Synthesis of transparent magnetic particle/organic hybrid film using iron–organics

2000 ◽  
Vol 15 (10) ◽  
pp. 2114-2120 ◽  
Author(s):  
Toshinobu Yogo ◽  
Tomoyuki Nakamura ◽  
Wataru Sakamoto ◽  
Shin-ichi Hirano
Keyword(s):  
Iron Oxide ◽  
Magnetization Curve ◽  
Magnetic Particles ◽  
Magnetic Particle ◽  
Hybrid Film ◽  
Oxide Particle ◽  
Iron Oxide Particle ◽  
Organic Hybrid ◽  
Hydrolysis Conditions

A transparent magnetic particle/organic film was synthesized from an iron–organic compound. Iron(III) 3-allylacetylacetonate (IAA) was polymerized followed by in situ hydrolysis yielding an iron oxide particle/oligomer hybrid. The sizes of magnetic particles were dependent upon the hydrolysis conditions of the IAA oligomers. A nanometer-sized ferrimagnetic iron oxide particle/oligomer hybrid showed a magnetization curve with no coercive force at 300 K and that with Hc of 200 Oe at 4.2 K, respectively. The magnetization versus H/T curves at 300 and 77 K were superimposed on each other and satisfied the Langevin equation. The transparent hybrid film showed a magnetization curve at room temperature. The absorption spectrum of the film was shifted to higher energy by 0.14 eV compared with that of bulk magnetite. The absorption edge of the film was blue-shifted.

Synthesis of magnetic particle/organic hybrid from metalorganic compounds

1999 ◽  
Vol 14 (7) ◽  
pp. 2855-2860 ◽  
Author(s):  
Toshinobu Yogo ◽  
Tomoyuki Nakamura ◽  
Wataru Sakamoto ◽  
Shin-ichi Hirano
Keyword(s):  
Iron Oxide ◽  
Magnetic Particle ◽  
Oxide Particle ◽  
Iron Oxide Particle ◽  
X Ray Diffraction ◽  
Organic Hybrid ◽  
Reducing Conditions ◽  
Nanocrystalline Particles ◽  
Oxide Spinel

A nanocrystalline magnetic particle/oligomer hybrid was successfully synthesized by polymerization of iron(III) 3-allylacetylacetonate (IAA) followed by in situ hydrolysis. An iron oxide particle/oligomer hybrid was synthesized by hydrolysis of the IAA oligomer under alkaline and reducing conditions by the addition of hydrazine or methylhydrazine. Crystalline particles of approximately 10 nm were found to be dispersed in the oligomeric matrix. The nanocrystalline particles were identified to be iron oxide spinel by x-ray diffraction analysis and electron diffraction. The nanometer-sized ferrimagnetic iron oxide particle/oligomer hybrid showed a typical superparamagnetic behavior.

Synthesis of spinel iron oxide nanoparticle/organic hybrid for hyperthermia

2008 ◽  
Vol 23 (12) ◽  
pp. 3415-3424 ◽  
Author(s):  
Koichiro Hayashi ◽  
Toshifumi Shimizu ◽  
Hidefumi Asano ◽  
Wataru Sakamoto ◽  
Toshinobu Yogo
Keyword(s):  
Magnetic Field ◽  
Iron Oxide ◽  
Photoelectron Spectroscopy ◽  
Iron Oxide Nanoparticle ◽  
Organic Hybrid ◽  
Oxide Nanoparticle ◽  
Hydrolysis Conditions ◽  
Size Controlled ◽  
Controlled Hydrolysis

Size-controlled spinel iron oxide (SIO) nanoparticle/organic hybrid was synthesized in situ from iron (III) allylacetylacetonate (IAA) at around 80 °C. The formation of SIO particles chemically bound with organics was confirmed by infrared and x-ray photoelectron spectroscopy. The sizes of SIO nanoparticles in the hybrids were monodispersed and ranged from 7 to 23 nm under controlled hydrolysis conditions. The hybrid including SIO particles of 7.3 nm was superparamagnetic, whereas those dispersed with particles above 11 nm were ferrimagnetic. The specific absorption rate (SAR) value was dependent upon the magnetic properties of the hybrid at 100 Oe. The SAR was 15.2 W g−1 in a 230 kHz alternating magnetic field and 100 Oe when the crystallite size of SIO particle in the hybrid was 16 nm. The temperatures of agars dispersed with hybrid powders of 5 and 8 mg ml−1 reached the optimum temperature (42 °C) for 17 and 8 min, respectively. The increase in temperature was controlled in terms of the strength of magnetic field. The simulation of heat transfer in the agar phantom model revealed that the suitable temperature distribution for therapy was attained from 15 to 20 min at 230 kHz and 100 Oe.

In situ Synthesis of Nickel Ferrite Nanoparticle/organic Hybrid

2005 ◽  
Vol 20 (6) ◽  
pp. 1590-1596 ◽  
Author(s):  
Satoshi Nakamura ◽  
Wataru Sakamoto ◽  
Toshinobu Yogo
Keyword(s):  
Photoelectron Spectroscopy ◽  
Nickel Ferrite ◽  
Oxide Particle ◽  
Organic Matrix ◽  
X Ray ◽  
Organic Hybrid ◽  
Ferrite Particle ◽  
Ferrite Nanoparticle ◽  
Hydrolysis Conditions

A NiFe2O4 particle/organic hybrid was synthesized in situ from iron-organic and nickel organic compounds below 100 °C. A mixture of nickel (II) acetylacetonate (NA) and iron (III) 3-allylacetylacetonate (IAA) was hydrolyzed and polymerized yielding spinel oxide particle/oligomer hybrid. X-ray diffraction analysis revealed that the crystallinity of spinel particles was dependent upon the hydrolysis conditions of NA-IAA. Nanocrystalline nickel ferrite particles around 10 nm were uniformly dispersed in the organic matrix. The formation of nickel ferrite was confirmed by energy-dispersive x-ray and x-ray photoelectron spectroscopy. The saturation magnetization of hybrid increased with increasing water amount for hydrolysis. Nano-sized nickel ferrite particle/organic hybrid showed a BH curve with no remanence above 75 K. The magnetization versus H/T curves at 300, 200, and 75 K were superimposed on the same curve and satisfied the Langevin equation. The remanent magnetization and coercive field of the hybrid were 7.4 emu/g and 460 Oe, respectively, at 5 K.

