Binary Zn Research Articles

Preparation, Mechanical Properties, and Degradation Behavior of Zn-1Fe-xSr Alloys for Biomedical Applications.

As biodegradable materials, zinc (Zn) and zinc-based alloys have attracted wide attention owing to their great potential in biomedical applications. However, the poor strength of pure Zn and binary Zn alloys limits their wide application. In this work, a stir casting method was used to prepare the Zn-1Fe-xSr (x = 0.5, 1, 1.5, 2 wt.%) ternary alloys, and the phase composition, microstructure, tensile properties, hardness, and degradation behavior were studied. The results indicated that the SrZn13 phase was generated in the Zn matrix when the Sr element was added, and the grain size of Zn-1Fe-xSr alloy decreased with the increase in Sr content. The ultimate tensile strength (UTS) and Brinell hardness increased with the increase in Sr content. The UTS and hardness of Zn-1Fe-2Sr alloy were 141.65 MPa and 87.69 HBW, which were 55.7% and 58.4% higher than those of Zn-1Fe alloy, respectively. As the Sr content increased, the corrosion current density of Zn-1Fe-xSr alloy increased, and the charge transfer resistance decreased significantly. Zn-1Fe-2Sr alloy had a degradation rate of 0.157 mg·cm-2·d-1, which was 118.1% higher than the degradation rate of Zn-1Fe alloy. Moreover, the degradation rate of Zn-1Fe-xSr alloy decreased significantly with the increase in immersion time.

Preparing High Strength and Elongation of Biodegradable Zinc–Magnesium Alloys with Superior Antibacterial Properties and Biocompatibility

The extrusion-formed Zn–0.5Mg alloy got a improved elongation and tensile strength by the addition of Mn. The influence of Mn on the strength contribution was investigated by comparing the microstructures of the designed Zn–0.5Mg and Zn–0.5Mg–0.2Mn alloys. The deformed binary Zn–Mg alloy had a grain size of 9 μm, and the grain size of the deformed ternary Zn–Mg–Mn alloy was 3 m. This result indicated that the extrusion-formed Zn–Mg–Mn alloy had a greater contribution to grain boundary strengthening than the extrusion-formed Zn–Mg alloy. Furthermore, the precipitates in the two alloys show significant differences in size, morphology, density, and variety. Precipitates in the Mn-containing Zn alloy showed a smaller size, higher density, and the ratio of length and diameter. The high elongation rate of the extrusion-formed Zn–Mg–Mn alloy was attributed to the fully fragmented Mg2Zn11 and deformable MnZn13 phases. In addition to enhancing its mechanical characteristics, the Zn–Mg–Mn alloy, as extruded, exhibits the same corrosion rates, antibacterial properties, and biocompatibility. These results are helpful in expanding the applications of Zn alloys in the orthopaedic field.

Two Birds with One Stone: Ammonium-Induced Carbon Nanotube Structure and Low-Crystalline Cobalt Nanoparticles Enabling High Performance of Lithium-Sulfur Batteries

The electrochemical performance of lithium–sulfur batteries (LiSBs) has been hampered by the slow redox kinetics and shuttle effect of lithium polysulfides (LiPSs), which require the rational design and synthesis of highly active electrocatalysts towards this reaction. Herein, worm-like N-doped porous carbon nanotube-supported low-crystalline Co nanoparticles (a-Co-NC@C) were derived from binary Zn–Co ZIF via a two-step thermal annealing method. Initial thermal annealing 950 °C in Ar + H2 atmosphere results in the carbonization of binary Zn–Co ZIF and the formation of high crystalline Co nanoparticles. Thermal annealing in ammonia atmosphere at 350 °C not only results in the reduced crystallinity of cobalt nanoparticles; it also promotes the growth of highly graphitized and heavily N-doped intertwined carbon nanotubes. The enlarged porous carbon nanotube structure offers accommodation for sulfur content, while the doped carbon and Co nanoparticles with reduced crystallinity facilitate the redox kinetics of LiPSs, improving the cycling stability, rate performance and capacity of LiSBs batteries. As a result, the a-Co-NC@C cathode displays a specific capacity of 559 mAh g−1 after 500 cycles at 1 C, and a specific capacity of 572 mAh g−1 at 3 C. It delivers a specific capacity of 579 mAh g−1 at high sulfur loading of a 2.55 mg cm−2 at 1 C after 400 cycles. This work highlights the importance of phase engineering of carbon matrix and transition metal nanoparticles in electrochemical performance of Li-S batteries.

