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Low-temperature (1.8 K) excitonic absorption, reflection and photoluminescence spectra of mixed Zn(P1-xAsx)2 crystals have been studied at x = 0.01, 0.02, 0.03 and 0.05. Energy gap and rydbergs of excitonic B-, C- and A-series decrease monotonically with increasing of x. The spectral half-widths of the absorption n = 1 lines of the B- and A-series increase monotonically with increase in x due to fluctuations of crystal potential. Emission lines of excitonic molecules have been observed in photoluminescence spectra of Zn(P1-xAsx)2 crystals. The binding energy of the molecule increases with increase in x due to the decrease of the electron-hole mass ratio.

The effect of a pulsed laser beam (YAG at 532 nm) on zinc deposition in a sulfate medium is studied. The deposition was carried out either in stagnant conditions or under forced laminar or turbulent convection of the electrolyte solution. The effect of pulse laser irradiation was investigated in terms of current density enhancement under controlled potential; it was also observed through the change in the deposit's morphology. The sharp temperature increase of the substrate surface, due to pulsed irradiation, results in higher current densities, a reduction in grain size, and coalescence phenomena corresponding to zinc diffusion into the zinc substrate. The influence of electrode potential, zinc sulfate concentration, and flow velocity is discussed: circulation of the solution is shown to hinder the laser effect due to the quenching of the zinc surface.

Tin-zinc (Sn-Zn) alloy with low tin content was deposited on gold electrode and steel substrate with use of chronoamperometric technique from an acidic bath. In order to evaluate coating efficiency of Sn-Zn alloy in 0.5 M NaCl solution, open circuit potential-time curve (EOCP-t), polarization curves, mass change of the electrode (Δm-t) using quartz crystal microbalance (QCM) were compared to those of pure Sn and Zn coatings. Anodic stripping measurements were carried out simultaneously with the mass loss of the deposit. Scanning electron microscopy (SEM) and energy dispersive X-ray spectra (EDS) analysis were performed to characterize the surface morphology. Anodic stripping experiment and EDS analysis indicated that Sn, Zn, and SnO2 formed on the electrode surface when Sn-Zn was coated from acidic bath. Furthermore, local mapping demonstrated homogeneous distribution of Sn and Zn atoms throughout the surface.

Binary zinc and cadmium antimonides and their ternary relatives with indium display complex crystal structures, but reveal at the same time narrow band gaps in their electronic structure at or close to the Fermi level. It is argued that these systems represent electron-poor framework semiconductors (EPFS) with average valence electron concentrations between three and four. EPFS materials constituted of metal and semimetal atoms form a common, weakly polar framework containing multi-center bonded structural entities. The localized multi-center bonding feature is thought to be the key to structurally complex semiconductors. In this respect electron-poor antimonides become related to modifications of elemental boron. Electron-poor antimonides show promising thermoelectric properties, especially through a remarkably low thermal conductivity. At the same time the thermal stability of these compounds is rather limited because of temperature polymorphism and/or comparatively low melting or decomposition temperatures (usually below 600 K).

The composition of the corrosion products of pure Zn galvanic coatings as well as of some zinc alloys (Zn-Mn and Zn-Co) after treatment in selected free aerated model media (5% NaCl and 1N Na2SO4) is studied and discussed. X-ray diffraction and X-ray photoelectron spectroscopy investigations are used for this purpose. It is concluded that the corrosion products (zinc hydroxide chloride hydrate in 5% NaCl and zinc hydroxide sulfates hydrates in 1N Na2SO4) play a very important role for the improved protective ability of the zinc alloys toward the iron substrate, compared to the pure Zn coatings. Another result is that, for a given medium, the corrosion products are one and the same for both alloys independently of the fact that the alloying component is electrically more positive or negative than the zinc. Some suggestions about the models of the appearance of these products and their protective influence are also discussed.

Complex reducing agents NaH-RONa-MXn (referred to as MCRA) are new versatile reagents that have already found many applications in organic synthesis.In the present study, the composition and structure of NiCRA and ZnCRA (CRA prepared from a nickel salt and a zinc salt, respectively) have been investigated.It has been found that, in both reagents, the metal (Ni or Zn) is formallly in a zero-valent oxidation state.The active part of NiCRA is constituted of new species (formed from Ni0 (1 equiv), RONa (R = t-Bu) (2 equiv), NaH (2 equiv), and maybe some AcONa) in which each constituent has lost its own characteristics.A picture of the structure of these new species is proposed.The composition of the active part of ZnCRA is less clear.Indeed, associations between RONa (R = t-Am) and Zn0 have been evidenced, but these species do not exhibit the reducing properties of ZnCRA, e.g., toward carbonyl compounds.In fact, control experiments have shown that no ketone reduction occured in the absence of NaH.These observations led us to propose that the active part of ZnCRA should be constituted of associations of the type n, which may be formed, in low concentration, from NaH and the inactive species n.

The understanding of the thermal stability of zinc carbonates and the relative stability of hydrous carbonates including hydrozincite and hydromagnesite is extremely important to the sequestration process for the removal of atmospheric CO2. The hydration-carbonation or hydration-and-carbonation reaction path in the ZnO-CO2-H2O system at ambient temperature and atmospheric CO2 is of environmental significance from the standpoint of carbon balance and the removal of green house gases from the atmosphere. The dynamic thermal analysis of hydrozincite shows a 22.1% mass loss at 247°C. The controlled rate thermal analysis (CRTA) pattern of hydrozincite shows dehydration at 38°C, some dehydroxylation at 170°C and dehydroxylation and decarbonation in a long isothermal step at 190°C. The CRTA pattern of smithsonite shows a long isothermal decomposition with loss of CO2 at 226°C. CRTA technology offers better resolution and a more detailed interpretation of the decomposition processes of zinc carbonate minerals via approaching equilibrium conditions of decomposition through the elimination of the slow transfer of heat to the sample as a controlling parameter on the process of decomposition. The CRTA technology offers a mechanism for the study of the thermal decomposition and relative stability of minerals such as hydrozincite and smithsonite.

Optical and photocatalytic properties were determined for the solid solution series (GaN)1-x(ZnO)x synthesized at high pressure over the entire compositional range (x = 0.07 to 0.9). We report for the first time photocatalytic H2 evolution activity from water for (GaN)1-x(ZnO)x without cocatalysts, pH modifiers and sacrificial reagents. Syntheses were carried out by reacting GaN and ZnO in appropriate amounts at temperatures ranging from 1150 to 1200 °C, and at a pressure of 1 GPa. ZnGa2O4 was observed as a second phase, with the amount decreasing from 12.8 wt% at x = 0.07 to ～0.5 wt% at x = 0.9. The smallest band gap of 2.65 eV and the largest average photocatalytic H2 evolution rate of 2.31 μmol h-1 were observed at x = 0.51. Samples with x = 0.07, 0.24 and 0.76 have band gaps of 2.89 eV, 2.78 eV and 2.83 eV, and average hydrogen evolution rates of 1.8 μmol h-1, 0.55 μmol h-1 and 0.48 μmol h-1, respectively. The sample with x = 0.9 has a band gap of 2.82 eV, but did not evolve hydrogen. An extended photocatalytic test showed considerable reduction of activity over 20 hours.

Zinc nanoparticles were grown within gel-derived silica films by applying a direct current voltage. Pattern formation of metallic Zn was studied as a function of applied voltage and metal-silica ratio. Average particle size varied from 5.2 to 20.2 nm by changing the applied voltage and silica concentration. It was found that the transition from fractal to dendritic morphology was possible due to crystalline anisotropy. From high-resolution transmission electron microscopy images and X-ray diffraction pattern a possible model is proposed to explain this observation.

