共查询到20条相似文献,搜索用时 203 毫秒
1.
Tevhide Özkaya Abdulhadi Baykal Muhammet Sadaka Toprak 《Central European Journal of Chemistry》2008,6(3):465-469
Water-soluble Mn3O4 nanocrystals have been prepared through thermal decomposition in a high temperature boiling solvent, 2-pyrrolidone. The final
product was characterized with XRD, SEM, TEM, FTIR and Zeta Potential measurements. Average crystallite size was calculated
as ∼15 nm using XRD peak broadening. TEM analysis revealed spherical nanoparticles with an average diameter of 14±0.4 nm.
FTIR analysis indicated that 2-pyrrolidone coordinates with the Mn3O4 nanocrystals only via O from the carbonyl group, thus confining their growth and protecting their surfaces from interaction
with neighboring particles.
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2.
Zehra Durmus Hüseyin Kavas Abdulhadi Baykal Muhammet S. Toprak 《Central European Journal of Chemistry》2009,7(3):555-559
A novel environmental friendly, room temperature route using an ionic liquid 1-n-butyl-3-methylimidazolium hydroxide ([BMIM]OH)
for the synthesis of Mn3O4 nanoparticles is presented. The product was characterized using Fourier transform infrared spectroscopy, X-ray powder diffraction,
and transmission electron microscopy. Phase purity was confirmed by XRD, and X-ray line profile fitting determined a crystallite
size of 42 ± 11 nm. TEM analysis revealed various morphologies. EPR measurements have indicated the existence of long-range
interactions, due to the wide range of particle sizes and morphologies observed.
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3.
Abdülhadi Baykal Yüksel Köseoğlu Mehmet Şenel 《Central European Journal of Chemistry》2007,5(1):169-176
Heating hydrous manganese (II) hydroxide gel at 85 °C for 12 hours produces Mn3O4 nanoparticles. They were characterized by X-ray powder diffraction (XRD) and infrared spectroscopy (FTIR). The particle size
estimated from the SEM and X-ray peak broadening is approximately 32 nm, showing them to be nanocrystalline. EPR measurements
confirm a typical Mn2+signal with a highly resolved hyperfine structure.
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4.
Jorge García-Barrasa José M. López-de-Luzuriaga Miguel Monge 《Central European Journal of Chemistry》2011,9(1):7-19
Chemical methods provide an easy way to synthesize silver nanoparticles (Ag NPs) in solution. These metal nanoparticles have
a great potential for biomedical applications as an antibacterial, antifungal, and antiviral agent or in wound healing. The
adjustment of the parameters involved in these reactions permits a precise control over the size, shape, monodispersity, and
the surfaces of the nanoparticles. These nanoparticles are being used in the design of new hybrid organic-inorganic or inorganic
nanomaterials for biomedical applications.
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5.
Nadezhda Rangelova Lachezar Radev Sanchi Nenkova Isabel M. Miranda Salvado Maria H. Vas Fernandes Michael Herzog 《Central European Journal of Chemistry》2011,9(1):112-118
Methylcellulose (MC) / SiO2 organic / inorganic hybrid materials have been prepared from MC and methyltriethoxysilane or ethyltrimethoxysilane, and characterized
by XRD, FTIR and AFM. XRD showed peak shifts. FTIR shows intermolecular hydrogen bonding between MC and SiO2. AFM depicts surface roughness which depends on the silica precursor and MC content.
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6.
Without any surfactant, antiferromagnetic Co3O4 nanoparticles were synthesized successfully for the first time by means of an oxidation-reduction method with cobalt sulfate
as starting material, which was oxidized to cobalt salt by NaNO3 after alkalinizing with NaOH. Morphological, structural, spectroscopic and magnetic characterization of the product were
done by SEM, TEM, XRD, and VSM, respectively. The average crystallite size (on the base of line profile fitting method), D
and σ, is estimated as 30 ± 6 nm. Some anomalous magnetic properties and their enhanced effect have been observed in Co3O4 antiferromagnetic nanocrystallites, including a bias field, coercivity, permanent magnetic moments and an open loop. These
phenomena are attributed to the unidirectional anisotropy which is caused by the exchange coupling between AFM and FM layers,
the existence of the spin glass like surface spins of Co3O4 nanoparticles due to size effects and surface-area effect.
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7.