Experimental investigations of electrodeposited Zn–Ni, Zn–Co, and Ni–Cr–Co–based novel coatings on AA7075 substrate to ameliorate the mechanical, abrasion, morphological, and corrosion properties for automotive applications

Abstract The aluminum (Al) alloy AA7075 is widely used in various industries due to its high strength-to-weight ratio, which is comparable and replaceable to steel in many applications. However, it has poor resistance to wear and corrosion compared to other Al alloys. The conventional pressure die coating with Cr and cadmium has led to premature failure while the load is applied. It is indeed to develop a novel coating method to improve the mechanical, wear, and corrosion properties of AA7075 Al alloy. In the present investigation, the binary and ternary metals such as zinc–nickel (Zn–Ni), zinc–cobalt (Zn–Co), and nickel–chromium–cobalt (Ni–Cr–Co) are electroplated on the substrate material (AA7075). In order to ensure optimal coating adhesion, the surface of the substrate material was pre-treated with laser surface treatment (LST). The mechanical and corrosion studies have been carried out on the uncoated and coated materials. It is observed from the findings that the ternary coating has higher wear resistance than the binary-coated material. The ternary coating has 64% higher resistance in the non-heat-treated status and 67% higher resistance in the heat-treated condition compared to the uncoated specimens. The tensile strength (MPa) of Ni–Cr–Co on AA7075 pressure die casting (PDC) is higher than the other deposits (582.24 of Ni–Cr–Co > 566.07 of Zn–Co > 560.05 of Zn–Ni > 553.64 of uncoated condition). The presence of a crystalline structure with the high alignment of Co and Ni atoms could significantly improve the corrosion resistance of Ni–Cr–Co coatings on AA 7075 PDC substrates when compared to binary coatings. The scanning electron microscopy (SEM) images, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy findings on the coated materials have been corroborated with the analyses on mechanical and corrosion properties. The XRD analysis of the Zn–Ni binary coating has reported that the diffraction peaks of γ-NiZn3 (831), γ -Ni2Zn11 (330), and 631 with 2θ values 38, 43, and 73° are confirming the presence of Zn–Ni binary deposit on AA7075 PDC substrate. The XRD pattern of Zn–Co-coated material has revealed that the presence of three strong peaks such as Zn (110), Co (111), and CoZn (211) and two feeble peaks such as ε-CoZn3 (220) and ε-CoZn3 (301) are clearly visible. The XRD pattern of Ni–Cr–Co ternary coating has exhibited that the Ni–Cr–Co ternary deposit is a solid solution with a body-centered cubic structure due to the formation peaks at lattice plane such as (110), (220), and (210) with a crystal lattice constant of 2.88 A°. The SEM image for both the binary- and ternary-coated materials has exhibited that the deposited surface has displayed many shallow pits due to hitting by progressive particles. The SEM image has illustrated the presence of Zn–Ni atoms with smaller globular structure. The surface morphology of binary Zn–Co coating on the PDC AA7075 substrate has unveiled the evenly distributed dot-like structure and submerged Co particles in the galaxy of Zn atoms. To understand the effectiveness of bonding by laser texturing, cross-section SEM has been carried out which furthermore revealed the effective adhesion of Ni–Cr–Co on AA7075 PDC; this could also be the reason for the enhancement of microhardness, wear, and corrosion resistance of the said coating.

