Zn Core Research Articles

Microencapsulation of Zn-10 mass% Al alloy phase change material via dry synthesis method

Thermal energy storage (TES) via latent heat storage (LHS) using metal alloy phase change material (PCM) offers advantages in medium-to-high temperature operation around 400 °C and high heat storage capacity. Microencapsulation of alloys as PCMs can mitigate issues of reactivity and improve handling properties of PCM. This research presents the novel development of microencapsulated PCM (MEPCM) with a core of Zn–10 mass% Al that operates around 400 °C. The MEPCMs were synthesized using high-speed impact blending (HIB), where fine AlOOH particles mechanically coat the surface of Zn–10 mass% Al alloy microspheres, resulting in robust surface modification. Subsequent heat-oxidation treatment at 800 °C was performed to obtain stable oxide coating. The HIB treatment resulted in an AlOOH coating containing Zn nanoparticles, which the heat-oxidation process transformed into α-Al2O3 and ZnO nanoparticles. The MEPCMs exhibited heat storage densities, including latent and sensible heat (ΔT=200 °C), that were 1.9 times higher than the capacity of solar salt, which is commonly used as a sensible heat storage material. Furthermore, the MEPCMs maintained their shape and latent heat capacity after 300 and 1000 cyclic tests. These superior MEPCM characteristics hold the potential to significantly advance the development of LHS-based TES systems operating around 400 °C, with applications in energy generation and industrial processes.

Revealing the activity of inert Zn-based ZIF-L/aerogel composites in Fenton-like catalysis: Electron-deficient N ([sbnd]C[dbnd]N[sbnd]C) triggering 1O2 evolution

The inertness of Zn with fully occupied 3d10 configurations makes original Zn-based MOFs inactive, which are rarely reported in Fenton-like reactions. Herein, the prepared ZIF-L (Zn) was immobilized on foaming gelatin aerogel to fabricate composite catalysts (ZIF-L/FGA150) for PMS-based Fenton-like reactions. Unexpectedly, ZIF-L/FGA150 exhibited high Fenton-like activity in activating PMS for antibiotic norfloxacin (NOF) removal, by which over 99 % NOF could be degraded in 30 min. 1O2 was proved to be the sole contributor to mediating the non-radical oxidization process without the participation and evolution of free radicals. Mechanism investigation further revealed that the uncoordinated N (CNC) at edge 2-methylimidazole bonding with one Zn core were electron-deficient as a result of the deviation of electron density towards Zn-N4 coordination, and the electron-deficient N were identified as the active sites responsible for triggering electron transfer from the nucleophilic peroxy bonds of PMS accompanied by PMS decomposition into SO5− to generate singlet oxygen (1O2), thus driving NOF degradation. Owing to the 1O2-mediating non-radical oxidization, ZIF-L/FGA150 possessed high Fenton-like activity, unaffected by the interference of various environmental factors and in multiple actual water matrixes. This work might provide a novel insight into the reactivity of Zn-based MOFs in Fenton-like catalysis and develop an effective approach for antibiotic remediation.

Electrochemically structured tantalum surfaces via anodization for core-shell nanostructures: Optimization and characterization of Zn-ZnO nanoparticle deposition using magnetron sputtering

This study explores the electrochemical anodization of tantalum surfaces to create nanostructured substrates for the deposition of Zn-ZnO nanoparticles (NPs) through magnetron sputtering. The anodization process, conducted at different potentials (25 V and 50 V), resulted in tantalum surfaces with distinct dimple structures. The formation of these nano-level dimples is attributed to the dynamic equilibrium between the continuous formation and dissolution of the anodic TaOx layer. The dimple diameter is observed to increase with applied potential, correlating with the dissolution rate of the anodic oxide. The NP deposition parameters were studied in two steps. First, the effect of the deposition conditions on the nanoparticle size and distribution was evaluated and optimized on silicon substrates. Second, the conditions that resulted in the optimum size and distribution of the nanoparticles were utilized in tantalum substrates and evaluated to which extent these conditions were reproduced onto the anodized Ta substrate. Comparisons of Zn-ZnO nanoparticle depositions on silicon and tantalum substrates reveal similar island growth trends, with differences in nanoparticle size and distribution attributed to substrate properties. Further investigation involves anodized tantalum substrates with varying dimple sizes, and deposition conditions are adjusted with bias voltage, pressure, and deposition time to control nanoparticle characteristics. Characterization of the Zn-ZnO nanoparticles deposited on anodized tantalum surfaces is performed using scanning electron microscopy, high-angle annular dark-field scanning transmission electron microscopy, and energy-dispersive x-ray spectroscopy. The resulting core-shell structures are confirmed through structural analysis, revealing a core of hexagonal close-packed Zn and a shell of ZnO. The study demonstrates the influence of substrate properties and deposition conditions on the morphology and composition of Zn-ZnO nanoparticles, providing insights for applications in nanoelectronics and catalysis.

