- Kinetics and mechanism of chromium electrodeposition from formate and oxalate solutions of Cr(III) compounds
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Kinetics of multistep reaction of Cr(III) ions discharge to metal was studied on a stationary electrode and on a rotating disk electrode from the solutions containing formic acid or oxalic acid. The electroreduction of Cr(III) complex ions in aqueous solu
- Protsenko,Danilov
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- Electrolytic preparation and characterization of VCr alloys in molten salt from vanadium slag
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Vanadium slag contains several critical elements like V, Ti, Cr, Fe and Mn. In our previous work, V and Cr have been enriched by selective chlorination, increasing from 10.05% to 14.95% and 5.84%–8.69% separately. V and Cr still maintain the trivalence state in molten salt. In the current work, the electrodeposition behaviors of V3+ and Cr3+ in NaCl–KCl molten salt at 800 °C were investigated using cyclic voltammetry (CV) and square wave voltammetry (SWV) with a tungsten electrode. It was found that the reduction processes of V3+ and Cr3+ consist of two steps, M3+/M2+, M2+/M. The diffusion coefficients of V3+ and Cr3+ in NaCl–KCl molten salt were measured by CV. The effect of VCl3/CrCl3 mass ratio on VCr alloy was investigated by a two-electrode under constant voltage. Pure Cr can be obtained at 2.8 V in the NaCl–KCl molten salt, while VCr alloy (3.71 mass % V-94.28 mass% Cr-2.01 mass % O) was obtained when electrolysis voltage was controlled to 2.8 V at 800 °C. The composition of VCr alloy can be designed by changing the molten salt composition. This method can be applied for direct preparation of VCr alloy from vanadium slag, thus offering the use of low cost raw materials with direct environmental benefits.
- Liu, Shiyuan,Wang, Lijun,Chou, Kuo-chih,Kumar, Ramachandran Vasant
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- Powders of chromium and chromium carbides of different morphology and narrow size distribution
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Powders of Cr and Cr carbides (Cr2C, Cr7C3, and Cr23C6) have been prepared by hydrogen reduction of CrO1.9 and Cr3C2 powders of different morphology, texture and specific surface area. The Cr and Cr carbides particles have the morphology of the parent compound and a narrow size distribution. Depending on the shape, the average size is of the order of some micrometers or some tens of micrometers. Starting with Cr3C2 allows the preparation of Cr powders at a temperature (1000 °C) markedly lower than that required when CrO1.9 is used as the precursor (1300 °C). However, a Cr3C2 specific surface area of the order of 10 m2/g is necessary to achieve this within a reasonably short time (6 to 12 h). Powders of the lower carbides are prepared by using a milder hydrogen thermal treatment.
- Loubiere,Laurent,Bonino,Rousset
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- Reactions of Cr atoms with NO, N2O, CO2, NO 2, and SO2 molecules
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Experimental results on the interaction of Cr atoms with various oxygen-containing molecules (NO, N2O, CO2, NO2, and SO2) at high temperatures (>1000 K) are presented. It is demonstrated that activation barrier
- Smirnov,Akhmadov
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- Photoactivation of methyl acetate by chromium atoms
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Photolysis of the cocondensate of methyl acetate and chromium vapor yields a complex that decomposes to acetaldehyde and formaldehyde.
- Billups,Bell, John P.,Hauge, Robert H.,Kline, Ellen S.,Wesley Moorehead,Margrave, John L.,McCormick, Fred B.
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- Fabrication and characterization of electrodeposited Co1-xCrx nanowires
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Co1-xCrx alloy nanowires with 0.0 1 a porous alumina membrane from an electrolyte containing Co and Cr ions. The composition, structure and magnetic properties of the nanowires have been characterized. Cobalt-rich nanowires were electrodeposited at a potential of -1.0 V relative to Ag/AgCl and chromium-rich nanowires were deposited beyond -3.5 V. The optimized processing conditions include hydrogen annealing to give hysteresis loops for the Co80Cr20 nanowires with coercivity of up to 200 mT and squareness of up to 0.95. Magnetization of the Co80Cr20 nanowire is 77 A m2 kg-1 and the energy product of the arrays is 35 kJ m-3.
- Chaure,Coey
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- Valence-to-core X-ray emission spectroscopy identification of carbide compounds in nanocrystalline Cr coatings deposited from Cr(III) electrolytes containing organic substances
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Valence-to-core X-ray emission spectroscopy was applied to study a composition of chromium coatings electrodeposited from Cr(III) sulfate electrolytes with the addition of formic or oxalic acid. It was shown that the obtained crystallographically amorphous deposits contain chromium carbide compounds. These results indicate that nanodimensional Cr crystallites formed during the electrodeposition process are characterized by very high electrocatalytic activity.
- Safonov, Viktor A.,Vykhodtseva, Ludmila N.,Polukarov, Yurii M.,Safonova, Olga V.,Smolentsev, Grigory,Sikora, Marcin,Eeckhout, Sigrid G.,Glatzel, Pieter
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- Thermal studies of chromium, molybdenum and ruthenium complexes of chloranilic acid
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Chromium, molybdenum and ruthenium complexes of chloranilic acid (H2CA) were investigated by the thermogravimetric (TG) technique. The TG plot of Cr(H2CA)3 showed three decompositions in the temperature range 336-802°K. On
- Soliman,Ali,Khalil,Ramadan
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- Synthesis of monodisperse chromium nanoparticles from the thermolysis of a Fischer carbene complex
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We successfully synthesized monodisperse chromium nanoparticles from the thermolysis of a Fischer carbene complex.
- Son, Seung Uk,Jang, Youngjin,Yoon, Ki Youl,An, Changhua,Hwang, Yosun,Park, Je-Geun,Noh, Han-Jin,Kim, Jae-Young,Park, Jae-Hoon,Hyeon, Taeghwan
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- Reactions of chromium atoms with chloromethanes
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The rate constants of the gas-phase reactions of the chromium atom with CCl4, CHCl3, and CH2Cl2 were measured behind shock waves at 800-1400 K. The rate constants of hexacarbonyl decomposition and chromium atom yield agreed well. The rate of formation of chromium atoms was slightly lower than the rate of consumption of parent molecules. At > 800 K (lower-temperature boundary of the reactions of chromium atoms with chloromethanes), the yield of chromium atoms in the course of Cr(CO)6 thermal decomposition may be considered an instantaneous process, i.e., its characteristic time is much shorter than the characteristic resolution time of the optical system. The rate constants were determined via monitoring a decrease in the chromium atom concentration with time. The available thermochemical data on the detachment of the chlorine atom from studied chloromethanes and on the dissociation of CrCl molecules showed that the reactions with the participation of CCl4 and CHCl3 were probably exothermic. A more detailed theoretical treatment of the reactions studied was complicated by the absence of accurate thermochemical data, primarily for the dissociation energy of the Cr-Cl bond.
