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Herein, we designed Er3+-incorporated zincate-based nanomaterials via a rapid, low-cost, and environmentally friendly urea-combustion route. X-ray powder diffraction (XRPD) profiles revealed their orthogonal crystalline structure. Electron microscopy showed nanoscale (48–70 nm) non-uniform agglomerated particles. The presence of [BaO11] and [ZnO5] structural units in the present samples was shown by Fourier-transform infrared (FT-IR) spectroscopy. Emission spectra yielded a characteristic peak at 551 nm, which contributed to their bright-green light. The optimal nanomaterial had 3.0 mol% of Er3+ content, and it exhibited excellent bright-green light. Exchange-type multipolar inter-linkages via cross-relaxation predominantly direct the quenching of luminescence post x = 0.03 Er3+ content, as shown by the Inokuti-Hirayama (I-H) model. The optical bandgap and Urbach energy were obtained from experimental data-fitting with Tauc’s hypothesis and an empirical correlation. Excellent color-purity (87.86%) and color temperature (6916 K) with chromaticity coordinates (0.2531, 0.6106) of the optimized nanomaterial were similar to National Television Standards Committee (NTSC) and NICHIA Corporation fabricated light-emitting diode (LED) green standards. Hence, the developed nanomaterials appear to be a good candidates for generating cool-green light in high-performance blue/green/red (B/G/R) white-light-emitting diodes (wLEDs), sensors, and laser applications.

In this focused review, I present an overview of our recent research on the zincate complex dilithium tetra-tert-butylzincate (TBZL)-catalyzed ring-opening polymerization (ROP) of e-caprolactone, efficient acylation and transesterification of alcohols with vinyl acetate and carboxylic esters, and polymer synthesis with a high transesterification ability. In the first part of this report, the ROP of e-caprolactone catalyzed by TBZL in toluene is described. In a subsequent study of the ROP of e-caprolactone in the presence of 2-hydroxyethyl methacrylate (HEMA), TBZL was found to act not only as an anionic initiator but also as a transesterification catalyst. In the second part of this report, the acylation and transesterification of alcohols with vinyl acetate and carboxylic esters catalyzed by TBZL are summarized. The acylation proceeded quantitatively at 0 °C within 1 h. A wide range of combinations of esters and alcohols were suitable for the transesterification at 0 to −40 °C. In addition, the transesterification proceeded chemoselectively even in the presence of H2O and amines. Next, TBZL-catalyzed polycondensations of diphenyl carbonate (DPC) with diols are discussed. Irreversible polycondensations catalyzed by TBZL occurred to yield aliphatic polycarbonates under atmospheric pressure. In the last part of this report, the transesterifications of poly(phenyl methacrylate) (PPhMA) side chains with alcohols catalyzed by TBZL are described. The transesterification reaction not only with alkyl alcohols but also with fluoroalcohols occurred. By changing the reaction solvent and temperature, the degree of conversion could be controlled. The present system permits the partial, quantitative, or terminal conversion of polymethacrylates. Our recent studies on the zincate complex dilithium tetra-tert-butylzincate-catalyzed transesterification and polymerization are reviewed. In the first part of this report, the ROP of e-caprolactone catalyzed by TBZL is described. In the second part of this report, the acylation and transesterification of alcohols with vinyl acetate and carboxylic esters catalyzed by TBZL are summarized. Next, TBZL-catalyzed polycondensations of diphenyl carbonate (DPC) with diols are discussed. In the last part of this report, the transesterifications of poly(phenyl methacrylate) (PPhMA) side chains with alcohols catalyzed by TBZL are described.

In order to replace the highly poisonous cyanide zincate process of Al alloy, an eco-friendly approach was developed, i.e., electrodeposition of Cu-Zn coating from ionic liquid/ethanol mixed bath. It was demonstrated that the Cu5Zn8 alloy produced from 1-ethyl-3-methylimidazolium trifluoromethylsulfonate (EMImTfO) and 20% (Volume percent) ethanol mixtures under optimal conditions showed cauliflower-shaped structure with a (330) preferred orientation, which could significantly improve the corrosion resistance of Al substrate in Watts bath, thereby elevating Ni coating quality. The overall property of Cu-Zn intermediate layer and its subsequent coating, including compactness, adhesive strength and corrosion resistance is approximately the same as that of cyanide zincate layer and its surface coating, suggesting that the new method is an ideal alternative to conventional zincate treatment.

Several approaches have been tried to reduce Al corrosion in primary and secondary alkaline batteries. The most successful to date has been the addition of ZnO to the electrolyte, which results in the spontaneous deposition of a protective metallic Zn film on the Al surface. However, there is a limited understanding in the literature of the structure of this Zn film and how that structure (i) influences the protection of Al, and (ii) is influenced by the electrolyte composition. This work aims to develop a fundamental understanding of the protection mechanism against Al corrosion when zincate is added to KOH electrolytes. This was accomplished through morphological studies of the resulting Zn film using SEM, XRD, N2 adsorption, and measurements of H2 gas evolution as well as electrochemical characterization during discharge. It was found that adding saturated ZnO to KOH electrolytes provides the most protective Zn film with good adherence and high density, which can lower the Al corrosion rate by 2 orders of magnitude. Moreover, configurations with a capacity near the Al theoretical capacity were achieved.