Synthesis, structure, and catalytic performance of solvent induced zinc clusters in furan synthesis by cycloisomerization reaction

Two Zn(II) clusters were synthesized by the reaction of Zn(OAc)2·2H2O and 1,2‐bis(2‐hydroxy‐3‐methoxybenzylidene)hydrazine as a N2O4‐donor Schiff base ligand in 1:3 molar ratio. The reaction in methanol gave yellow‐brown needle crystals, while block yellow crystals were achieved in a mixture of methanol:water (50:50 v/v). Investigation of the crystals by single crystal X‐ray analysis showed that solvent has considerable effect on the structure and composition of the products. In methanol, two independent pentanuclear Zn(II) clusters with the same general formula of [Zn5(L)2(μ‐OAc)4(OAc)2(CH3OH)2] but different coordination environments around Zn(II) cores, and bridging mode of the acetate ligands are present in the unit cell. In a mixture of methanol:water, a pentanuclear cluster and a 1D coordination polymer with pentanuclear repetitive unit are simultaneously present in the crystal structure. These compounds were further characterized by spectroscopic techniques, and they were used as catalysts for intramolecular cycloisomerization of 1,4‐diphenylbut‐3‐yn‐1‐one. The results indicated that these Zn(II) clusters can efficiently produce 2,5‐diphenylfuran through catalytic cycloisomerization reaction.

Comparison of neuroprotective effects of a topiramate-loaded biocomposite based on mesoporous silica nanoparticles with pure topiramate against methylphenidate-induced neurodegeneration.

Methylphenidate (MPH) abuse has been criticized for its role in neurodegeneration. Also, a high risk of seizure was reported in the first month of MPH treatment. Topiramate, a broad-spectrum Antiepileptic Drug (AED), has been used as a neuroprotective agent in both aforementioned complications. Nanotechnology is introduced to increase desirable neurological treatment with minimum side effects. We aimed to investigate the potential neuroprotective activity of topiramate loaded on nanoparticles. MTT assay was performed to evaluate the cellular cytotoxicity of Mesoporous Silica Nanoparticles (MSN). Male rats were randomly divided into eight groups. Rats received an intraperitoneal (i.p) MPH (10mg/kg) injection and a daily oral dose of topiramate (TPM, 30mg/kg), MSN with Zn core (10 and 30mg/kg), and MSN with Cu core (10 and 30mg/kg) for three weeks. On day 21, a seizure was induced by a single injection of pentylenetetrazole (PTZ) to evaluate the protective effects of TPM-loaded nanoparticles on seizure latency and duration following MPH-induced neurotoxicity. Moreover, the hippocampal content of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), malondialdehyde (MDA), and the anti-oxidant enzymes (SOD, GPx, and GR) activities were assessed. Also, BAX and Bcl-2 as two main apoptotic markers were evaluated. MPH neurotoxicity was observed as a raised duration and reduced latency in PTZ-induced seizure. However, TPM-loaded MSN with Zn species (NE) treatment reduced the duration and improved the latency time. Also, NE and, somewhat, TPM-loaded MSN with Cu species (NM) administration reduced inflammatory cytokines, MDA, and Bax levels and increased activities in the rat hippocampus. TPM-loaded nanoparticles could be used as neuroprotective agents against MPH-induced neurodegeneration by improving seizure parameters and reducing inflammatory, oxidant, and apoptotic factors.