In photocatalytic H2 evolution using an aq. methanol system, high quality microcrystalline (cubic) ZnS powders have been found to be active under an appropriate light intensity, which is comparable in activity with freshly prepared ZnS suspensions.Compari

The influence of cobalt on the electrodeposition of zinc onto AISI 1018 steel was studied in weakly alkaline glycine solutions. Thermodynamic calculations were performed to construct predominance-zone diagrams to identify the stability of the zinc and cobalt glycine complexes, and experimental studies of electrochemical behavior and deposit properties were conducted. When zinc is present, cobalt deposition shifts to more negative potentials, producing ZnCo alloys. Two main reduction steps were observed for electrodeposition from the ZnCo bath: the first at low potentials was due to ZnCo electrodeposition. In the second, at more negative potentials, cobalt content in the deposit increased forming a range of intermediate phases, and the hydrogen-evolution reaction became significant. The presence of Co(II) in the bath modified the morphology of the deposits as well as reducing the faradaic metal-deposition efficiency. ZnCo-deposit morphology was modified by the applied current density as well as the metal composition of the coating. X-ray diffraction studies revealed that cobalt oxide or hydroxide is formed during ZnCo electrodeposition, indicating that an elevation of the interfacial pH plays a role in the alloy deposition process.

We report a novel method for covering a substrate with highly-oriented single crystalline hexagonal zinc structures under atmospheric pressure and room temperature without an external source of electric current, any templates or the use of epitaxial growt

The gas-phase photodissociation of (CH3)2Zn, (C2H5)2Zn, and (n-C3H7)2Zn has been examined at 248 nm using laser-induced fluorescence to detect the monoalkyl zinc radical and zinc atom photoproducts.For each compound, the monoalkyl zinc radical is the primary photoproduct and is formed sufficiently hot that it spontaneously dissociates to an alkyl radical and a Zn atom without absorption of a second photon.Photodissociation was examined in the presence of He buffer gas to measure the probability of quenching the secondary spontaneous dissociation of the monoalkyl zincspecies.For all three dialkyl zinc compounds, the probability of quenching the secondary dissociation step increases substantially over the He pressure range of 0-400 Torr.The quenching probability vs He pressure was fit using RRKM theory in conjunction with a time-dependent master equation, treating the nascent vibrational energy distribution of the monoalkyl zinc product as an adjustable function.The quenching data for C2H5Zn and n-C3H7Zn can be fit only if it is assumed that these species are formed with a hot, narrow vibrational energy distribution, much narrower than that predicted by phase-space theory.A dissociation mechanism involving crossover from an optically prepared singlet state to a repulsive triplet state is proposed to explain this observation.Spontaneous dissociation of CH3Zn is quenched much more strongly by He than is calculated using any reasonable vibrational energy distribution function for CH3Zn.This is attributed to the inapplicability of RRKM theory to reactionsinvolving very low-state-density molecules like CH3Zn.

We present an experimental study of the electrodeposition of zinc in a thin layer, three-electrode electrochemical cell. We show that as the steady-state current-potential behavior approaches mass transfer limited kinetics, the fractal dimension of the morphology of the deposit converges to the DLA value of 5/3. We also compare the evolution of the growth patterns with and without supporting electrolyte.

The influence of weak periodic electromagnetic pulses with a repetition rate of 215 kHz on the process of zinc electrochemical reduction at a structural-steel cathode under the conditions of working galvanic production was studied experimentally. The results of studying zinc coatings using scanning electron microscope and X-ray microanalyzer are presented. The effects are discussed in the context of external synchronization of the self-organized dissipative structures in the reaction zone.

A large quantity of metal Zn nanobelts have been synthesized by a simple approach, which involves thermal decomposition of ZnS powder, followed by Zn deposition.

The ternary nitride CaZn2N2, composed only of earth-abundant elements, is a novel semiconductor with a band gap of ～1.8 eV. First-principles calculations predict that continuous Mg substitution at the Zn site will change the optical band gap in a wide range from ～3.3-1.9 eV for Ca(Mg1-xZnx)2N2 (x = 0-1). In this study, we demonstrate that a solid-state reaction at ambient pressure and a high-pressure synthesis at 5 GPa produce x = 0 and 0.12 and 0.12 1-xZnx)2N2 converts its highly resistive state to a p-type conducting state. Particularly, the x = 0.50 sample exhibits intense green emission with a peak at 2.45 eV (506 nm) without any other emission from deep-level defects. These features meet the demands of III-V group nitride and arsenide/phosphide light-emitting semiconductors.

Liquid metal alkyls are strong Lewis acids and bases and useful solvents in which to conduct organometallic reactions. Cp2ZrMe2 undergoes rapid methyl exchange with pure Me3Al but reacts with EtAlMe2 in Me3Al to form Cp2Zr(μ-CH3)(μ-CH2CH 2)AlMe2. Neat R3Al reagents in which R has a hydrogen atom produce solvated Cp2ZrH2 derivatives. The gas-phase reaction of Cp2ZrCH3+ with Me3Al, studied by ion cyclotron resonance spectrometry, produces an ion formulated as Cp2Zr(μ-CH2)2Al+.

Two salt-free Zn2+-ligand-coordinated vesicle phases were prepared from the mixtures of alkyldimethylamine oxide (CnDMAO, n) 14 and 16, i.e., C14DMAO and C16DMAO) and zinc laurate [(CH3(CH2)10/s

The processes of development of semiconductor ceramics made up of bismuth, antimony and zinc often require during their preparation to know the nature of the involved phases. For that, it is always essential to refer to the diagrams of balance between pha

Boron suboxide B7O is synthesized with the aid of the oxidation of boron with zinc oxide ZnO under extreme conditions of high pressure, 3.50 GPa and high temperature, 1200 °C, and characterized by means of X-ray powder diffraction. This new rou

The temperature stability range of the zinc calcium oxysulfide CaZnSO has been determined in an inert atmosphere using high-temperature x-ray diffraction, thermogravimetry, and x-ray microanalysis. The lattice parameters and thermal expansion coefficients

Mixed complexes of the type: Zn(Han)2(Him)3, Zn(Han)2(Him)5, Zn(Han)2(4-MeHim)2 and Zn(Han)2(1,2-diMeim)2 (where Han: NH2C 6H4COO

In this work we present an electrochemical study of the underpotential deposition (UPD) and overpotential deposition (OPD) of zinc onto nickel electrode (NE) from a non-cyanide alkaline solution containing glycine. The studied parameters were zinc concentration, glycine concentration and scanning rate. The analysis of the experimental data clearly showed the presence of UPD and OPD processes that started at -0.8 V vs. SCE and -1.4 V vs. SCE, respectively. The voltammetric studies also indicate diffusion control of the zinc UPD and OPD processes onto the NE. From the potentiostatic transients we found instantaneous nucleation (2D) mechanisms, which agree to that observed in the AFM study. In order to compare the effect of zinc/glycine concentration, we calculate thermodynamic parameters for the OPD process.

The electrochemical nucleation and growth of zinc on low-carbon steel from acidic (pH 2.0-4.5) baths containing ZnSO4, NaCl, and H3BO3, was studied by means of chronoamperometry at various cathodic potentials under a charg

Laboratory-scale experiments of zinc electrowinning under periodical reverse current (PRC) were carried out in acidic sulfate solutions. To study the effects of lead impurities on the zinc cathode, 0.3-15 mg/l of lead were added to the electrolyte. A square wave of current was used to produce the PRC. Current densities of 500 and 1500 A/m2 were investigated under both direct current and PRC. In the case of PRC, the direct and reverse pulses had respective durations of 100s and 0.1-1.0s. The current density of the reverse pulse was set at half the value of the direct pulse. Comparisons were 93.2%, while in PRC it raised it from 93.2 to 97.6%, using a reverse pulse duration of 0.1s. Correlation between the current efficiencies and the presence of the crystallographic plane (101) was also observed. It suggests that lead in the zinc deposit and the use of PRC influence the crystallographic growth of the zinc deposit. The presence of plane (101) increases the overpotential of hydrogen evolution on zinc, and this results in a higher current efficiency. A way of obtaining the beneficial plane is to use PRC and lead in the electrolyte together.