Treatment of two equivalents of N,N′-bis(X-phenyl)oxamides (1) with one equivalent of [Zn(OAc)2(H2O)2] (2) in the presence of four equivalents of [nBu4N]OH produce the corresponding bis(N,N′-substituted oxamate) zincate(II) complexes with the general formula (nBu4N)2[Zn(X-phenyloxamide)2] (3) (a, X = 3-NO2; b, X = 4-NO2; c, X = 2,6 CH3; d, X = 3,4-CH3; e, X = 2-Br; f, X = 4-Br; g, X = 2-F; h, X = 4-F; i, X = 2-Cl; j, X = H). Complexes 3a–j have been characterized by elemental analysis, NMR (1H, 13C{1H}) and IR spectroscopy. In addition, 3a and 3f have been characterized by single crystal X-ray crystallography. The zinc (II) ion in the later complexes is four-coordinate with two ethanediamide-nitrogen atoms from two bidentate N,N′-disubstituted oxamate ligands at each metal center. In addition, the calculated electrostatic potentials of 3f rationalize the formation of chain structures via the Br…Br interaction. Complexes 3a–j showed a characteristic LLCT (π → π*) band in the UV-Vis spectra, which was confirmed by TD-DFT calculations. DFT calculations show that the Zn(II) orbitals are neither contributing to the HOMO nor to the LUMO, i.e. the HOMO and LUMO are mainly located on the ligands. The emission spectra analyses for Zn(II) complexes 3a–j show enhanced intensity and blue shifted emission compared to ligands 1a−j. The cyclic voltammetry measurements of complexes 3a–j showed reversible electrochemical processes for the (N,N′-substituted oxamate−2/−3) between −1.52 and −1.77 V using [NnBu4][B(C6F5)4] as the supporting electrolyte. It was found that the 3-nitro- (3a) and 4-nitro-functionalized (3b) derivatives resulted in a significantly higher Fc/Fc+ redox potential (E0′) compared to the more electron-rich 3, 4-dimethyl (3c) and 2,6-dimethyl (3d) derivatives.

Chain-end-functionalized poly(3-hexylthiophene)s (P3HTs) with benzyl alcohol (─PhCH2 OH), phenol (─PhOH), and benzoic acid (─PhCOOH) groups are directly synthesized based on the Negishi catalyst-transfer polycondensation method utilizing the zincate complex of t Bu4 ZnLi2 . In this system, neither protection nor deprotection steps are required, and also providing a living polymerization system to control the molecular weight while maintaining a low molar mass dispersity (ÐM ) of the obtained P3HT derivatives. Indeed, the chain-end-functionalized P3HTs can be synthesized along with controlled number-average molecular weights (Mn = 5100-20 000), low ÐM (1.06-1.14), and high chain-end functionality (Fn = 46-86%). The Fn values for the alcohol and phenol groups are found to be high (86% for ─PhCH2 OH and 71% for ─PhOH based on 1 H NMR, respectively), as also confirmed by matrix-assisted laser desorption/ionization time of flight mass spectroscopy. The easily synthesizable chain-end-functionalized P3HTs will be applicable for the facile synthesis of block and branched polymers containing P3HT as well as its related semiconducting polymer segments.

Hydrogen-bonding interactions play an important role in the rational design of crystal systems with desirable architectures. The crystal structures of benzene-1,2-diaminium sulfate sesquihydrate, C6H20N2 2+·SO4 2−·1.5H2O, (1), benzene-1,3-diaminium tetrachloridozincate(II), (C6H20N2)[ZnCl4], (3), and 3-aminoanilinium perchlorate, C6H9N2 +·ClO4 −, (4), are reported. Hydrated salt (1) is a polymorph (space group C2/c) of a previously reported [Anderson et al. (2011). Cryst. Growth Des. 11, 4904–4919] crystalline modification of salt (2) (space group P21/c). The contents of the asymmetric unit of (2) are twice that of (1). In each, the extended structures exhibit hydrogen bonds, resulting in chains of ions and hydrogen-bonded rings with an R 4 4(8) motif involving water molecules. Hirshfeld surface analysis shows that a significant difference between the two is the degree of C...C interaction. Salt (3) exhibits an extended structure having hydrogen-bonded rings and parallel benzene rings, with a centroid-to-centroid separation of 3.860 (2) Å. Salt (4) displays a three-dimensional superstructure that results from linked planes of ions joined by an extensive hydrogen-bonding network involving N—H...O, N—H...N and C—H...π interactions. The cation–anion and N—H...N interaction energies in (4), determined using density functional theory (DFT), show significantly stronger aminium–perchlorate than amine–perchlorate interactions.

The effects of additives on the surface and cross-sectional morphologies of zinc deposits on iron substrate from alkaline zincate solution were characterized by scanning electron microscope (SEM). The cathodic reaction mechanisms under various concentrations of additives were investigated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques. It is found that with increasing the additive A content in the bath solution, the nucleation overpotential (NOP) value is obviously increased and the inhibition effect is strengthened. This may be mainly due to the adsorption of additive A on the cathodic electrode surface, which can cover the active sites and block the discharge reduction. The results of EIS analysis indicate that the rate-determining step of zinc electrodeposition process is changed from mixed control step into electrochemical reduction step in the presence of additive A. However, any quantity of additive B has little effect on the NOP value and the inhibition effect is not obvious. Furthermore, addition of additive A and additive B at the same time displays the strongest inhibition effect and shows a strong synergism because of their co-adsorption on the cathodic electrode surface.

A tapered-end flow Zn–air fuel cell (ZAFC), mechanically refuelable with Zn microspheres, was employed to study the effect of aging of KOH electrolyte on the Zn anode. A complete description of the architecture of the adopted cell is reported. The electrochemical characterization of the ZAFC was performed by long-term current discharge tests in galvanostatic mode. An insightful investigation on the particulate Zn anode consisting of spheres of diameter 0.4 mm was performed by means of X-ray diffraction (XRD), scanning electron microscope (SEM), and Raman spectroscopy in order to characterize the crystallographic structure, surface morphology, and chemical nature of residual metal and solid corrosion products. Electrochemical impedance spectroscopy (EIS) allowed to obtain information on the charge-transfer mechanism of zinc anode reaction and on the thickness, compactness, and blocking features of the passive film as a function of the aging of the electrolyte. The results of our analysis revealed the formation of a passive layer of zinc consisting of a white and porous film of ZnO precipitate (type I) and a light-gray to black compact film (type II). The failure of the particulate anode was chiefly caused by the increase in zincate concentration in the electrolyte, but it was enhanced by the nonuniform spatial current distribution due to the instability of the passive film at high pH.

