Reaction Of Zinc Acetate Research Articles

Poly[bis(1H-imidazole)bis(μ2-1H-imidazolido)bis(μ2-7-oxabicyclo[2.2.1]heptane-2,3-dicarboxylato)trizinc(II)

The title polymer, [Zn3(C8H8O5)2(C3H3N2)2(C3H4N2)2]n, was formed by the reaction of zinc acetate with imidazole and 7-oxabicyclo­[2.2.1]heptane-2,3-dicarboxylic anhydride (norcan­tharidine). One of the two crystallographically unique ZnII atoms is four-coordinated by three N atoms of three imidazole ligands, two of which are deprotonated, and by one carboxyl­ate O atom of the demethyl­cantharate anion. The second ZnII atom is situated on an inversion centre and is six-coordinated by the bridging O atoms of two symmetry-related demethyl­cantharate anions and by four carboxyl­ate O atoms of the corresponding carboxyl­ate groups. The polymeric crystal structure is additionally stabilized by N—H⋯O hydrogen bonding between the imidazole ligands and carboxyl­ate O atoms.

Identification and Growth Mechanism of ZnS Nanoparticles with Mixed Cubic and Hexagonal Stacking

Nano-ZnS with mixed cubic and hexagonal stacking was synthesized via reaction of zinc acetate with thioacetamide in a weakly acidic solution, while nano-ZnS in primarily the sphalerite phase was synthesized in a basic solution. X-ray diffraction (XRD) and transmission electron microscopy were used to characterize the nanoparticle structures. The formation of nano-ZnS with mixed stacking was simulated numerically by generation of ZnS nanoparticles via random cubic and hexagonal stacking of the close packing layers. The numerically simulated stacking distribution is determined by the ratio of the probability of cubic vs hexagonal stacking. XRD patterns of ZnS nanoparticles with mixed stacking were simulated by using Debye function analysis. The wurtzite (102) peak is absent whereas the wurtzite (103) peak is present in nano-ZnS with mixed stacking, matching features of XRD results for synthesized ZnS. We conclude that crystallization of ZnS nanoparticles with mixed stacking occurs via a growth mechanism in which sequential addition of hexagonal vs. cubic stacked layers occurs with equal probability. The approach may be used for analysis of mixed stacking in other nanomaterials with related structures, such as CdS and CdSe.

Bis(μ-2-methylquinolin-8-olato)-κ3N,O:O;κ3O:N,O-bis[(acetato-κO)(methanol-κO)zinc(II)

The reaction of zinc acetate and 2-methyl-8-hydroxy­quinoline in methanol yielded the centrosymmetric dinuclear title compound, [Zn2(C10H8NO)2(CH3CO2)2(CH3OH)2], which has the Zn atom within a distorted NO4 trigonal–bipyramidal coordination geometry. Methanol–acetate O—H⋯O hydrogen bonds link the dinculear units into a linear supra­molecular chain extending parallel to [100].

Synthesis and optical characteristics of ZnO nanocrystals

Zinc oxide nanomaterials with an average particle size of 20–30 nm are readily synthesized by the reaction of zinc acetate and oxalic acid under hydrothermal conditions. The samples are characterized by XRD, SEM, TEM, UV and photoluminescence (PL) studies. The average crystal size of the as prepared ZnO nanopowder is determined by XRD and the values are in good agreement with the TEM analysis. UV absorption spectra revealed the absorption at wavelength < 370 nm indicating the smaller size of ZnO nanoparticles. The quality and purity of ZnO nanomaterial crystalline samples are confirmed by photoluminescence spectra.

Applications of Zinc Oxide Nanorods as Photocatalyst for the Decontamination of Imidacloprid and Spirotetramat Residues in Water

Zinc oxide nanorods having the size 100 to 250 nm and 1 to 2 � m length were prepared by reacting zinc acetate with triethanolamine. The structure of the nanorods was confirmed by scanning electron microscope analysis. Photocata- lytic activity of zinc oxide nanorods on the new class of ketoenole and chloronicotinyl in secticides spirotetramat and imi- dacloprid was investigated. The decontamination effect of catalyst on the residues of spirotetramat and imidacloprid in water was studied at three different buffer solutions (4.0, 7.0 and 9.0). The catalytic reaction was measured under direct sunlight at two different concentration levels and the optimum concentration of catalyst re quired for the decontamination was also established by varying the amount of catalyst from 0.02 to 0.2 g/L. Residues are quantified by a high perform- ance liquid chromatography UV method (HPLC-UV) and calculated the DT 50 and DT 90 from the dissipation data. The rate of the reaction showed first order ki netics in water. The addition of zinc oxide nanorods induced the photocatalytic reaction contributing significantly to the rapid dissipation of residues. Complete mineralization of the residues was con- firmed by liquid chromatography electrospray tandem mass spectrometry (LC-ESI-MS/MS). The method has the limit of quantification 0.1 � g/L in water.