The formation of chromate conversion coatings on zinc was studied by chronopotentiometric, electrochemical, and electrohydrodynamic impedances, and interfacial pH measurements. The electrochemical experiments were performed with a rotating disk electrode of pure zinc, and the pH measurements were obtained with a zinc deposit on a gold grid electrode in a submerged impinging jet cell. The electrolyte was an industrial chromate bath. The experimental results were achieved for different immersion times, temperatures, and rotation speeds. Kinetic reactions and physical model for the chromate layer formation on zinc were proposed, and the electrochemical and electrodynamic impedances were well simulated.

Highly crystalline single-phase nanoparticles of the important thermoelectric materials Zn4Sb3 and ZnSb were prepared from solvochemically activated powders of elemental zinc and elemental antimony. Low-temperature reactions with rea

New homoleptic and heteroleptic zinc(ii)-containing liquid metal salts with N-alkylimidazole (AlkIm) ligands and bis(trifluoromethylsulfonyl)imide (Tf 2N-) anions are described. The general formulae of the complexes are [Zn(AlkIm)6][Tf2N]2 and [Zn(AlkIm)6-x(AlkIm′)x][Tf2N] 2. Single-crystal X-ray diffraction revealed that, in the solid state, the cations consist of octahedral zinc(ii) centres. The heteroleptic complexes contain two different N-alkylimidazole ligands. The melting points of the liquid metal salts are below or slightly above room temperature. The dependence of the melting points, viscosity and crystal structure on the alkyl chain length of the N-alkylimidazole ligand for the homoleptic complexes and on the ratio of the two N-alkylimidazole ligands AlkIm and AlkIm′ for the heteroleptic compounds is discussed. The possibility of incongruent melting and the presence of a mixture of the four-coordinate zinc(ii) centre and neutral ligands is discussed. The new zinc(ii)-containing liquid metal salts have been used as non-aqueous electrolytes for electrodeposition of zinc. A highly reversible deposition-stripping behaviour was found. Zinc electroplating was possible at very high current densities of more than -200 mA cm-2 in unstirred solutions. Compact and highly crystalline zinc deposits were obtained.

The preparation of porous copper or copper-zinc surfaces by electrochemical formation of binary Cu-Zn alloys on Cu substrate and subsequent electrochemical etching of the zinc was investigated in a zinc chloride-1-ethyl-3- methylimidazolium chloride ionic liquid at 120°C. Cyclic voltammetry and X-ray diffraction measurements suggested that phase transformation from γ - to Β′ - Cu-Zn alloy occurred during constant potential dealloying. Essentially all the Zn content in the Cu-Zn could be removed from the alloy with dealloying at a sufficiently positive potential. Dealloyed materials exhibited well-developed bicontinuous porous structure. The dependence of the surface morphology of the porous Cu film on several experimental parameters, including deposition current and charge, and anodizing potential and temperature, were examined.

(Figure Presented) In this work, synthesis of some new five coordinated zinc halide/pseudo-halide complexes of a N3-tridentate ligand is presented. All complexes were subjected to spectroscopic and physical methods such as FTIR, UV-visible, 1H and 13C NMR spectra, thermal analyses and conductivity measurements for identification. Based on spectral data, the general formula of ZnLX2 (X = Cl-, Br-, I-, SCN- and N3-) was proposed for the zinc complexes. Zinc complexes have been also prepared in nano-structure sizes under ultrasonic irradiation. X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were applied for confirmation of nano-structure character for the complexes. Among the complexes, zinc azide complex structure was analyzed by X-ray crystallography. This complex crystallizes as a triplet in trigonal system with space group of P31. The coordination sphere around the zinc center is well shown as a distorted trigonal bipyramidal with three nitrogen atoms from Schiff base ligand and two terminal azide nitrogen atoms attached to zinc ion. Various intermolecular interactions such as N-Ha??N, C-Ha??N and C-Ha???? hydrogen bonding interactions stabilize crystalline lattice so that they causes a three dimensional supramolecular structure for the complex. In vitro screening of the compounds for their antimicrobial activities showed that ZnLI2, ZnL(N3)2, ZnLCl2 and ZnL(NCS)2 were found as the most effective compound against bacteria of Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli respectively. Also ZnLI2 and ZnLCl2 complexes were found more effective against two selected fungi than others. Finally, thermal behaviors of the zinc complexes showed that they are decomposed via 2-4 thermal steps from room temperature up to 1000?°C.

The reactions during high-temperature decomposition of Ba(Zn 1/2W1/2)O3 double perovskite, a potential microwave dielectric material, were studied by using X-ray diffraction, electron microscopy, and Knudsen effusion combined with mass spectrometry. The results show that above 1200°C, the perovskite decomposes due to the sublimation of ZnO, which results in the formation of BaWO4, Ba2WO 5, and amorphous BaO-rich phases. The simultaneous presence of BaWO4 and Ba2WO5 causes the formation of a liquid phase above 1320°C, which in the case of ceramics results in a progressive deterioration of the microstructure. As a consequence, the dielectric losses of Ba(Zn1/2W1/2)O3-based ceramics strongly depend on the processing parameters.

The influence of pulse electrodeposition parameters (current on-time Ton, current off-time Toff, and pulse current density Jp) was investigated on the surface morphology and grain size of zinc electrodeposited from a sulfate bath containing polyacrylamide and thiourea additives. The grain size and surface morphology of zinc deposits were studied by field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM), and the preferred orientation of the deposits was studied by X-ray diffraction. At constant current off-time and pulse current density, the grain size decreased asymptotically with increasing current on-time. In contrast, increase in the current off-time at constant current on-time and pulse current density resulted in grain growth. A progressive decrease of the grain size was observed with increasing pulse current density at constant current on-time and off-time. Nanocrystalline zinc with an average grain size of 38 nm was obtained at a pulse current density of 1200 mA/cm2. The crystallographic orientations developed were correlated with the change in the cathodic overpotential, the angle between the preferred oriented plane and the lowest energy of formation plane (0 0 0 2), and the pulse electrodeposition parameters.

The zinc electrodeposition onto steel substrates in the presence of surfactants with different charged head groups, namely anionic sodium dodecylsulphate (SDS), cationic dodecyltrimethylammonium bromide (CTAB), and non-ionic octylphenolpoly(ethyleneglycolether)n, n = 10 (Triton X-100) was studied by cyclic voltammetry. The effect of the switching potential and scanning rate on the deposition process was investigated. The structural characterisation and the chemical composition of the samples prepared potentiostaticaly, in the potential range where the voltammetric cathodic peaks appear, was performed by X-ray powder diffraction (XRD) and by energy-dispersive X-ray analysis (EDS), respectively. The experimental results show that the voltammetric behaviour, namely the deposition potential depends on the presence, nature and concentration of the tested surfactants. Zn deposition occurs at potential values more positive than the estimated equilibrium potential, peak C1, simultaneously with hydrogen formation. This fact is confirmed by XRD measurements. Zn bulk deposits prepared in the absence of surfactants and in the presence of SDS are more crystalline and with a higher grain size than the ones obtained in the presence of CTAB and Triton X-100. These facts may be justified by an increase on the overpotential deposition as the electrochemical study confirms.

A facile two-step strategy involving a polyol method and subsequent thermal annealing treatment is successfully developed for the large-scale preparation of ZnCo2O4 various hierarchical micro/nanostructures (twin mcrospheres and microcubes) without surfactant assistance. To the best of our knowledge, this is the first report on the synthesis of ZnCo2O 4 mesoporous twin microspheres and microcubes. More significantly, based on the effect of the reaction time on the morphology evolution of the precursor, a brand-new crystal growth mechanism, multistep splitting then in situ dissolution recrystallization accompanied by morphology and phase change, is first proposed to understand the formation of the 3D twin microshperes, providing new research opportunity for investigating the formation of novel micro/nanostructures. When evaluated as anode materials for lithium-ion batteries (LIBs), ZnCo2O4 hierarchical microstructures exhibit superior capacity retention, excellent cycling stability at the 5 A g-1 rate for 2000 cycles. Surprisingly, the ZnCo2O 4 twin microspheres show an exceptionally high rate capability up to the 10 A g-1 rate. It should be noted that such super-high rate performance and cycling stability at such high charge/discharge rates are significantly higher than most work previously reported on ZnCo 2O4 micro/nanostructures and ZnCo2O 4-based heterostructures. The ZnCo2O4 3D hierarchical micro/nanostructures demonstrate the great potential as negative electrode materials for high-performance LIBs. 3D hierarchical ZnCo 2O4 twin spheres are prepared via a convenient polyol process and subsequent thermal annealing. A multistep splitting in situ dissolution recrystallization originating from 1D nanorods is first proposed to understand the formation of the 3D nanoarchitectures. Lithium-ion batteries prepared with the 3D materials display remarkable performance in energy storage.