- Zaslonko,Smirnov
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- ELECTRODEPOSITION AND PROPERTIES OF AMORPHOUS CHROMIUM FILMS PREPARED FROM CHROMIC ACID SOLUTIONS.
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The addition of organic compounds containing a minus CHO or minus COOH group such as formamide, formaldehyde, glyoxal or formic acid to a chromium electroplating bath results in a chromium deposit which has greatly improved properties compared to conventional chromium deposits. These layers have fewer defects, and the as-deposited, amorphous layers have a Vicker's hardness of about 1000, which is comparable to that of conventional chromium plating deposits. With annealing in air, the hardness goes through a maximum of about 1700 at 500 degree -600 degree C, while the hardness of a conventional plating decreases monotonically from 1000 to 400, with annealing from 200 degree to 800 degree C. X-ray diffraction and differential thermal analysis show that annealing up to about 600 degree C causes formation and growth of chromium crystallites and that chromium carbides form above this temperature.
- Hoshino,Laitinen,Hoflund
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- Physicochemical model for choosing complexes for chromium-plating solutions based on Cr(III) compounds
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A prognostic physicochemical model for choosing complexes for chromium-plating solutions is constructed on the basis of a combination of the thermodynamic principles and data on the kinetics of some electrochemical reactions. It is shown that high-quality chromium coating can be produced from solutions of Cr(III) complexes, whose logarithm of stability constants ranges from 10 to 20, and the logarithm of stability constants of Cr(II) complexes formed in electrolysis ranges from 7 to 10. The influence of the nature of ligands on chromium electrodeposition is studied. Using the model proposed, a chromium-plating solution based on a chromium(III) malonate complex is developed. This solution makes it possible to produce high-quality coatings in a wide interval of current densities.
- Vinokurov,Demidov,Bondar'
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- Modeling, optimization, and comparative analysis of trivalent chromium electrodeposition from aqueous glycine and formic acid baths
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Trivalent chromium electrodeposition has been studied as an alternative to hazardous hexavalent chromium electroplating. Although limited by inability to deposit thick coatings with acceptable quality, it is useful for decorative chromium electroplating. In the present work, we illustrate the application of statistical design of experiments (DOE) in empirical modeling and optimization of electrodeposition of trivalent chromium from baths of chromium complexed with glycine. DOE shows that variations in current efficiency with glycine and chromium chloride concentrations can be explained by a quadratic model. The composition of the bath was optimized with respect to current efficiency to obtain faster deposition. We compare the effects of process parameters (pH, temperature, current density, and pulsed current) on current efficiency and deposit characteristics for both glycine and formic acid-containing baths. Experiments reveal that whether pulsed current increases or decreases current efficiency is determined by how current density influences current efficiency, and the range of lower and upper current density levels.
- Baral, Anil,Engelken, Robert
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- Time-Resolved Two-Laser Probe of Cr(CO)6 Photodissociation Dynamics
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We have examined the photodissociation of jet-cooled Cr(CO)6 using a time-resolved, two-laser multiphoton dissociation (MDP) technique with fluorescence detection of the atomic photofragments.We have observed that the rate of appearance of Cr(CO)4 via 248-nm photolysis of Cr(CO)6 is slower if the Cr(CO)6 has first been cooled in a supersonic expansion.We suggest the difference in the observed rates is due to slower internal conversion in the transient Cr(CO)5 following impulsive loss of the first CO ligand from the jet-cooled hexacarbonyl.The internal conversion is thought to be facilitated by low-energy OC-Cr-CO bending modes, which are probably not accessible by one-photon absorption from the ground state of Cr(CO)6.We discuss the utility of our time-resolved MDP/atomic fluorescence technique as a general dynamical probe for metal carbonyl photodissociation.
- Peifer, William R.,Garvey, James F.,DeLeon, Robert L.
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- Nano-synthesis, characterization, modeling and molecular docking analysis of Mn (II), Co (II), Cr (III) and Cu (II) complexes with azo pyrazolone ligand as new favorable antimicrobial and antitumor agents
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Novel nanosized Mn (II), Co (II), Cr (III) and Cu (II) complexes were synthesized with 2-((5-oxo-1,3-diphenyl-4,5-dihydro-1H-pyrazol-4-yl)diazenyl) benzoic acid, HL applying precipitation method. Their structures were characterized based on the elemental and thermal analyses, spectra (FT-IR, UV–Vis, MS, ESR and XRD), conductivity and magnetic moment measurements. IR spectra offered that HL behaves as monobasic tri-dentate ligand towards Mn (II), Cr (III) and Cu (II) and monobasic bi-dentate towards Co (II). The XRD results unambiguously confirmed the crystalline nature and nano-sized particles of Cu (II) complex while HL and other complexes exhibited amorphous phases. The magnetic moment data, UV–Vis and ESR spectra supported the formation of octahedral geometries for Mn (II), and Cr (III) complexes, whereas Co (II), and Cu (II) complexes showed tetrahedral arrangement. The activation parameters for the thermal degradation stages were theoretically calculated using TGA curves. The obtained data showed the inspected complexes as favorable antimicrobial drug candidates. The studied compounds were screened out for their antitumor and antimicrobial activities. The inspected compounds exhibited a reasonable antibacterial activity and weak antitumor efficacy. The in vitro results were confirmed using the in silico molecular docking analysis (docking server) applying x-ray crystallographic structures of the proteins (4?m01, 3?t88, 1zap & 4ynt) from PDB (Protein Data Bank). HL and probably its complexes displayed adequate binding with the receptors of 4?m01, 3?t88, 1zap, and 4ynt microorganisms. The obtained data show the inspected complexes as favorable antimicrobial drug candidates.
- Gaber, Mohamed,Khedr, Abdalla M.,Mansour, Mohammed A.,Elsharkawy, Mohsen
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- Excimer laser multiphoton dissociation of Cr(CO)6: Evidence for two distinct dissociation processes
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The excimer laser multiphoton dissociation of Cr(C0)6 has been investigated in the gas phase using emission spectroscopy to detect excited state photoproducts.Following laser irradiation at 193 nm (ArF*), 248 nm (KrF*), and 351 nm (X
- Tyndall, George W.,Jackson, Robert L.
