557-34-6Relevant articles and documents
Zinc-containing block copolymer as a precursor for the in situ formation of nano ZnO and PMMA/ZnO nanocomposites
Kos, Tomaz,Anzlovar, Alojz,Pahovnik, David,Zagar, Ema,Orel, Zorica Crnjak,Zigon, Majda
, p. 6942 - 6948 (2013)
We report on the synthesis of highly transparent and UV-absorbing PMMA/ZnO nanocomposites prepared by hydrolysis of a ZnO precursor, the A-b-(AB) diblock copolymer, poly(methyl methacrylate)-block-poly(methyl methacrylate-co-(zinc methacrylate acetate)), PMMA-b-P(MMA-co-ZnMAAc), synthesized by RAFT polymerization. The zinc content of the block copolymers was in the range from 3 to 13 wt %. The PMMA block provides inherent compatibility with the PMMA matrix, whereas the second block, P(MMA-co-ZnMAAc) with zinc ions, acts as a polymeric precursor for the formation of ZnO nanoparticles. The amphiphilic block copolymer self-organizes in THF and THF/H2O in ordered nanostructures, thereby influencing the nanoparticle formation during the hydrolysis of the precursor block copolymer with KOH in a solvent mixture THF/H2O. The ZnO nanoparticles were rod-shaped with lengths up to 80 nm and a diameter of 14 nm and were redispersible in THF. Dispersions in THF and thin films of PMMA/ZnO nanocomposite exhibit excellent transparency in the visible range and good absorption in the UV range below 400 nm. The block copolymer was characterized by SEC, NMR, DLS, and TGA, while PMMA/ZnO nanocomposites were characterized by IR, XRD, UV-vis, and STEM.
Hierarchical ZnO aggregates assembled by orderly aligned nanorods for dye-sensitized solar cells
Wu, Dapeng,Gao, Zhiyong,Xu, Fang,Chang, Jiuli,Tao, Wenguang,He, Jinjin,Gao, Shuyan,Jiang, Kai
, p. 1210 - 1217 (2013)
Hierarchical ZnO aggregates assembled by orderly aligned nanorods were prepared via a facile solvothermal method using diethylene glycol as solvent and zinc acetate dehydrate as precursor. Time dependent trails evidenced that the formation of the hierarchical aggregates experienced a multistep self-assembly process. Moreover, it was found that the reaction medium plays an important role in the assembling process and the diameter of the product could be tuned by simply altering the precursor dosage. The hierarchical product was further applied as scattering layer in bi-layered dye-sensitized solar cell (DSSC), and a high conversion efficiency of 5.2% was demonstrated, indicating a substantial improvement compared with the nanoparticle cell of 2.7%. Based on the optical and electrochemical investigations, the high conversion efficiency was mainly ascribed to the unique hierarchical structure of the ZnO aggregates. The rough surface of the nanorod subunits could enhance the dye loading capacity and the aggregates with micrometer sized diameter could improve the scattering effect. Moreover, the orderly aligned nanorods could minimize the grain boundaries, suppress the surface recombination and provide a direct pathway for fast electron transport, which therefore enhance the collection efficiency of the photoelectrons.
Kinetics and mechanism of the isothermal dehydration of zinc acetate dihydrate
Koga, Nobuyoshi,Tanaka, Haruhiko
, p. 69 - 76 (1997)
The overall kinetics of the thermal dehydration of zinc acetate dihydrate was investigated by means of isothermal mass-change measurements, complemented by microscopic observations of the reaction geometry and morphological change during the reaction. Under isothermal conditions, the compound loses its water of crystallization in a well-defined single step; Zn(CH3COO)2 · 2H2O → Zn(CH3COO)2 + 2H2O. The microscopic observations for the single crystals confirm that the reaction initiates at the edge surfaces of the hexagonal thin plate by nucleation and growth processes, consequently forming the reaction interface which advances inward, toward the center of the hexagon. The kinetic results obtained from the thermoanalytical measurements indicated agreement to the first-order law, in spite of the two-dimensional shrinkage of the reaction interface. This discrepancy is discussed in connection with the interactions of the elementary nucleation and growth processes at the reaction interfaces with the self-generated water vapor. The overall kinetic behavior of the crushed crystals of different particle-size fractions, under various atmospheric conditions, was investigated. The apparent kinetic results varied systematically with the sample and atmospheric conditions, accompanied by changes of the roles of surface reaction, diffusion of evolved water vapor from the reaction interface and gross diffusion of water vapor through the assemblage of sample particles.