Single crystals such as diammonium dibromodichloro calcinate(II), (NH4)2CaBr2Cl2, and diammonium dibromodichloro zincate(II), (NH4)2ZnBr2Cl2, abbreviated as DADBDC-Ca and DADBDC-Zn, respectively, were grown successfully by solution growth method. Single crystal X-ray diffraction, thermal analysis, AC conductivity; Fourier transform infra-red (FT-IR) spectroscopy, Differential scanning calorimetry were used to characterize the grown crystals. The surface morphology and chemical composition of the compound were analyzed by SEM and EDX studies. The cell parameters and crystallinity of the grown crystals were determined using single crystal and powder X-ray diffraction analysis. FT-IR spectra are used to confirm the presence of various functional groups in the sample. The phase transition of the sample was analyzed by differential scanning analysis. The electrical conductivity for the grown crystals has been calculated through impedance at various temperatures. It can be foreseen that the transition temperature reveals the ferroelectricity of the compound. The ferroelectric characteristics of the grown crystals have been studied by PE loop tracer.

Understanding zinc deposition during charging is important for the development of electrically rechargeable zinc-air batteries. For this purpose, the influences of cathodic overpotential and zincate concentration on zinc deposition in 6 M KOH solution were investigated by electrochemical and morphology characterization. When the zincate concentration is lower than 0.1 M, or the cathodic overpotential is more positive than −30 mV, the first charge-transfer reaction (Zn(OH)2 + e− → Zn(OH) + OH−) tends to be the rate-determining step. The second charge-transfer reaction (Zn(OH) + e− → Zn + OH−) becomes the rate-determining step at zincate concentration higher than 0.2 M and cathodic overpotentials larger than −50 mV. A low zincate concentration and small cathodic overpotential help suppress dendritic zinc deposition. These results will promote the performance of zinc anodes during the charging of zinc-air batteries. In this study, the influences of cathodic overpotential and zincate concentration on zinc deposition in 6 M KOH solution were investigated and the mechanism of zinc deposition under different conditions was revealed. From Fig. 4, we can easily determine the rate-determining step of zinc deposition in 6 M KOH solution corresponding with cathodic overpotential and zincate concentration.

Herein we report the successful fabrication of highly flexible, reversibly stretchable, transparent, and conductive poly(vinyl alcohol) (PVA) nanocomposite (NC) films with a hydrophobic surface by reinforcing varying amounts, viz., 0, 0.5, 1, 2, and 4 wt %, of calcium zincate (Ca0.2Zn0.8O) nanofillers. The developed nanocomposite films show appreciable UVA screening efficacies as established by a novel (UV-transillumination studies) method. The Fourier transform infrared (FTIR) studies reveal a positive interaction between PVA matrix and incorporated nanofiller, while scanning electron microscopic (SEM) studies support uniform filler dispersions. The electronic spectral studies substantiate the changes in electronic band structure of composite films leading to appreciable changes in the optoelectronic properties. The fluorescent emission studies reveal dopant-dependent photonic emissions, while the dielectric properties, such as dielectric constant (e′) and dielectric loss (e″), increase with an increase ...

A new kind of 3D hierarchical flower-like calcium zincate is successfully achieved by a simple microemulsion method. The obtained sample is constructed with many interconnected rhomboid calcium zincate nanosheets with a thickness of 80–100 nm. When served as anode active material for zinc-based battery, the as-prepared calcium zincate delivers superior high-rate properties and improved cycling stability. At 2, 5, 10, 15, 20C, the flower-like calcium zincate shows higher specific discharge capacities of ～297.7, ～254.6, ～232.5, ～202.8 and ～170.5 mAh g−1, respectively, which are significantly higher than those of the conventional hexagon and rhomboid calcium zincate. Especially, after 400 cycles at 1C/1C, the flower-like CZO achieves a capacity retention of 90.8%, whereas the values for the hexagon and rhomboid samples are only 70.2% and 54.7%, respectively. The pronounced high-rate and cycling properties are attributable to its unique 3D hierarchical flower-like structure and small particle size, which leads to the reduced charge transfer resistance, enhanced reversibility, and improved structural stability. Therefore, the proposed 3D hierarchical flower-like calcium zincate is promising anode material with excellent high-rate and cycling properties for advanced zinc-based rechargeable batteries.

Coordination of supramolecular assemblies was investigated by reacting a series of lanthanide cations (Ln3+) with an inverted cucurbituril (iQ[6]) in the presence of tetrachloride zincate anion [ZnCl4]2−, as an structure directing agent in aqueous HCl (3.0 mol/L). Single crystal X-ray diffraction analysis revealed that the coordination of iQ[6] with Ln3+ gave rise to different interaction products and isomorphous groups with increasing atomic number. The interaction of iQ[6] with La3+ and Ce3+ immediately yielded precipitations and single crystal solids containing Pr3+ and Nd3+. No solids resulted from coordination of iQ[6] with Sm3+ and Eu3+, whereas single crystals solids were obtained from coordination of iQ[6] with heavy Ln3+, such as Gd3+, Tb3+, Dy3+, Ho3+, Er3+, Tm3+, Yb3+ and Lu3+. Such coordination characteristics may offer a strategy for isolating a series of Ln3+ cations in patches.