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- INTERACTION OF TRIETHYLALUMINIUM WITH ACETYLACETONATES OF TRANSITION METALS
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The reaction of AlEt3 with acetylacetonates of CrIII, FeIII, CoIII, NiII and PdII in benzene and cyclohexane has been studied in a wide range of initial ratios of AlEt3/M(acac)n.Quantitative analysis of the reaction mixture, performed with the help of UV spectra, showed that acetylacetonate ligands were transferred from the transition metals to aluminium.A scheme involving stepwise substitution of ethyl radicals by acetylacetonate ligands on AlEt3 with further formation of an Al(acac)3Et2Al(acac) mixture is proposed for Al/M III, CoIII, NiII were reduced to the zerovalent state in their reaction with AlEt3 (Al/Mn n).The content of the finely dispersed metal component is negligible small and the greater part of transition metal is present as M0 complexes, where Et2Al(acac) formed in the reaction is the main stabilizing ligand.
- Schmidt, F. K.,Ratovskii, G. V.,Dmitrieva, T. V.,Ivleva, I. N.,Borodko, Yu. G.
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- Influence of pulse plating on the crystal structure and orientation of chromium
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Chromium deposits with various structures and orientations were prepared by pulse plating from a sulfate-catalyzed chromic acid solution and without formic acid addition. The influences of the puls duration, off-time, curent density, formic acid concentration, and plating time on the structure and orientation were studied by X-Ray diffraction and transmition electron microcsopy.
- Tsai,Wu
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- Electrochemical corrosion behavior of carbon nanotube-doped hard chromium coatings electrodeposited from Cr(III) baths
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Homogeneous chromium-multiwalled carbon nanotube (Cr-MWNT) composite coatings were electrodeposited from trivalent chromium [Cr(III)] electrolyte containing MWNTs under ultrasonic agitation. The microstructure, mechanical properties, and electrochemical c
- Zeng, Zhixiang,Yu, Yuanlie,Zhang, Junyan
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- Coordination modes of multidentate azodye ligand derived from 4,4′-methylenedianiline towards some transition metal ions: Synthesis, spectral characterization, thermal investigation and biological activity
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Nine new azodye metal complexes of Mn(II), Co(II), Ni(II), Cu(II), Cr(III), Fe(III), Ru(III), Hf(IV) and Zr(IV) ions have been prepared via the reaction of 5,5′-((1E,1′E)-(methylenebis(1,4-phenylene))bis(diazene-2,1-diyl))bis(6-hydroxy-2-thioxo-2,3-dihydropyrimidin-4(5H)-one) (H4L) with the corresponding metal salts affording sandwich (1?L:1?M), mononuclear (2?L:1?M), binuclear (1?L,2?M) and tetranuclear (1?L,4?M) complexes. Elemental analyses, spectral methods, magnetic moment measurements and thermal studies were utilized to confirm the mode of bonding and geometrical structure for the ligand and its metal complexes. Infrared spectral data show that the H4L ligand chelates with some metal ions in keto–enol–thione or keto–thione manner. It behaves in a neutral/dibasic tetradentate fashion in sandwich and binuclear complexes. Also, it acts as a neutral bidentate moiety in the Cr(III) complex. The spectra reveal that azo group participates in chelation in all complexes. Octahedral geometry was suggested for all chelates but the Cu(II) complex with square planar geometry. The thermal stability and decomposition of the compounds were studied, the data showing that the thermal decomposition ended with metal or metal oxide mixed with carbon as final product. The electron spin resonance spectrum of the Cu(II) complex demonstrates that the free electron is located in the (d x2-y2) orbital. Measurements of biological activity against human cell lines Hep-G2 and MCF-7 reveal that the Cu(II) complex has a higher cytotoxicity in comparison to the free ligand and other metal complexes, with IC50 values of 6.10 and 5.2 μg ml?1, respectively, while the ligand has anti-tumour activity relative to some of the investigated metal complexes.
- Abouel-Enein, Saeyda A.,Emam, Sanaa M.,Monir, Eman
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- Molecular modeling, spectral investigation and thermal studies of the new asymmetric Schiff base ligand; (E)-N'-(1-(4-((E)-2-hydroxybenzylideneamino)phenyl)ethylidene)morpholine-4-carbothiohydrazide and its metal complexes: Evaluation of their antibacterial and anti-molluscicidal activity
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A new tetradentate asymmetric Schiff base ligand; (E)-N'-(1-(4-((E)-2-hydroxybenzylideneamino)phenyl)ethylidene)morpholine-4-carbothiohydrazide (H2L) was prepared by consecutive condensation reactions between p-aminoacetophenone, salicylaldehyde and 4-morpholinethiosemicarbazide. The structures of the obtained ligand along with its Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Cr(III), Fe(III) and Ru(III) complexes were authenticated by different analytical and spectral techniques. The ligand behaves as a monobasic tetradentate one and chelates with metal ions through the deprotonated phenolic oxygen, imine nitrogen, thione sulfur and azomethine nitrogen atoms (ONNS chromophore). All nonelectrolyte metal complexes possess octahedral geometry, except Ni(II) and Cu(II) complexes (2, 3) which have tetra-coordinate structures. The thermal stability of metal complexes is higher than that of the free ligand and the general thermal degradation pathways were discussed based on thermogravimetric technique. The activation thermodynamic parameters as well as the order of reaction (n) were estimated from DTG curves by using Piloyan method. Thermogravimetric analyses and mass spectra of metal complexes confirm the number of solvents in their inner and outer spheres. Molecular modeling data were used to demonstrate the thermal decomposition pathways of the ligand and its metal complexes, confirming their chemical structures. The ESR spectra of Cu(II) complexes indicate that the unpaired electron is localized mainly in the d(x 2 -y 2 ) orbital with axial symmetry. Powder X-ray diffraction analyses for Co(II), Cu(II) and Ru(III) complexes (1, 3, 7) show that copper complex has a crystalline nature, whereas, cobalt and ruthenium complexes are amorphous. The ligand and its metal complexes were tested in vitro for their anti-molluscicidal activity against Eobania vermiculata. The results reveal that the investigated compounds have remarkable anti-molluscicidal activities against the tested land snail with various sensitivity levels. The synthesized compounds were also screened in vitro for their antibacterial activity against Gram-positive bacteria; Staphylococcus aureus and Gram-negative bacteria; Escherichia coli and the results were compared with the activity of ceftriaxone. The data show that all investigated compounds display a high antibacterial activity against the tested bacterial strains with different inhibition degrees and the activity is significantly higher against Staphylococcus aureus than Escherichia coli.