Synthesis of nickel zinc ferrite nanoparticle/organic hybrid from metalorganics

2007 ◽  
Vol 22 (7) ◽  
pp. 1967-1974 ◽  
Author(s):  
Yasuaki Hayashimto ◽  
Wataru Sakamoto ◽  
Toshinobu Yogo
Keyword(s):  
Zinc Ferrite ◽  
Oxide Particle ◽  
Organic Matrix ◽  
X Ray Diffraction ◽  
Organic Hybrid ◽  
Nickel Zinc ◽  
Ferrite Particle ◽  
Ferrite Nanoparticle ◽  
Hydrolysis Conditions

(Ni,Zn)Fe2O4 particle/organic hybrid was synthesized in situ from metalorganics below 100 °C. A mixture of nickel (II) acetylacetonate (NA), zinc acetylacetonate (ZA), and iron (III) 3-allylacetylacetonate (IAA) was hydrolyzed and polymerized yielding a spinel oxide particle/organic hybrid. X-ray diffraction analysis revealed that the crystallinity of spinel particles was dependent upon the hydrolysis conditions of NA-ZA-IAA. Nanocrystalline nickel zinc ferrite particles below 5 nm were uniformly dispersed in the organic matrix. The magnetization of hybrid increased with an increasing amount of water for hydrolysis. Nano-sized nickel zinc ferrite particle/organic hybrid showed a magnetization-applied field (BH) curve with no remanence above 40 K. The magnetization versus H/T curves from 40 to 100 K were superimposed on the same curve and satisfied the Langevin equation. The remanent magnetization and coercive field of the hybrid were 7.2 emu/g and 150 Oe, respectively, at 4.2 K. The absorption edge of the hybrid was blue-shifted compared with that of bulk ferrite.

scholarly journals Iron Oxide Particle-Enhanced MRI Suggests Variability of Brain Inflammation at Early Stages After Ischemic Stroke

Stroke ◽  
2007 ◽  
Vol 38 (10) ◽  
pp. 2733-2737 ◽  
Author(s):  
Andreas Saleh ◽  
Michael Schroeter ◽  
Adrian Ringelstein ◽  
Hans-Peter Hartung ◽  
Mario Siebler ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Iron Oxide ◽  
Oxide Particle ◽  
Brain Inflammation ◽  
Iron Oxide Particle ◽  
Early Stages ◽  
Enhanced Mri

scholarly journals Soluble iron modulates iron oxide particle-induced inflammatory responses via prostaglandin E2 synthesis: In vitro and in vivo studies

2009 ◽  
Vol 6 (1) ◽  
pp. 34 ◽  
Author(s):  
Ingrid Beck-Speier ◽  
Wolfgang G Kreyling ◽  
Konrad L Maier ◽  
Niru Dayal ◽  
Mette C Schladweiler ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Prostaglandin E2 ◽  
Inflammatory Responses ◽  
Oxide Particle ◽  
In Vivo Studies ◽  
Iron Oxide Particle ◽  
Soluble Iron

High transversal relaxivities of silica coated multicore iron oxide nanoparticles suitable for magnetic resonance imaging

2010 ◽  
Vol 1257 ◽  
Author(s):  
Anna Roig ◽  
Elena Taboada ◽  
Elisenda Rodríguez
Keyword(s):  
Iron Oxide ◽  
Sol Gel ◽  
Oxide Particle ◽  
Silica Shell ◽  
Composite Particles ◽  
Iron Oxide Particle ◽  
Maghemite Nanoparticles ◽  
High Temperature Process ◽  
Reaction Media ◽  
Very High

AbstractWe report on high transversal relaxivity values of composite iron oxide-silica nanoparticles. To obtain the material, pre-formed maghemite nanoparticles were coated with silica by sol-gel chemistry, using supercritical fluids as the reaction media. The composite particles were monodisperse and consisted of a core of several maghemite nanoparticles, surrounded by a thick silica shell. The high pressure and high temperature process did not affect the iron oxide particle size but induced an increase on their saturation magnetization values, possibly due to an improvement of the particle crystallinity. These iron oxide-based materials present very high transversal relaxivity values which can be correlated to the magnetic moment and to the silica shell width of the composite particles. Moreover, composite particles are not cytotoxic and they are dispersable in polar solvents.

Ultrasmall Iron Oxide Particle Contrast Agent and MRI Can Be Used to Monitor the Effect of Anti-Rejection Treatment

2007 ◽  
Vol 84 (3) ◽  
pp. 374-379 ◽  
Author(s):  
Eva Penno ◽  
Lars Johansson ◽  
H??kan Ahlstr??m ◽  
Cecilia Johnsson
Keyword(s):  
Iron Oxide ◽  
Contrast Agent ◽  
Oxide Particle ◽  
Iron Oxide Particle
Sign in / Sign up

Export Citation Format

Share Document