Fabrication of Zn(OH)2/ZnO nanosheet-ZnO nanoarray hybrid structured films by a dissolution-recrystallization Route
Hu, Xiulan,Masuda, Yoshitake,Ohji, Tatsuki,Kato, Kazumi
, p. 881 - 886 (2010)
Zn(OH)2/ZnO nanosheet-ZnO nanoarray hybrid structured films were fabricated on F-doped SnO2-coated glass by a dissolution- recrystallization route without any additives. The as-deposited c-axis-oriented ZnO nanowhisker films were soaked in hot distilled water for various periods of time. X-ray diffraction, field-emission scanning electron microscopy, and transmission electron microscopy clarified that the dissolution of ZnO induced Zn(OH)2 to grow on the surface of the ZnO nanowhiskers film by heterogeneous nucleation and growth. The morphology of the Zn(OH)2 nanosheets was found to be controllable by the dissolution-recrystallization of as-deposited ZnO nanowhiskers in hot distilled water. ZnO with an almost identical morphology could also be produced by a dehydration reaction. Given the highly porous nature and the strong adsorption properties of the as-fabricated hybrid structured films, it is expected that they will have a variety of potential applications including dye-sensitized gas sensors and solar cells, and photocatalysis systems.
Thermal stability of new zinc acetate-based complex compounds
Gyoryova,Balek
, p. 519 - 532 (1993)
The compounds were characterized by IR spectroscopy, chemical analysis and thermal analysis. Thermal analysis showed that no changes in crystallographic modifications of the compounds take place during (heating in nitrogen before) the thermal decompositio
On the reactivity of zinc hydroxide acetate dihydrate in ethanol
Moezzi, Amir,Cortie, Michael B.,Shimmon, Ronald,McDonagh, Andrew M.
, p. 5133 - 5137 (2013)
Zinc hydroxide acetate dihydrate, Zn5(OH)8(CH 3CO2)2·2H2O, reacts in ethanol at room temperature to yield a mixture of zinc oxide and anhydrous zinc acetate. The process is driven by dehydration of the starting salt. Dehydration of Zn5(OH)8(CH3CO2) 2·2H2O also occurs when it is heated in air, but the product obtained in that case depends on the heating rate, environment and temperature. For example, when it is kept in a sealed silica capillary at 100 °C, Zn5(OH)8(CH3CO2) 2·1.5H2O is formed after 15 min, whereas treatment in the range 90-100°C in an open environment results in the formation of anhydrous zinc hydroxide acetate. Heating of any of these products further causes their decomposition to Zn(CH3CO2)2 and ZnO. The coordination bonding mode of the acetate groups in the anhydrous layered zinc hydroxide acetate prepared by reaction with ethanol was studied by using solid-state NMR spectroscopy. The presence of chelating, unidentate and bidentate bridging modes for the carbonyl carbon atom was revealed, but there was no evidence for the inclusion of ethanol in the resultant structure. Therefore, the reaction in ethanol offers a convenient strategy to prepare anhydrous zinc hydroxide acetate and/or zinc oxide, because it avoids the sensitivity of the thermally induced dehydroxlation process to time, temperature and environment. Decomposition of zinc hydroxide acetate dihydrate in ethanol can be exploited to generate ZnO nanoparticles at room temperature. The mechanism involves the removal of waters of hydration and the formation of Zn5(OH)8(CH3CO2)2 followed by the generation of Zn(CH3CO)2 and ZnO. Copyright
Zn(II) carboxylates containing heterocyclic secondary ligands: synthesis and structure manifestation through DFT studies