Investigation of microstructure related to corrosion evolution, mechanical and electrochemical properties on doped Si of binary Zn–Al coating

The cycling corrosion test is the first evaluation for silicon doped of 55 wt% Al–Zn coated (GL) steel and microstructure related to corrosion evolution, mechanical and electrochemical properties on the GL steel is investigated. Native oxides grown on the GL surface were hydrolyzed to form the hydroxide, followed by the formation of the hydrozincite and layered double hydroxides products. Galvanic corrosion selectively occurred at the boundary Zn-rich phase to form simonkolleite. These corrosion products played a role in GL protection. We clearly expressed images that the pitting morphology began to occur at the boundary Zn-rich region and stopped corroding on the Fe–Al intermetallic compound layer. Following this, the primary Al-rich region started to be corroded until GL corrosion finish, then red rust of steel corrosion occurred. Moreover, we were the first to study that the tensile surface by bending could accelerate the GL corrosion at the intersection of the boundary phase; in contrast, the compressive surface inhibited corrosion slightly. Electrochemical impedance measurements combined with an equivalent circuit model were developed to support specific corrosion evolution.

Effects of thermomechanical processing on microstructures, mechanical properties, and biodegradation behaviour of dilute Zn–Mg alloys

Currently, zinc has been considered as one new attractive biodegradable metal for medical implant applications due to its favoured properties such as biocompatibility and recyclability. However, the cast pure zinc usually possesses coarsening microstructures, which hinders it to obtain a suitable combination of mechanical strength and degradation rate. Here, the microstructural controlling of zinc was firstly realized via alloying dilute Mg contents and thermomechanical processing. Then, the in vitro biodegradation behaviour of dilute Zn–Mg alloys was investigated accordingly using the Hank's solution. Finally, the mechanisms of mechanical strengthening and in vitro biodegradation were explored. Specifically, the Mg-50wt%Zn master alloy was added into cast Zn melt to form the binary Zn–Mg alloys with different Mg addition contents (i.e. 0, 0.05wt%, 0.1wt%, and 0.4wt%). The initial reduction of grain sizes was achieved by over 90% owing to the grain refinement generated by master alloy. In the as-cast alloys, the average grain size was decreased from over 2 mm for pure Zn to 23.7 μm for Zn-0.4wt%Mg. Subsequently, the thermomechanical processing (i.e. hot rolling at room temperature, 100°C, 150°C, and 250°C) was applied onto the cast Zn–Mg alloys to achieve further microstructural manipulation. Further grain refinement occurred in the different as-rolled Zn–Mg alloys. The in vitro corrosion resistance of all samples was assessed through the potentiodynamic polarization (PDP) test in the Hanks' solution for 14 days at 37°C. The corrosion rates depended on alloying contents, grain sizes, twins and texture. The synergetic regulation of mechanical strength and degradation rate could be adjusted by appropriately using master alloys and thermomechanical processing. For practical medical applications, the present work provides some insights on solving the dilemma between mechanical properties and biodegradation process.

Regulating mechanical properties and degradation behavior of biodegradable Zn–0.6Mg alloy via ECAP plus cold rolling