- El-Samanody, El-Sayed A.,AbouEl-Enein, Saeyda A.,Emara, Esam M.
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- Fabrication and characterization of thermoelectric CrSi2 compound by mechanical alloying and spark plasma sintering
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A mixture of elemental Cr-Si powders has been subjected to mechanical alloying (MA) at room temperature to prepare CrSi2 thermoelectric compound.The MA powders were sintered at 800-1000?°C Cunder 60 MPa using spark plasma sintering (SPS) technique. Due to the observed larger loss of Si relative Cr during ball milling, the starting composition was modified to Cr30Si70, Cr31.5Si68.5 and Cr33Si67 to get a single phase of CrSi2 compound. The single phase CrSi2 has been obtained by MA of Cr31.5Si68.5 mixture powders for 70 h and subsequently sintered at 1000?°C. X-ray diffraction data shows that the SPS compact sintered at 1000?°C consists of only nanocrystalline CrSi2 compound with a grain size of 250 nm. The value of Seebeck coefficient of CrSi2 compound increases with temperature and reaches maximum value of 245 ??V/K at 300?°C.
- Lee, Chung-Hyo
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p. 5070 - 5073
(2015/03/03)
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- Preparation of reduced iron powder using combined distribution of wood-charcoal by microwave heating
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In this paper, the influences of microwave heating with wood-charcoal as the reducing agent, on the reducing characterization of mill-scale were systematically investigated. The microstructures of the samples were characterized before and after microwave
- Ye, Qianxu,Zhu, Hongbo,Zhang, Libo,Ma, Ji,Zhou, Li,Liu, Peng,Chen, Jian,Chen, Guo,Peng, Jinhui
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p. 102 - 106
(2014/07/08)
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- Carbon monoxide oxidation by atmospheric oxygen on catalysts prepared by pyrolysis of transition metal β-diketonates on the synthetic foam ceramics
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The results of development of new catalytic systems for the carbon monoxide oxidation to dioxide are systematized. The catalysts were produced by gas-phase thermal decomposition of the transition metal acetylacetonates on the synthetic foam ceramics. The kinetic and activation parameters of the oxidation on the catalysts were studied and their relative activity was explored. The activity of catalysts at the oxidation with air oxygen were found to depend on the nature of the deposited metal and the carrier. A synergistic effect in the bimetallic copper catalysts was revealed.
- Didenkulova,Tsyganova,Shekunova,Aleksandrov
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p. 106 - 115
(2012/06/04)
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- Synthesis and characterization of new chromium, molybdenum and tungsten complexes of 2-[2-(methylaminoethyl)] pyridine
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A green chemistry route of synthesis using direct sunlight irradiation for the reactions of [M(CO)6] M = Cr, Mo or W with 2-[2- (methylaminoethyl)] pyridine (maepy) in THF. The reactions resulted in the formation of the oxo complex [Cr2(O)4(maepy)2] (1) and the tetracarbonyl complexes [Mo(CO)4(maepy)] (2) and [W(CO)4(maepy)] (3). The prepared complexes were characterized by elemental analysis, IR, NMR, mass spectrometry and magnetic measurement. The complexes (1-3) were further investigated by thermogravimetric technique (TG). The biological activity of maepy and complexes as antibacterial and antifungal reagents have been investigated.
- Ali, Saadia A.,Soliman, Ahmed A.,Marei, Amany H.,Nassar, Doaa H.
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p. 164 - 168
(2012/07/13)
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- Spectral, thermal, kinetic, molecular modeling and eukaryotic DNA degradation studies for a new series of albendazole (HABZ) complexes
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This work represents the elaborated investigation for the ligational behavior of the albendazole ligand through its coordination with, Cu(II), Mn(II), Ni(II), Co(II) and Cr(III) ions. Elemental analysis, molar conductance, magnetic moment, spectral studies (IR, UV-Vis and ESR) and thermogravimetric analysis (TG and DTG) have been used to characterize the isolated complexes. A deliberate comparison for the IR spectra reveals that the ligand coordinated with all mentioned metal ions by the same manner as a neutral bidentate through carbonyl of ester moiety and NH groups. The proposed chelation form for such complexes is expected through out the preparation conditions in a relatively acidic medium. The powder XRD study reflects the amorphous nature for the investigated complexes except Mn(II). The conductivity measurements reflect the non-electrolytic feature for all complexes. In comparing with the constants for the magnetic measurements as well as the electronic spectral data, the octahedral structure was proposed strongly for Cr(III) and Ni(II), the tetrahedral for Co(II) and Mn(II) complexes but the square-pyramidal for the Cu(II) one. The thermogravimetric analysis confirms the presence or absence of water molecules by any type of attachments. Also, the kinetic parameters are estimated from DTG and TG curves. ESR spectrum data for Cu(II) solid complex confirms the square-pyramidal state is the most fitted one for the coordinated structure. The albendazole ligand and its complexes are biologically investigated against two bacteria as well as their effective effect on degradation of calf thymus DNA.
- El-Metwaly, Nashwa M.,Refat, Moamen S.
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p. 196 - 204
(2011/03/21)
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- Volatility and high thermal stability in mid- to late-first-row transition-metal diazadienyl complexes
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Treatment of MCl2 (M = Cr, Mn, Fe, Co, Ni) with 2 equiv of lithium metal and 1,4-di-tert-butyl-1,3-diazadiene (tBu2DAD) in tetrahydrofuran at ambient temperature afforded Cr(tBu2DAD) 2 (38%), Mn(tBu2DAD)2 (81%), Fe( tBu2DAD)2 (47%), Co(tBu2DAD)2 (36%), and Ni(tBu2DAD)2 (41%). Crystal structure determinations revealed monomeric complexes that adopt tetrahedral coordination environments and were consistent with tBu2DAD radical anion ligands. To evaluate the viability of M(tBu2DAD)2 (M = Cr, Mn, Fe, Co, Ni) as potential film growth precursors, thermogravimetric analyses, preparative sublimations, and solid-state decomposition studies were performed. Mn( tBu2DAD)2 is the most thermally robust among the series, with a solid-state decomposition temperature of 325 °C, a sublimation temperature of 120 °C/0.05 Torr, and a nonvolatile residue of 4.3% in a preparative sublimation. Thermogravimetric traces of all complexes show weight loss regimes from 150 to 225 °C with final percent residues at 500 °C ranging from 1.5 to 3.6%. Thermolysis studies reveal that all complexes except Mn(tBu2DAD)2 decompose into their respective crystalline metal powders under an inert atmosphere. Mn(tBu2DAD)2 may afford amorphous manganese metal upon thermolysis.
