽  
Virus Inhibitor ◽  
The Core

Synthesis and Characteristic of NiFe/NiFe2O4 Core-Shell Magnetic Nanocomposite Particles

2012 ◽  
Vol 486 ◽  
pp. 65-69
Author(s):  
Jun Hu ◽  
Ai Min Chen
Keyword(s):  
Structural Evolution ◽  
Treatment Temperature ◽  
Oxide Shell ◽  
Core Shell ◽  
Nanocomposite Particles ◽  
X Ray ◽  
The Core ◽  
Transmission Electron ◽  
Diffraction Patterns ◽  
Feni Alloy

NiFe/NiFe2O4 core-shell bimagnetic nanocomposite particles were successfully synthesized by colloidal chemical method combined with H2 reduction. The whole structural evolution process has been well studied through analysis of X-ray diffraction patterns and Infrared spectra. It has been found that FeNi alloy concentrated in the ferrite phase. The core/shell structure, a FeNi alloy core surrounded by NiFe2O4 spinel oxide shell were verified by X-ray powder diffraction (XRD), fourier transform infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM). The influence of post H2 heat treatment temperature on nanoparticles was investigated. The core-shell NiFe/ NiFe2O4 nanoparticles was about 100 nm after reduced at 727 K, The powders exhibited paramagnetic properties and the magnetization was 29.9 emu·g-1.

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