Decomposition of the organometallic precursor [Zn(C6H11)2] in wet anisole leads to the formation of monodisperse spherical Zn particles of 6 nm mean diameter. High resolution electron microscopy (HRTEM) indicates the crystalline nature of these particles and photoelectron studies (XPS) are consistent with the presence of both zinc and zinc oxide. In the presence of polyvinylpyrolidone (PVP), the decomposition leads to well dispersed nanoparticles for which HRTEM studies evidenced the presence of hexagonal zinc (0) surrounded by a thin layer of hexagonal zinc oxide of wurtzite type. The thermal oxidation of these zinc nanoparticles yields well-crystallized nanoparticles of ZnO without coalescence or size change. An X-ray diffraction pattern shows that the powder consists of pure hexagonal wurtzite-type phase.

The compounds, Li3MZn5(BH4)15, M = Mg and Mn, represent the first trimetallic borohydrides and are also new cationic solid solutions. These materials were prepared by mechanochemical synthesis from LiBH4, MCl2 or M(BH4) 2, and ZnCl2. The compounds are isostructural, and their crystal structure was characterized by in situ synchrotron radiation powder X-ray and neutron diffraction and DFT calculations. While diffraction provides an average view of the structure as hexagonal (a = 15.371(3), c = 8.586(2) A, space group P63/mcm for Mg-compound at room temperature), the DFT optimization of locally ordered models suggests a related ortho-hexagonal cell. Ordered models that maximize Mg-Mg separation have the lowest DFT energy, suggesting that the hexagonal structure seen by diffraction is a superposition of three such orthorhombic structures in three orientations along the hexagonal c-axis. No conclusion about the coherent length of the orthorhombic structure can be however done. The framework in Li 3MZn5(BH4)15 is of a new type. It contains channels built from face-sharing (BH4)6 octahedra. While X-ray and neutron powder diffraction preferentially localize lithium in the center of the octahedra, thus resulting in two weakly interconnected frameworks of a new type, the DFT calculations clearly favor lithium inside the shared triangular faces, leading to two interpenetrated mco-nets (mco-c type) with the basic tile being built from three tfa tiles, which is the framework type of the related bimetallic LiZn2(BH 4)5. The new borohydrides Li3MZn 5(BH4)15 are potentially interesting as solid-state electrolytes, if the lithium mobility within the octahedral channels is improved by disordering the site via heterovalent substitution. From a hydrogen storage point of view, their application seems to be limited as the compounds decompose to three known metal borohydrides.

Metallic zinc is a promising negative electrode for high energy rechargeable batteries due to its abundance, low-cost and non-toxic nature. However, the formation of dendritic zinc and low Columbic efficiency in aqueous alkaline solutions during charge/discharge processes remain a great challenge. Here we demonstrate that the dendritic growth of zinc can be effectively suppressed in an ionic liquid electrolyte containing highly concentrated cationic and anionic zinc complexes obtained by dissolving zinc oxide and zinc trifluoromethylsulfonate in a protic ionic liquid, 1-ethylimidazolium trifluoromethylsulfonate. The presence of both cationic and anionic zinc complexes alters the interfacial structure at the electrode/electrolyte interface and influences the nucleation and growth of zinc, leading to compact, homogeneous and dendrite-free zinc coatings. This study also provides insights into the development of highly concentrated metal salts in ionic liquids as electrolytes to deposit dendrite-free zinc as an anode material for energy storage applications.

The new complex bis(2-bromobenzoato-O,O′)-bis(methyl-3-pyridylcarbamate-N)-zinc(II ), [Zn(2-BrC6H4COO)2mpc2] (1), has been prepared and characterized by elemental analysis, IR spectroscopy, thermal analysis and

A study of the relation between electrodeposition process parameters, structure and ductility of electrodeposited zinc foils was carried out. A stretching test was used to determine the ductility of zinc coatings after stripping them from the substrate. Depending on the relative texture coefficient coatings appeared to be more or less ductile. A loss of ductility when the pH of the electrolyte exceeds 4, was identified as due to zinc hydroxide precipitates. These particulates precipitate at the cathode and/or at the anode, then are transferred to the vicinity of the cathode where they can be codeposited with zinc.

A simple method is proposed for the determination of the fractal dimension during the electrodeposition of zinc by current integration. Under various experimental conditions, 0.01M ZnSO4, 2-12V, the patterns formed exhibit scale-invariance characteristics. The fractal dimension of the two-dimensional zinc deposits increases with the applied voltage (or applied current), while the morphology changes from highly branched random aggregate to the radial dense structure. A stochastic model based on the dielectric breakdown model (DBM) is proposed and the simulation analysis indicates that the relative resistivity between the zinc aggregate and the electrolytic solution can play an important role in the pattern transformation. A theoretical model based on the fractal theory is derived to estimate this ratio.

We demonstrate a technique for the deposition of nanometric Zn dots by photodissociation of gas-phase diethylzinc using an optical near field under nonresonant conditions. The observed deposited Zn dot was less than 50 nm in size. The photodissociation mechanisms are based on the unique properties of optical near fields, i.e., enhanced two-photon absorption, induced near-field transition, and a direct excitation of the vibration-dissociation mode of diethylzinc.

Zinc and zinc oxide electrodes with fibrous morphologies were prepared to exploit their high interfacial areas and superior electrical conductivity for the enhancement of electrochemical and photoelectrochemical properties. The Royal Society of Chemistry

New metal ion complexes were isolated after coupling with 4-(2,4-dihydroxy-5-formylphen-1-ylazo)-N-(4-methylpyrimidin-2-yl)benzenesulfonamide (H2L) drug ligand. The structural and molecular formulae of drug derivative and its complexes were elucidated using spectral, analytical and theoretical tools. Vibrational spectral data proved that H2L behaves as a monobasic bidentate ligand through one nitrogen from azo group and ionized hydroxyl oxygen towards all metal ions. UV–visible and magnetic moment measurements indicated that Fe(III), Cr(III), Mn(II) and Ni(II) complexes have octahedral configuration whereas Cd(II), Zn(II) and Co(II) complexes are in tetrahedral form. The Cu(II)complex has square planar geometry as verified through electron spin resonance essential parameters. X-ray diffraction data indicated the amorphous nature of all compounds with no regular arrangement for the solid constituents during the precipitation process. Transmission electron microscopy images showed homogeneous metal ion distribution on the surface of the complexes with nanometric particles. Coats–Redfern equations were applied for calculating thermo-kinetic parameters for suitable thermal decomposition stages. Gaussian09 and quantitative structure–activity relationship modelling studies were used to verify the structural and biological features. Docking study using microorganism protein receptors was implemented to throw light on the biological behaviour of the proposed drug. The investigated ligand and metal complexes were screened for their in vitro antimicrobial activities against fungal and bacterial strains. The resulting data indicated that the investigated compounds are highly promising bactericides and fungicides. The antitumour activities of all compounds were evaluated towards human liver carcinoma (HEPG2) cell line.