- Knisley, Thomas J.,Saly, Mark J.,Heeg, Mary Jane,Roberts, John L.,Winter, Charles H.
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p. 5010 - 5017
(2011/11/13)
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- Synthesis, spectroscopic characterization, thermal studies, catalytic epoxidation and biological activity of chromium and molybdenum hexacarbonyl bound to a novel N2O2 Schiff base
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Complexes of M(CO)6 (M = Cr and Mo) with novel Schiff base N,N′-bis(salicylidene)4,5-dichloro-1,2-phenylenediamine (H2L) were prepared in benzene in two different conditions: (i) under reduced pressure resulting the dicarbonyl precursors [Cr(CO)2(H2L)] and [Mo(CO)2(L)] and (ii) in air resulting the oxo complex [Cr(O)(L)] and the dioxo complex [Mo(O)2(L)]. The complexes were characterized by elemental analysis, IR, 1H NMR, mass spectrometry, and magnetic measurement. Thermal behaviors of the complexes were also studied by using thermogravimetric analysis (TGA). The catalytic activity of the novel complexes in the epoxidation of cyclooctene, cyclohexene, 1-octene and 1-hexene with tert-butyl-hydroperoxide (TBHP) in methylene chloride was investigated. The antimicrobial activities of the ligand and their complexes have been screened against various strains of bacteria and fungi and the results have been compared with some known antibiotics.
- Abdel Aziz, Ayman A.
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- The thermodynamic properties of bis(n6-ethoxybenzene)chromium fulleride from T → 0 to 340 K
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The temperature dependence of the heat capacity of crystalline bis-(n6-ethoxybenzene)chro- mmm fulleride [(n6-(EtOPh))2Cr]-+[C 60]- was studied for the first time by adiabatic vacuum calorimetry over the temperature range 6-340 K with errors of ±0.2%. The temperature dependence of the EPR signal parameters of bi's-(n6-ethoxybenzene)chromium fulleride was studied for the first time from 120 to 340 K. A reversible endothermic transformation was observed between 160 and 250 K during heating; it was caused by the dissociation of the [(C60)2]2- dimer and the formation of the [(n6-(EtOPh))2Cr]+[C60]- fulleride; its standard thermodynamic characteristics were estimated and analyzed. The experimental data were used to calculate the standard thermodynamic functions, including the heat capacity, enthalpy, entropy, and Gibbs function of the fulleride dimer from T→ 0 to 160 K and the [(n6-(EtOPh))2Cr] +[C60] monomeric complex over the temperature range 250-340 K. The standard thermodynamic properties of the fulleride studied, fullerides studied earlier, and fullerite C60 were compared. Pleiades Publishing, Ltd., 2010.
- Ruchenin,Smirnova,Markin,Shevelev,Kuropatov,Lopatin,Domrachev,Markin
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p. 928 - 933
(2011/01/10)
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- The thermodynamic properties of bis(η6-o-xylene)chromium(I) fulleride over the temperature range from T → 0 to 340 K
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The temperature dependence of the heat capacity of bis(η6-o- xylene)chromium(I) fulleride, [(η6-(o-xylene)) 2Cr]+?[C60]?-, over the temperature range 6-340 K was measured on an adiabatic va
- Markin,Ruchenin,Smirnova,Markin,Shevelev, Yu. A.,Kuropatov,Domrachev
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p. 1289 - 1294
(2010/03/04)
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- Regularities governing the two-stage synthesis of cast Cr2O 3/Al2O3 under conditions of the autowave synthesis
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The study of the chemical, roentgen phase and structural properties of the products of combustion of system Cr2O3-Al-Fe 2O3 was carried out. The analysis of the results shows the presence in the system of a set
- Sviderskii
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p. 1716 - 1720
(2011/06/20)
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- Thermodynamics of the bis(η6-t-butylphenyl)chromium fulleride [Cr{η6-(t-BuPh)}2]?+C60 ?-
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In this work, the temperature dependence of heat capacity C p,mo = f(T) of crystalline bis(η6-t- butylphenyl)chromium fullende between T= 6 and 360K was measured for the first time by precision adiabatic vacuum calorimetry
- Ruchenin, Vitaly A.,Markin, Alexey V.,Smirnova, Natalia N.,Markin, Gennady V.,Shevelev, Yurii A.,Cherkasov, Vladimir K.,Kuropatov, Vyatcheslav A.,Ketkov, Sergey Y.,Lopatin, Mikhail A.,Domrachev, Georgy A.
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- Use of ionic liquids (ILs) for the IL-anion size-dependent formation of Cr, Mo and W nanoparticles from metal carbonyl M(CO)6 precursors
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Stable chromium, molybdenum and tungsten nanoparticles are obtained reproducibly by thermal or photolytic decomposition under argon from mononuclear metal carbonyl precursors M(CO)6 (M = Cr, Mo, W) suspended in the ionic liquids BMim+BF4-, BMim +OTf- and BtMA+Tf2N- (BMim+ = n-butyl-methyl-imidazolium, BtMA+ = n-butyl-trimethyl-ammonium, Tf2N = N(O2SCF 3)2, OTf = O3SCF3) with a very small and uniform size of 1 to 1.5 nm in BMim+BF4- which increases with the molecular volume of the ionic liquid anion to ~100 nm in BtMA+Tf2N- [characterization by transmission electron microscopy (TEM), dynamic light scattering and transmission electron diffraction (TED) analysis]. The Royal Society of Chemistry.
