Coordination Engineering of N,O Co-Doped Cu Single Atom on Porous Carbon for High Performance Zinc Metal Anodes

Traditional challenges of poor cycling stability and low Coulombic efficiency in Zinc (Zn) metal anodes have limited their practical application. To overcome these issues, this work introduces a single metal-atom design featuring atomically dispersed single copper (Cu) atoms on 3D nitrogen (N) and oxygen (O) co-doped porous carbon (CuNOC) as a highly reversible Zn host. The CuNOC structure provides highly active sites for initial Zn nucleation and further promotes uniform Zn deposition. The 3D porous architecture further mitigates the volume changes during the cycle with homogeneous Zn²⁺ flux. Consequently, CuNOC demonstrates exceptional reversibility in Zn plating/stripping processes over 1000 cycles at 2 and 5 mA cm⁻² with a fixed capacity of 1 mAh cm⁻², while achieving stable operation and low voltage hysteresis over 700 h at 5 mA cm⁻² and 5 mAh cm⁻². Furthermore, density functional theory calculations show that co-doping N and O on porous carbon with atomically dispersed single Cu atoms creates an efficient zincophilic site for stable Zn nucleation. A full cell with the CuNOC host anode and high loading V₂O₅ cathode exhibits outstanding rate-capability up to 5 A g⁻¹ and a stable cycle life over 400 cycles at 0.5 A g⁻¹.     

Hydrothermal growth of Zn2SnO4:Eu,Ca for red emission

Zinc stannate (Zn₂SnO₄) and Zn₂SnO₄ codoped with Eu³⁺ and Ca²⁺ (ZTO:Eu,Ca) were synthesized by hydrothermal method and characterized with X‐ray diffraction (XRD), energy‐dispersive X‐ray analysis (EDAX), Raman spectrometer, field emission scanning electron microscopy (FESEM), ultraviolet‐visible (UV‐vis) and photoluminescence (PL) spectrophotometers. PL analysis of Zn₂SnO₄ gives broad defect induced emission in the region 500–750 nm. The crystal structure of Zn₂SnO₄ was retained even with a nominal doping of Eu, Ca and its combination in the Zn₂SnO₄. The Eu³⁺ ions were found to occupy the non‐centrosymmetric sites of the Zn₂SnO₄ and gave emissions at 592, 615 and 702 nm. Zn₂SnO₄:Eu,Ca showed red emission at 615 nm attributed to the electronic transition from the excited state ⁵D₀ → ⁷F₂ of the 4f⁶ configuration of Eu³⁺. Nominal codoping of Eu³⁺ and Ca²⁺ ions promoted the quenching of orange emission from Eu³⁺ in Zn₂SnO₄:Eu,Ca.     

Hydroxyl group as a substituent with varying electronic properties: Effect of strength of H-bonding on charge density changes in Ph–OH…F<Superscript>−</Superscript> complexes

Due to gradual and controlled changes of interatomic distances between heavy atoms in OH…F⁻ of C₆H₅OH…F⁻ systems it was possible to study the electronic structure evolution. Computation at B3LYP/6-311+G(d,p) level of theory was performed for this purpose. Changes in charges at atoms and characteristics at bond critical points (BCPs) of the H-bond region and also in distant parts of the systems were investigated by means of natural bond orbitals (NBO) and atoms in molecules (AIM) analyses. It is shown that at the border line between partially covalent and non-covalent H-bonding (Espinosa et al. in J Chem Phys 117:5529, 2002; Grabowski et al. in J Phys Chem B 110:6444, 2006) with the H…F interatomic distance ∼1.8 Ǻ the hydrogen atom has the most positive charge. In addition, the change in the atomic charge values in the interacting region affects the phenyl ring properties. The decrease of the sum of atomic charges as well as of the aromaticity was noticed when the OH….F distance is shortened.     