Binary Zn–Mg alloys have great potential as biodegradable implants due to their good biological safety and moderate degradation rates. Herein, a new combined process of ECAP plus cold rolling of as-cast Zn–0.6Mg alloy was developed to address its application problem of insufficient mechanical properties and serious localized corrosion. Cold rolling process can break the eutectic phase and refine grains, while deformed grains were dominant with a lot of dislocations. 8-pass ECAP process can refine grains by recrystallization, and the grains were equiaxed with less dislocations. The strength and ductility were greatly improved after cold rolling (CR) or ECAP processing compared with that of as-cast alloy, but the strength still cannot meet the requirement of orthopedic implant materials. After 8-pass ECAP+CR75% (ER) processing, the strength was further improved, which benefited from fine grain strengthening, second phase strengthening, and strain strengthening mechanisms. Tensile yield strength (σYS), ultimate tensile strength (σUTS), and fractured elongation of ER alloy were 301.2 MPa, 411.8 MPa, and 28.5%, respectively, which can meet the requirement of orthopedic implants. The eutectic phase fragmentation and grain refinement caused by cold rolling and ECAP process can reduce the galvanic corrosion tendency of the Zn–0.6Mg alloy. The corrosion resistance was further improved after 8-pass ECAP+CR75% processing with the degradation rate of 0.025 mm/y, and the alloy tended to corrode uniformly.

Thermodynamic assessment of the miscibility gaps and the metastable liquidi in the Zn‐Bi, Zn‐Pb, and Zn‐Tl systems

Abstract In monotectic systems, there are thermodynamic restrictions on compositions and temperatures below the monotectic where the equilibrium solid cannot form directly from the undercooled homogeneous liquid. In this region, the solid can form only after liquid – liquid phase separation has occurred. As suggested by earlier research, the thermodynamic restrictions on the solidification process may be useful to control the microstructure of rapidly solidified materials. Thus, it could be commercially important to understand the thermodynamic limitations on the formation of the solid in monotectic systems. The liquid miscibility gaps, metastable liquidi, and spinodal curves in the binary Zn– Bi, Zn–Pb, and Zn–Tl systems were assessed by using a subregular solution model to describe the Gibbs energies of the liquid phases. The present results were compared and discussed with other experimental and assessed data available in the literature.

Mechanical characteristics and in vitro degradation of biodegradable Zn-Al alloy

Zn-5wt.%Al alloy was cast and extruded into the tube in the present work. The mechanical properties and degradation behavior of as-cast and extruded alloys were investigated. Compared with other binary Zn alloys, the extruded Zn-5wt.%Al alloy tube showed a ultra-high elongation to failure (383.3%) and medium strength (257 MPa). The superplasticity is attributed to the grain boundary slip due to unique microstructure, i.e. the ultrafine-grained α-phase accumulated mainly along the fine-grained η-phase boundary. Furthermore, after 32 days’ immersion, the corrosion rates of as-cast and extruded alloy were 0.11 mm/y and 0.15 mm/y, respectively. The electrochemical polarization test and corrosion surface analysis indicate an initial ultrafine-grained Al-rich phase dissolution for extruded Zn-5wt.%Al alloy.

Binary Zn–Ti alloys for orthopedic applications: Corrosion and degradation behaviors, friction and wear performance, and cytotoxicity

Zinc (Zn) and its biocompatible and biodegradable alloys have substantial potential for use in orthopedic implants. Nevertheless, pure Zn with a hexagonal close-packed crystal structure has only two independent slip systems, therefore exhibiting extremely low elongation and yield strength in its as-cast condition, which restricts its clinical applications. In this study, as-cast Zn–xTi (titanium) (x = 0.05, 0.10, 0.20, and 0.30 wt.%) binary alloys were hot-rolled and their microstructures, mechanical properties, wear resistance, and cytocompatibility were comprehensively investigated for orthopedic implant applications. The microstructures of both as-cast and hot-rolled Zn–xTi alloys consisted of an α-Zn matrix phase and a TiZn16 phase, while Zn–0.2Ti and Zn–0.3Ti exhibited a finer α-Zn phase due to the grain-refining effect of Ti. The hot-rolled Zn–0.2Ti alloy exhibited the highest yield strength (144.5 MPa), ultimate strength (218.7 MPa), and elongation (54.2%) among all the Zn–xTi alloys. The corrosion resistance of Zn–xTi alloys in Hanks’ solution decreased with increasing addition of Ti, and the hot-rolled Zn–0.3Ti alloy exhibited the highest corrosion rates of 432 μm/y as measured by electrochemical testing and 57.9 μm/y as measured by immersion testing. The as-cast Zn–xTi alloys showed lower wear losses than their hot-rolled counterparts. The extracts of hot-rolled Zn–xTi alloys at concentrations of ≤ 25% showed no cytotoxicity to MG-63 osteosarcoma cells and the extracts of Zn–xTi alloys exhibited enhanced cytocompatibility with increasing Ti content.