- Redel, Engelbert,Thomann, Ralf,Janiak, Christoph
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p. 1789 - 1791
(2008/12/22)
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- Stoichiometric and homogeneous-catalytic diboration of the N=N double bond of azobenzene
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The diboration of the N=N double bond of azobenzene was achieved by reaction of the [3]diboraplatinametalloarenophanes derived from ferrocene, [Fe(η5-C5H4)B(NMe2)Pt(PEt3)2B(NMe2)
- Braunschweig, Holger,Kupfer, Thomas
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p. 4242 - 4243
(2008/09/20)
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- Effect of temperature on N-ethylcarbazole chromium tricarbonyl complex studied by two-dimensional infrared correlation spectroscopy
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Temperature-dependent variation of N-ethylcarbazole chromium tricarbonyl complex by itself without the solid support has been studied by carefully examining their IR spectra with the aid of two-dimensional correlation analysis. Two obvious stages have been observed during the heating process. In the first stage, the crystalline ECzC undergoes a slow process to change into the amorphous form due to the strong interactions of the hydrogen bonding. In the second stage, ECzC gradually decomposes, which results in the formation of Cr(CO)6. The results suggest that the interaction between the organometallics and its solid support may not have direct influence to the final product generated under the thermal treatment.
- Shen, Yi,Wu, Peiyi
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- Thermolysis specifics of Tin(IV) and Tin(II) complex derivatives: Thermolysis of (Acac)2SnX2 (X = Cl, N3), (CO)5MSnCl2(thf) (M = Cr, Mo, W), (CO) 5MSn(Acac)2, (CO)5MSn
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Differential scanning calorimetry and thermogravimetry are used to study the thermolysis of following complexes: (Acac)2Sn(N3)Cl (1); (Acac)2SnCl2 (2); (CO)5MSn(Acac) 2 with M = Cr (3) or W
- Dobrokhotova,Koroteev,Novotortsev,Egorov,Nefedov
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p. 1109 - 1119
(2008/10/09)
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- The question of the Cr oxidation state in the {Cr(SNS)} catalyst for selective ethylene trimerization: An unanticipated re-oxidation pathway
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(Chemical Equation Presented) An unprecedented oxidation of chromium(II) by trimethylaluminum which, despite the reducing environment, forms a cationic organochromium(III) complex (see picture; SNS = RSCH2CH 2N(H)-CH2CH2SR, Cy = cyclohexyl, X = [Me 6Al2Cl]), provides a possible catalyst re-activation pathway.
- Temple, Claire,Jabri, Amir,Crewdson, Patrick,Gambarotta, Sandro,Korobkov, Ilia,Duchateau, Robbert
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p. 7050 - 7053
(2007/10/03)
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- Spectroscopic and thermal studies of chromium(III), molybdenum(VI) and ruthenium(0) complexes of maleic hydrazide
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Interaction of maleic hydrazide (LH2) with [Cr(CO)6] in air at atmospheric pressure resulted in the formation of the complex [(LH)Cr(μ-O)2Cr(LH)] (1). Reaction of LH2 with [Mo(CO)6] in air also gave t
- Mohamed, Hassan A.,Ali, Saadia A.,Ramadan, Ramadan M.
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p. 913 - 917
(2007/10/03)
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- Ionic liquids and their use
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Ionic compounds having a freezing point of no more than 50° C., formed by the reaction of at least one amine salt of the formula R1R2R3R4N+X? (I) with at least one hydrated salt, which is a chloride, nitrate, sulphate or acetate of Li, Mg, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, Pb, Bi, La or Ce; wherein R1, R2 and R3 are each independently a C1 to C5 alkyl or a C6 to C10 cycloalkyl group, or wherein R2 and R3 taken together represent a C4 to C10 alkylene group, thereby forming with the N atom of formula (I) a 5 to 11 membered heterocyclic ring, and wherein R4 is hydrogen, or phenyl, or C1 to C12 alkyl or cycloalkyl group, optionally substituted with at least one group selected from OH, Cl, Br, F, I, phenyl, NH2, CN, NO2, COOR5, CHO, COR5 and OR5, wherein R5 is a C1 to C10 alkyl or cycloalkyl group, and X? is an anion capable of being complexed by the said hydrated salt. The compounds are useful as solvents, electrolytes, and catalysts, and have particular application in solvents/electrolytes for metal plating and electropolishing processes, in particular in chromium plating.
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- Nutritional supplement
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A nutritional supplement is provided that is designed to provide nutritional benefits as well as to assist the body with detoxification. By providing a supplement that serves both of these functions, the present invention may enable persons to improve their overall wellness.
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- Synthesis and characterization of nicotinamide coordinated metal carbonyl complexes
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Three new nicotinamide coordinated group VI B metal carbonyl complexes fac-[M(CO)3(nicotinamide)3] (M = Cr, Mo, and W; 4, 5, and 6) (nicotinamide = 3-H2NOCC5H4N) have been synthesized. Reaction of the 'in situ' generated complex precursors fac-[M(CO)3(CH3CN)3] (M = Cr, Mo, and W: 1, 2, and 3) with three equivalents of nicotinamide in methanol at room temperature give nicotinamide coordinated metal carbonyl complexes 4, 5, and 6 in good yields. The complexes exhibit two bands corresponding to v(C≡O) of metal carbonyl groups and v(C=O) of nicotinamide ligands. All the complexes exhibit a very strong stretching band corresponding to v(C=O) of coordinated nicotinamide ligands at 1684 (Cr, 4); 1669 (Mo, 5); and 1683 cm.1 (W, 6). The occurrence of single v(C=O) band suggests the coordination of three nicotinamide molecules that are arranged cis to each other and representing a C3v configuration of ligands around the metal atom in the facial geometry of the complexes. The 1H NMR spectra of the complexes shows signals at four different chemical shift regions, corresponding to the four protons on the pyridine ring of the nicotinamide ligand. The calculated integral value of each signal is present in the ratio 1:1:2:2. The powder X-ray diffractogram of the complexes exhibit similar pattern suggesting the similar arrangements of atoms in the crystal lattice and geometry.