Physical basis of structural and catalytic Zn-binding sites in proteins

Zn²⁺, an element that is essential to all life forms, can play a catalytic or a solely structural role. Previous works have shown that Zn²⁺ binds preferentially to water molecules and His in catalytic sites, but to Cys⁻ instructural sites, but the molecular basis for the observed ligand preference is unclear. Here, we show that the different Zn²⁺ roles are also reflected in the different bond distances to Zn²⁺ in structural and catalytic sites. We reveal the physical basis for the observed differences between structural and catalytic Zn sites: In most catalytic sites, water is found bound to Zn²⁺ as it transfers the least charge to Zn²⁺ and is less bulky compared to the protein ligands, enabling Zn²⁺ to serve as a Lewis acid in catalysis. In most structural sites, however, ≥ 2 Cys⁻ are found bound to Zn²⁺, as Cys⁻ transfers the most charge to Zn²⁺ and reduces the Zn charge to such an extent that Zn²⁺ can no longer act as a Lewis acid; furthermore, steric repulsion among the bulky Cys(S⁻) prevents Zn²⁺ from accommodating another ligand. Based on the observed ligand preference and Zn-ligand distance differences between structural and catalytic Zn sites, we present a simple method for distinguishing the two types of sites and for verifying the catalytic role of Zn²⁺. Finally, we discuss how the physical bases revealed aid in designing potential drug molecules that target Zn proteins.     

EFFECT OF ZINC AVAILABILITY ON GROWTH,MORPHOLOGY, AND NUTRIENT INCORPORATION IN A COASTAL AND AN OCEANIC DIATOM1

We investigated the effect of Zn availability on growth rate (μ), cell morphology, and elemental stoichiometry and incorporation rate in two marine diatoms. For the coastal diatom Skeletonema costatum (Grev.) Cleve, the half‐saturation constant (K_S) for growth was 4.1 pM Zn²⁺, and growth ceased at ≤ 2.6 pM Zn²⁺, whereas for the oceanic diatom Thalassiosira oceanica Hasle, K_S was 0.5 pM Zn²⁺, and μ remained at ～40%μ_max even at 0.3 pM Zn²⁺. Under Zn‐limiting (Zn‐L) conditions, S. costatum decreased cell size significantly, leading to an 80% increase in surface area to volume ratio (SA/V) at Zn²⁺ of 3.5 pM compared to Zn‐replete (Zn‐R) conditions (at Zn²⁺ of 13.2 pM), whereas T. oceanica’s morphology did not change appreciably. Cell quotas of C, N, P, Si, and chl a significantly decreased under Zn limitation in S. costatum (at Zn²⁺ of 3.5 pM), whereas Zn limitation in T. oceanica (at Zn²⁺ of 0.3 pM) had little effect on quotas. Elemental stoichiometry was ～85C:10N:9Si:1P and 81C:9N:5Si:1P for S. costatum, and 66C:5N:2Si:1P and 52C:6N:2Si:1P for T. oceanica, under Zn‐R and Zn‐L conditions, respectively. Incorporation rates of all elements were significantly reduced under Zn limitation for both diatoms, but particularly for Si in S. costatum, and for C in T. oceanica, despite its apparent tolerance of low Zn conditions. With [Zn²⁺] in some parts of the ocean being of the same order (～0.2 to 2 pM) as our low Zn conditions for T. oceanica, our results support the hypothesis that in situ growth and C acquisition may be limited by Zn in some oceanic species.     

Enhanced photoluminescence of the Ca0.8Zn0.2TiO3:0.05% Pr3+ phosphor by optimized hydrothermal conditions