Electroplating of Al on a Mg alloy using a dimethyl sulfone–aluminum chloride bath was studied. Although dense and uniform Al films were electrodeposited on the Mg alloy from the bath at 110 °C, the adhesion of the Al film was poor when the electrodeposition was carried out directly onto the bare alloy. Subjecting the Mg alloy to zincate pretreatment resulted in Al films with good adhesion. The adhesion strength of the Al films was measured using a pull-off test. The fractured interface was observed with SEM–EDX, which revealed that the Mg alloy substrate reacted with the bath before the electrodeposition of Al started. The reaction products formed on the substrate were detrimental to the adhesion of the electrodeposited Al film. Polarization curves measured for the Al-coated Mg alloy in a 3.5 wt.% NaCl solution at room temperature (25 °C) showed that the Al film electrodeposited from the DMSO2–AlCl3 bath can effectively prevent the Mg alloy from rapid corrosion.

Organophosphonate zincate corrosion inhibitor (CCDC 919565) contains the Zn-N bond closing three fivemembered chelate rings with the formation of a common bonding electronic subsystem of N-Zn-O-P atoms. Zinc is coordinated in a distorted trigonal bipyramidal configuration involving the oxygen atom of the neighboring molecule of the complex. Space group \(P\bar 1\), Z = 2, a = 11.2208(2) A, b = 11.2666(3) A, c = 12.3286(3) A, α = 108.455(2)°, β = 97.168(2)°, γ = 117.103(2)°. The inhibitor does not form polymeric structures, provides the stability and reproducibility of technological quality parameters. The initial decomposition temperature is 250 °C. The corrosion inhibition factor is 14.3 (GOST 9.502-82, steel grade 20, medium No. 2, static conditions, natural aeration, 10 days exposure).

An intermediate protective layer of Zn was formed on the AZ91D surface to prevent dissolution of the substrate surface and to obtain a uniform deposition layer of Al in an electroplating process from a molten salt bath. Simple zincate treatment did not result in the formation of a Zn layer with sufficient thickness and coverage for substrate protection. Electrodeposition of Zn was thus conducted after the zincating process to thicken the Zn layer. A Zn layer of a few μm in thickness sufficiently protected the AZ91D substrate. A uniform Al layer was then electrodeposited on Zn-protected AZ91D without degradation of the substrate. Since the Mg alloy surface and Zn surface were not sufficiently active for Zn deposition and Al deposition, respectively, Cu-nanoparticle predeposition was applied to each surface before the electrodeposition processes.

A series of CdTe thin film solar cells were prepared by applying aqueous solutions of ZnCl 2 or tetrachlorozincates M n ZnCl 4 (M = Na or NH 4 for n = 2; M = Mg or Ca for n = 1) as flux reagents in the activation process, instead of established but highly toxic CdCl 2 . The remaining process steps for the generation of solar cells have not been varied and activation-temperature and -duration were kept constant with 400 °C/25 min. The back contact comprised an etching step followed by deposition of ca. 150 nm gold. In contrast to Na 2 ZnCl 4 and (NH 4 ) 2 ZnCl 4 , the application of ZnCl 2 or CaZnCl 4 in 30% concentration gave promising results with current–voltage and quantum efficiency cell-data well comparable to CdCl 2 standard activated reference cells. The aqueous solutions were either applied manually by dip-coating or sponge roller procedure. Microstructural and interfacial investigations were performed with high resolution field emission scanning electron microscopy imaging on polished cross sections of ZnCl 2 - or CaZnCl 4 -derived devices using ion beam preparation techniques. Moreover, the measurement of the electron beam induced current was achieved, yielding a similar appearance for a CaZnCl 4 -activated substrate compared to referential CdCl 2 samples.

In this work, the effect of ZnO precipitation on the electrochemical cycling stability of Zn–air batteries was systematically investigated. The results suggest that sustained electrical rechargeability can be achieved by simply appropriately choosing the amount of Zn metal anode, such that the amount of zincate ions released into the electrolyte upon full discharge of the anode is below the supersaturated solubility limit. For example, there was almost no capacity fading up to 50 cycles when the anode was designed such that the amount of zincate ions released into the electrolyte was a bit less than the chemical solubility limit of ZnO in KOH solution. Despite its limited energy density, the results presented in this study provide an important direction to the future work on electrically rechargeable Zn–air batteries.

This study focuses on the electrochemical behavior of brass in acidic and alkaline tap water. Both conditions were studied using corrosion potential, cyclic polarization and electrochemical impedance spectroscopy. Weight loss experiments were also performed to validate corrosion behavior. It was evaluated from corrosion potential values and Pourbaix diagrams that brass surface was aggressively attacked at low pH due to dissolution of zinc-rich phase and solvation of cuprite and zincate at high pH by breakdown of the passive film. Under near neutral conditions the increase in charge transfer resistance corresponded to formation of a stable passive film. Brass exhibited peculiar behavior at pH 1 and 12 by showing low charge transfer resistance due to preferential attack of zinc and solvation of copper/zinc rich phases, respectively, as validated by impedance spectroscopy.