- Jesudurai,Vancheesan
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p. 2260 - 2267
(2007/10/03)
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- Rapid solid-state synthesis of tantalum, chromium, and molybdenum nitrides
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Solid-state metathesis (exchange) reactions can be used to synthesize many different transition-metal nitrides under ambient conditions including TiN, ZrN, and NbN. Typical metathesis reactions reach temperatures of greater than 1300 °C in a fraction of a second to produce these refractory materials in highly crystalline form. Likely due to the large amount of heat produced in these solid-state reactions, some transition-metal nitrides such as TaN, CrN, and γ-Mo2N cannot easily be synthesized under ambient conditions. Here metathesis reactions are demonstrated to produce the cubic nitrides TaN, CrN, and γ-Mo2N when sufficient pressure is applied before the reaction is initiated. By pressing a pellet of TaCl5 and Li3N with an embedded iron wire, crystalline cubic TaN forms under 45 kbar of pressure after a small current is used to initiate the chemical reaction. Crystalline cubic CrN is synthesized from CrCl3 and Li3N initiated under 49 kbar of pressure. Crystalline γ-Mo2N is produced from MoCl5 and Ca3N2 (since MOCl5 and Li3N self-detonate) initiated under 57 kbar of pressure. The addition of ammonium chloride to these metathesis reactions drastically lowers the pressure requirements for the synthesis of these cubic nitrides. For example, when 3 mol of NH4Cl is added to CrCl3 and Li3N, crystalline CrN forms when the reaction is initiated with a resistively heated wire under ambient conditions. Cubic γ-Mo2N also forms at ambient pressure when 3 mol of NH4Cl is added to the reactants MoCl5 and Ca3N2 and ignited with a resistively heated wire. A potential advantage of synthesizing γ-Mo2N under ambient conditions is the possibility of forming high-surface-area materials, which could prove useful for catalysis. Nitrogen adsorption (BET) indicates a surface area of up to 30 m2/g using a Langmuir model for γ-Mo2N produced by a metathesis reaction at ambient pressure. The enhanced surface area is confirmed using scanning electron microscopy.
- O'Loughlin,Wallace,Knox,Kaner
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p. 2240 - 2245
(2008/10/08)
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- Luminescent Photofragments of (1,1,1,5,5,5-Hexafluoro-2,4-pentanedionato) Metal Complexes in the Gas Phase
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The luminescence that is observed under gas phase photolytic deposition conditions is studied for Cr(hfac)3, Ni(hfac)2, and Pt(hfac)2. This luminescence is analyzed under a variety of conditions, including the relatively high pressures of an evacuated gas cell and the collision-free conditions of a molecular beam. The effects of inert buffer gas are also studied. Features in these spectra indicate that, in general, multiple photolysis processes occur. Some simple fragments that are produced from these compounds are identified, including bare metal atoms (Ni, Cr), metal monofluorides (NiF, CrF), CH (in the case of Ni(hfac)2), and metal carbide from Pt(hfac)2. It is postulated that the difference in the observed photofragmentation pathway in the case of platinum is due to σ bonding to the β carbon of the hfac moiety as opposed to the bidentate bonding of the other two metals. Possible mechanisms are presented. Detailed analysis of the spectra allows characterization of the internal energy of the platinum carbide photofragment.
- Talaga, David S.,Hanna, Stephen D.,Zink, Jeffrey I.
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p. 2880 - 2887
(2008/10/08)
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- Characterization, kinetics and mechanism of thermal decomposition of photosubstituted ethylenediamine complexes of molybdate(IV) and tungstate(IV) with chromium(III).
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Photoinitiated substitution complexes of [M(CN)8]4- (where M= Mo(IV) or W(IV)) and ethylenediamine with chromium(III) have been synthesized and characterized. On the basis of elemental analysis, the complexes have been assigned formulas as folows:Cr[Mo(CN)(C2H8N2)(OH) 6]·2H2O I for Mo(IV); andCr[W(C2H8N2)(O2)(OH) 3]·H2O II for W(IV)The characteristic IR absorption peaks for different entities present support the assigned formulas. Complex I shows the absorption peaks due to ν(CN) stretching bond, NH asymmetric deformation, NH symmetric deformation and NH3 rocking mode showing the presence of cyanide and ethylenediamine. The loss of the absorption peak due to ν(CN) stretching in the spectra of complex II confirms the substitution of all the cyanide ligands. The thermal degradation of the complexes has been studied by TG and DSC techniques. Both the complexes have a similar thermal decomposition behavior: involving expulsion of water molecules in the first step followed by the expulsion of other ligands. Kinetics and a thermal decomposition mechanism have been proposed for each complex. Thermodynamic parameters such as activation energy (Ea), pre-exponential factor (A) and entropy of activation (ΔS#) have been calculated for each step, employing different integral methods of Doyle, Coats and Redfern, and Arrhenius. The reaction enthalpy is obtained from DSC data.
- Ali,Majid, Kowsar
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p. 183 - 192
(2008/10/09)
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- Vaporization of LaCrO3: Partial and integral thermodynamic properties
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The vaporization of LaCrO3(s) and samples of the composition LaCrO3 + La2O3 was investigated in the temperature range of 1887-2333 K by Knudsen effusion mass spectrometry using Knudsen cells made of tungsten lined completely with iridium. The species Cr(g), CrO(g), CrO2(g), and LaO(g) were identified in the vapor. Their partial pressures were determined by calibration with pure platinum solid. The thermodynamic activity of Cr2O3, aCr2O3, in LaCrO3 for the Cr2O3-poor phase boundary of this phase was In aCr2O3 = -(17953/T) - 0.485 (temperature T given in K) for the temperature range of the measurements with a probable overall error of ±13%. The following values and temperature dependence of ΔG°f,T resulted for the formation of LaCrO3(s) according to the reaction 0.5Cr2O3(s) + 0.5La2O3(s) → LaCrO3(s): ΔG°f,2100 = -78.9 ± 1.1 kJ/mol, ΔH°f,298 = -76.8 ± 5.2 kJ/mol, and ΔG°f,T(kJ/mol) = -74.7 - 0.00202T. Computations for the vaporization of LaCrO3 were conducted to show the volatility of this material in different atmospheres at high temperatures.
- Peck, Dong-Huyn,Miller, Miroslaw,Kobertz, Dietmar,Nickel, Hubertus,Hilpert, Klaus
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p. 3266 - 3272
(2008/10/08)
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- Sodium azide as a reagent for solid state metathesis preparations of refractory metal nitrides
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Thermal initiation (.apprx.300°C) of a reaction between sodium azide and anhydrous metal chlorides (LaCl3, SmCl3, TiCl3, ZrCl4, HfCl4, VCl3, TaCl5, CrCl2, WCl6 and MnCl2) in sealed evacuated ampoules rapidly produces binary metal nitrides, dinitrogen and sodium chloride. The metalnitrides were purified by trituration with methanol and characterized b y powder X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis and FT-IR.
- Hector, Andrew L.,Parkin, Ivan P.
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p. 913 - 918
(2008/10/08)
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- Kinetics of Thermal Decomposition of Chromium on a Molybdenum Surface
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Thermal decomposition of chromium carbonyl on a molybdenum surface was studied.The kinetic characteristics of the process are determined.
- Baev, A. K.,Kiselevich, V. P.