A new tetradentate Schiff base ligand (L) (L = obtained by condensation reaction between triethylenetetraamine and (E)-3-(2-nitrophenyl)acrylaldehyde) and some of its zinc (II) complexes formulated as ZnLX2 in which X = halide/pseudohalide were synthesized and characterized by some physical and spectral techniques such as infra-red (IR), nuclear magnetic resonance (NMR), UV–Visible, microanalyses, and conductivity measurements. Among the complexes, zinc chloride, iodide, and nitrate complexes were also prepared as nanostructure powder under sonication conditions confirmed by x-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive x-ray analysis (EDAX). Moreover, zinc oxide nanoparticles were prepared by direct thermolysis of nanopowder of ZnLI2 complex under air atmosphere. Moreover, the thermal behaviors of the compounds were studied based on thermo-gravimetric (TG)/differential thermal gravimetric (DTG)/differential thermal analyses (DTA) analyses data under nitrogen atmosphere. Furthermore, antibacterial/antifungal activities of the ligand and its zinc complexes were screened by the well diffusion method against some bacteria and funguses. Ultimately, the DNA cleavage potential of the compounds was evaluated by gel electrophoresis technique.

A series of N-heterocyclic carbene (NHC) supported group 12 acetate complexes were prepared and their use as building blocks toward soluble group 12 sulfide precursors was explored. The highly moisture-sensitive NHC-ligated zinc dithiolato complex [(IPr)Zn(SSiMe3)2] was also synthesized [IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene], and its partial hydrolysis gave the dianionic zinc sulfide cluster [Zn3(μ3-S)(μ2-SSiMe3)3(SSiMe3)3]2?, which contained a rare example of a Zn3S structural motif. This preliminary observation indicates that the future growth of related metallosulfide clusters from [(IPr)Zn(SSiMe3)2] should be possible.

A number of new Cr(III), Mn(II), Cu(II) Zn(II) and Cd(II) chelates of (E)-3-(4-(dimethyl-amino)phenyl)-1-(pyridin-2-yl)prop-2-en-1-one were synthesized. The structures were elucidated by elemental and thermal analysis as well as spectral techniques (mass, IR, and electronic spectra) and magnetic measurements. The IR data suggested that the investigated chalcone acted as a bidentate ligand via the O and N atoms of the C[dbnd]O and C[dbnd]N groups, respectively. The spectral plus magnetic data revealed the formation of octahedral structures for all chelates while Cu(II) chelate has the square planar geometry. The kinetic and thermodynamic parameters of the thermal decomposition stages have been evaluated. Molecular orbital calculations have been performed to confirm the geometry of the isolated compounds. The in vitro antimicrobial activities of the chalcone and its metal chelates have been performed against some bacterial strains. The data indicated that all the metal chelates demonstrated a higher activity than the free chalcone. The anticancer activity of the mentioned metal chelates is evaluated against MCF7 cell. These compounds exhibited a moderate and weak activity against the tested cell line. The results were correlated with the experimental data.

A pyrimidine-based ligand, 2-(pyrimidin-2-ylamino)naphthalene-1,4-dione (L), has been synthesized by the reaction of 2-aminopyrimidine with 2-hydroxy-1,4-napthoquinone. Reaction of the ligand with Ni(II), Co(II), Mn(II) and Zn(II) acetate gave the corresponding metal complexes which were characterized by spectroscopic techniques, (infrared, electronic), elemental analysis, room-temperature magnetometry, conductance measurements and thermogravimetry-differential scanning calorimetry (TG-DSC) analyses. The room-temperature magnetic data and electronic spectral measurements of the complexes gave evidence of 4-coordinate square planar/tetrahedral geometry. The thermal analyses values obtained indicated the monohydrate complexes. The antimicrobial screening of the compounds showed mild to very good results. The Mn(II) complex showed the best result within in the range of 11.5–29 mm. The electronic, structural and spectroscopic properties of the complexes were further discussed using density functional theory. Molecular docking studies showed significant binding affinity with the drug targets and the metal complexes have potentials to be used as drugs.

In this paper, five new zinc-Schiff base compounds formulated as ZnLX2 (L is a new N3-Schiff base ligand obtained by condensation reaction between diethylenetriamine and (Z)-3-(4-(dimethylamino)phenyl) acrylaldehyde and X is (Cl?, Br?, I?, N3?, and NCS?)) were synthesized and characterized by Fourier transform infrared, 1H and 13C NMR, UV–visible, thermal analyses, and molar conductivity measurements. Low molar conductivity values of the compounds in dimethylformamide (DMF) showed nonelectrolyte character of them. Zinc complexes have been also prepared in nanostructure sizes under ultrasonic irradiation confirmed by X-ray powder diffraction and scanning electron microscopy. Thereafter, ZnO nanoparticles were prepared by direct calcination process of zinc iodide complex at 600°C under air atmosphere. Furthermore, thermogravimetric analyses of the complexes were used for the investigation of thermal behavior of the tiled compounds. Based on TG/DTG plots, some kinetics activation parameters of the compounds at all thermal decomposition steps were calculated. In final, antimicrobial activities of the compounds were investigated by the well diffusion technique against the gram-positive bacteria of Staphylococcus aureus and Bacillus subtilis, and the gram-negative bacteria of Escherichia coli and Pseudomonas aeruginosa and the fungi strains of Aspergillus oryzae and Candida albicans. The results showed that all zinc-Schiff base organic compounds are more antimicrobial active than free ligand.

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.

Abstract: Conditions of synthesis are optimized and XRD and thermoanalytical studies are performed for normal maleate [Zn(H2O)2(C4H2O4)] and acid maleate [Zn(H2O)4(C4H3O4)2], along with acid Co(II)–Zn(II), Ni(II)–Zn(II) maleates. It is shown that when solid solutions thermally decompose in acidic maleate systems, the kinetically less stable component causes the temperature of decomposition of the more stable component to fall. It is established that the solid residue of Zn(II) maleate after heating to 500°C in a He atmosphere is a composite containing Zn oxide whose reduction to metal begins at 675°C. The decomposition of [(Co0.1Zn0.9)(H2O)4(С4H3O4)2] leads to the oozing of metallic cobalt atoms embedded in the channels of the ZnO structure that act as a catalyst for the spontaneous growth of uniform carbon nanotubes on the surface of the composite. After thermal decomposition of the samples in a system of acid Ni(II) maleate–acid Zn(II) maleate, only the bimetallic phase is observed in the composites, and there is no zinc oxide.

A method comprises contacting a compound having formulae (1) with a compound having formula MLo to form a metal: [in-line-formulae][M(SiR3)m(L1)p]n??(1)[/in-line-formulae] wherein M is Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Al, a second row transition metal or a third row transition metal;R are each independently H, C1-C6 alkyl or —Si(R″)3;R″ are each independently H or C1-C6 alkyl;m is an integer from 1 to 3;n is a number representing the formation of aggregates or polymeric material;L1 is a neutral donor ligand; L is a ligand; p is an integer from 0 to 6; and o is an integer representing the number of ligands bonded to MLo.

The structures of two isostructural phases of [M(Еn)3](ReO4)2 (M = Ni, Zn; Еn is ethylenediamine) are studied. The crystal structures belong to the triclinic system, but demonstrate a pseudohexagonal packing motif. It is shown that the product of thermal decomposition of [Zn(Еn)3](ReO4)2 (hydrogen atmosphere, 400 °C) is a homogeneous mixture of nanocrystalline zinc and rhenium powders with coherent scattering regions of ~30 nm.

The reversible electrodeposition of zinc was investigated in an aqueous electrolyte containing zinc bromide (50mM) and 1-ethylpyridinium bromide ([C2Py]Br, 50mM) by cyclic voltammetry, chronoamperometry, and scanning electron microscopy. Unusual voltammetric behaviour for the Zn/ZnII redox couple was observed in the presence of [C2Py]Br. Passivation of the redox couple was observed after a single deposition-stripping cycle at switching potentials more negative than-1.25V versus Ag/AgCl. This unusual behaviour was attributed to the reduction of 1-ethylpyridinium cations to pyridyl radicals and their follow-up reactions, which influenced the zinc electrochemistry. This behaviour was further seen to modify the nucleation process of electrodeposition, which altered the morphology of zinc electrodeposits.