Novel zinc alloys for biodegradable surgical staples.

The development of biodegradable surgical staples is desirable as non-biodegradable Ti alloy staples reside in the human body long after wound healing, which can cause allergic/foreign-body reactions, adhesion, or other adverse effects. In order to develop a biodegradable alloy suitable for the fabrication of surgical staples, we hypothesized that Zn, a known biodegradable metal, could be alloyed with various elements to improve the mechanical properties while retaining biodegradability and biocompatibility. Considering their biocompatibility, Mg, Ca, Mn, and Cu were selected as candidate alloying elements, alongside Ti, the main material of clinically available surgical staples. To investigate the in vitro mechanical properties and degradation behavior and in vivo safety and feasibility of biodegradable Zn alloy staples. Tensile and bending tests were conducted to evaluate the mechanical properties of binary Zn alloys with 0.1-6 wt.% Mg, Ca, Mn, Cu, or Ti. Based on the results, three promising Zn alloy compositions were devised for staple applications (wt.%): Zn-1.0Cu-0.2Mn-0.1Ti (Zn alloy 1), Zn-1.0Mn-0.1Ti (Zn alloy 2), and Zn-1.0Cu-0.1Ti (Zn alloy 3). Immersion tests were performed at 37 °C for 4 wk using fed-state simulated intestinal fluid (FeSSIF) and Hank's balanced salt solution (HBSS). The corrosion rate was estimated from the weight loss of staples during immersion. Nine rabbits were subjected to gastric resection using each Zn alloy staple, and a clinically available Ti staple was used for another group of nine rabbits. Three in each group were sacrificed at 1, 4, and 12 wk post-operation. Additions of ≤1 wt.% Mn or Cu and 0.1 wt.% Ti improved the yield strength without excessive deterioration of elongation or bendability. Immersion tests revealed no gas evolution or staple fracture in any of the Zn alloy staples. The corrosion rates of Zn alloy staples 1, 2, and 3 were 0.02 mm/year in HBSS and 0.12, 0.11, and 0.13 mm/year, respectively, in FeSSIF. These degradation times are sufficient for wound healing. The degradation rate is notably increased under low pH conditions. Scanning electron microscopy and energy dispersive spectrometry surface analyses of the staples after immersion indicated that the component elements eluted as ions in FeSSIF, whereas corrosion products were produced in HBSS, inhibiting Zn dissolution. In the animal study, none of the Zn alloy staples caused technical failure, and all rabbits survived without complications. Histopathological analysis revealed no severe inflammatory reaction around the Zn alloy staples. Staples made of Zn-1.0Cu-0.2Mn-0.1Ti, Zn-1.0Mn-0.1Ti, and Zn-1.0Cu-0.1Ti exhibit acceptable in vitro mechanical properties, proper degradation behavior, and in vivo safety and feasibility. They are promising candidates for biodegradable staples.

Alloying design of biodegradable zinc as promising bone implants for load-bearing applications

Magnesium-based biodegradable metals (BMs) as bone implants have better mechanical properties than biodegradable polymers, yet their strength is roughly less than 350 MPa. In this work, binary Zn alloys with alloying elements Mg, Ca, Sr, Li, Mn, Fe, Cu, and Ag respectively, are screened systemically by in vitro and in vivo studies. Li exhibits the most effective strengthening role in Zn, followed by Mg. Alloying leads to accelerated degradation, but adequate mechanical integrity can be expected for Zn alloys when considering bone fracture healing. Adding elements Mg, Ca, Sr and Li into Zn can improve the cytocompatibility, osteogenesis, and osseointegration. Further optimization of the ternary Zn-Li alloy system results in Zn-0.8Li-0.4Mg alloy with the ultimate tensile strength 646.69 ± 12.79 MPa and Zn-0.8Li-0.8Mn alloy with elongation 103.27 ± 20%. In summary, biocompatible Zn-based BMs with strength close to pure Ti are promising candidates in orthopedics for load-bearing applications.

