Acetylacetonate Salts Research Articles

Formation of inorganic nanocomposites by filling TiO2 nanopores with indium and antimony sulfide precursor aerosols

Nanocomposites of nanoporous-TiO2/In2S3 and np-TiO2/Sb2S3 were formed by deposition of In2S3 or Sb2S3 using spray ion layer gas reaction technique from their precursor solutions onto nanoporous TiO2 substrates at temperatures of 150, 175 and 200°C. The least penetration of the precursor into np-TiO2 was achieved for np-TiO2/In2S3 nanocomposites from indium acetylacetonate salt. The deepest penetration was obtained for both np-TiO2/In2S3(Cl) and np-TiO2/Sb2S3 nanocomposites with effective diffusion coefficients of 3.3×10−3cm2/s and 3.2×10−3cm2/s, respectively. The transport of the precursors in np-TiO2 and the formation of different nanocomposites were described the regime of the Knudsen diffusion model.

Large exchange bias with remarkable thermostability in an inverted quasi core/shell CoO/γ-Fe2O3 granular system

An inverted quasi core/shell CoO/γ-Fe2O3 granular system was synthesized through two-step thermal decomposition of acetylacetonate salt. A large exchange bias (EB) effect with remarkable thermostability was found in this granular system. The EB field revealed a large value about 8 kOe at 5 K. A temperature independent-like plateau feature from 75 to 200 K and a high-blocking temperature of EB about 280 K were observed, indicating a remarkable thermostability of EB. Both horizontal and vertical shifts observed in this system could be tuned by the temperature and the cooling field. The linear relation between EB field and pinned uncompensated spins indicated that the uncompensated spins at the interface between CoO and γ-Fe2O3 played an important role in the observed EB effect.

Novel near-IR absorbing phenyl-substituted phthalo- and naphthalocyanine complexes of lanthanide(iii): synthesis and spectral and electrochemical properties

A series of novel phenyl-substituted planar and sandwich-type complexes of Eu, Er and Lu with phthalo and naphthalocyanine ligands was obtained. A successful synthesis of dinaphthalocyanines from the ligand is described. A selective synthetic approach to the phenyl-substituted triphthalocyanine complexes from the ligand and acetylacetonate salts of lanthanides was developed. Correlations between the ionic radii of the central metal and absorption maxima were obtained for sandwich-type complexes. It was found that intervalence (IV) bands for dinaphthalocyanine complexes were red-shifted about 200 nm in comparison with corresponding diphthalocyanines, reaching 1797 nm for the Eu complex. The electrochemical behaviour of planar and sandwich-type Lu complexes was investigated. For the first time a spectroelectrochemical study of multistep reduction and oxidation processes for a triple-decker complex was carried out using the example of the triphthalocyanine of Lu. The structures of the compounds obtained were determined by (1)H NMR and high resolution MALDI TOF/TOF. The first single-crystal structure for an aryl-substituted double-decker complex was described using the example of the diphthalocyanine of Lu, showing the presence of intramolecular π-π interactions between phenyl groups.

Cyclic Voltammetry of Metallic Acetylacetonate Salts in Quaternary Ammonium and Phosphonium Based Deep Eutectic Solvents

Seven commercially sourced acetylacetonate salts were investigated in deep eutectic solvents (DESs that were prepared from ethylene glycol and trifluoroacetamide hydrogen bond donors) by cyclic voltammetry, to identify electrolytes suitable for future applications in electrochemical energy storage devices. Although the solubilities are low and on the order of 0.02 mol·L−1 for the most soluble salts, some were found to display encouraging quasi-reversible electrochemical kinetics. For instance, the diffusion coefficients of copper(II) acetylacetonate and iron(III) acetylacetonate in the trifluoroacetamide based DES are 1.14 × 10−8 and 5.12 × 10−9 cm2·s−1, which yields rate constants of 3.16 × 10−3 and 8.43 × 10−6 cm·s−1, respectively. These results are better than those obtained with the DESs prepared from ethylene glycol. The poor kinetics of the iron(III) acetylacetonate system was possibly due to the hygroscopic nature of the DESs that resulted in a continuous build-up of moisture in the system in spite of the maintenance of an inert atmosphere by means of a plastic glove bag. Further work is thus envisaged in an inert dry box that could lead to H-type glass cell charge/discharge experiments in the future.