The reaction of isophthaloyl dichloride with 1H-1,2,4-triazole afforded the new ligand 1,3-phenylenebis(1,2,4-triazole-1-yl)methanone (1). A series of Co(II), Cu(II), Zn(II) and Ni(II) complexes were synthesized using 1 and then characterized by melting p

Mg60Zn30Ti5Si5amorphous alloy was prepared via mechanical alloying (MA) and heat treated in different way. X-ray diffractometer (XRD) was used to detect the phases of alloy. The crystallization characteristics a

The main target of this paper is to get an interesting data for the preparation and characterizations of metal oxide (MO) nanoparticles using H2L Schiff base complexes as precursors through the thermal decomposition procedure. Five Schiff base complexes of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) metal ions were synthesized from 2-[(2-hydroxy-naphthalen-1-ylmethylene)-amino]-benzoic acid new adduct (H2L). Theses complexes were characterized using infrared, electronic, mass and 1H NMR spectroscopic techniques. The elemental analysis data was confirmed that the stoichiometry of (metal:H2L) is 1:1 molar ratio. The molar conductance indicates that all of complexes are non electrolytic. The general chemical formulas of these complexes is [M(L)(NH3)]·nH2O. All complexes are tetrahedral geometry. The thermal decomposition behavior of H2L hydrated and anhydrous complexes has been discussed using thermogravimetric analysis (TG/DTG) and differential thermal analyses (DTA) under nitrogen atmosphere. The crystalline phases of the reaction products were checked using X-ray diffractometer (XRD) and scanning electron microscopy (SEM).

Metallic gallium can reduce ions of silver, copper or gold in a slow spontaneous reaction to form the free metals. However, when the reduction is performed with molten gallium under ultrasonic irradiation, the gallium is dispersed into micrometric spheres and the reduction rate is enhanced dramatically. This is due to the large surface area of unoxidized gallium that is formed, on which the heterogeneous reduction occurs. Each of these metals formed also a certain amount of an intermetallic compound with the gallium: Ag2Ga, CuGa2 and AuGa2. Zinc has a more negative reduction potential than gallium and therefore no reduction of zinc ions was expected. Nevertheless we conducted an experiment using a solution of zinc ions to check whether the extremely high temperature that develops near the surface of the particles during cavitation can overcome the energetic barrier for such reduction.

Abstract Reactions of ZnCl2 + nLiNH2 at a range of molar ratios and temperatures gave a mixture of Zn3N2 and LiZnN as products; no stable amide chloride, imide chloride or nitride chloride phases were identified. Temperature-programmed desorption with mass spectrometry (TPD-MS) showed that the main gas emitted was ammonia (NH3). The addition of lithium hydride (LiH) changed the main gaseous product from NH3 to H2, which was released at a low temperature beginning around 90°C. Neither pure LiZnN nor Zn3N2 could be rehydrogenated under the conditions studied. However, mixtures of LiZnN and Zn3N2, and LiZnN and LiCl reacted with H2 at 300°C to form LiNH2 and zinc metal.

Treatment of Zn(Si(SiMe3)3)2 with ZnX2 (X = Cl, Br, I) in tetrahydrofuran (THF) at 23 °C afforded [Zn(Si(SiMe3)3)X(THF)]2 in 83-99% yield. X-ray crystal structures revealed dimeric structures with Zn2X2 cores. Thermogravimetric analyses of [Zn(Si(SiMe3)3)X(THF)]2 demonstrated a loss of coordinated THF between 50 and 155°C and then single-step weight losses between 200 and 275°C. The nonvolatile residue was zinc metal in all cases. Bulk thermolyses of [Zn(Si(SiMe3)3)X(THF)]2 between 210 and 250°C afforded zinc metal in 97-99% yield, Si(SiMe3)3X in 91-94% yield, and THF in 81-98% yield. Density functional theory calculations confirmed that zinc formation becomes energetically favorable upon THF loss. Similar reactions are likely to be general for M(SiR3)n/MXn pairs and may lead to new metal-film-growth processes for chemical vapor deposition and atomic layer deposition.

The metal complexes of 4-ethyl-1-(2-hydroxybenzoyl) thiosemicarbazide (L1) with MCl2 (M = Co2+, Cu2+ and Zn2+) and Zn(Ac)2 in EtOH were synthesized and characterized using spectral (IR, 1H-NMR, mass, UV-Visible), magnetic moment and thermal measurements. Binary and ternary complexes with the general formulae, [Cu(L1-H)2]·EtOH, [Co(L1-H)2], [Zn3(L1-H)(L1)(Ac)5], [Cu2(L2)2(L1-2H)2(H2O)2]·4H2O, [Co(L2)(L1-2H)]·3H2O and [Zn2(L2)(OH)(L1-3H)(H2O)]·1/2EtOH where L2 is 2,2′-dipyridyl, have been suggested and characterized. The bond lengths, bond angles, chemical reactivates, energy components, binding energies and dipole moments for the isolated complexes were evaluated by DFT method from DMOL3. Also, the MEP for L1 is illustrated. The existence of the OH group in the Zn2+ ternary complexes is confirmed by IR, mass and 1H-NMR spectra. Biological activity for the L1 and some its complexes was tested against DNA. Comparative studies between the ligation behavior and reactivity of our previous work derived from 4-phenyl- and 4-allyl-1-(2-hydroxybenzoyl) thiosemicarbazides have been investigated.

Silicon (Si) nanoparticles have been prepared by a "metathesis" reaction of magnesium silicide (Mg2Si) and zinc chloride (ZnCl2) in an autoclave at 300°C. The as-prepared Si nanoparticles exhibit a reversible capacity of 795 mA h g-1 at a current density of 3.6 A g-1 over 250 cycles.

1,4-Dioxo-3, 4, 4e, 5, 10, 10a-hexahydro-1H-5,10-benzenobenzo [g] phthalazin-2-yl-thioamide [6a]; 1,4-dioxo-3, 4, 4e, 5, 10, 10a-hexahydro-1H-5, 10-benzenobenzo [g] phthalazin-2-yl-N-pyridylthioamide [6b] and 1,4-dioxo-3, 4, 4e, 5, 10, 10a-hexahydro-1H-5, 10-benzenobenzo[g]phthalazin-2-yl-N-ethylthioamide [6c] and their [Cu(6a-H)(OAc)], [Zn(6a-H)(OAc)], [Cu(6b-H)(H2O)2(OAc)]·3H2O and [Zn(6b-H)(OAc)], [Cu2(6c-H)](OAc)3]·2H2O and [Zn(6c-H)(OAc)] complexes have been synthesized via a reaction between phthalazinedione 6a-c derivatives and the acetate salt of Cu(II) or Zn(II). These compounds were characterized by elemental analysis, spectra (UV-Vis, IR, 1H NMR, 13C NMR, ESR), conductance, thermal analysis and magnetic moments.

In this work, sintering of Zn4Sb3 was performed by open die pressing at 558 K, investigating the role of different starting materials (powders obtained from slowly cooled master alloy ingots or rapidly solidified ribbons) on microstructure, phase stability, thermoelectric properties and mechanical properties. With respect to the master alloy, sintered samples show lower porosity, a slight decrease in Zn content and a partial decomposition of Zn4Sb3 into ZnSb and Zn. Sintering of ground rapidly solidified ribbons further reduces porosity and partially inhibits the decomposition of Zn4Sb3. As sintered samples show a temperature behaviour of the Seebeck coefficient that is intermediate between those of Zn4Sb3 and ZnSb. Thermal cycling between 300 K and 700 K favours the homogenization of the microstructure, due to the recombination of ZnSb and Zn into Zn4Sb3, leading to a Seebeck coefficient typical of Zn4Sb3 single phase. The phase evolution observed upon sintering and thermal cycling is described in terms of competing reactions ruled by thermodynamics and kinetics, and the different behaviour of the samples is explained by the different free energy level of the starting materials. All samples show a brittle behaviour upon stress-strain compressive test and microindentation measurements. A remarkable increase of the fracture strength is observed as the porosity decreases, whereas microhardness values are similar for all samples (220-240 HVN). For the sintered samples, values of the indentation fracture toughness (0.8-0.9 MPa m1/2) are estimated from the length of Palmqvist-type radial cracks.