We report herein the synthesis, crystallographic analysis and a study of the noncovalent interactions observed in the new 4′-substituted terpyridine-based derivative bis[4′-(isoquinolin-2-ium-4-yl)-2,2′:6′,2′′-terpyridine-1,1′′-diium] tris[tetrachloridozincate(II)] monohydrate, (C24H19N4)2[ZnCl4]3·H2O or (ITPH3)2[ZnCl4]3·H2O, where (ITPH3)3+ is the triply protonated cation derived from 4′-(isoquinolin-4-yl)-2,2′:6′,2′′-terpyridine (ITP) [Granifo et al. (2016). Acta Cryst. C72, 932-938]. The (ITPH3)3+ cation presents a number of interesting similarities and differences compared with its neutral ITP relative, mainly in the role fulfilled in the packing arrangement by the profuse set of D - H...A [D (donor) = C, N or O; A (acceptor) = O or Cl], π-π and anion...π noncovalent interactions present. We discuss these interactions in two different complementary ways, viz. using a point-to-point approach in the light of Bader's theory of Atoms In Molecules (AIM), analyzing the individual significance of each interaction, and in a more 'global' analysis, making use of the Hirshfeld surfaces and the associated enrichment ratio (ER) approach, evaluating the surprisingly large co-operative effect of the superabundant weaker contacts.The structural analysis of the terpyridine-based compound (ITPH3)2[ZnCl4]3·H2O [(ITPH3)3+ is the triply protonated cation of 4′-(isoquinolin-4-yl)-2,2′:6′,2′′-terpyridine] demonstrates the concerted way in which a variety of noncovalent interactions, viz. hydrogen bonding, π-π and anion...π, participate in the crystal packing. An unexpected large enrichment ratio between the cationic C...N contacts can be understood in the light of their correlation with the atomic and ring NBO (natural bond order) charges. Fil: Granifo, Juan. Universidad de La Frontera; Chile Fil: Suarez, Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentina Fil: Boubeta, Fernando Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentina Fil: Baggio, Ricardo Fortunato. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; Argentina

Modified alloy zincate (MAZ) is a surface-treatment process for depositing Zn on Al by galvanic displacement reaction prior to application of functional coatings. Two-step zincating i.e. double zincating (DZ) is a preferred technique in comparison to single zincating (SZ) because of imparting excellent adhesion of coatings on Al. Prior to second step of zincating during DZ, the single zincated Al substrate undergoes nitric dissolution. In this study, the intriguing role of this nitric acid etching on second step nucleation and growth of Zn has been investigated in detail. For this, time dependent Zn-nucleation and growth morphology on Al surface was monitored by AFM and FESEM examinations and revealed scattered but coarse nucleation during SZ; and finer nucleation along with uniform coverage of Zn during DZ. Post single zincating, nitric acid etch led to generation of micro/nanoporous Al surface as revealed by microscopic investigations. The porous Al surface along with trace amount of noble metals such as Cu and Fe was found to play significant role on Zn root growth into Al matrix and fine grain Zn deposit on top surface confirmed by cross-section FESEM analysis of focused ion beam (FIB) cut Zn/Al sample. Rutherford Backscattering Spectroscopy (RBS) was used as a non-destructive technique to estimate Zn film thickness and growth rate. The observed Zn nucleation and growth results were further substantiated by analyzing the open circuit potential (OCP) data during zincating. Difference in nucleation and growth pattern of Zn on Al surface during SZ and DZ was fundamentally understood with the help of classical nucleation theory and galvanic kinetics.

Regioregular poly(3-hexylthiophene) (P3HT) has been a commonly used p-type semiconducting material for solution processable organic electronics. To establish a living system of “Negishi-type catalyst-transfer polycondensation (NCTP)” using zincate complex as a synthetic method for well-defined P3HT having predictable molecular weight (MW) and low dispersity (Đ), the ligands of Ni catalyst were optimized. As a result, a ligand of 1,2-bis(dicyclohexylphosphino)ethane produced P3HTs with highly controlled number average MWs (1650–32,800) and very low Đ values (1.03–1.17). The polymerization results were strongly influenced by steric hindrance based on the factors of cone angle and bite angle of Ni catalysts, and/or electron-donating ability of phosphine ligands. In addition, we succeeded in the two-stage polymerization of P3HT and the synthesis of P3HT-b-poly(3-octadecylthiophene), the latter of which is the first demonstration by NCTP using zincate complex. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 2287–2296

This paper reviews the development of zincate-complex metathesis polymerization (ZCMP) and its application to protection-free direct synthesis of poly(3-(6-hydroxyhexyl)thiophene) as well as block copolythiophene. The modified ZCMP system using Ni(dcpe)Cl2 as a catalyst accomplished the preparation of well-defined poly(3-hexylthiophene)s (P3HTs) (Mn up to 35 000 g mol−1) with extremely low PDI (1.03∼1.11). In addition, the first example of all-conjugated block copolythiophene, P3HT-b-poly(3-octadecylthiophene), could be synthesized on the basis of the sequential monomer addition approach based on ZCMP.

We report the reaction of a sterically congested NHC–Zn(CH2CH3)2 Lewis adduct (1) prepared through reaction of an equimolar ratio of 1,3-di-tert-butylimidazol-2-ylidene and diethyl zinc, with various substituted phenols (4-tert-butyl-phenol, 2,6-di-tert-butyl-4-methyl phenol, and 1-bromo-4,6-di-tert-butyl phenol). The NHC–Zn dative bond was cleaved in each of the reactions with the substituted phenols to afford the corresponding ionic complexes of imidazolium cation and aryloxo-zincate, [{(4-CMe3C6H4O)2Zn(μ-OC6H4-4-CMe3)}2{(1,3-(CMe3)2-ImCH}2] (2), [{(2,6-(CMe3)2-4-Me-C6H3O)2}Zn{(1,3-(CMe3)2-ImCH}] (3), and [{(1-Br-3,5-(CMe3)2C6H2O)2}2-Zn{(1,3-(CMe3)2-ImCH}] (4), where 1,3-(CMe3)2-ImCH) is imidazolium carbocation. The molecular structures of 1–4 were established by X-ray diffraction analyses and from the solid-state structures of 2–4, it was confirmed that, in all the compounds, zinc ions are coordinated through substituted phenolate groups.