A cancer cell and lysosome dual-targeted photosensitizer for fluorescence imaging and photodynamic therapy

A novel cancer cell and lysosome dual-targeted photosensitizer (PS) termed by BMP was developed for fluorescence imaging and photodynamic therapy (PDT). BMP consists of a porphyrin(Zn) core with appropriate singlet-triplet state distribution enables it to function as an imaging agent as well as a PS, a biotin moiety that can target cancer cells, and a morpholine group specific to lysosomes. Intracellular experiments demonstrated that the dual-targeted photosensitizer BMP could preferably accumulate in cancer cells and subsequently locate within lysosome organelles. Upon irradiation, BMP could generate red fluorescence emission (Φem = 6.3%) and singlet oxygen (1O2, ΦΔ = 55%) for the dual functionality of cell imaging and PDT, respectively. Notably, BMP exhibited much higher photocytotoxicity toward cancer cells (A549 cells) compared to normal cells (BEAS-2B cells). Importantly, 1O2 produced by BMP induced oxidative damage of lysosomes, and subsequently triggered cell death of A549 cells, as evidenced by the loss of morphological integrity and cell rupture.

Characterizing Distribution and Morphology of ZnO Discharge Products in Commercial Alkaline Zn-MnO2 Batteries

During the discharge of alkaline Zn-MnO2 batteries, the dissolution of Zn particles in the anode saturate the electrolyte with zincate, prompting the formation of solid ZnO. Zincate is highly mobile in the electrolyte, giving rise to complex spatial distributions and morphologies of ZnO discharge products. The passivating behavior of ZnO is dependent on its distribution and morphology, as the active Zn particles within the anode must maintain a connection with the electronic network, while also having access to hydroxide ions from the electrolyte.1 Therefore, characterizing the factors that impact ZnO formation is critical to understanding how battery performance is impacted.2 Past attempts to model these batteries fail to adequately predict the behavior of Zn anodes under discharge conditions aimed at simulating real-world use cases.3 This work seeks to better characterize the behavior of Zn anodes in an effort to improve modeling capabilities based on experimental results.4 High resolution synchrotron CT was used to create in situ volumetric reconstructions of anodes from commercial AA and AAA batteries to determine ZnO morphology and radial distribution at various discharge conditions. Through a novel segmentation algorithm, quantitative data show a shift in ZnO radial distribution and microporosity depending on the rate and depth at which the anodes were discharged. High rate discharge leads to ZnO formation preferentially near the separator with a lower microporosity, increasing its passivating characteristics. Microporosity calculations show the discharge products form in two types, namely type I ZnO and ZnO hydrate. The latter type had only ever been reported on planar electrodes, yet it has a significant presence in commercial alkaline batteries discharged under certain conditions.4,5 In addition to a decreased microporosity, the morphology of ZnO also showed increased passivating characteristics when discharging using a continuous protocol. Shells of ZnO form around undischarged Zn cores during a continuous discharge, restricting hydroxide transport to the Zn surface and potentially isolating the core from the electronically conductive Zn network. When using a pulsed discharge protocol, ZnO formed distributed regions of microporous ZnO not adhered to undischarged Zn surfaces, leaving the remaining Zn in good contact with the electrolyte. Developing a more robust understanding of the factors that impact ZnO formation will enable more advanced models to be created. Acknowledgements This research was supported by funding from Energizer Holdings, Inc. We acknowledge collaborators Xiaotong Chadderdon, Matthew Wendling, Andrew Chihpin Chuang, and John Okasinski. This research also used resources of the Advanced Photon Source beamline 6-BM, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357.

