- Thin films of ZnO:M synthesized by ultrasonic spray pyrolysis
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High optical quality ZnO:M@Si nanocomposites (where M is the doping element) were obtained by ultrasonic spray pyrolysis. The variation of experimental conditions, the use of various precursors and dopants demonstrated that the morphology of zinc oxide nanoparticles is mainly determined by the sort of the doping element. The luminescence spectra confirm indirectly the isomorphous incorporation of the dopant ions into the zinc oxide lattice.
- Demyanets,Kireev,Li,Artemov
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Read Online
- A new simultaneous apparatus for X-ray diffractometry and differential scanning calorimetry (XRD-DSC)
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An instrument was developed for performing simultaneous X-ray diffractometric and differential scanning calorimetric (XRD-DSC) measurement using a power compensation DSC (pc-DSC). The feasibility of the technique is demonstrated by examining the thermal dehydration measurement of zinc formate dihydrate (Zn(HCO2)2·2H2O). The DSC curve shows apparent double endothermic peaks during the dehydration process, while X-ray diffraction analysis indicated that the resulting anhydrous product, Zn(HCO2)2, was crystalline. The simultaneous measurement reveals that the DSC curve arises from a combination of the endothermic dehydration peak and the exothermic crystallization peak which resulted from the progression of the anhydrous products.
- Arii, Tadashi,Kishi, Akira,Kobayashi, Yuji
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- Deaggregation of Zinc Dihydride by Lewis Acids including Carbon Dioxide in the Presence of Nitrogen Donors
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Thermally sensitive polymeric zinc dihydride [ZnH2]n can conveniently be prepared by the reaction of ZnEt2 with [AlH3(NEt3)]. When reacted with CO2 (1 bar) in the presence of chelating N-donor ligands Ln = N,N,N′,N′-tetramethylethylenediamine (TMEDA), N,N,N′,N′-tetramethyl-1,3-propanediamine (TMPDA), N,N,N′,N″,N′′-pentamethyldiethylenetriamine (PMDTA), and 1,4,7,10-tetramethyl-1,4,7,10-tetraazacyclododecane (Me4TACD), insertion into the Zn-H bond readily occurred. Depending on the denticity n, formates [(Ln)Zn(OCHO)2] were isolated and structurally characterized, either as a molecule (Ln = TMEDA, TMPDA, PMDTA) or a charge-separated ion pair [(Ln)Zn(OCHO)][OCHO] (Ln = Me4TACD). The reaction of [ZnH2]n with the mild Lewis acid BPh3 in the presence of chelating N-donor ligands Ln gave a series of hydridotriphenylborates, either as a contact ion pair [(L2)Zn(H)(HBPh3)] (L2 = TMEDA, TMPDA) or a separated ion pair [(Ln)Zn(H)][HBPh3] (Ln = PMDTA, Me4TACD). In the crystal, the contact ion pair [(TMEDA)Zn(H)(HBPh3)] showed a bent Zn-H-B bridge indicative of a delocalized Zn-H-B interaction. In contrast, a linear Zn-H-B bridge for [(TMPDA)Zn(H)(HBPh3)] was observed, suggesting a contact ion pair. In THF solution, both complexes show an exchange with free BPh3 as well as [HBPh3]-. DFT calculations suggest the presence of [HBPh3]- anion with a highly polarized B-H bond that interacts with the Lewis acidic zinc hydride cation [(L2)Zn(H)]+. The hydridotriphenylborates [(Ln)Zn(H)(HBPh3)] underwent CO2 insertion to give (formato)zinc (formoxy)triphenylborate complexes [(Ln)Zn(OCHO)][(OCHO)BPh3] (Ln = TMPDA, PMDTA, Me4TACD). For Ln = TMEDA, a dinuclear complex [(Ln)2Zn2(μ-OCHO)3][(OCHO)BPh3] was isolated. Hydridotriphenylborates [(Ln)Zn(H)(HBPh3)] catalyzed the hydrosilylation of CO2 (1 bar) by nBuMe2SiH in THF at 70 °C to give formoxysilane and (methoxy)silane.