Synthesis, Optical Properties, and Photocatalytic Activity of One-Dimensional CdS@ZnS Core-Shell Nanocomposites

One-dimensional (1D) CdS@ZnS core-shell nanocomposites were successfully synthesized via a two-step solvothermal method. Preformed CdS nanowires with a diameter of ca. 45 nm and a length up to several tens of micrometers were coated with a layer of ZnS shell by the reaction of zinc acetate and thiourea at 180 °C for 10 h. It was found that uniform ZnS shell was composed of ZnS nanoparticles with a diameter of ca. 4 nm, which anchored on the nanowires without any surface pretreatment. The 1D CdS@ZnS core-shell nanocomposites were confirmed by XRD, SEM, TEM, HR-TEM, ED, and EDS techniques. The optical properties and photocatalytic activities of the 1D CdS@ZnS core-shell nanocomposites towards methylene blue (MB) and 4-chlorophenol (4CP) under visible light (λ > 420 nm) were separately investigated. The results show that the ZnS shell can effectively passivate the surface electronic states of the CdS cores, which accounts for the enhanced photocatalytic activities of the 1D CdS@ZnS core-shell nanocomposites compared to that of the uncoated CdS nanowires.

A second modification of poly[diaquadi-μ-citrato(3-)-trizinc(II)

A second modification of the zinc(II) coordination polymer with citric acid, [Zn3(C6H5O7)2(H2O)2]n or [Zn(citrate)2(H2O)2], has been synthesized under hydro­thermal conditions by reacting zinc acetate with citric acid. The structure contains two unique Zn atoms, one with a distorted octa­hedral coordination and located on an inversion centre, and one with a distorted tetra­hedral coordination. The ZnO6 and ZnO4 units are linked into layers extending parallel to (010).

(2-Morpholinoethyl)(2-pyridylmethylene)amine]dithiocyanatozinc(II)

The title compound, [Zn(NCS)2(C12H17N3O)], was prepared by the reaction of zinc acetate with pyridine-2-carbaldehyde, 2-morpholinoethyl­amine and ammonium thio­cyanate in an ethanol solution. The ZnII atom is five coordinate with a distorted trigonal–bipyramidal geometry, coordinating with three N atoms of the Schiff base (2-morpholinoeth­yl)(2-pyridylmethyl­idene)amine and two N atoms from two thio­cyanate ligands. The morpholine ring adopts a chair configuration.

Micro Segmented-Flow Technique for Continuous Synthesis of Different Kinds of ZnO Nanoparticles in Aqueous and in DMSO Solution

The segmented flow technique is used for continuous synthesis of ZnO nanoparticles under micro reaction conditions. The experimental setup consisted of syringe pumps and T-type injectors, PTFE tubings as well as PTFE knot mixers in a thermostated bath. ZnO nanoparticles were obtained by generation under strong alkaline conditions and elevated temperature in aqueous solution and by precipitation under moderate alkaline conditions in DMSO solution. In aqueous solution, small compact nanoparticles (diameters below 100 nm) were obtained at high temperature (90°C) and high reactant concentrations. Larger crystals, nanoneedles and nanoflowers (submicron and lower micro range) were obtained at reduced concentrations and reduced temperature (70°C). Compact nanocrystals with diameters of a few hundred nanometers are formed by the reaction of zinc acetate with tetramethylammoniumhydroxide in the presence of polyethylene glycole (at 80°C). In nearly all cases, a strong effect of flow rate on nanoparticle quality was observed. Enhanced flow rates (up to 5000 μL/min) lead to an improvement of shape homogeneity and size distribution.