The red‐emitting phosphor Ca_0.8Zn_0.2TiO₃:Pr³⁺ was synthesized using an ethylene glycol (EG)‐assisted hydrothermal method. The effects of additional amounts of and order of adding EG, plus hydrothermal temperature, time, and pH on the composition, morphology and optical properties of the titanate phosphors were studied. The crystalline phases of the titanate phosphors were confirmed to be constituted of a series of co‐existing CaTiO₃, Zn₂TiO₄ and Ca₂Zn₄Ti₁₆O₃₈ compounds in various proportions that were visualized using an X‐ray diffractometer (XRD). The optical properties of the phosphors were studied using photoluminescence spectra and UV–visible spectroscopy. The results show that the impurities Zn₂TiO₄:Pr³⁺ and Ca₂Zn₄Ti₁₆O₃₈:Pr³⁺ significantly contributed to the enhancement of an absorption band around 380 nm. The optimum Ca_0.8Zn_0.2TiO₃:Pr³⁺ phosphor consisting of appropriate amounts of CaTiO₃, Ca₂Zn₄Ti₁₆O₃₈ and Zn₂TiO₄ in three phases was achieved by controlling the hydrothermal conditions, and the obtained red phosphor exhibited the highest red emission (¹D₂ → ³H₄ transition of Pr³⁺) with an ideal chromaticity coordinate located at (x = 0.667, y = 0.332) under 380 nm excitation.     

Synthesis of trans-1,4-cyclohexanedisulfonic acid and its zinc salt - A belt-like metal-organic coordination polymer with tetrahedrally and octahedrally coordinated zinc ions

Diastereomerically pure trans-1,4-cyclohexanedisulfonic acid H₂CDS was prepared in three steps from 1,4-cyclohexanediol (cis/trans-mixture) as a new linker molecule for metal-organic coordination polymers. The crystalline zinc salt contained two molecules DMF per formular unit. Infinite polymeric belts were observed in the solid state structure of [Zn(CDS)(dmf)₂]. These flat belts were formed by connecting two chains of Zn(dmf)-CDS-polymers bearing tetrahedrally coordinated Zn²⁺ ions in one chain and octahedrally coordinated Zn²⁺ centers in the second. Thermal analysis of this polymer revealed its stability up to 400 °C, above which it decomposed cleanly under formation of crystalline ZnO.     

Characterization of Desmodesmus pleiomorphus isolated from a heavy metal-contaminated site: biosorption of zinc

Microalgae have been proven efficient biological vectors for heavy metal uptake. In order to further study their biosorption potential, a strain of Desmodesmus pleiomorphus (L) was isolated from a strongly contaminated industrial site in Portugal. Under different initial Zn²⁺ concentrations, metal removal by that strain reached a maximum of 360 mg Zn/g biomass after 7 days, at 30 mg Zn/l, after an initial rapid phase of uptake. Comparative studies were carried out using a strain of the same microalgal species that is commercially available (ACOI 561): when exposed to 30 mg Zn/l, it could remove only 81.8 mg Zn/g biomass. Biosorption experiments using inactivated biomass of the isolated strain reached a maximum Zn²⁺ uptake of 103.7 mg/g. Metal removal at various initial pH values was studied as well; higher removal was obtained at pH 5.0. The microalga strain L, isolated from the contaminated site, exhibited a much higher removal capacity than the commercial strain, and the living biomass yielded higher levels of metal removal than its inactivated form.     

Competitive adsorption of Pb, Cd and Zn ions onto Eichhornia crassipes in binary and ternary systems

A batch sorption technique was used to study the biosorption of Pb²⁺, Cd²⁺ and Zn²⁺ ions onto the vastly abundant water hyacinth weed, Eichhornia crassipes biomass in binary and ternary systems at a temperature of 30 °C and pH 4.84. Mutual interference effects were probed using equilibrium adsorption capacity ratios, , where the prime indicates the presence of one or two other metal ions. The combined action of the metals was found to be antagonistic, and the metal sorption followed the order Pb²⁺  Cd²⁺  Zn²⁺. The behaviour of competitive biosorption for Pb–Cd and Pb–Zn combinations were successfully described by the Langmuir Competitive Model (CLM), whilst the model showed poor fitting to the Cd–Zn data. In conclusion, Pb²⁺ ions could still be effectively removed from aqueous solution in the presence of both Cd²⁺ and Zn²⁺ ions, but removal of the Cd²⁺ and Zn²⁺ ions would be suppressed in the presence of Pb²⁺.     