- Ritter, Florian,Morris, Louis J.,McCabe, Karl N.,Spaniol, Thomas P.,Maron, Laurent,Okuda, Jun
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supporting information
p. 15583 - 15592
(2021/10/20)
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- Supramolecular Metallacycles and Their Binding of Fullerenes
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The synthesis of a new triaminoguanidinium-based ligand with three tris-chelating [NNO]-binding pockets and C3 symmetry is described. The reaction of tris-(2-pyridinylene-N-oxide)triaminoguanidinium salts with zinc(II) formate leads to the formation of cyclic supramolecular coordination compounds which in solution bind fullerenes in their spherical cavities. The rapid encapsulation of C60 can be observed by NMR spectroscopy and single-crystal X-ray diffraction and is verified using computation.
- Ehnbom, Andreas,G?b, Christian R.,Oppel, Iris M.,Sturm, Lisa,Tobe, Yoshito
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supporting information
(2020/03/19)
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- Structurally diverse coordination compounds of zinc as effective precursors of zinc oxide nanoparticles with various morphologies
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The structurally diverse coordination compounds of zinc were designed and synthesized using two types of building blocks: short-chain carboxylate ions and hexamethylenetetraamine. They were characterized by X-ray crystallography, infrared spectroscopy and thermal analysis. The studied compounds were used as precursors for production (via controlled thermal conversion) of zinc oxide nanoparticles. The conversion process was optimized in terms of two parameters (heating rate and maximum temperature). Such an approach, combined with proper design of the precursor structure, allows fabrication of various zinc oxide micro- and nanoparticles. The influence of a precursor structure and modifications of conversion parameters on size and morphology of ZnO particles were studied and discussed.
- Swiatkowski, Marcin,Kruszynski, Rafal
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- Solution synthesis and characterization of indium-zinc formate precursors for transparent conducting oxides
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A series of In-Zn formate mixtures were investigated as potential precursors to amorphous In-Zn-oxide (IZO) for transparent conducting oxide (TCO) applications. These mixtures were prepared by neutralization from formic acid and characterized by elemental analysis, IR spectroscopy, powder X-ray diffraction, and thermogravimetry-differential scanning calorimetry (TG-DSC) measurements. Thermal analysis revealed that a mixture of In and Zn formates reduced the overall decomposition temperature compared to the individual constituents and that OH-substitution enhanced the effect. In terms of precursor feasibility, it was demonstrated that the decomposition products of In-Zn formate could be directed toward oxidation or reduction by controlling the decomposition atmosphere or with solution acid additives. For TCO applications, amorphous IZO films were prepared by ultrasonic spray deposition from In-Zn formate solutions with annealing at 300-400 °C.
- Pasquarelli, Robert M.,Curtis, Calvin J.,Miedaner, Alexander,Van Hest, Maikel F.A.M.,OHayre, Ryan P.,Ginley, David S.
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p. 5424 - 5431
(2010/08/05)
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- Thermal, spectral and biological properties of Zn(II) complex compounds with phenazone
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The thermal decomposition of the complexes Zn(form)2 2phen (I), Zn(ac)2 2phen (II), Zn(prop)2 2phen (III), Zn(but) 2 2phen (IV), where phen=phenazone, form=formiate, ac=acetate, prop=propionate, but=butyrate has
- Szunyogova, Erika,Gyoeryova, Katarina,Hudecova, Daniela,Piknova, Lenka,Chomic,Vargova, Zuzanna,Zelenak
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p. 219 - 223
(2008/10/09)
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- Synthesis and characterization of new metal(II) complexes with formates and some nitrogen donor ligands
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New mixed-ligands complexes with empirical formulae: M(2,4'-bpy) 2L2?H2O (M(II)Zn, Cd), Zn(2-bpy) 3L2?4H2O, Cd(2-bpy)2L 2?3H2O, M(phen)L2?2H
- Czakis-Sulikowska,Czylkowska,Radwanska-Doczekalska,Grodzki,Wojciechowska
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p. 557 - 564
(2008/10/09)
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- METHOD FOR THE PRODUCTION OF METAL CARBOXYLATES AND THE METAL AMINOATE OR METAL HYDROXY ANALOGUE METHIONATE DERIVATIVES THEREOF, AND USE OF SAME AS GROWTH PROMOTERS IN ANIMAL FEED
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A method of production of metal carboxylates and of their metal carboxylate-aminoate or metal carboxylate-methioninate hydroxy analog derivatives, and their use as growth promoters in animal nutrition. It comprises mixing stoichiometric quantities of formic or butyric acid and oxide and of the dry basic salt of divalent metal, the oxide or hydroxide of Zn2+ or Cu2+, to give an exothermic reaction, without addiction of solvents, giving rise to a dry carboxylate of divalent metal that is easy to use. It also describes the use of a stage of mixing with metal aminoates or hydroxy analogs of methionine in the process, for forming either a carboxylate-aminoate of divalent metal or a carboxylate-methioninate hydroxy analog of divalent metal, products that are finally obtained in a dry form that is easy to use. Finally it describes the use of the compounds that can be obtained in the feeding of monogastric animals for improving the productivity, the bioavailability of the metals, and achieve a reduction of their emission to the environment, owing to the growth-promoting effect that they all display.