Fabrication of nanosheets of a fluorescent metal–organic framework [Zn(BDC)(H 2O)] n (BDC = 1,4-benzenedicarboxylate): Ultrasonic synthesis and sensing of ethylamine

A supramolecular metal–organic framework (MOF) constructed by two-dimensional (2D) infinite coordination polymers, [Zn(BDC)(H 2O)] n ( 1, BDC = 1,4-benzenedicarboxylate), was synthesized by the reaction of zinc acetate with H 2BDC in dimethylformamide (DMF) under ultrasonic irradiation at ambient temperature and atmospheric pressure. Yield of 1 varied from 43.4% to 53.2% for the reaction time of 10–90 min. Samples with different morphologies, i.e. nanobelts, nanosheets, and microcrystals, were obtained under ultrasound irradiation for different reaction times. Fluorescence emission of nanosheets of [Zn(BDC)(H 2O)] n was found to be highly sensitive to ethylamine, and solid state fluorescence intensity decreased with increasing contents of ethylamine in acetonitrile solution due to weak fluorescence quenching effect.

Lessons from a “Failed” Experiment: Zinc Silicates with Complex Morphology by Reaction of Zinc Acetate, the Ionic Liquid Precursor (ILP) Tetrabutylammonium Hydroxide (TBAH), and Glass

At elevated temperatures, the ionic liquid precursor (ILP) tetrabutylammonium hydroxide reacts with zinc acetate and the glass wall of the reaction vessel. While the reaction of OH- with the glass wall is not surprising as such and could be considered a failed experiment, the resulting materials are interesting for a variety of applications. If done on purpose and under controlled conditions, the reaction with the glass wall results in uniform, well-defined hemimorphite Zn4Si2O7(OH)2·nH2O and willemite Zn2SiO4 microcrystals and films. Their morphology can be adjusted by variation of the reaction time and reaction temperature. The hemimorphite can be transformed to Zn2SiO4 via calcination. The process is therefore a viable approach for the fabrication of porous films on glass surfaces with potential applications as catalyst support, among others.

Evolution of ZnO nanostructures in sol–gel synthesis

Evolution of the microstructure and optical properties of ZnO nanoparticles in a mild sol–gel synthesis process is studied. The ZnO nanostructures were prepared by reacting zinc acetate dihydrate with NaOH in water at 50−60°C. Evolution of ZnO nanostructures with reaction time is studied using UV–Vis spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrared (FT-IR) spectroscopy techniques. During the process of Zn2+ hydroxylation, well defined rod-like crystals were formed within 15min. Further hydroxylation leads to the formation of a gel-like structure within about 45min. However, XRD, FT-IR and energy dispersive spectroscopy (EDS) confirmed that these initial products were zinc hydroxyl double salts (Zn-HDS), not ZnO. On ageing the reaction mixture, ZnO nanoparticles with wurtzite structure evolved.

Synthesis and Characterization of Zinc Oxide Nanocrystals by Solid-State and Solvothermal Techniques

The nanostructural zinc oxide (ZnO) particles have been synthesized by two techniques, solid-state reaction and solvothermal method. The solid-state reaction method, the ZnO nanoparticles were carried out by reacting zinc acetate with sodium hydroxide in sodium dodecyl sulfate (SDS) and beta-cyclodextrin (b-CD). The effects of reaction condition on the nanocrystal morphology were investigated. The physical properties of ZnO were characterized using X-ray diffraction technique and transmission electron microscopy. The results showed that the obtained ZnO nanorods were in the wurtzite structure with various sizes of single crystals. FT-IR analysis also confirmed the binding of SDS with ZnO nanorods. For the solvothermal technique, ZnO nanostructures with various morphologies were synthesized from the treatment of zinc acetate at 80°C with the selected polymeric surfactant, poly(vinyl pyrrolidone) (PVP), in aqueous solution and ethylene glycol. The results showed that the selected surfactant and solvent play a different role in controlling the morphologies of the ZnO nanocrystals. The ZnO nanorods and nanoparticles were successfully obtained. The XRD result revealed that the ZnO is in the wurtzite structure with the particle size in range of 270-1300 nm. The optical properties of the samples were also studied via UV-vis spectrophotometer.

Synthesis of ZnO/polystyrene composites particles by Pickering emulsion polymerization

ZnO/polystyrene composite particles were synthesized by Pickering emulsion polymerization. ZnO nanoparticles were first prepared by reaction of zinc acetate and sodium hydroxide in ethanol medium. Then different amount of styrene monomer was emulsified in water in the presence of ZnO nanoparticles either by mechanical stirring or by sonication, followed by polymerization of styrene. Two kinds of initiators were used to start the polymerization, azobisisobutyronitrile (AIBN) and potassium persulfate (KPS). The X-ray diffraction pattern verified the crystal structure of ZnO and FT-IR spectra evidenced the existence of ZnO and polystyrene (PS) in ZnO/polystyrene composite particles. Different morphologies were observed for the composite particles when using different initiators. From TEM photographs, AIBN-initiated system produced mainly core-shell composite particles with PS as core and ZnO as shell, while KPS-initiated system showed both composite particles and pure PS particles. Two schemes of reaction mechanism were proposed to explain the morphologies accordingly. Both systems of composite particles showed good pH adjusting ability.