Deposition of CIGS films by hydrazine-free solution method

In this paper, copper indium gallium diselenide (CIGS) thin films were deposited by a hydrazine-free solutions method. In the proposed method, acetylacetonate salts and Se powder were simply dissolved in triethylenetetramine under ambient conditions, respectively. These two solutions were mixed in a certain percentage to form the final CIGS precursor solution. CIGS films were obtained by a drop-coating method and subsequently annealed in nitrogen atmosphere. The facile formation of the precursor solution without the need to prefabricate nanoparticles enables a rapid and easy processing. The high stability of the solution in air further ensures the precursor preparation and the film deposition in ambient conditions without a glove box. The crystal structure, morphology, composition, electronic state, optical, and electrical qualities of CIGS films were characterized by XRD, SEM, EDS, XPS, UV–vis, and I–V. The easy preparation and low-cost nature of the proposed strategy make it quite attractive. The proposed synthesis strategy developed in this work may be used as a general process for low-cost deposition of CIGS film and may have bright application prospects in high-efficiency, yet low-cost, photovoltaic areas in the future.

Synthesis of CuInxGa1-xSe2 nanocrystals for potential thin film photovoltaic application under air condition

A one-step process has been proposed and used for the preparation of CuIn1-xGaxSe2 nanocrystals. In the proposed method, acetylacetonate salts and Se powder were simply refluxed in triethylenetetramine under air condition for 6h. The as-prepared CuIn1-xGaxSe2 nanocrystals were characterized by means of scanning electron microscopy (SEM), transmission election microscopy (TEM), X-ray diffraction (XRD), energy dispersive spectrometry (EDS) and UV–vis spectroscopy. The size distributions of CuIn1-xGaxSe2 nanocrystals were in the ranges of 15–25nm and could be obtained by adjusting the reaction time and/or the acetylacetonate salts concentrations. The synthesis strategy developed in this work may be used as a general process for the synthesis of CuIn1-xGaxSe2 nanocrystals, and may have great potential to be applied in high efficiency, yet low cost photovoltaic areas.

Low temperature solventless synthesis and characterization of Ni and Fe magnetic nanoparticles

We have successfully implemented a facile, one-pot solventless synthesis procedure starting from acetylacetonate salts and CaH(2) to obtain carbon-coated ferromagnetic metallic Ni and Fe nanoparticles at low temperature. The use of CaH(2) as a reductant drastically reduces reaction temperature down to 140 °C.

Structure and morphology of spinel MFe 2O 4 (M = Fe, Co, Ni) nanoparticles chemically synthesized from heterometallic complexes

We synthesized magnetic spinel ferrites from trimetallic single-source precursors. Fe(II), Co(II), and Ni(II) ferrite nanoparticles in the range of 9–25 nm were synthesized by solvothermal decomposition of trimetallic acetate complex precursors in benzyl ether in the presence of oleic acid and oleylamine, using 1,2-dodecanediol as the reducing agent. For comparison, spinel ferrite nanoparticles were synthesized by stoichiometric mixtures of metal acetate or acetylacetonate salts. The nanoparticles (NP) were characterized by TEM, DLS, powder XRD, and Raman spectroscopy; and their magnetic properties were characterized by ZFC–FC and M(H) measurements. The ferrite-NP were more homogeneous and had a narrower size distribution when trimetallic complexes were used as precursors. As a consequence, the magnetic properties of these ferrite-NP are closer to the aimed room temperature superparamagnetic behavior, than are those of other ferrites obtained by a mixture of salts.

Structure and Electrochemical Properties of Li<sub>1-X</sub>Ni<sub>0.5</sub>Mn<sub>0.5</sub>O<sub>2</sub> Thin Film Using Different Raw Material by Sol-Gel Method

Lithium-deficient thin films Li1-xNi0.5Mn0.5O2 were synthesized by sol-gel method using metal lithium, manganese and nickel acetate salts and acetylacetonate salts as started materials, respectively. The microstructures and electrochemical performance of Li1-xNi0.5Mn0.5O2 thin films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and galvanostatic charge–discharge measurements. Lithium-deficient was due to the formation of spinel LiNi0.5Mn1.5O4 impurities. The lithium-deficient was more seriously for SB film due to contain crystal water in the acetate salts. The raw material had great influence on the morphology of the films. The SA film had better electrochemical properties than that of SB film. The first discharge capacity was about 51 μAh/cm2-μm. After 40 cycles, 76% of its discharge capacity can be retained. The metal acetylacetonate salts without crystal water are more suitable for the preparation of LiNi0.5Mn0.5O2 film by sol-gel method.