A reversible calix[4]arene armed phenolphthalein based fluorescent probe for the detection of Zn2+ and an application in living cells

A reversible and easy assembled fluorescent sensor based on calix[4]arene and phenolphthalein (C4P) was developed for selective zinc ion (Zn²⁺) sensing in aqueous samples. The probe C4P demonstrated high selective and sensitive detection towards Zn²⁺ over other competitive metal ions. Interaction of Zn²⁺ with a solution of C4P resulted in a considerable increment in emission intensity at 440 nm (λ_ex = 365 nm) due to the suppression of photoinduced electron transfer (PET) process and the restriction of C=N isomerization . The binding constant (K_a) of C4P with Zn²⁺ was calculated to be 4.50 × 10¹¹ M^?2 and also the limit of detection of C4P for Zn²⁺ was as low as 0.108 μM (at 10^?7 M level). Moreover, the fluorescence imaging in the human colon cancer cells suggested that C4P had great potential to be used to examine Zn²⁺ in vivo.     

43Ca and 67Zn NMR study of Ca2+, Zn2+-thermolysin complexes

⁴³Ca NMR spectroscopy of Ca²⁺-thermolysin complexes reveals that the structure and/or exchange rate of Ca²⁺ bound to the regulative-site of the enzyme are not essentially changed by adding Zn²⁺ or an inhibitor, L-leucine hydroxamate, both of which may be bound to the active-site of the enzyme. It is shown that the chemical exchange mechanism dominates the ⁴³Ca NMR of Ca²⁺ bound to the enzyme on the basis of temperature-dependences of the NMR. In contrast with the ⁴³Ca NMR findings, first application of ⁶⁷Zn NMR to the Zn²⁺-thermolysin complexes offers convincing evidences that the structure and/or exchange rate of Zn²⁺ bound to the active-site of the enzyme are remarkably changed by adding Ca²⁺ or the inhibitor, L-leucine hydroxamate.     

Effects of divalent metal cations on lovastatin biosynthesis from <Emphasis Type="Italic">Aspergillus terreus</Emphasis> in chemically defined medium

Effects of six divalent metal cations: Fe²⁺, Ca²⁺, Zn²⁺, Mg²⁺, Cu²⁺and Mn²⁺ on fungal cell growth and lovastatin biosynthesis were investigated by submerged cultivation of Aspergillus terreus in a modified chemically defined medium. The influences of different initial concentrations of the above six metal cations were also examined at 1, 2, and 5 mM, respectively. Cu²⁺ apparently inhibited the cell growth, but had no influence on biosynthesis of lovastatin. All of Fe²⁺, Ca²⁺, Zn²⁺, Mg²⁺ and Mn²⁺ promoted the cell growth and lovastatin biosynthesis in different extents. The highest biomass of 13.8 ± 0.5 g l⁻¹ and specific lovastatin titres of 49.2 ± 1.4 mg gDCW⁻¹ were obtained at the level of 2 and 5 mM in the presence of Zn²⁺, respectively. The values were improved double and 14.4-fold. Excess Zn²⁺ inhibited the cell growth, but enhanced lovastatin biosynthesis with an increment of 17.6 mg l⁻¹ per mM. The interactions of all metal cations slightly inhibited the lovastatin production comparing with the existence of Zn²⁺, Fe²⁺ and Mg²⁺ solely, yet remarkably improved the cell growth. These results suggest that the divalent metal ions Zn²⁺ or Fe²⁺ influence the production by regulating the action of key enzymes such as LovD or LovF in lovastatin biosynthesis.     