Iwona Binkowska Włodzimierz Gałęzowski Arnold Jarczewski 《Central European Journal of Chemistry》2010,8(3):582-586
Proton transfer reactions rates between carbon acids 1-nitro-1-(4-nitrophenyl)ethane (NPNE), 2-methyl-1-nitro-1-(4-nitrophenyl)propane
(MNPNP)) and phosphazenes (BEMP, BTPP, P1-t-Oct) in tetrahydrofuran have been measured, and the activation parameters were determined. The results are compared with
those previously obtained for P1-t-Bu phosphazene, guanidines and amidines.
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8.
9.
Takashiro Akitsu Chiaki Ishioka Tsubasa Itoh 《Central European Journal of Chemistry》2009,7(4):690-696
A series of organic/inorganic hybrid materials containing the single-molecule magnet [Mn12(CH3COO)16(H2O)4O12]·2CH3COOH·4H2O with the photochromic compounds azobenzene or disperse red 1 cast into polymethyl methacrylate films was prepared. To understand
the photomodulation of analogous mixtures’ AC susceptibility, we investigated the molecular alignment based on Weigert’s effect
accompanying cycles of cis-trans photoisomerization by alternate irradiations with polarized UV and visible light. Polarized
electronic spectra of the hybrid materials demonstrated gradually increasing anisotropy. These features suggest interactions
between photochromic compounds and the Mn12 complex in polymethyl methacrylate.
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10.
Mehmet Senel Hüseyin Kavas Mehmet Tutgun Abdulhadi Baykal 《Central European Journal of Chemistry》2013,11(11):1768-1779
Nanocomposites of Polyacrylic acid/polyvinylimidazole (PAA/PVI) with grafted and ungrafted iron oxide nanoparticles were prepared by a Reflux method. The Fe3O4 nanoparticles with 10 nm average diameter were synthesized by controlled co-precipitation and silanization of Si-PVI on Fe3O4 was used to obtain the grafted ones. Grafting becomes important at composites of less PVI that cause drastic decreases in AC conductivity. The content of PVI has important effects on the conductivity mechanism of these composites. The effect of grafting and Polyacrylic acid/polyvinylimidazole molar ratio on the conduction mechanism were studied. The conduction mechanism of iron oxide nanocomposites can be adjusted by changing molar ratio of Polyacrylic acid/polyvinylimidazole and grafting of Fe3O4 NPs. 相似文献
11.
Phase equilibria established in the PbO - BiVO4 system over the whole component concentration range up to 1000°C have been investigated. A phase diagram has been constructed
using DTA and XRD.
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12.
Alexandru Cecal Doina Humelnicu Valeriu Rudic Liliana Cepoi Angela Cojocari 《Central European Journal of Chemistry》2012,10(5):1669-1675
This paper deals with a study of the biosorption of UO2 2+ ions on two green algae: Chlorella vulgaris and Dunaliella salina. By investigating the retention degree versus contact time from Langmuir and Freundlich biosorption isotherms, kinetic investigations and FTIR spectra it was found that the biosorption process was greater for Chlorella vulgaris than for Dunaliella salina. A new kinetics method is proposed to establish the reaction order concerning the biosorption process of uranyl ions on these biomasses. 相似文献
13.
Mn3O4 powders have been produced from Electrolytic Manganese Residue (EMR). After leaching of EMR in sulfuric acid, MnSO4 solution containing various ions was obtained. Purifying the solution obtained and then adding aqueous alkali to the purified
MnSO4 solution, Mn(OH)2 was prepared. Two methods were employed to produce Mn3O4. One way was oxidation of Mn(OH)2 in aqueous phase under atmosphere pressure to obtain Mn3O4. The other way was roasting Mn(OH)2 precursors in the range of 500°C to 700°C. The prepared samples were investigated by using several techniques including X-ray
powder diffraction (XRD), Fourier Transformation Infra-Red (FTIR) spectra, and Brunauer-Emmett-Teller (BET) specific surface
area instrument. Particle distribution and magnetic measurements were carried out on laser particle size analyzer, vibrating
sample magnetometer (VSM). Through XRD, FTIR and determination of total Mn content (TMC), the products prepared were confirmed
to be a single phase Mn3O4. BET specific surface areas can reach to 32 m2 g−1. The results indicated that products synthesized by aqueous solution oxidation method had higher specific surface areas and
smaller particle size than those prepared by means of roasting. However the products prepared using the above two methods
showed no obvious differences in magnetic property.