Discharge intermittency considerably changes ZnO spatial distribution in porous Zn anodes

Porous Zn anodes are ubiquitous in primary batteries and are under development for low-cost rechargeable batteries. Spatial distribution of ZnO discharge product is a critical factor in these, because it can passivate the active material. In rechargeable cells this is related to a major failure mechanism called shape change, in which ZnO is relocated to inactive locations. In this work we demonstrate rest steps during discharge of primary Zn anodes dramatically alter the placement of ZnO in the anode. In alkaline electrolyte, ZnO discharge product is typically modeled as precipitating close to Zn particles, forming a porous ZnO shell around the Zn core. Anodes discharged continuously at low-rate are compared to anodes similarly discharged intermittently, using in situ computed tomography from a synchrotron source. Zn–ZnO core-shell structures are produced during continuous discharge but are not found in cells discharged intermittently. Continuously discharged cells showed that ZnO was formed most strongly near the separator, in agreement with Zn anode battery models. In pulse-discharged cells, ZnO was more radially distributed and was in large formations not physically connected to Zn particles. Thus, discharge intermittency changes spatial distribution of ZnO in ways that are unpredicted by Zn anode models.

Effects of swift heavy ion irradiation on the InAs and Zn-based nanoparticles ion-beam synthesized in silica

Till now, a shape elongation effect under swift heavy ions (SHI) irradiation was observed predominantly for metal nanoparticles (NPs). We report this effect for InAs and Zn(core)/ZnO(shell) NPs embedded in silica matrix. In case of InAs NPs, SHI irradiation results in the formation of nanorods. A diversity of elongated features is observed for Zn-based NPs: chains of small ZnO clusters, elongated (Zn)core/(ZnO)shell structures and drop-like elongated Zn particles. The intense silica sputtering due to electronic excitations has been found for the “SiO2 + Zn-based NPs” composite. Photoluminescence (PL) spectroscopy reveals an emission in the visible range for both nanocomposites before SHI irradiation. This emission is attributed to the oxygen excess-related defect (NBOHC) as well as to the oxygen deficiency-related centres created in silica matrix during the implantation of cluster-forming ions (In + As or Zn). An intensive band in the spectral region of 2.8–3.1 eV is observed in PL spectrum of annealed “SiO2 + InAs NPs” composite. SHI irradiation results in its quenching and formation of an asymmetrical band centred at 1.9 eV. In case of “SiO2 + Zn-based NPs”, SHIs irradiation results in substantial increase of PL in orange spectral range.

Density and Volume Fraction Distribution of ZnO Discharge Products in Cylindrical Alkaline Battery Anodes after Intermittent Use

The discharge of an alkaline Zn anode involves the conversion of active material to aqueous zincate ions and solid ZnO. With the mobility of zincate in the electrolyte, complex ZnO morphologies and radial distributions have been observed to occur when using different discharge protocols. An apparent continuum of ZnO densities can be seen in an intermittently discharged anode, and can be appropriately binned into two forms, namely type I and type II, which differ in density and passivating character.1 Not only are the relative amounts of these two types impacted by the discharge protocol, but their morphologies and volume distributions are also affected. This has implications for both primary cells, where undesirable ZnO formation near the separator can lead to cell failure, and secondary cells, where redistribution of active material inhibits cyclability. Previously reported models of Zn anodes poorly describe the behavior seen when using an intermittent discharge protocol meant to simulate typical real-world applications, and therefore require further development.2 Additionally, prior literature reported that ZnO forms passivating shells around undischarged Zn cores, restricting hydroxide transport, and thus resulting in reduced cell performance.3 In this work, we characterize the ZnO morphology and radial distribution for an array of discharge conditions that simulate both intermittent and continuous use. We then use these results to identify the impact of discharge protocol on ZnO formation within alkaline Zn anodes.This work paired high resolution synchrotron tomography with a novel segmentation algorithm to observe phase morphology and quantify radial distributions in situ. The results obtained when using a continuous discharge protocol matched that of previous literature.3 However, the results when using an intermittent discharge protocol were vastly different than that seen with a continuous protocol. The discharge products in a cell simulating intermittent use formed two distinct phases of varying densities, both of which preferentially formed in the inner portion of the anode. This is radically different than ZnO formation in continuously discharged cells, wherein an apparent single ZnO phase is concentrated at the outer portions of the anode near the separator, creating a dense crust around the remaining Zn. This outer crust can be detrimental to cell performance due to poor hydroxide transport from the cathode to the remaining undischarged Zn, suggesting superior cell performance with intermittent use. Acknowledgements This research was supported by funding from Energizer Holdings, Inc. This research also used resources of the Advanced Photon Source beamline 6-BM, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357.