The photoreduction of Zn(II) to Zn metal catalyzed by 8-hydroxyquinoline derivatives is reported. Structure-activity relationships, ideal reaction conditions, and the reaction kinetics are described and a mechanism involving an in situ formed quinolate complex is portrayed. the Partner Organisations 2014.

The course of differential capacity curves of the electric double layer at the mercury electrode/surfactant solution interface was described for three different surfactants from different groups. Using square-wave voltammetry (SWV) it was found that the surfactants had a varying effect on the kinetics of electroreduction of Zn2+ ions. Simple relationships were presented between SWVpeaks and the course of differential capacity curves in the presence of surfactants as compared with the curve of differential capacity for the basic electrolyte.

The red-emitting phosphor CaZnOS:Eu2+ was synthesized from CaCO3, ZnS, Eu2O3 and CeCl3 by controlling the sintering condition. It was found that Ce3+ ions can play a role of reductant to contribute to the formation of Eu2+ in CaZnOS matrix under inert protective atmosphere. While the gas flow changed to H2/N2, the product turned to CaS easily. XRD, photoluminescence spectra, UV-vis and IR absorption spectra were evaluated to investigate the origin of the distinctions of the optical properties and stabilities between the two divalent europium ions doped phosphors CaZnOS:Eu2+ and CaS:Eu2+. The similarities and differences between them were analyzed.

FeCoZn nanowires with controlled diameters have been prepared using pulse electrochemical deposition in anodized aluminum oxide templates. The magnetic measurements revealed significant effect of annealing on the saturation magnetization (Ms) a

MgB12H12 has been widely discussed as an intermediate in the hydrogen sorption cycles of Mg(BH4)2, but its properties such as stability and reactivity are still unknown. We achieved the synthesis of MgB12H12via the reaction between Mg(BH 4)2 and B2H6 at 100 to 150 °C. When bulk Mg(BH4)2 was used as the starting material, a yield of 10.2 to 22.3 mol% was obtained, which was improved to 92.5 mol% by using Mg(BH4)2 nanoparticles. The as-synthesized MgB 12H12 decomposed into boron between 400 and 600 °C, preceded by a possible polymerization process. The formation mechanism of MgB12H12 and its role in the decomposition process of Mg(BH4)2 are discussed. the Partner Organisations 2014.

Easily oxidized metals are of interest as a means of storing solar energy in the form of fuels. While their efficient metal/air batteries make them attractive solar fuel candidates, the photoreduction of the corresponding metal ions remains difficult. Accordingly, this work describes the photon driven reduction of Zn2+ by an iridium(III) photosensitizer (PS) and catalyst. [Ir(ppy)2(dtbbpy)](PF6) (ppy = 2-phenylpyridine, dtbbpy = 4,4′-di-tert-butyl-2,2′-bipyridine) was found to be the most robust photocatalyst, and the use of ZnCl2 as the Zn 2+ starting material and acetonitrile as the solvent afforded the highest yield of Zn metal product. Under these conditions, a maximum of 430 catalyst turnover numbers were achieved. Cyclic voltammetry of ZnCl2 in different solvents and of different zinc salts in acetonitrile (MeCN) demonstrated the roles of MeCN and Cl- in the photoreduction mechanism. Kinetics measurements revealed a first order dependence of the initial rate on both [Ir(ppy)2(dtbbpy)](PF6) and ZnCl 2. A first order decay of the reaction rate was also observed.

Transition metal [Co, Ni, Cu and Zn(II) acetates] complexes of salicylaldehyde derived Schiff bases, 2-{(E)-[(4-chlorophenyl)imino]methyl} phenol (CIMP) and 2-{(E)-[(4-bromophenyl)imino]methyl}phenol (BIMP) were synthesized and characterized by various analytical and spectroscopic studies. The Schiff base ligands and their metal complexes were also screened for their urease, α-chymotrypsin, acetylcholinesterse and butyrylcholinesterase inhibition activities. The ligands were found active against α-chymotrypsin with IC50 ± S.E.M. = 305.0 ± 3.2 and 330.6 ± 1.6 μM respectively. The copper complexes of both the ligands were found active in inhibiting urease enzyme with IC50 ± S.E.M. = 10.7 ± 0.2 and 5.0 ± 0.1 μM respectively, as compared to standard inhibitor. Structure activity relationship (SAR) was evaluated using autodock programme. It was found that the active complexes block the entrance cavity to the enzyme. All the complexes were evaluated for their thermal degradation studies using TG-DTA analytical methods in static air. Thermodynamic and kinetic parameters were evaluated from the TG/DTA curves using Horowitz-Metzger method.

A series of new mixed-metal oxalates containing U4+ and divalent transition metal cations, Na2U2M(C2O 4)6(H2O)4 (M = Mn2+, Fe2+, Co2+,

In the present work, the decomposition behaviour of NaZn(BH 4)3 nanoconfined in mesoporous SBA-15 has been investigated in detail and compared to bulk NaZn(BH4)3 that was ball milled with SBA-15, but not nanoconfined. The successful incorporation of nanoconfined NaZn(BH4)3 into mesopores of SBA-15 was confirmed by scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, 11B nuclear magnetic resonance, nitrogen absorption/desorption isotherms, and Fourier transform infrared spectroscopy measurements. It is demonstrated that the dehydrogenation of the space-confined NaZn(BH4)3 is free of emission of boric by-products, and significantly improved hydrogen release kinetics is also achieved, with pure hydrogen release at temperatures ranging from 50 to 150 °C. By the Arrhenius method, the activation energy for the modified NaZn(BH4)3 was calculated to be only 38.9 kJ mol-1, a reduction of 5.3 kJ mol-1 compared to that of bulk NaZn(BH4)3. This work indicates that nanoconfinement within a mesoporous scaffold is a promising approach towards stabilizing unstable metal borohydrides to achieve hydrogen release with high purity.

A new series of Zn(II), Cd(II) and Hg(II) complexes of (1E,5E)-1,5-bis(1- (pyridin-2-yl)ethylidene)carbonohydrazide (H2APC) have been prepared and characterized by elemental analyses, spectral (IR, UV-visible, mass and 1H NMR) as well as magnetic and thermal measurements. The data revealed that the ligand acts a monobasic hexadentate, neutral tri- and monodentate in Zn(II), Cd(II) and Hg(II) complexes, respectively. An octahedral geometry is proposed for Zn(II) complex, a trigonal bi-pyramid for Cd(II) complex and a tetrahedral one for Hg(II) complex. The bond length, bond angle, HOMO, LUMO and charges on the atoms have been calculated to confirm the geometry of the ligand and the investigated complexes using material studio program. Kinetic parameters were determined for each thermal degradation stage of some complexes using Coats-Redfern and Horowitz-Metzger methods. The antioxidant, anti-hemolytic, and cytotoxic activities of the compounds have been screened. H2APC showed moderate antioxidant activity using ABTS and DPPH methods. With respect to erythrocyte hemolysis and in vitro Ehrlich ascites assay, H2APC exhibited the potent antioxidative activity followed by Cd(II) and Zn(II) complexes while Hg(II) complex showed very weak activity.

Anodic oxidation of Co, Cu, Zn, and Sn metals in an anhydrous acetone solution of 1,1-oxalyl-, malonyl- or succinyl-bis(4-p- chlorophenylthiosemicarbazide) yields a new polynuclear complexes. The isolated complexes have the general composition [M2(L)(H2O) 6], L = pClSuTS and M = Co(II), Cu(II) or Sn(II), [M 2(L)(H2O)n]·nH2O where M = Cu(II), Co(II) or Sn(II), L = pClOxTS and n = 2 or 6, and [M2(L)(ac) 2]·nH2O where M = Co(II) or Zn(II), L = pClOxTS or pClSuTS and n = 2. The thermogravimetry (TG) and derivative thermogravimetry (DTG) have been used to study the thermal decomposition of the investigated bisthiosemicarbazide ligands and their metal complexes. The kinetic thermodynamic parameters such as: E, ΔH, ΔS and ΔG are calculated using Horowitz-Metzger (HM) and Coats-Redfern (CR) equations. The kinetic thermodynamic parameters such as: E, ΔH, ΔSand ΔG are calculated from the DTG curves. The tested compounds show a reasonable activity against four strains of Gram-negative bacteria; Escherichia coli, Pseudomonas aeruginosa species and Gram-positive bacteria; Bacillus cereus and Staphylococcus aureus.