Cyclic voltammetry of zinc plated from flowing alkaline zincate electrolyte with a bismuth additive showed a marked mass transport effect during metal layer deplating. This bismuth was added as Bi2O3 and had a saturated concentration of 26 ppm bismuth. Using a small, transparent window flow cell the mechanism was studied in situ using synchrotron X-rays. X-ray microdiffraction revealed that the metal-electrolyte interface was bismuth rich, and bismuth behaved in a manner similar to a surfactant. Transmission X-ray microscopy revealed that in the presence of bismuth additive, 5 μm raised features on the metal layer were preferentially dissolved during deplating. However, macro-morphology experiments demonstrated that at 26 ppm a detrimental bismuth buildup occurred over many cycles. By reducing additive concentration to 3 ppm a metal layer was planarized compared to a no-additive control, while avoiding the bismuth buildup. These findings suggested that 3 ppm bismuth could be used to planarize zinc metal layers such as those in flow-assisted zinc batteries. However, concentration will need to be well-controlled.

Two different types of interlayers were produced on aluminum alloy specimens prior to electroless nickel coating in an attempt to improve the structure and adhesion of such coatings to aluminum substrates. The amorphous Ni-P layer of medium phosphorous content was deposited on 3004 aluminum alloy sheet either without interlayer or over an interlayer of a zinc coating (zincate process) or an oxide coating (anodizing process). Formation of the nickel electroless coating and the effect of heat treatment were evaluated by x-ray diffraction (XRD) and microanalysis (EDS). The surface morphology and topography of the coatings were characterized by scanning electron microscope (SEM) and atomic force microscope (AFM). Adhesion of the coatings to aluminum substrate was qualitatively evaluated by the bend test. It was observed that application of a nano-porous aluminum anodic oxide as an interlayer caused a much finer morphology of Ni-P electroless coating. In addition, this interlayer effectively increased the adhesion of coating to aluminum surface; the crack density calculated after the bend test was about four times that obtained in the specimen with zincate interlayer and six times more than without interlayer.

Ni–P alloys with 7 wt% to 10 wt% phosphorus were deposited by sodium hypophosphite onto industrially pure aluminum substrates after different pretreatments. Two nickel immersion pretreatments (NIPs) were tested prior to electroless Ni–P plating, and their effects on the corrosion properties of the Ni–P alloy layers were evaluated using polarization curves and electrochemical impedance spectroscopy. The surface morphology and chemical composition of the Ni–P coatings were investigated by scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction analysis. Both proposed NIPs were found to improve the corrosion resistance. Thus, a double NIP method similar to the double zincate treatment method was developed. The alloy layer pretreated by this developed method showed the highest corrosion resistance, which can be mainly attributed to the high phosphorus content and low microporosity.

This paper deals with synthesis of ZnO nanoparticles through two different baths: Ammonium zincate bath and sodium zincate bath. Synthesized ZnO nanoparticles were characterized by means of TG/DTA, FTIR, UV-vis, XRD, and FESEM. ZnO nanoparticles were then mixed with commercial TiO2 in various percentage (3 wt%, 5 wt%, 10 wt%) and lead free thick films were prepared. XRD analysis for the films reveals presence of ZnO, Zn2TiO4 and TiO2. SEM analyses show that presence of larger amount of Zn2TiO4 and higher surface to volume ratio in 10 wt% TiO2 added ZnO films are the primary reason for higher sensitivity.

Zinc–Magnesium (Zn–Mg) alloys have been addressed as potential biodegradable biomaterials. These alloys enable to overcome the main drawbacks of Mg, its high corrosion rate and hydrogen evolution. Moreover, homogeneous corrosion degradation is also an interesting issue to ensure the success of load-bearing biodegradable implants. In this work, two directionally solidified dilute alloys, Zn-0.3wt-%Mg and Zn-0.5wt-%Mg were studied. Both alloys having different microstructural morphologies (cellular and dendritic arrays) depending of the distance to the cooling bottom were evaluated to correlate their microstructural features with corrosion properties. Kinetics and corrosion mechanism have been evaluated by means of DC and AC electrochemical techniques in low chloride containing solution, 0.06 M NaCl. Coarser microstructures are shown to promote higher corrosion rate. Like Zn the corrosion mechanism occurs throughout a multistep dissolution process involving the formation of intermediate monovalent Zn, and soluble zinc hydroxychloride compounds resulting of the reaction of zincate ions with chloride ions., The authors acknowledge the financial support provided by FAPESP- São Paulo Research Foundation, Brazil (grants 2012/16328-2; 2013/15478-3; 2013/23396-7; 2014/50502-5), CNPq - The Brazilian Research Council, CAPES and CSIC-Spanish National Research Council (Project i-link0944).