THE INFLUENCE OF CHROMIUM ON THE CORROSION RESISTANCE OF TERNARY ZN–CO–CR ALLOY COATINGS DEPOSITED FROM CITRATE–SULPHATE BATH

The present study consistsan experimentation of Zinc-Cobalt composite coatings. For this, the Chromium concentration influence was the principal object to improve the corrosionresistance of the coatings, which has been made by electroplating on steel substrates previously treated; it hasbeen studied by several characterization methodssuch as the X-ray diffraction, micro-hardness measurement and scanning electron microscopy (SEM). The protection against corrosion properties has been studied by potentiodynamic polarization measurements (Tafel) and electrochemical impedance spectroscopy (EIS) to the potential of corrosion-free. The parameters characterizingthe corrosion behaviour,can be determined from the Nyquist plots. It has been observed that the ternary Zn-Co-Cr alloy is characterized by enhanced the corrosionresistance compared to the binary Zn–Co alloys. Also, the addition of Cr in the Zn-Co increases the micro-hardness, XRD and SEM results and identifies any coatings Zn-Co-Cr alloy composition reveals that zinc phase.

ZnO nanopowders doped with bismuth oxide, from synthesis to electrical application

Bismuth doped ZnO nanopowders with doping concentrations between 0 and 7 %mol were successfully synthesized with a soft chemistry method: the sol-gel route. This method allows obtaining powders with a good quality in a nanometric size range. The well-defined optimal conditions for the synthesized powders are given. The hydrated zinc acetate dissolved in ethylene glycol is used as a precursor for the zinc oxide (ZnO), with different small amount of Bi concentrations (1%, 3%, 5% and 7%). After calcination at 500 °C, the powders are consolidated into pellets and sintered using a conventional furnace and then characterized by: X-ray diffraction, SEM, TEM, and J(E) electrical measurements. Finally, the obtained material has been used to prepare varistors.The XRD patterns indicate that pure and Bi doped ZnO are solid solutions with average grain sizes varying between 65 nm and 48 nm. The β-Bi2O3 liquid phase of tetragonal structures appears as a secondary phase for a 5% mol concentration of Bi. High-resolution TEM images of Bi doped ZnO particles indicate that during the sintering of Bi-doped ZnO, the growth of particles leads to a change in the microstructure of ZnO giving semi-transparent cylindrical nanotubes.J(E) results indicate that the content of Bi increases the nonlinearity coefficient α and the breakdown fields VB of the binary Zn %Bi-O varistors. The 7% doped Bi-ZnO varistor gives the best electrical characteristics for varistors.

Capacitive properties, structure, and composition of porous Co hydroxide/oxide layers formed by dealloying of Zn–Co alloy

Thin porous binder-free layers of Co hydroxide/oxide for electrochemical capacitors were formed by dealloying an electrochemically deposited binary Zn–Co alloy, consisting of single homogeneous γ-Zn21Co5 phase. Scanning electron microscopy with energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy (XPS) was used to assess the structure, thickness, and distribution of elements in the as-deposited alloy and the dealloyed layers. The most developed porous layers were formed at a dealloying potential of − 0.965 V versus Ag/AgCl. Both the as-deposited Zn–Co and the dealloyed layers were characterized by a relatively uniform distribution of the components. As determined by XPS, the top of the dealloyed layers before cycling consisted of Co(II) hydroxide with traces of Co(0) and Co(III). The capacitive properties and stability of the formed layers of porous Co oxides were assessed using the electrochemical cyclic voltammetry (CV) and the constant current charge–discharge (C–D) methods. The areal and volumetric pseudo-capacitance values of ~ 0.38 F cm−2 and ~ 880 F cm−3, respectively, were calculated for a 4.3-µm-thick layer. The stability of the studied Co hydroxide/oxides layers was evaluated by CV and C–D cycling. After 300 cycles of C–D, the retention of pseudo-capacitance ~ 80% and the Coulombic efficiency of ~ 98% were determined. The long-term pseudo-capacitance retention was estimated at ~ 78.3% of the initial value.