Unlocking Molecular Secrets in a Monomer-Assembly-Promoted Zn-Metalated Catalytic Porous Organic Polymer for Light-Responsive CO2 Insertion.

Anthropogenic carbon dioxide (CO2) emission is soaring day by day due to fossil fuel combustion to fulfill the daily energy requirements of our society. The CO2 concentration should be stabilized to evade the deadly consequences of it, as climate change is one of the major consequences of greenhouse gas emission. Chemical fixation of CO2 to other value-added chemicals requires high energy due to its stability at the highest oxidation state, creating a tremendous challenge to the scientific community to fix CO2 and prevent global warming caused by it. In this work, we have introduced a novel monomer-assembly-directed strategy to design va isible-light-responsive conjugated Zn-metalated porous organic polymer (Zn@MA-POP) with a dynamic covalent acyl hydrazone linkage, via a one-pot condensation between the self-assembled monomer 1,3,5-benzenetricarbohydrazide (TPH) and a Zn complex (Zn@COM). We have successfully explored as-synthesized Zn@MA-POP as a potential photocatalyst in visible-light-driven CO2 photofixation with styrene epoxide (SE) to styrene carbonate (SC). Nearly 90% desired product (SC) selectivity has been achieved with our Zn@MA-POP, which is significantly better than that for the conventional Zn@TiO2 (∼29%) and Zn@gC3N4 (∼26%) photocatalytic systems. The excellent light-harvesting nature with longer lifetime minimizes the radiative recombination rate of photoexcited electrons as a result of extended π-conjugation in Zn@MA-POP and increased CO2 uptake, eventually boosting the photocatalytic activity. Local structural results from a first-shell EXAFS analysis reveals the existence of a Zn(N2O4) core structure in Zn@MA-POP, which plays a pivotal role in activating the epoxide ring as well as capturing the CO2 molecules. An in-depth study of the POP-CO2 interaction via a density functional theory (DFT) analysis reveals two feasible interactions, Zn@MA-POP-CO2-A and Zn@MA-POP-CO2-B, of which the latter has a lower relative energy of 0.90 kcal/mol in comparison to the former. A density of states (DOS) calculation demonstrates the lowering of the LUMO energy (EL) of Zn@MA-POP by 0.35 and 0.42 eV, respectively, for the two feasible interactions, in comparison to Zn@COM. Moreover, the potential energy profile also unveils the spontaneous and exergonic photoconversion pathways for the SE to SC conversion. Our contribution is expected to spur further interest in the precise design of visible-light-active conjugated porous organic polymers for CO2 photofixation to value-added chemicals.

Using High Energy X-Ray White Beam Tomography to Quantify the Location and Morphology of ZnO Discharge Products in Alkaline Batteries

In alkaline Zn anodes, the active material is discharged to both aqueous zincate ions and solid ZnO. The mobility of zincate in the electrolyte allows considerable transport of the discharge products, which can form directly on the Zn active material or far from it, effectively relocating material long distances inside the cell. Additionally, ZnO can exist in more than one form, namely type I and type II, which differ in their density and passivating character.1 This leads to complex compositions of discharged primary Zn anodes and can cause cell failure due to redistribution of Zn in rechargeable cells. Models of Zn anodes are typically designed for continuous discharge,2 yet real-world use conditions usually involve intermittent discharge. Therefore, the ability of these models to predict ZnO morphology and distribution for cells used in real-world applications is questionable.It has been previously reported that when alkaline AA cells are discharged, ZnO forms passivating shells around undischarged Zn cores. At high discharge rates, this passivation of Zn increases in severity and hinders cell performance. Additionally, higher discharge rates increase the non-uniformity of ZnO distribution within the anode, preferentially precipitating ZnO near the separator which impedes hydroxide transport from the cathode to the inner portion of the anode.3 In this work, we analyze cylindrical cells discharged using intermittent profiles that approximate real battery use. We then compare the ZnO distribution to that found after continuous discharge.Synchrotron X-ray tomography was used to obtain in situ volumetric reconstructions at a spatial resolution of 3 microns. To observe the spatial distribution and morphology of ZnO formation in partially discharged Zn anodes, multiple AAA cells were discharged using distinct protocols. When using a continuous discharge, the reconstructions verified previous findings that core-shell structure is the primary morphology of ZnO and is non-uniformly distributed towards the separator.3 However, a radically different morphology and spatial distribution of ZnO was observed when using an intermittent discharge protocol. Specifically, when providing an 8 hour rest after each hour of discharge, ZnO forms isolated clumps distributed throughout the anode. Using this intermittent discharge protocol avoids passivating active material and potentially enables a higher Zn utilization by minimizing isolation of active material.