Solvation Modulation and Reversible SiO2-Enriched Interphase Enabled by Deep Eutectic Sol Electrolytes for Low-Temperature Zinc Metal Batteries

Zinc metal batteries (ZMBs) hold great promise for large-scale energy storage in renewable solar and wind farms. However, their widespread application is hindered by poor stability and unsatisfactory low-temperature performance, attributed to issues such as dendrite formation, strong Zn²⁺-H₂O coordination, and electrolyte freezing. Herein, a deep eutectic sol electrolyte (DESE) is proposed by mixing SiO₂ nanoparticles with a solution composed of 1,3-dioxolane (DOL) and Zn(ClO₄)₂·6H₂O for stable low-temperature ZMBs. By substituting the strong Zn²⁺- H₂O coordination with favorable Zn²⁺-DOL coordination, the DESE exhibits exceptional antifreezing capability at temperatures beyond −40 °C. The formation of Si-O-Zn²⁺ bond near SiO₂ nanoparticles further improves the low-temperature performance of the DESE by decreasing Zn²⁺ desolvation energy. Moreover, the SiO₂ nanoparticles co-plating/co-stripping with Zn metal, forming a reversible and homogeneous SiO₂-enriched interphase to protect the Zn anode from dendrite growth and interfacial side reactions. Remarkably, the DESE-based ZMB full cells exhibit significantly prolonged cycle life of 8000 cycles at 1 A g⁻¹ at 25 °C and 700 cycles at 0.2 A g⁻¹ at -40 °C. This work provides a promising strategy to design advanced electrolytes for practical low-temperature ZMBs.     

Macrocyclic dinuclear Zn(II) complexes: synthesis, structure and hydrolysis of tris(p-nitrophenyl) phosphate

A series of mono- and dinuclear zinc complexes of 3,6,9,17,20,23-hexaaza-29,30-dihydroxy-13,27-dimethyl-tricyclo[23,3,1^11,15]triaconta-1(28),11,13,15(30),25,26-hexaene (H₂L or BDBPH) have been defined in solution by potentiometry. The crystal structure of [Zn₂C₂₆H₄₀N₆O₂(CH₃OH)₂]·Br₂ has been determined by X-ray. Each zinc ion is coordinated to three nitrogen atoms, a bridged-phenolic oxygen atom, and a methanolic oxygen atom, which define a six-coordinated octahedron. Bond lengths of ZnN are in the range of 2.104(3)-2.120(3) Å and distances between Zn and O (bridged-phenolic oxygen) are 2.052(2), 2.062(2) Å, respectively. The dinuclear complexes: [Zn₂L]²⁺ and [Zn₂L(OH)]⁺ play crucial roles in hydrolytic reaction of tris(4-nitrophenyl)phosphate. A possible mechanism showed that [Zn₂L(OH)]⁺ acts as a nucleophile and [Zn₂L]²⁺ stabilizes the formation of the intermediate: [Zn₂L-BNP].     

Factors affecting immobilization of heavy metals by purple nonsulfur bacteria isolated from contaminated shrimp ponds

In order to remove heavy metals (HMs) from contaminated shrimp pond at the highest concentrations found of; 0.75 mg/l Cd²⁺, 62.63 mg/l Pb²⁺, 34.60 mg/l Cu²⁺ and 58.50 mg/l Zn²⁺, two strains of purple nonsulfur bacteria isolated from shrimp ponds (NW16 and KMS24) were investigated for their ability to immobilize HMs in 3% NaCl in both microaerobic-light and aerobic-dark conditions. Based on metabolic inhibition and metabolic-dependent studies, it was concluded that both strains removed HMs using biosorption and also bioaccumulation. The efficiency of removal by both strains with both incubating conditions tested was in the order of lead (Pb) > copper (Cu) > zinc (Zn) > cadmium (Cd). Optimal conditions for removal of HMs by strain NW16 were; cells in the log phase at 4.5 mg DCW/ml, pH 6.0, and 30°C for 30 min. With microaerobic-light conditions, the relative percent removal of HMs was: Pb, 83; Cu, 59; Zn, 39; Cd, 23 and slightly more with the aerobic-dark conditions (Pb, 90; Cu, 69; Zn, 46; Cd, 28). Cells in the log phase at 5.0 mg DCW/ml, pH 5.5, and 35°C for 45 min were optimal conditions for strain KMS24 and there were no significant differences for the removal percentages of HMs with either incubating conditions (averages: Pb, 96; Cu, 75; Zn, 46; Cd, 30). The presence of Ca²⁺ and Mg²⁺ significantly decreased the removal capacity of HMs for both strains.     