Kinetic Studies of Zn(II) Removal from Single and Binary Solutions by Synthetic Hydroxyapatite - Based Nanopowders

A kinetic study has been carried out with two hydroxyapatite nanopowders to establish the mechanism involved in heavy metals removal from aqueous synthetic solutions. The samples of nanohydroxyapatite have been previously characterized. The first sample represents a pure hydroxyapatite (HAP) nanopowder named HAP-1, and the second sample (HAP-2) consist of a mixture of hydroxyapatite (HAP; Ca10(PO4)6(OH)2) and b-tricalcium phosphate (b-TCP; Ca3(PO4)2). Batch experiments with single and binary Zn(II) and Pb(II) aqueous solutions have been performed. According to this research study, it was found that the both nanohydroxyapatite samples show good heavy metals adsorption capacity, and selectivity for Pb(II) ions. A more pronounced decreasing of sorption capacity of Zn(II) ions from binary solutions compared to that registered from single heavy metal ion solutions has been observed. From the kinetic point of view, the sorption process can be described for both heavy metals as a pseudo-second-order kinetic process. According to this model, the Zn(II) and Pb(II) sorption can be achieved by chemical reactions between heavy metals and functional groups of adsorbents. The obtained results are indicative of good hydroxyapatite adsorption ability towards Pb(II) and Zn(II) ions.

Water‐based synthesis of ZnO nanoparticles via decomposition of a ternary zinc complex containing Schiff‐base, chelating, and Phen ligands

The recent environmental awareness has been the motivation for the growing preference for environmentally friendly and water‐based systems in chemical synthesis. In the present work, ZnO nanoparticles were synthesized via a novel method without any water‐insoluble compounds. At the first step, a binary Zn Schiff‐base complex was prepared from sodium salicylaldehyde‐5‐sulfonate, L‐alanine, and zinc acetate. Then, a ternary Zn complex containing the Schiff‐base, chelating, and Phen ligands was synthesized from the as‐synthesized binary Zn Schiff base and 1,10‐phenanthroline monohydrate. This intermediate product showed high water solubility and long‐term stability. Finally, ZnO nanoparticles were synthesized through the calcination of the ternary complex powder at 400, 500, and 600 °C. Combining X‐ray diffraction (XRD) and energy dispersive spectroscopy (EDS) results, it was concluded that the samples contained the ZnO phase without any impurity phases, but Fourier transform infrared (FTIR) spectra implied the presence of a remaining impurity. According to the XRD, FTIR, and photoluminescence (PL) analyses, the as‐synthesized samples differed in terms of the defect content and lattice strain. The sample calcined at 500 °C possessed the lowest defect content and lattice strain. Transmission electron microscopy (TEM) imaging revealed the formation of ZnO nanoparticles with particles sizes of <20, ~50, and ~100 nm for samples heat‐treated at the different temperatures.