Promiscuous Catalytic Activity of a Binuclear Metallohydrolase: Peptide and Phosphoester Hydrolyses.

In this study, chemical promiscuity of a binuclear metallohydrolase Streptomyces griseus aminopeptidase (SgAP) has been investigated using DFT calculations. SgAP catalyzes two diverse reactions, peptide and phosphoester hydrolyses, using its binuclear (Zn-Zn) core. On the basis of the experimental information, mechanisms of these reactions have been investigated utilizing leucine p-nitro aniline (Leu-pNA) and bis(4-nitrophenyl) phosphate (BNPP) as the substrates. The computed barriers of 16.5 and 16.8 kcal/mol for the most plausible mechanisms proposed by the DFT calculations are in good agreement with the measured values of 13.9 and 18.3 kcal/mol for the Leu-pNA and BNPP hydrolyses, respectively. The former was found to occur through the transfer of two protons, while the latter with only one proton transfer. They are in line with the experimental observations. The cleavage of the peptide bond was the rate-determining process for the Leu-pNA hydrolysis. However, the creation of the nucleophile and its attack on the electrophile phosphorus atom was the rate-determining step for the BNPP hydrolysis. These calculations showed that the chemical nature of the substrate and its binding mode influence the nucleophilicity of the metal bound hydroxyl nucleophile. Additionally, the nucleophilicity was found to be critical for the Leu-pNA hydrolysis, whereas double Lewis acid activation was needed for the BNPP hydrolysis. That could be one of the reasons why peptide hydrolysis can be catalyzed by both mononuclear and binuclear metal cofactors containing hydrolases, while phosphoester hydrolysis is almost exclusively by binuclear metallohydrolases. These results will be helpful in the development of versatile catalysts for chemically distinct hydrolytic reactions.

Analysis of Whole Blood and Urine Trace Elements in Children with Autism Spectrum Disorders and Autistic Behaviors

The relationship between trace elements and neurological development is an emerging research focus. We performed a case–control study to explore (1) the differences of 13 trace elements chromium (Cr), manganese (Mn), cobalt (Co), zinc (Zn), arsenic (As), selenium (Se), molybdenum (Mo), cadmium (Cd), stannum (Sn), stibium (Sb), mercury (Hg), titanium (TI), and plumbum (Pb) concentration in whole blood and urine between autism spectrum disorder (ASD) children and their typical development peers, and (2) the association between the 13 trace elements and core behaviors of ASD. Thirty ASD subjects (cases) and 30 age-sex-matched healthy subjects from Baise City, Guangxi Zhuang Autonomous Region, China, were recruited. Element analysis was carried out by inductively coupled plasma-optical emission spectrometry. Autistic behaviors were assessed using Autism Behavior Checklist (ABC), Childhood Autism Rating Scale (CARS), and Children Neuropsychological and Behavior Scale (CNBS). The whole blood concentrations of Mo (p = 0.004), Cd (0.007), Sn (p = 0.003), and Pb (p = 0.037) were significantly higher in the ASD cases than in the controls. Moreover, Se (0.393), Hg (0.408), and Mn (− 0.373) concentrations were significantly correlated between whole blood and urine levels in ASD case subjects. There were significant correlations between whole blood Sb (0.406), Tl (0.365), Mo (− 0.4237), Mn (− 0.389), Zn (0.476), and Se (0.375) levels and core behaviors of ASD. Although the mechanism of trace element imbalance in ASD is unclear, these data demonstrate that core behaviors of ASD may be affected by certain trace elements. Further studies are recommended for exploring the mechanism of element imbalance and providing corresponding clinical treatment measures.