Zn‐doped CaTiO3:Eu3+ red phosphors for enhanced photoluminescence in white LEDs by solid‐state reaction

Zn‐doped CaTiO₃:Eu³⁺ red phosphors for enhanced photoluminescence in white light‐emitting diodes (LEDs) were synthesized by a solid‐state method. The structure and morphology of the obtained phosphor samples were observed by X‐ray diffraction (XRD) and scanning electron microscopy (SEM), and the impact of Ca, Zn and Eu content on their photoluminescence properties was studied. The results indicated that Zn not only participates in the formation of defects in suitable lattice matrices but also has a role in flux in the transformation from ZnO to Zn₂TiO₄, which is beneficial for the enhancement of photoluminescence properties. Photoluminescence test data showed that the Zn‐doped phosphor is excited efficiently by near‐ultraviolet (NUV) light at wavelengths around 398 nm and emits an intense red light with a broad peak around 616 nm corresponding to the ⁵D₀→⁷F₂ transition of Eu³⁺. The intensity of this phosphor emission is three times stronger than that without Zn‐doping. Furthermore, this phosphor has very good thermal stability, high color purity and a low sintered temperature, all of which suggest its potential as a promising red phosphor for white LEDs. Copyright © 2015 John Wiley & Sons, Ltd.     

A study of the impacts of Zn and Cu on two rhizobial species in soils of a long-term field experiment

Two agriculturally important species of rhizobia, Rhizobium leguminosarum biovar viciae (pea rhizobia) and R. leguminosarum bv. trifolii (white clover rhizobia), were enumerated in soils of a long-term field experiment to which sewage sludges contaminated predominantly with Zn or Cu, or Zn plus Cu, were added in the past. In addition to total soil Zn and Cu concentrations, soil pore water soluble Zn and free Zn²⁺, and soluble Cu concentrations are reported. Pea and white clover rhizobia were greatly reduced in soils containing ≥200 mg Zn kg^-1, and soil pore water soluble Zn and free Zn²⁺ concentrations ≥7 and ≥3 mg l^-1, respectively, in soils of pH 5.9–6. Copper also reduced rhizobial numbers, but only at high total soil concentrations (>250 mg kg^-1) and not to the same extent as Zn. Yields of field grown peas decreased significantly as total soil Zn, soil pore water soluble Zn and free Zn⁺² increased (R² = 0.79, 0.75 and 0.75, respectively; P < 0.001). A 50% reduction in seed yield occurred at a total soil Zn concentration of about 290 mg kg^-1, in soils of pH 5.9–6. The corresponding soil pore water soluble Zn and free Zn²⁺ concentrations were about 9 and 4 mg l^-1, respectively. Pea seed yields were not significantly correlated with total soil Cu (R² = 0.33) or soil pore water soluble Cu (R² = 0.39). Yield reductions were due to a combination of greatly reduced numbers of free-living rhizobia in the soil due to Zn toxicity, thus indirectly affecting N₂-fixation, and Zn phytotoxicity. These effects were exacerbated in slightly acidic soils due to increased solubility of Zn, and to some extent Cu, and an increase in the free Zn²⁺ fraction in soil pore water. The current United Kingdom, German and United States limits for Zn and Cu in soils are discussed in view of the current study. None of these limits are based on toxicity thresholds in soil pore water, which may have wider validity for different soil types and at different pH values than total soil concentrations. This revised version was published online in June 2006 with corrections to the Cover Date.     