The effect of alloying elements and the generation of hydrogen gas during zincate treatment and electroless nickel-phosphorus plating were studied by electron microscopy. Hydrogen gas was vigorously evolved during the zincate treatment for binary Al-2at%Mg and Al-2at%Si alloys, and the zincated surfaces were nonuniformly covered with excess coarse zinc particles due to the continuing oxidation of the substrate and reduction of proton and zincate ions. On the other hand, the surfaces of the ternary Al-2at%Zn-0.2at%Mg and Al-2at%Zn-4.5at%Mg alloys were immediately covered with a thin and uniform film of zinc. Magnesium in aluminum alloys and the excess precipitation of zinc were found to lower the adhesion of the electroless nickel-phosphorus plated films. When the zincated Al-2Mg and Al-2Si alloys were immersed in the plating solution, dissolution of the excess zinc generated hydrogen gas, and the plated films were poorly adhered to the substrates. Despite the thin and uniform zincate film, the plated film on the Al- 2Zn-4.5Mg alloy was easily peeled off due to the voids formed between the plated film and the substrate. Magnesium in the alloy may suppress precipitation of the nickel and accelerate generation of hydrogen gas at the beginning of the plating. (doi:10.2320/matertrans.M2014385) Aluminum alloys are indispensable in reducing the weight of automobiles and electronic equipment, and improvement of their properties and addition of functions by surface modification are required as well as improvement of their strength and workability by controlling the micro- structure. Wet surface modification, such as electroplating and electroless plating, is applied especially when the surfaces need to be corrosion resistive, wear resistive and show improved appearance or electromagnetic properties. However, since the surfaces of aluminum alloys are protected by a stable passivation film, activation by acid or alkaline solutions and inhibiting passivation to keep the surfaces active are indispensable prior to plating. For this purpose, zincate treatment, in which the surface of the aluminum alloys are covered by a zinc film formed by a conversion reaction between the metallic aluminum and zincate ion in an alkaline solution, is commonly used prior to plating. In previous reports, 1,2) it was shown that the formation mode of zincate films during zincate treatment was significantly affected by aluminum alloying elements such as manganese, iron, copper and zinc. The effect of the typical alloying elements (zinc, magnesium and silicon) on the zincate treatment and electroless nickel-phosphorus plating, and the generation of hydrogen gas during the sequence were investigated in this study. The electroless nickel-phosphorus plating will be described simply as 'plating' in the following sections. 2. Experimental Binary aluminum alloys, which contain 2.0at% magne- sium or silicon, and ternary alloys, which contain zinc and magnesium, were used as substrates for the zincate treatment and plating. The concentration of zinc in the ternary alloy is 2.0at%, and that of magnesium is either 0.2 or 4.5at%. The content of magnesium (4.5at%) in the ternary alloy is the same as that in the cast alloy for automobile wheels which was discussed in a previous report. 3) The alloys are described as 'Al-2Mg', 'Al-2Si', 'Al-2Zn-0.2Mg', 'Al-2Zn-4.5Mg' in the following sections. Ingots of these alloys were obtained by casting the molten alloys into a steel mold as previously reported, 2) then the ingots were homogenized in still air. The homogenizing temperatures for the Al-2Mg, Al-2Si, Al-2Zn- 0.2Mg and Al-2Zn-4.5Mg were 573, 823, 703 and 703K, respectively. The ingots were cooled in water immediately after the homogenizations for 173ks, then sliced and polished to a mirror-like surface with waterproof silicon carbide abrasive papers and loose abrasive of 1µm diamond. The polished surfaces were used for evaluation of the zincate treatment and plating. The zincate treatment and plating were conducted follow- ing the procedure in a previous report. 2) After pretreatment by alkaline degreasing and activation by nitric-hydrofluoric acid, the substrate was immersed in a zincate solution as the first zincate treatment. The zinc film was then removed by nitric acid, and the second zincate treatment was conducted. A solution of sodium hydroxide and zinc oxide was used for the zincate treatment in order to increase the amount of

Electrodeposition behavior of Zn-Ni alloys was investigated at current densities of 5-500 A•m -2 and a charge of 5 × 10 4 C•m -2 at 308 K in an unagitated zincate solution containing ethylenediamine (EDA), which forms a stable complex with Ni 2+ ions. In the case of the TEA solution, the Zn-Ni alloy exhibited normal codeposition at low current densities, wherein electrochemically more noble Ni deposited preferentially, while it exhibited anomalous codeposition at high current densities, wherein less noble Zn deposited preferentially. In the EDA solution, the alloy exhibited anomalous codeposition at high current densities; on the other hand, even at low current densities, the Ni content in the deposit was almost identical with the composition reference line, showing a behavior similar to anomalous codeposition. In the EDA solution, Ni deposition and H 2 evolution were significantly suppressed over a larger region of current densities, showing the formation of an inhibitor for deposition, which results from Zn 2+ ions in the cathode layer. The dependence of the current efficiency for alloy deposition on the current density was smaller in the EDA solution than in that containing TEA. In the TEA solution, the underpotential deposition of Zn apparently occurred with Ni, while in the EDA solution, the underpotential deposition of Zn never occurred, because Ni deposition was suppressed by the coexistence of Zn 2+ ions even at low current densities. The throwing power of Zn-Ni alloys in the EDA solution was better than that in the TEA solution.

Tetrathiourea cadmium tetrathiocyanato zincate (TCTZ) has been synthesised by the chemical reaction method. The solubility of the synthesised material was determined in water, acetone and water–acetone mixed solvents. Based on the solubility studies, the single crystals of TCTZ were grown from the 3:1 water–acetone mixed solvent by the solvent evaporation method. The crystallinity of the grown crystals was proved from the powder XRD data. TCTZ was found to crystallise in tetragonal symmetry with non-centrosymmetric space group I¯4. The presence of functional group and the coordination of the metal with the ligands were proved from the FTIR studies. The compound exhibits good physicochemical stability up to 182 °C. The UV transparency cut off wavelength of TCTZ was found to be 290 nm and the complex is transparent (69%) over the entire range of visible region showing that it is a good candidate for NLO applications. The growth feature of the TCTZ single crystals was observed by etching studies, which reveals the formation of layer growth pattern. The mechanical property of the crystal was estimated by Vickers hardness test.

Adhesive strength of Al coatings electrodeposited on AZ91D in aluminum chloride/1-ethyl-3-methylimidazolium chloride was improved by the development of a zincate pretreatment and optimized current pulse electrodeposition method. A dense Zn layer was deposited on both the α- and β-phase surfaces of AZ91D substrate pre-treated in a Cu 2+ added activation bath prior to the zincate process. On this zincated substrate an Al coating was electrodeposited by bipolar current pulse polarization and the adhesive strength of the Al coating to the substrate was better than 11 MPa. The Al coating obtained under the optimal condition also showed good corrosion resistance in 3.5 wt.% NaCl solutions.