Synthesis and characterization of ZnS/hyperbranched polyester nanocomposite and its optical properties

The ZnS/hyperbranched polyester nanocomposite with higher refractive index was prepared by incorporating the acrylated 2-(2-mercapto-acetoxy)-ethyl ester-capped ZnS nanoparticles into the acrylated Boltorn™ H20 (H20). The acrylated 2-(2-mercapto-acetoxy)-ethyl ester-capped colloidal ZnS nanoparticles were synthesized by the reaction of zinc acetate with thioacetamide in N, N-dimethylformamide. The acrylated hyperbranched polyester was obtained by reacting acryloyl chloride with hydroxyl group of H20. The acrylated H20 plays an important role in stabilizing and dispersing ZnS nanoparticles with a diameter of 1–4 nm. The refractive indices of ZnS/hyperbranched polyester nanocomposites, depending on ZnS content, were determined to be in the ranges of 1.48–1.65.

Solvothermal synthesis of nanorods of ZnO, N-doped ZnO and CdO

ZnO nanorods with diameters in the 80–800 nm range are readily synthesized by the reaction of zinc acetate, ethanol and ethylenediamine under solvothermal conditions. The best products are obtained at 330 °C with a slow heating rate. Addition of the surfactant Triton ®-X 100 gave nanorods of uniform (300 nm) diameter. By adding a small amount of liquid NH 3 to the reaction mixture, N-doped ZnO nanorods, with distinct spectroscopic features are obtained. CdO nanorods of 80 nm diameter have been prepared under solvothermal conditions using a mixture of cadmium cupferronate, ethylenediamine and ethanol at 330 °C. Similarly, Zn 1− x Cd x O nanorods of a 70 nm diameter are obtained under solvothermal conditions starting with a mixture of zinc acetate, cadmium cupferronate, ethanol and ethylenediamine.

Dynamic recovery and optical properties changes in He-implanted ZnO nanoparticles

A study of the effects of ion-implanted He+ on the photoluminescence (PL) of ZnO nanoparticles is presented. This investigation is motivated by the need to further understand the effects of damage resulting from the implantation process on the luminescence response of the nanoparticles. ZnO nanoparticles were synthesized by reacting zinc acetate with lithium hydroxide. The nanoparticle suspension was then dip coated on SiO2 substrates producing thin films of ZnO nanoparticles, which were then implanted with He+ ions at either room temperature or 400°C. Following implantation, the PL spectrum of the ZnO nanoparticles was investigated and compared to that obtained from He-implanted bulk ZnO. Change in the overall luminescence efficiency was found to depend on both the size of the nanoparticles and the implantation temperature, and is attributed to the dynamic recovery of collision cascades in the ZnO nanoparticles. In addition, a comparison of He+-implanted ZnO nanoparticles with He+-implanted ZnO single crystals indicates that the origin of the green luminescence occurring from the ZnO nanoparticles is near-surface complex defects.

Self-assembly of two zinc(II) supramolecular architectures with carboxylate and chelating aromatic amine ligands: [Zn(nba)2(phen)(H2O)] and [Zn(nip)(phen)]n (nba = 4-nitrobenzoic acid, nip = 5-nitroisophthalic acid)

Two new zinc(II) compounds, [Zn(nba)2(phen)(H2O)] (1) and [Zn(nip)(phen)] n (2) [nba = 4-nitrobenzoic acid, nip = 5-nitroisophthalic acid, phen = 1,10-phenanthroline] have been hydrothermally synthesized by reaction of zinc acetate and phen with the ligands nba and nip, respectively. Compound (1) consists of mononuclear zinc(II) molecules which forms a 2D supramolecular structure based on hydrogen bonds between the hydroxyl groups (and aromatic groups as well) and carboxylate oxygen atoms. Compound (2) displays 1D zigzag chains which are combined to 1D supramolecular double-chains by π–π stacking and further assembled into a 3D supramolecular framework through hydrogen bonds.