Zahoor, Ayesha,Imtiaz-Ud-Din,Andleeb, Sohaila,Raheel, Ahmad,Ayub, Rabia,Abbas, Sumaira,Tahir, Muhammad Nawaz
, p. 1978 - 1991 (2021)
New Zn(II) complexes (1–8) of general formula [Zn(R)2(L')2], where R = cinnamic acid (1–7), L' = 3-pyridine carboxamide (1), 2,2'-bipyridine (2), 3-pyridinecarbonitrile (3), 2-amino-5-(4-pyridinyl)-1,3,4-thiadiazole (4), 2-methylimidazole (5), 2-phenylimidazole (6), 2-imidazolidinethione (7) and for (8), R = acetic acid; L' = 2-amino-5-(4-pyridinyl)-1,3,4-thiadiazole)2, have been synthesized by a stoichiometric reaction between Zn(II) carboxylate(s) and the respective nitrogen-based ligands. The prepared compounds are analyzed by FTIR, NMR spectroscopy and single crystal X-ray diffraction techniques for their structural manifestations along with elemental analyses. The crystallographic data for 6 and 8 exhibit four-coordinated zinc having distorted tetrahedral molecular geometry. The thermogravimetric data demonstrate high stability of the compounds with gradual loss of acetate and thiadiazol fragments that ultimately lead to zinc oxide as the residual mass of 8. Quantum chemical calculations indicate that 7 is the softest in reactivity having the lowest band gap as determined from the energies of frontier molecular orbitals whereas 8 is highly polar with the highest dipole moment value of 12.61 D. The computational data are a complement to the success of the research.
Stability of nonplanar N-methylporphyrins and their zinc complexes
Berezin,Mis'ko,Antina,Berezin
, p. 482 - 487 (2006)
Resistance of N-methyl-substituted porphyrins and their Zn(II) complexes to thermooxidative degradation and to the action of a DMSO-AcOH proton-donor solvent was studied by thermogravimetry and chemical kinetics. The fairly low stability of the complexes is caused by decreased planarity and, as a consequence, aromaticity of the macrorings and also by the tendency of the complexes to demethylation. The stability of the zinc complexes in AcOH varies in parallel with the degree of nonplanarity and resistance to thermooxidative degradation of their ligands. Pleiades Publishing, Inc., 2006.
A phosgene-free process for the synthesis of methyl N-phenyl carbamate by the reaction of aniline with methyl carbamate
Li, Qi-Feng,Wang, Jun-Wei,Dong, Wen-Sheng,Kang, Mao-Qing,Wang, Xin-Kui,Peng, Shao-Yi
, p. 99 - 105 (2004)
A phosgene-free route for the synthesis of methyl N-phenyl carbamate (MPC) by the reaction of aniline with methyl carbamate in the presence of methanol was studied. Effects of catalysts, reaction temperature, reaction time, and catalyst content, the molar ratio of reactants and the content of water on the reaction were investigated. The results demonstrated that an aniline conversion of 90.1% and MPC selectivity of 99.7% were achieved when the reaction was carried out at 433 K for 4 h using ZnCl2 as a catalyst. A possible reaction mechanism was proposed based on the product distribution.
Isolation and structural characterization of a binuclear intermediate species pertinent to transmetalation of Zn(salphen) complexes and the formation of polynuclear salen structures
Felices, Leire San,Escudero-Adan, Eduardo C.,Benet-Buchholz, Jordi,Kleij, Arjan W.
, p. 846 - 853 (2009)
Zinc(II) salphen complexes equipped with additional alkoxy donor groups at the 3-position of the salicylideneimine groups have been prepared to bind metal acetates in a second coordination sphere close to the central Zn(II) ion. The isolated binuclear mon