不同浓度Fe2+与Zn2+对羊草幼苗生长和生理特性的影响

以羊草幼苗为研究对象,通过调整全营养培养基(CK,0.05 mmol/L Fe²⁺、0.015 mmol/L Zn²⁺)中铁或者锌含量设置0、10倍、20倍Fe²⁺(Zn²⁺)浓度处理Fe₀(Zn₀)、Fe₁₀(Zn₁₀)、Fe₂₀(Zn₂₀),以及在高铁培养基中单独添加0.15 mmol/L Zn²⁺或同时添加10 mmol/L Ca²⁺、5 mmol/L Mg²⁺、20 mmol/L K⁺处理,测定培养6 d后幼苗生长指标和矿质元素含量、以及高铁(Fe₂₀)处理下幼苗根中抗氧化指标和相关基因表达量,探究不同浓度Fe²⁺、Zn²⁺对羊草幼苗生长、矿质元素吸收积累及抗氧化指标、基因表达的影响。结果表明：(1)缺锌(Zn₀)显著抑制羊草幼苗鲜重的增加和Zn元素的积累,但促进Fe、Mg元素的积累;高浓度锌(Zn₁₀、Zn₂₀)显著促进幼苗叶片生长和Zn元素的积累;缺铁(Fe₀)显著抑制幼苗的根长、鲜重和Fe元素的积累,促进Mg、Zn元素的积累;高浓度铁(Fe₁₀、Fe₂₀)显著抑制羊草幼苗根叶生长、根毛发育和Ca、Zn、Mg、K元素的积累。(2)增加Zn²⁺和Ca²⁺、Mg²⁺、K⁺浓度无法恢复高铁胁迫对幼苗生长的抑制作用。(3)高浓度铁(Fe₂₀)处理羊草幼苗48 h后,根部过氧化物酶、超氧化物歧化酶、过氧化氢酶、抗坏血酸过氧化物酶、谷胱甘肽还原酶活性和丙二醛、抗坏血酸、还原型谷胱甘肽含量显著升高;烟酰胺合成酶基因、过氧化物酶基因表达量显著下调,植物类萌发素蛋白基因表达量显著上调。研究发现,羊草幼苗生长发育和矿质元素积累对环境中Zn²⁺浓度变化不敏感,却受到环境中高浓度Fe²⁺的显著抑制,并造成严重的氧化胁迫伤害,这种伤害无法在添加Zn²⁺或同时添加Ca²⁺、Mg²⁺、K⁺的条件下恢复。     

8-Aminoquinoline-based ratiometric zinc probe: Unexpected binding mode and its application in living cells

PMQA, an 8-aminoquinoline-based ratiometric fluorescent sensor, demonstrates the Zn²⁺-induced red-shift of emission (85 nm), and was successfully applied to image zinc in living cells. Compared to 2:1 stoichiometry in PMQA–Zn²⁺, PMQA–Cu²⁺ shows 1:1 composition. Both nitrogen atoms from the aminoquinoline are missing in binding of zinc, while they are critically involved in Cu²⁺ chelation. The structure difference between PMQA–Zn²⁺ and PMQA–Cu²⁺ might shed light in designing novel zinc probes without suffering from copper interference.     

‘Turn‐on’ fluorescent chemosensors based on naphthaldehyde‐2‐pyridinehydrazone compounds for the detection of zinc ion in water at neutral pH

A series of naphthaldehyde‐2‐pyridinehydrazone derivatives were discovered to display interesting ‘turn‐on’ fluorescence response to Zn²⁺ in 99% water/DMSO (v/v) at pH 7.0. Mechanism study indicated that different substituent groups in the naphthaldehyde moiety exhibited significant influence on the detection of Zn²⁺. The electron rich group resulted in longer fluorescence wavelengths but smaller fluorescence enhancement for Zn²⁺. Among these compounds, 1 showed the highest fluorescence enhancement of 19‐fold with the lowest detection limit of 0.17 μmol/L toward Zn²⁺. The corresponding linear range was at least from 0.6 to 6.0 μmol/L. Significantly, 1 showed an excellent selectivity toward Zn²⁺ over other metal ions including Cd²⁺.