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Page/Page column 7-8
(2008/06/13)
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- Decomposition of organic salts of some d and f metals: Non-isothermal kinetics and FT-IR studies
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The thermal decomposition in non-isothermal conditions of formates, acetates, propionates and butyrates of Mn, Co, Zn, Cd, Eu, Sm and Ni was studied. The observed compensation effect allows us to calculate the isokinetic temperature. A selective activation mechanism was suggested. This leads to a good agreement between kinetic and spectroscopic data.
- Vlase,Vlase,Chiriac,Doca
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p. 839 - 845
(2008/10/08)
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- Thermal dehydration of cobalt and zinc formate dihydrates by controlled-rate thermogravimetry (CRTG) and simultaneous X-ray diffractometry-differential scanning calorimetry (XRD-DSC)
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The thermal dehydration study of the similar hydrated salts, cobalt and zinc formate dihydrates, have been carried out successfully by means of X-ray diffractometry-differential scanning calorimetry (XRD-DSC) and controlled-rate thermogravimetry (CRTG). X-ray diffraction analysis recorded simultaneously indicates that the resulting anhydrous product, Zn(HCO2)2, was crystalline, while Co(HCO2)2 was amorphous. The XRD-DSC data are proven to be invaluable in verifying the interpretation of overlapping processes in thermal events. In addition, these differences in the resulting anhydrous products can be explained from kinetic analysis results based on the CRTG data. The kinetic mechanism governing the dehydration of zinc formate dihydrate is a nucleation and growth process, while in the case of cobalt formate dihydrate a phase boundary controlled reaction is the governing mechanism.
- Arii, Tadashi,Kishi, Akira
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p. 157 - 165
(2008/10/09)
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- Measurement of equilibrium water vapor pressures for the thermal dehydrations of some formate dihydrates by means of the transpiration method
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The equilibrium water vapor pressures, PH2O for the thermal dehydrations of some formate dihydrates, M(HCO2)2·2H2O, where M is Mg, Mn, Co, Ni and Zn, were measured by means of the transpiration method using a laboratory-made apparatus. These hydrates have a monoclinic isomorphous crystal structure with a space group, P21/C. The thermodynamic data such as ΔG, ΔH and ΔS for the dehydration were derived from the PH2O and correlated to the crystal structures of these hydrates. Although the values of ΔH were expected to increase in the order of the hydrates of Mn2+-OH2 bond, they increased in the order of Mn2)2·2H2O and Zn(HCO2)2·2H2O seemed to be due to the relatively strong hydrogen bond between the water molecules and the formate ions. The values of ΔG obtained at 373 K, ΔG(373) showed a good correlation with the beginning temperatures of the dehydrations, Ti.
- Masuda, Yoshio,Hatakeyama, Makiko
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p. 165 - 170
(2008/10/09)
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- Ultrasonic Absorption Study of the Complex Formation of Zinc(II) Carboxylates in Aqueous Solution
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Ultrasonic absorption of aqueous zinc(II) formate, acetate, and propionate is measured in the metal-rich concentration regions with a pulse technique over the frequency range 3-260 MHz.The single relaxations observed in all cases are attributed to the complex formation of zinc(II) carboxylates via the Eigen-Tamm mechanism of stepwise association.The reaction parameters are determined from the concentration dependences of the relaxation frequency and amplitude.Both the association constant of outer-sphere complex and the rate constant of ligand substitution indicate ligand dependences; the former is larger while the latter is smaller with the higher carboxylate.However, the uncertainties involved in these reaction parameters prevent the elucidation of the above feature.The volume changes of the outer-sphere complexing are substantially less than those of the ligand substitution; the volume change of the latter is larger for the higher carboxylate.
- Tamura, Kiyoshi
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p. 7358 - 7362
(2007/10/02)
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