Various metal nanoparticles including base metal were produced by a brief accelerated electron beam irradiation of 1-alkyl-3-methylimidazolium bis((trifluoromethyl)sulfonyl)amide room-temperature ionic liquid without a stabilizing agent, which is usually employed so as to prevent aggregation.

Zinc-nickel alloys (γ-phase) with 8-15% nickel were electrochemically deposited onto stainless steel for increased corrosion protection. Alkaline deposition conditions were studied using ammonium hydroxide as the base source and a working pH range between 9.0-9.5. Sodium acetate was used as a complexing ligand and found to stabilize the metal ions in the electrolytic solution. Strongly adhering, quality deposits were obtained with room temperature electrodeposition. Uniform grain size and smooth deposits were observed with scanning electron microscopy, which lead to increased corrosion protection. X-ray diffraction and atomic absorption spectroscopy confirmed the deposits were γ-phase zinc-nickel with nickel content of 8-15% within the alloy. The corrosion potential for the γ-phase coatings was improved over that of pure zinc coatings by about 200 mV cathodic with respect to stainless steel but at a lower corrosion potential, thereby impeding the corrosion rate.

Zn nanoparticles with different size and distribution were loaded on/into TiO2 nanotube arrays (Zn/TiO2NTs) via pulsed electrodeposition method. The morphology of Zn/TiO2NTs was studied by field emission scanning electron microscopy (FESEM). The morphology influence of Zn nanoparticles on the photoelectrochemical properties of Zn/TiO 2NTs were investigated by UV-vis diffuse reflectance spectrum (UV-vis DRS) and photoelectrochemical measurements. The results showed that Zn/TiO 2NTs composites with an average size at 40-50 nm and uniformly distributed of Zn nanoparticles possessed the narrowest band gap, the best photocurrent response, the highest charge carriers density and minimum charge-transfer resistance. These discrepancies in photoelectrochemical properties of different Zn/TiO2NTs samples can be ascribed to the size and distribution effect (morphology effect) of Zn nanoparticles which can influence the transfer and separation of photo-induced carriers generated by TiO2NTs.

Molecular charge-transfer complexes of the tetramethylethylenediamine (TMEDA) with picric acid (Pi-OH), benzene-1,4-diol (QL), tin(IV) tetrachloride (SnCl4), iodine, bromine, and zinc chloride (ZnCl2) have been synthesized and investigated by elemental and thermal analysis, electronic, infrared, Raman and proton-NMR, energy-dispersive X-ray spectroscopy, X-ray powder diffraction and positron annihilation lifetime spectroscopy, and scanning electron microscopy. In this work, three types of acceptors π-acceptors (Pi-OH and QL), σ-acceptors (iodine and bromine), and vacant orbital acceptors (SnCl4 and ZnCl2) were covered. The results of elemental analysis indicated that the CT complexes were formed with ratios 1:1 and 1:2 for QL, SnCl4, and ZnCl2 acceptors and iodine, Pi-OH, and Br2 acceptors, respectively. The type of chelating between the TMEDA donor and the mentioned acceptors depends upon the behavior of both items. The positron annihilation lifetime parameters were found to be dependent on the structure, electronic configuration, and the power of acceptors. The correlation between these parameters and the molecular weight and biological activities of studied complexes was also observed. Regarding the electrical properties, the AC conductivity and the dielectric coefficients were measured as a function of frequency at room temperature. The TMEDA charge-transfer complexes were screened against antibacterial (Escherichia coli, Staphylococcus aureus, Bacillus subtilis, and Pseudomonas aeruginosa) and antifungal (Aspergillus flavus and Candida albicans) activities.

Zinc coatings were electrodeposited on steel substrate. The effect of oxalate anions as chelating agents on nucleation and growth mechanism, surface morphology, predominant texture and corrosion behaviour of zinc electrodeposits was investigated. Evaluation of nucleation mode of zinc in the presence and absence of oxalate anions showed that the instantaneous nucleation is predominant in both cases. From the AFM images, the nuclei densities for zinc deposition were 3.5 109 and 2 109 cm-2 in the absence and presence of oxalate anions, respectively. These are one order of magnitude higher than those obtained by analysis. Electrochemical impedance spectroscopy revealed that in the bath containing oxalate anions, the growth of deposit is semi-infinite diffusion controlled. While in the absence of oxalate anions, the charge transfer control was governed. In the absence of oxalate anions, the texture components of zinc coating were mostly basal and low angle pyramidal planes, whereas in the presence of oxalate anions, the high angle pyramidal and prism planes were dominant. Furthermore, oxalate anions changed the zinc surface morphology from packets of hexagonal platelets to a granular nature. In the presence of oxalate anions, the zinc coating produced had a better corrosion resistance than that deposited from bath without oxalate anions.

The kinetics of zinc electrodeposition from acid sulphate solution on a platinum electrode was investigated by means of stationary polarization curves, interfacial pH measurement and electrochemical impedance spectroscopy. The effect of pH, namely pH 2, 3 and 4, was analyzed. A significant dependence of Zn electrodeposition with solution pH was verified. The results obtained cannot be predicted by the available models for Zn electrodeposition. A reaction model is then proposed based on the predominant steps as a function of the potential and the electrode surface nature.

Bulk semi-organic single crystal of dichlorido diglycine zinc dihydrate has been grown by unidirectional crystal growth method from aqueous solution. The phase of the grown crystal was identified using single crystal XRD analysis. The functional groups present in the crystal were confirmed using FTIR and 1H NMR analysis. Transmission study shows 70% of transmission in the entire visible region, which reveals the good optical quality of the grown crystal. A stable broad peak in the range of violetgreen emission was observed in the emission spectrum, which is due to the existence of defects in the crystal. The thermal and mechanical properties of the grown crystal were studied using TG/DTA and the Vickers microhardness tester, respectively.

We present several results concerning the preparation by means of electrolysis and characterization of ZnCo alloys thin films. Films of Zn, Co and ZnCo with various compositions (816 at% Co) were prepared in sulfate baths, using potentiostatic control, envisaging applications in the domain of corrosion resistant magnetic sensors. The effects of applied voltage on the magnetic properties, microstructure and phase content of the electrodeposited ZnCo films were investigated. The applied voltage significantly influenced the film composition and their magnetic properties. These films, when deposited at an applied voltage of 4.5 V exhibited multiphase behavior due to the inclusion of new phases (cobalt hydroxide), whereas at 3.0 V, only ZnCo alloys were deposited. The structure and morphology of the samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM).

Electrodeposition and dissolution of zinc in methanesulfonic acid were studied as the negative electrode reactions in a hybrid redox flow battery. Cyclic voltammetry at a rotating disk electrode was used to characterize the electrochemistry and the effect of process conditions on the deposition and dissolution rate of zinc in aqueous methanesulfonic acid. At a sufficiently high current density, the deposition process became a mass transport controlled reaction. The diffusion coefficient of Zn2+ ions was 7.5 × 10-6 cm2 s-1. The performance of the zinc negative electrode in a parallel plate flow cell was also studied as a function of Zn2+ ion concentration, methanesulfonic acid concentration, current density, electrolyte flow rate, operating temperature and the addition of electrolytic additives, including potassium sodium tartarate, tetrabutylammonium hydroxide, and indium oxide. The current-, voltage- and energy efficiencies of the zinc-half cell reaction and the morphologies of the zinc deposits are also discussed. The energy efficiency improved from 62% in the absence of additives to 73% upon the addition of 2 × 10-3 mol dm-3 of indium oxide as a hydrogen suppressant. In aqueous methanesulfonic acid with or without additives, there was no significant dendrite formation after zinc electrodeposition for 4 h at 50 mA cm -2.