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14.
Raúl Terrazas Reza Carlos A. Martínez Pérez Claudia A. Rodríguez González Humberto Monreal Romero Perla E. García Casillas 《Central European Journal of Chemistry》2010,8(5):1041-1046
In this work, the synthesis of magnetite nanoparticles by two variant chemical coprecipitation methods that involve reflux
and aging conditions was investigated. The influence of the synthesis conditions on particle size, morphology, magnetic properties
and protein adsorption were studied. The synthesized magnetite nanoparticles showed a spherical shape with an average particle
size directly influenced by the synthesis technique. Particles of average size 27 nm and 200 nm were obtained. When the coprecipitation
method was used without reflux and aging, the smallest particles were obtained. Magnetite nanoparticles obtained from both
methods exhibited a superparamagnetic behavior and their saturation magnetization was particle size dependent. Values of 67
and 78 emu g−1 were obtained for the 27 nm and 200 nm magnetite particles, respectively. The nanoparticles were coated with silica, aminosilane,
and silica-aminosilane shell. The influence of the coating on protein absorption was studied using Bovine Serum Albumin (BSA)
protein.
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15.
A one-pot multi-component reaction is developed for the efficient synthesis of 4,5-dibenzylidene octahydroacridines in high
yields. The reaction is performed by the tandem reaction of three molar equivalent aromatic aldehydes with two molar equivalent
4-alkylcyclohexanone in the system of NH4OAc/HOAc under microwave irradiation.
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16.
The Diels-Alder reaction between cyclopentadiene and dienophiles in deanol derivatives containing bis(trifluoromethylsulfonyl)imide
anion as media have been studied. The effect of the substituents attached to the cation on the endo:exo selectivity as well
as the reaction yield have been evaluated in the absence and presence of Lewis acid catalyst - Y(OTf)3. Catalytic activity of metal triflates and the recycling of chosen catalytic systems have also been investigated
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17.
Sandip A. Sadaphal Kiran F. Shelke Swapnil S. Sonar Murlidhar S. Shingare 《Central European Journal of Chemistry》2008,6(4):622-626
1-benzyl-3-methyl imidazolium hydrogen sulphate [bnmim][HSO4] was found to be an effective catalyst for the condensation reaction of indoles and derivatives with benzaldehydes in microwave
irradiation with lower reaction time and higher yields to give bis(indolyl) methanes.
相似文献
18.
Maria-Gabriela Alexandru Tanja Cirkovic Velickovic Ioana Jitaru Sanja Grguric-Sipka Constantin Draghici 《Central European Journal of Chemistry》2010,8(3):639-645
This paper presents the synthesis of complex compounds of type [M(L1)2], where M(II)= Cu (1), Co (2), Zn (3), L1=2-aminothiazole-4-acetate and [Mn(L1)2(H2O)] (4) using ethyl 2-(2-aminothiazole-4-yl) acetate (L), and characterization by elemental analysis, magnetic susceptibilities,
IR, 1H-NMR, UV-Vis spectroscopy and for [Mn(L1)2(H2O)] also by X-ray diffraction. In vitro cytotoxicity studies were performed on human cervix adenocarcinoma, HeLa cells. The
antitumor selectivity was assessed using normal human peripheral blood mononuclear cells, PBMC as control.
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19.
The triplet excited state properties and photosensitization mechanisms of indigo were investigated based on density functional
theory calculations. The solvent effects on the photosensitization mechanisms of indigo have also been considered. The thermodynamic
feasibility of the possible 1O2 and O2·−-photogeneration pathways by triplet excited state indigo in different solvents was explored, in order to gain some deeper
insights into the photosensitization characters of the dye.
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20.
Petr Bělina Petra Šulcová Miroslav Trojan Pavel Mazurek 《Central European Journal of Chemistry》2007,5(3):706-714
New binary lanthanum-aluminum triphosphates were synthesized by thermal-condensation method from H3PO4, La2O3 and Al(OH)3. These pigments could be potentially used as special inorganic pigments; their corrosion-inhibition properties were widely
studied. Synthesis conditions were determined on the basis of DTA and TG measurements. The products were also characterized
by X-ray diffraction analysis. Physical properties — density by pycnometric method, particle size distribution, oil number
and critical pigment volume concentration (CPVC), pH and specific conductivity of their aqueous extracts were also determined.
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