In situ synthesis of catalytic metal nanoparticle-PDMS membranes by thermal decomposition process

Nanoparticles of various transition elements such as palladium, iron, and nickel were synthesized in situ in the polydimethylsiloxane (PDMS) matrix by thermal decomposition of their corresponding acetylacetonate salts. Various complementary techniques such as XRD, TEM and XPS were used to characterize the nanoparticles formed in the polymer matrix. This synthesis route results in relatively monodisperse nanoparticles with a narrow particle size distribution. In addition, the composite films are pore-free and mechanically stable, making them attractive for a range of applications. Palladium-PDMS membranes can be used as catalytic membrane reactors and show enhanced catalytic activity in ethylene hydrogenation.

Synthesis and characterization of chemically ordered FePt magnetic nano-particles

Monodispersed FePt alloy magnetic nano-particles are prepared by reduction of platinum acetyl acetonate and iron acetyl acetonate salts together in the presence of oleic acid and oleyl amine stabilizers by polyol process. The particle size of FePt is in the range of 2–3 nm confirmed by transmission electron microscopy (TEM). As-synthesized FePt nano-particles are chemically disordered with face centre cubic (fcc) structure where as after vacuum annealing these particles changed to face centre tetragonal (fct) ordered structure confirmed by the X-ray diffraction technique. Magnetic coercivity of 5.247 KOe was observed for fct structure.

Ammoxidation of ethylene to acetonitrile over chromium or cobalt alumina catalysts prepared by sol–gel method

A series of Cr/Al2O3 and Co/Al2O3 catalysts were tested in the selective ammoxidation of ethylene to acetonitrile. Catalysts were prepared either by sol–gel method or by impregnation with chromium or cobalt acetylacetonate salts. Physicochemical properties of catalysts were accomplished by several techniques such as chemical analysis, physisorption of N2, X-ray diffraction (XRD), 27Al MAS NMR, UV–Visible diffuse reflectance (DRS) and Raman spectroscopy and temperature programmed reduction of H2 (H2–TPR). Textural analysis reveals that mesoporous materials with pronounced surface areas were obtained using sol–gel procedure while impregnation of the support produces a moderate decrease of its surface area and pore volume. XRD analysis confirms the presence of highly dispersed metal species which reside essentially on the surface and measure less than 4 nm. Furthermore, 27Al MAS NMR shows that for xerogels, part of metal species occupies sites on/in A12O3 in close vicinity of octahedral 27Al. This, apparently, is not the case for aerogels. For Cr/Al2O3 catalysts, isolated Cr6+, mono and polychromate species were identified using DRS, Raman Spectroscopy and H2–TPR which seem to play a key role in the ammoxidation of ethylene. Furthermore, for cobalt doped catalysts, CoAl2O4 was identified as active phase on the basis of DRS and H2–TPR results. From the supercritical drying, it results generally better catalysts than catalysts calcined by ordinary procedure which leads to inactive agglomerated Co3O4 and CoO–Al2O3 phase.

First-principles calculations of the palladium(II) acetylacetonate crystal structure

The geometry of palladium(II) acetylacetonate in a monoclinic crystal lattice is calculated using the planewave-pseudopotential implementation of density-functional theory. Both the Troullier–Martin pseudopotential with the generalized gradient Perdew–Burke–Ernzerhof approximation and the Goedecker pseudopotential with the local density approximation are employed. The non-planar, step-like, structure of the molecule observed experimentally is successfully reproduced. A topological analysis of the electron localization function suggests a weak interaction between a Pd cation and the nearest carbon atom of the neighboring molecule of the closed-shell, non-electron-sharing type, presumably of electrostatic or dispersive nature, and possibly responsible for the bending of the palladium(II) acetylacetonate salt molecule in the crystal structure.

Single-step synthesis of metal-coated well-aligned CN x nanotubes using an aerosol-technique

Metal-coated nitrogen-containing carbon nanotubes were produced on oxidized silicon substrates using catalytic chemical vapor deposition from an aerosol-containing droplets of a solution of ferrocene and an acetylacetonate salt of a noble metal (Pt, Ru or Pd) in acetonitrile. The aerosol was carried into the reactor with an argon flow. Scanning and transmission electron microscopy, X-ray photoelectron spectroscopy, and selected area energy-dispersive X-ray analysis were used to analyze the nanotubes. They show the presence of well-aligned nanotubes coated with nanoparticles of iron and the noble metal making them possible heterogeneous catalysts for applications where a carbonaceous support is important.