Multiwalled Carbon Nanotubes Beaded with ZnO Nanoparticles for Ultrafast Nonlinear Optical Switching

Nanoparticles—particles with sizes at the nanometer scale in all three dimensions—have attracted much attention because of their unique photonic, electronic, magnetic, and catalytic properties. The assembly of isotropic nanoparticles onto one-dimensional (1D) architectures represents an important step towards the integration of nanoparticles into nanodevices. In particular, nanoparticles of one material can be assembled on a 1D nanostructure of a different material to form unique and interesting hybrid nanomaterial systems. Recently, carbon nanotubes (CNTs) have been used as templates or scaffolds for the hybrid assembly of nanoparticles. Because of their great hardness and toughness, CNTs keep their morphology and structure even at high nanoparticle loadings. Using different methods, many types of metal and semiconductor nanoparticles, such as Au, Ag, Pt, SnO2, [7] TiO2, [8] and CdSe, have been assembled on CNTs. Recently, CNTs beaded with a variety of nanoparticles have been reported. More importantly, some of these beaded CNT hybrid systems exhibit unique properties. For example, supercapacitance in a RuO2/CNT composite, [16] diode-like rectification based on Co3O4-beaded CNTs, [11] and improved optical limiting from Auand Ag-coated CNTs have been demonstrated. As an important wide-bandgap semiconductor (3.37 eV) with a large exciton binding energy (60 meV), ZnO has received widespread attention because of its excellent performance in electronics, optics, and photonics systems. A range of 1D ZnO nanostructures have been fabricated. ZnO nanoparticles and quantum dots have been synthesized by different methods, and can also be assembled into 1D structures. The two important building blocks in nanotechnology, ZnO nanoparticles and CNTs, have rarely been assembled as hybrid structures. Kim and Sigmund and Park and co-workers have reported the coating of ZnO nanorods on CNTs by chemical vapor deposition (CVD) in a tube furnace. Gao and co-workers have reported the deposition of ZnO particles on multiwalled CNTs (MWNTs) and their enhanced photocatalytic activity. The method includes decoration of MWNTs with sodium dodecyl sulfate (SDS) followed by reaction of zinc acetate with lithium hydroxide monohydrate in anhydrous ethanol. In hybrid systems, control of the particle size and interparticle distance is essential to their applications in electronic and photonic devices. In addition, the functionalization of CNTs in order to anchor nanoparticles changes the surface properties of CNTs. Hence, the potential of ZnO nanoparticles on CNT scaffolds for applications needs to be further investigated. In this work, we report on a hybrid system of ZnO nanoparticles on MWNT scaffolds synthesized via a very simple and straightforward process. This involves the coating of pure Zn on as-grown, aligned MWNT films, followed by oxidization by simply heating the coated sample in air. After cooling, ZnO nanoparticles were found to have formed chain-like structures along the MWNTs, while the morphology of the aligned MWNTs remained unaltered. By directly changing the duration of the Zn coating step and thus the coating thickness, the average ZnO particle size and interparticle distance can be readily controlled. Based on this ZnO/MWNT hybrid system, an ultrafast nonlinear optical switching behavior has been demonstrated. Furthermore, three-photon adsorption of ZnO nanoparticles has been observed. Our results highlight opportunities for integrating CNTs with other functional oxide nanoparticles via a simple method, and for exploring the collective properties of nanoparticles/CNT hybrid materials. C O M M U N IC A IO N S

Kinetically controlled formation of a novel nanoparticulate ZnS with mixed cubic and hexagonal stacking

Nanoparticulate ZnS with mixed cubic and hexagonal close packed stacking was synthesized by reaction of zinc acetate with thioacetamide in weakly acidic solutions. The influences of temperature, reaction time, amounts of reagents and solution pH on the nanoparticle size and phase constitution were investigated. Experimental results suggest that the stacking in the nano-ZnS is controlled primarily by the precipitation kinetics. Factors that slow the precipitation rate favor the growth of nanoparticles with mixed stacking, probably because the probabilities of forming wurtzite-like layers and sphalerite-like layers under these conditions are approximately equal. Under conditions of rapid precipitation, the growth of sphalerite is favored, probably due to the aggregation of molecular clusters with sphalerite-like structure. UV–vis spectroscopy reveals that twins and stacking faults in nano-ZnS result in an electronic structure that differs from those of nano-scale sphalerite and wurtzite. New vibrational modes present in IR spectra of the nano-ZnS with mixed stacking indicate that the materials have novel optical properties. Control of defect microstructure may allow use of nano-ZnS in new technological applications.