A detailed kinetic investigation and activation parameters are reported for copper catalyzed coupling reaction of mixed zincate, n-BuPh2ZnMgBr and homozincate, Ph3ZnMgBr with n-pentyl bromide in THF at 25-65 degrees C. An empirical rate law can be expressed as rate = k[zincate](0) [alkyl bromide](1) [CuI](1). The reaction rate of transferable phenyl group in mixed catalytic cuprate, n-BuPhCuMgBr derived from mixed zincate is higher than the rate of catalytic homocuprate Ph2CuMgBr derived from homozincate. A catalytic cycle and the mechanism which accommodates the kinetic data and activation parameters is given. These results show that the reaction rate of transferable group changes depending on the residual group in the reactions of mixed diorganocuprates and also provide a kinetic support for the commonly accepted hypothesis regarding the dependence of the R-1 group transfer ability on the strength of R-2-Cu bond in reactions of (RRCuMgBr)-R-1-Cu-2 reagents. (C) 2011 Elsevier B.V. All rights reserved.

The controlled synthesis of head-to-tail regioregular poly(3-hexylthiophene) (P3HT) using a dianion-type zincate complex, tBu4ZnLi2, is described. The molecular weights of P3HTs could be increased up to 30 kDa by increasing the feed ratio of the monomer to Ni catalyst while maintaining a low polydispersity (PDI 97%, when Mn > 10 kDa). Surprisingly, this new system can be used in as-received THF as well as in THF containing protic impurities, such as isopropanol, methanol, and even 1000 ppm water. In addition, the direct synthesis of poly[3-(6-hydroxyhexyl)thiophene] (P3HHT) could be performed without protection based on the developed system.

An ionic metal–dithiolene complex, 1,1'-didecyl-4,4'-bipyridinium bis(maleonitriledithiolato)zincate(II) ([Zn(mnt)2]2−), was synthesized and characterized by elemental analysis, infrared spectroscopy and crystal structure. In the [Zn(mnt)2]2− moiety, the complex shows distorted tetrahedral geometry with Zn2+ coordinated to four S-atoms from two mnt2− ligands, and its long molecular axis adopts a similar orientation with 1,1'-didecyl-4,4'-bipyridinium. Two distinguishable redox processes occur in the voltage region of − 1.0 to 1.0 V, with the irreversible and reversible redox couples corresponding to [Zn(mnt)2]2−/[Zn(mnt)2] − and 1,1'-didecyl-4,4'-bipyridinium +/1,1'-didecyl-4,4'-bipyridinium2+, respectively. An uncommon nematic mesophase behavior in this complex was confirmed by polarized-light optical microscopy (POM) and differential scanning calorimetry (DSC) measurements.

Four new compounds of the general formula: (Ph4P)2[Zn(RSO2N CS2)2] where Ph4P = tetraphenylphosphonium cation, R = 4-FC6H4 (1), 4-ClC6H4 (2), 4-BrC6H4 (3) and 4-IC6H4 (4), were obtained by the reaction of the appropriate potassium N-R-sulfonyldithiocarbimate (RSO2N CS2K2) with zinc(II) acetate dihydrate in dimethylformamide. All compounds crystallize in the centrosymmetric space group of the triclinic system. The compounds 2, 3 and 4 are isostructural but compound 1 crystallizes as hemihydrate. The elemental analyses and the IR, 1H NMR and 13C NMR data for 1–4 are consistent with the formation of bis(dithiocarbimato)zinc(II) complexes. These compounds are active against the phytopathogenic fungus Colletotrichum gloeosporioides.

Cu was electrodeposited on AZ91 D Mg alloy with zincate pretreatment in an alkaline plating bath, and the effect of zincate pretreatment on adhesion strength of the Cu layer was investigated. Scanning electron microscopy results showed that Zn was mainly deposited on the α-phase surface, and ultrasonic agitation at the initial stage of the zincate pretreatment improved the coverage of the Zn layer even on the β-phase surface, resulting in enhancement of the adhesion strength of the Zn layer and the successive Cu layer to the substrate. Adhesion tests revealed that the plating layer peeled off at the mixed layer of Zn and Cu deposits formed at the interface between the zincated layer and the electrodeposited Cu layer. A smooth Cu surface was obtained in the plating bath containing H 3 BO 3 .

A polymeric chelate based on salicylidene-o-aminophenol (SAP) chelating with zinc (Zn(II)) ion was studied by several spectroscopic techniques. A simple, rapid and sensitive method for the spectrophotometric determination of trace amounts of Zn(II) ion in solution by chelating with SAP is proposed. This method has been applied successfully to the determination of Zn(II) ion in Immu-C sachets samples (mg/g). The proposed method is in excellent agreement with the determination of Zn(II) ion by atomic absorption spectrometry.

The effects of zinc oxide and/or polyethylene glycol (PEG) as electrolyte additives on the corrosion and electrochemical performances of pure aluminum in 4.0?M KOH solutions were investigated by means of hydrogen collection, polarization curve, galvanostatic discharge, scanning electron microscopy (SEM), and energy dispersive analysis of X-ray (EDAX). The addition of ZnO markedly inhibited the corrosion of aluminum in 4.0?M KOH solutions, resulting from the deposition of zinc with high hydrogen evolution overpotential in aluminum surfaces. The introduction of PEG in the alkaline zincate solution obviously improved the deposition of zinc by increase in the overpotential of zinc deposition, thus the corrosion rate of aluminum in the alkaline zincate solutions with PEG was further decreased. The enhancement effect of PEG on the inhibition of zinc oxide first increased and then decreased with increasing the content of PEG in the electrolyte. The electrolyte system with 0.2?M ZnO and 2.0?mM PEG presented the highest inhibition efficiency (98.8%) for the corrosion of aluminum. The results of galvanostatic discharge indicated that the aluminum anode shows excellent discharge performances in the 4.0?M KOH solution with 0.2?M ZnO and 2.0?mM PEG.