Octakis(dodecyl)phthalocyanines: Influence of Peripheral versus Non-Peripheral Substitution on Synthetic Routes, Spectroscopy and Electrochemical Behaviour.

Non-peripherally octakis-substituted phthalocyanines (npPc’s), MPc(C12H25)8 with M = 2H (3) or Zn (4), as well as peripherally octakis-substituted phthalocyanines (pPc’s) with M = Zn (6), Mg (7) and 2H (8), were synthesized by cyclotetramerization of 3,6- (2) or 4,5-bis(dodecyl)phthalonitrile (5), template cyclotetramerization of precursor phthalonitriles in the presence of Zn or Mg, metal insertion into metal-free phthalocyanines, and removal of Mg or Zn from the phthalocyaninato coordination cavity. The more effective synthetic route towards pPc 8 was demetalation of 7. npPc’s were more soluble than pPc’s. The Q-band λmax of npPc’s was red-shifted with ca. 18 nm, compared to that of pPc’s. X-ray photoelectron spectroscopy (XPS) differentiated between N–H, Nmeso and Ncore nitrogen atoms for metal-free phthalocyanines. Binding energies were ca. 399.6, 398.2 and 397.7 eV respectively. X-ray photoelectron spectroscopy (XPS) also showed zinc phthalocyanines 4 and 6 have four equivalent Nmeso and four equivalent N–Zn core nitrogens. In contrast, the Mg phthalocyanine 7 has two sets of core N atoms. One set involves two Ncore atoms strongly coordinated to Mg, while the other encompasses the two remaining Ncore atoms that are weakly associated with Mg. pPc’s 6, 7, and 8 have cyclic voltammetry features consistent with dimerization to form [Pc][Pc+] intermediates upon oxidation but npPc’s 3 and 4 do not. Metalation of metal-free pPc’s and npPc’s shifted all redox potentials to lower values.

Surface modification of the Ti surface with nanoscale bio-MOF-1 for improving biocompatibility and osteointegration in vitro and in vivo.

Biocompatibility and osteointegration of implants are highly desired in orthopedic and dentistry applications. The synthesis of a coating with ideal biocompatibility and osteogenic effect carries practical significance for improving the bio-inertness of pure Ti implants. Metal-organic frameworks (MOFs) are effective surface modification agents in bone regeneration applications. Bio-MOF-1, a classic type of biofriendly MOF with a bio-derived constitution, possesses biocompatibility and osteogenic potential resulting from its Zn core and adenine ligand. In this study, bio-MOF-1 coatings at multiple concentrations were synthesized on alkali-heat treated Ti, and their cytocompatibility and osteogenic properties were systematically examined both in vitro and in vivo. Coatings were characterized to confirm the successful synthesis of bio-MOF-1 coatings. These coatings exhibited advanced thermostability, excellent biocompatibility, and stable Zn2+ release, which up-regulated the expression of osteogenesis-related genes and proteins. Furthermore, bio-MOF-1 coating of Ti implants enhanced early osseointegration at the bone-implant interface. This study demonstrates the promising potential of bio-MOF-1 coatings with the osteogenic effect for surface modification in bone tissue engineering.

A heterotrinuclear bioinspired coordination complex capable of binding to DNA and emulation of nuclease activity

The investigation of compounds capable of strongly and selectively interacting with DNA comprises a field of research in constant development. In this work, we demonstrate that a trinuclear coordination complex based on a dinuclear Fe(III)Zn(II) core designed for biomimicry of the hydrolytic enzyme kidney bean purple acid phosphatase, containing an additional pendant arm coordinating a Pd(II) ion, has the ability to interact with DNA and to promote its hydrolytic cleavage. These results were found through analysis of plasmid DNA interaction and cleavage by the trinuclear complex 1 and its derivatives 2 and 3, in addition to the analysis of alteration in the DNA structure in the presence of the complexes through circular dichroism and DNA footprinting techniques. The suggested covalent interaction of the palladium-containing complex with DNA was analysed using an electrophoretic mobility assay, circular dichroism, high resolution gel separation techniques and kinetic analysis. This is a new and promising metal complex targeted to nucleic acids and acting in two separate ways: strong DNA interaction and hydrolytic cleavage.