06/01165 Variability of inorganic and organic constituents in lime spray dryer ash: Taerakul, P. et al. Fuel, 2005, 84, (14–15), 1820–1829

Activated carbon fibers (ACFs) prepared from petroleum isotropic pitch and the same containing silver and cobalt nitrate, cobalt and palladium acetylacetonates, as well as mixtures of two salts with a total metal or metal mixture content of 1 wt% have been studied. The processing parameters are summarized for activated carbon fibers containing individual metals and metal mixtures. The results suggest that the generation of metal-containing particles and the formation of pore structure depend on many different factors including the composition of the metal and pitch precursors, the interaction of the metal and pitch precursors during the fiber production process, and the interaction between the two metal precursors when more than one metal salt is used. The addition of silver and cobalt in the form of nitrate salts enlarges the micropores and generates small mesopores with a narrow range of sizes. The addition of palladium as an acetylacetonate salt leads to the formation of both small micropores and larger mesopores. The cobalt additive as an acetylacetonate salt catalyzes the activation process, creating large mesopores and macropores. Mixing of two different metal precursors affects the particle composition and size. This, in turn, controls the pore structure of the final activated fibers. During activation, the two metal precursors can act independently (Ag/Co mixture). However, in other cases their effect can be additive (Co/Pd mixture), or even synergistic (Ag/Pd mixture).

The effect of precursor chemistry and preparation conditions on the formation of pore structure in metal-containing carbon fibers

Activated carbon fibers (ACFs) prepared from petroleum isotropic pitch and the same containing silver and cobalt nitrate, cobalt and palladium acetylacetonates, as well as mixtures of two salts with a total metal or metal mixture content of 1 wt% have been studied. The processing parameters are summarized for activated carbon fibers containing individual metals and metal mixtures. The results suggest that the generation of metal-containing particles and the formation of pore structure depend on many different factors including the composition of the metal and pitch precursors, the interaction of the metal and pitch precursors during the fiber production process, and the interaction between the two metal precursors when more than one metal salt is used. The addition of silver and cobalt in the form of nitrate salts enlarges the micropores and generates small mesopores with a narrow range of sizes. The addition of palladium as an acetylacetonate salt leads to the formation of both small micropores and larger mesopores. The cobalt additive as an acetylacetonate salt catalyzes the activation process, creating large mesopores and macropores. Mixing of two different metal precursors affects the particle composition and size. This, in turn, controls the pore structure of the final activated fibers. During activation, the two metal precursors can act independently (Ag/Co mixture). However, in other cases their effect can be additive (Co/Pd mixture), or even synergistic (Ag/Pd mixture).

Differential Toxicity of Aluminum Salts in Human Cell Lines of Neural Origin: Implications for Neurodegeneration

Aluminum is highly oxophilic and its minerals are usually found surrounded by six oxygen atoms. A role for the metal has been established in dialysis encephalopathy and Al-induced osteomalacia. The metal has been implicated in Alzheimer’s disease but the issue is at present controversial. Human cell lines of neural origin were utilized to study the effect of lipophilic aluminum acetylacetonate and non-lipophilic aluminum sulfate on cell proliferation and viability. Although analysis of Al species in the cell culture media demonstrated that there are positively charged Al species present in solutions prepared with both Al salts, only the aluminum acetylacetonate salt caused changes in cell proliferation and viability. Therefore, the lipophilic nature of the organic Al salt is a critical determinant of toxicity. The effect of aluminum acetylacetonate was dose-dependent and time-dependent. Neuroblastoma (SK-N-SH) cells were more susceptible to decreased cell proliferation although the lipophilic Al salt was more toxic to the glioblastoma (T98G) cells. While the toxicity of aluminum acetylacetonate was inhibited in the T98G cells by the addition of phosphate, the same treatment did not reverse cell death in the SK-N-SH cells. Thus, the mechanism of Al toxicity appears to be different in the two cell lines. It is possible that the principal neurotoxic target of the metal is glial and when these cells are in a compromised state, this may secondarily impact the neuronal population and thus eventually lead to neurodegeneration.