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- Low-temperature Routes to Early Transition-metal Nitrides
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Thermal initiation of the reaction of lithium nitride with anhydrous transition-metal halides produces crystalline transition-metal nitrides of various compositions MxNy (M = Y, La, Ti, Zr, Hf, V, Nb, Ta, Cr or Mn) via an exothermic solid-state metathesis
- Fitzmaurice, Jonathan C.,Hector, Andrew L.,Parkin, Ivan P.
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p. 2435 - 2438
(2007/10/02)
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- Visible Laser-Induced Nucleation and Growth of Cr, Mo, and W Films from the Hexacarbonyls. Reactivity of CO on Film Surfaces
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Continuous visible laser irradiation is used to deposit Cr, Mo, and W films from the hexacarbonyls by thermal excitation.Detailed analyses of the films by scanning Auger microscopy show that the Mo and Cr films are spatially inhomogeneous, having clean metal centers surrounded by contaminated metal rings.W films are completely pure.Depth profiles reveal that, prior to formation of clean Mo and Cr, an interfacial layer of contaminated material is deposited which becomes progressively metal rich as thickness increases.If such a layer is formed for W, it is very thin.The measured composition profiles are compared to calculated surface temperature distributions in order to extract information on the kinetics of CO dissociation and desorption during growth.The temperature and mechanism simulations show that CO desorption dominates above about 450 K, ensuring that pure metal is deposited.Below that temperature contamination occurs.Previous investigations of film growth from metal hexacarbonyls have led to the conclusion that film purity will only be high at temperatures exceeding 800 K, where recombinative desorption of CO is fast.The origins of the large discrepancy in temperatures are discussed.Chemical processes leading to growth of metal oxycarbide material at the film edges and film-substrate interface are explored using data from the catalysis literature.The strong parallels found between the laser-deposited material and supported catalysts formed from the hexacarbonyls suggest that the oxycarbide films may have significant Lewis acid-base character, leading to faster CO and metal-CO bond dissociation rates.Thus, formation of contaminated material appears to depend on local surface composition as well as temperature.
- Houle, F. A.,Singmaster, K. A.
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p. 10425 - 10439
(2007/10/02)
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- Process for the preparation of monocarboxylic anhydrides
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In the process for the preparation of monocarboxylic anhydrides of the general formula (RCO) 2 O by reacting a carboxylic acid ester of dialkyl ether of the general formula RCOOR or ROR, where R in each case denotes the same alkyl radical having 1 to 4 carbon atoms, with carbon monoxide in the gas phase in the presence of iodine or bromine or compounds thereof as reaction promoter, and in the presence of a supported catalyst, at temperatures of from 130° to 400° C. and pressures of from 1 to 150 bar, where, in the supported catalyst, an organosilicon compound is bonded, as a polyfunctional coupling agent, on the one hand to a support material and on the other hand to a noble-metal compound from group VIII of the Periodic Table, a chelate-forming organosilicon compound of the general formula STR1 is employed as the polyfunctional coupling agent, where X=Cl, Br or --OR 2 ;Y=-NR 2 4, a nitrogen-containing aryl radical, --PR 2 4, AsR 2 4, --SR 4 or --SH;Z=zero, arylene or phenylene (optionally ortho-, meta-or para-substituted),R 1 =C 1 to C 5 -alkyl;R 2 =C 1 to C 5 -alkyl or --C 6 H 5 ;R 3 =--H or C 1 to C 3 -alkyl;R 4 =C 1 to C 5 -alkyl, C 5 or C 6 -cycloalkyl or --C 6 H 5 or --CH 2 C 6 H 5, which are optionally substutited by halogen, methoxy, ethoxy or C 1 to C 3 -alkyl groups;n=0 or 1 or 2;m=2 to 6, preferably 2 to 4.
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- Vapor Phase Hydrogen Reduction of Chromic Oxide in an RF Plasma.
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Die Gasphasenreduktion von Chromoxiden in Radiofrequenzplasma (Ar-H2) wurde in einem neuen Forschungssystem untersucht.Die Reaktionen verliefen ganz in der Gasphase.Das Diffusionsmodell der Schichtbildung auf der Wand wurde diskutiert.Unter identischen Bedingungen war die Konversion Cr2O3 ---> in der Gasphasenreduktion etwa 6mal hoeher als in heterogenen Prozessen.
- Huczko, A.,Meubus, P.
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p. 561 - 568
(2007/10/02)
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- (η6-1,4-(CH3SO3)2C6H4)Cr(CO)3: synthesis, characterization, and reactivity
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Reaction of (MeCN)3Cr(CO)3 with hydroquinone in refluxing tetrahydrofuran (THF) produced (η6-1,4-C6H4(OH)2)Cr(CO)3 (1) which was subsequently converted to (η6-1,4-(CH3SO3)2C6H4)Cr(CO)3 (2) by treatment with methanesulfonyl chloride and triethylamine.A single-crystal X-ray study of 2 has been completed and is reported.Treatment of 2 with an oxygen nucleophile gave reaction at sulfur; whereas, treatment of 2 with lithium phenylacetylide resulted in decomposition of the complex to metallic chromium.
- Wright, Michael E.
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p. 353 - 358
(2007/10/02)
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- Corrosion and wear characteristics of pulse-plated chromium deposits
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Corrosion and wear characteristics of pulse-plated chromium deposits obtained from a self-regulating high speed bath have been studied as a function of pulse current parameters such as duty cycle, average current density and pulse period. The chromium deposits obtained at duty cycles of 100 (direct current) to 60% were composed of a hemispherical nodular growth with a body centred cubic (b c c) lattice while those obtained at 20% duty cycle were composed of a needle-like structure containing a mixture of b c c lattice and hexagonal hydride. Corrosion rate, wear loss of chromium deposits and occluded hydrogen content in the deposits decreased up to 60% duty cycle, and then increased with further decrease in duty cycle to 20%. A two-stage variation of corrosion and wear properties with decreasing duty cycle is discussed in terms of crack density and the crystal structure of chromium deposits.
- Jong-Sang, Kim,Rak-Hyun, Song,Su-Il, Pyun,Kim, H. C.
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- Stability and the gas chromatography of alkyl-substituted η6-benzenetricarbonylchromium(0) complexes
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Thermoanalytical and gas chromatographic data are reported for benzenetricarbonylchromium(0) and nine of its methyl- and t-butyl-substituted derivatives.The distinct trends found for the volatilities, thermal stabilities, air stabilities and gas chromatog
- Patsalides, E.,Pratten, S. J.,Robards, K.
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p. 169 - 180
(2007/10/02)
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