Shi Irradiation of A IIIB v Nanoparticles and (Zn)Core /(ZnO)Shell Nanostructures Ion-Beam Synthesized in Silica: Shape Elongation, Enhanced Sputtering and Photoluminescence

Till now, shape elongation phenomenon was observed predominantly for metal nanoparticles irradiated with swift heavy ions (SHI). For the first time, we report the shape elongation of InAs and Zn(core)/ZnO(shell) nanoparticles (NPs) embedded in a silica matrix and irradiated with swift Xe ions. In case of InAs NPs, SHI irradiation results in the formation of nanorods. A diversity of elongated features is observed for Zn-based NPs: chains of small ZnO clusters, elongated (Zn)core/(ZnO)shell structures and drop-like elongated Zn particles. The intense sputtering of the silicon dioxide layer due to electronic excitations has revealed for “SiO2+Zn-based NPs” composite. Photoluminescence (PL) spectroscopy reveals emission in the visible range for two types of nanocomposites before SHIs irradiation. This emission is attributed to the oxygen excess-related defect (NBOHC) as well as to the oxygen deficiency-related centres created in silica matrix during the implantation of cluster-forming ions (In + As or Zn). The intensive band in the spectral region of 2.8 – 3.1 eV is observed in PL spectrum of annealed “SiO2+InAs NPs” composite. SHI irradiation results in its quenching and formation of an asymmetrical band centred at 1.9 eV. In case of “SiO2+Zn-based NPs” composite, SHIs irradiation results in substantial increase of PL in orange spectral range. The origin of observed emission is discussed.

Oxygen vacancies induced photoluminescence in hbox {SrZnO}_2 nanophosphors probed by theoretical and experimental analysis

We report, for the first time, the influence of oxygen vacancies on band structure and local electronic structure of hbox {SrZnO}_2 (SZO) nanophosphors by combined first principle calculations based on density functional theory and full multiple scattering theory, correlated with experimental results obtained from X-ray absorption and photoluminescence spectroscopies. The band structure analysis from density functional theory revealed the formation of new energy states in the forbidden gap due to introduction of oxygen vacancies in the system, thereby causing disruption in intrinsic symmetry and altering bond lengths in SZO system. These defect states are anticipated as origin of observed photoluminescence in SZO nanophosphors. The experimental X-ray absorption near edge structure (XANES) at Zn and Sr K-edges were successfully imitated by simulated XANES obtained after removing oxygen atoms around Zn and Sr cores, which affirmed the presence and signature of oxygen vacancies on near edge structure.

Electrochemical Fixation of Carbon Dioxide in Molten Salts on Liquid Zinc Cathode to Zinc@Graphitic Carbon Spheres for Enhanced Energy Storage

AbstractFixation of carbon dioxide into advanced energy materials is an ideal protocol to address challenges in energy and environmental sustainability, with the efficiency of CO2 fixation and the functionality of derived materials being the key‐enabling factors. Herein, using a liquid zinc cathode for CO2 fixation in molten salts, CO2 is electrochemically converted to graphitic carbon shells over spherical Zn cores, namely, Zn@C. The liquid Zn serves as a depolarizer to facilitate the reduction of CO2, and also a soft template to direct the generation of core–shell Zn@C spheres. Density functional theory calculations reveal that the coexisting Zn can enlarge the interlayer gap of graphitic carbon and induce a strong electronic interaction with AlCl4−. Such a strong coupling between Zn and carbon hence offers an enhanced energy storage capability of the Zn@C. The present study provides suggestions for enhancing efficiency of CO2 fixation and value‐added utilization of nonferrous metals.