Zinc–Azatrane Complexes as Efficient Catalysts for the Conversion of Carbon Dioxide into Cyclic Carbonates

AbstractThree Zn complexes based on the N4‐tris(2‐aminoethyl)amine (tren) chelating ligand and presenting a C3‐symmetrical axis were synthesized and successfully applied in the coupling of CO2 with terminal and internal epoxides. These complexes proved to be efficient catalysts if associated with tetrabutylammonium iodide, even at a low catalyst loading (0.005 mol %) or at room temperature, and allowed the production of cyclic carbonates in good to high yields. Variation of the substitution pattern on the tren ligand was shown to impact the catalyst performance greatly, and the highest turnover number (TON) (up to 11 200) was achieved with the less sterically hindered methyl‐substituted ZnII–azatrane complex. These binary Zn–azatrane/NBu4I catalytic systems could be applied to a wide range of epoxide substrates, including the more challenging internal epoxides. Moreover, although soluble in the reaction medium, Zn–azatrane catalysts could be easily recovered and reused up to three times without any substantial loss in activity, proving their robustness under the reaction conditions.

Study on a Novel Binary Zn n Eu Layered Double Hydroxide with Excellent Fluorescence.

A group of binary ZnnEu-LDHs with Zn2+/Eu3+ molar ratios of 5.0, 6.0, 7.0, and 8.0 have been obtained in ammonia water media by hydrothermal treatment. The structure, composition, and fluorescent property of samples have been investigated using various techniques. Compositional analyses revealed that the composition of samples was in agreement with that of the initial reactants. X-ray diffraction (XRD) suggested that the ZnnEu-LDHs exhibited typical layered structure with orthorhombic symmetry. All the ZnnEu-LDHs appeared strong red emissions attributed to 5D0 → 7F J (J = 1, 2) transitions of Eu3+. Moreover, the intensity of emissions due to 5D0 → 7FJ (J = 1, 2) transitions of Eu3+ tended to increase with the Zn2+/Eu3+ molar ratio varied from 8.0, 7.0 to 6.0, then decreased as the Zn2+/Eu3+ molar ratio reduced to 5.0. The strongest fluorescence was found to be at Zn2+/Eu3+ molar ratio of 6.0. Further the fluorescence decay spectra show that the Zn n Eu-LDH have similar behavior of fluorescent decay and decayed more slowly than that of the Eu(OH)3. These results indicate that the novel binary ZnnEu-LDHs have better fluorescent property and may be potential application as fluorescent materials.

In vitro structure-specific Zn(II)-induced adipogenesis and structure-function bioreactivity correlations

The advent of Zn(II) metallodrugs in metabolic syndrome pathologies generates a strong challenge toward synthetic endeavors targeting well-defined, atoxic and biologically active binary/ternary species of Zn(II). Proper formulation of that metal ion's coordination sphere sets the stage for construction of appropriately configured Schiff ligands based on tromethamine and variably modified vanillin core components. The arising Schiff ligands react with Zn(II) in a defined stoichiometry, thereby delivering new binary Zn(II)-L species with defined physicochemical properties. Analytical (elemental), spectroscopic (FT-IR, Thermogravimetric Analysis) and crystallographic techniques attest to the distinct nature of the derived binary-ternary materials, bearing defined Zn(II):L molecular stoichiometry, variable nuclearity, charge, bulk and balance mix of hydrophilicity-hydrophobicity, thereby providing the physicochemical profile based on which biological studies could ensue. The structurally based selection of species was applied onto in vitro 3T3-L1 cultures, essentially exploring toxicity, migration, morphology, cell differentiation and maturation. The systematic effort toward comparative work on appropriately defined Zn(II) species and insulin in inducing adipogenesis reveals the salient structural features in the Schiff family of ligands configuring Zn(II) so as to promote complex formation sufficient to engage biomolecular targets during the process of initiation and maturation. Molecular targets of importance in adipogenesis were examined under the influence of Zn(II) and their expression levels suggest the structural composition that a Zn(II) ion might have to optimally pursue cell differentiation. Thus, a well-defined selection of binary Zn(II)-L species is tightly associated with the incurred bioactivity, thereby setting the stage for the development of efficient Zn(II) metallodrugs to combat Diabetes mellitus II.