Central Ion Research Articles

Carboxamide Fe(III) complex as the electrocatalyst of water oxidation reaction: WNA and I2M O–O bond formation pathways

A single-site Fe(III) carboxamide complex, [Fe(HbpH) (Cl)2] (1), (HbpH‾ = N,N′-Bis(picolinoyl)hydrazine) anion), was synthesized and used as the electrocatalyst of water oxidation reaction. Complex 1 catalyzes the oxidation of water to O2 at the pH of 8 in phosphate buffer solution with the onset of a catalytic wave at about 0.45 V versus RHE with the turnover frequency (TOF) of 5.8 s−1 at room temperature. The stability of the catalyst in water oxidation processes by electrochemical and UV–vis measurements, demonstrated the realistic molecular electrocatalysis of 1. Differential pulse voltammetry (DPV) of 1 in different pH values showed the dependency of oxidation potential to the pH of the environment, establishing the fact that the catalytic cycle involves the proton-coupled electron transfer (PCET) process. Density functional theory (DFT) calculations on the mechanism of water oxidation process of 1 shows that the oxygen evolution reaction is carried out through the water nucleophilic attack (WNA) to the metal center ion, resulted to the formation of FeIV(O) species. Also, DFT calculations showed that the formation of an O–O bond proceeds through the interaction two molecular mechanism (I2M), which compete with the WNA mechanism following from experimental analysis. The electroactivity of the metal centre and carboxamide ligand and the ability of the ligand to stabilize the high oxidation numbers of the metal-ion centre during the oxidation process, provide different oxidation pathways for an OER process.

One-pot synthesized copper-imidazole-2-carboxaldehyde complex material with oxidase-like activity for the colorimetric detection of glutathione and ascorbic acid

Due to the copper (Cu) active sites, its complexes with oxidase-like activity have superior catalytic properties, which can catalyze a series of specific substrates like 3,3′,5,5′-tetramethylbenzidine (TMB), producing colorimetric reactions for the detection of different reducing small-molecule compounds. Attribute to the competitive coordination effects between water molecules and central Cu ions, most of the Cu complexes can hardly be used in the pure aqueous reaction system. In this study, a Cu-based material (Cu-imidazole-2-carboxaldehyde, Cu-ICA) was prepared using copper ions and ICA through a one-step process in the water solution. After the morphology of the material being characterized, the mimetic enzyme behavior of the Cu-ICA was demonstrated through the TMB oxidation. Compared to the other reported oxidase-like mimics, Cu-ICA has better aqueous stability and oxidase-like activity, and shows a higher vmax. Furthermore, basing on the oxidase-like activity of Cu-ICA, a colorimetric method was developed for the ascorbic acid and glutathione detections with linear ranges of 0.5–5 μM and 0.5–4 μM, and limit of detection of 0.1304 μM and 0.097 μM, respectively. Owing to its excellent aqueous stability and oxidase-like activity, Cu-ICA has bright application prospects in the analysis of reducing small-molecule compounds.

Effective electrocatalytic hydrogen evolution of carbon paste electrode modified by Fe (II) and Ni (II) phenylimidazole‐dicarboxylate complexes

The structure determined is helpful to explore the reaction mechanism and provide a design strategy for the synthesis of high‐performance hydrogen evolution reaction (HER) electricity catalysts. Therefore, two structurally tunable and deterministic metal complexes, [Fe(m‐H2MOPhIDC)2(H2O)2]·2H2O (1) and [Ni(m‐HMOPhIDC)(H2O)2)]n (2) (m‐H3MOPhIDC = 2‐[3‐methoxyphenyl]‐1H‐imidazole‐4,5‐dicarboxylic acid), were synthesized under solvothermal conditions and used to assemble modified carbon paste electrodes (CPE 1–2) to explore the relationship between structure and catalytic performance. Structural analysis revealed that complexes 1 and 2 had a mononuclear structure and 1D linear structure, respectively, and that the central ions of the two complexes had the same coordination environment of the octahedral spatial configuration. In 0.5 M H2SO4 and 293 K, linear sweep voltammetry and Tafel curve indicate that the η10 (overpotential, 10 mA cm−2) of two modified carbon paste electrodes are −574 and −539 mV and Tafel slopes are 161 and 128 mV dec−1. Comparing the overpotential of CPE 1–2 with that of unmodified solid carbon paste electrode (sCPE, −976 mV), it was found that the overpotential of CPE1–2 shifted positively and the Tafel slopes are obviously reduced compared to sCPE (221 mV dec−1), which proves that the CPE 1–2 has effective electrocatalytic hydrogen evolution activity. The controlled potential electrolysis and impedance spectroscopy further validated the above conclusions. The higher HER activity of the CPE 2 than CPE 1 can be attributed to the fact that complex 2 is a one‐dimensional polymer, which can efficiently disperse the catalytic active site. The use of metal complexes as HER electrocatalysts provides a new idea for an effective method for converting electric energy into hydrogen energy and is beneficial to the development of the HER research field.

Electrochemical Properties and Structure of Membranes from Perfluorinated Copolymers Modified with Nanodiamonds.

In this study, we aimed to design and research proton-conducting membranes based on Aquivion®-type material that had been modified with detonation nanodiamonds (particle size 4-5 nm, 0.25-5.0 wt. %). These nanodiamonds carried different functional groups (H, OH, COOH, F) that provided the hydrophilicity of the diamond surface with positive or negative potential, or that strengthened the hydrophobicity of the diamonds. These variations in diamond properties allowed us to find ways to improve the composite structure so as to achieve better ion conductivity. For this purpose, we prepared three series of membrane films by first casting solutions of perfluorinated Aquivion®-type copolymers with short side chains mixed with diamonds dispersed on solid substrates. Then, we removed the solvent and the membranes were structurally stabilized during thermal treatment and transformed into their final form with -SO3H ionic groups. We found that the diamonds with a hydrogen-saturated surface, with a positive charge in aqueous media, contributed to the increase in proton conductivity of membranes to a greater rate. Meanwhile, a more developed conducting diamond-copolymer interface was formed due to electrostatic attraction to the sulfonic acid groups of the copolymer than in the case of diamonds grafted with negatively charged carboxyls, similar to sulfonic groups of the copolymer. The modification of membranes with fluorinated diamonds led to a 5-fold decrease in the conductivity of the composite, even when only a fraction of diamonds of 1 wt. % were used, which was explained by the disruption in the connectivity of ion channels during the interaction of such diamonds mainly with fluorocarbon chains of the copolymer. We discussed the specifics of the mechanism of conductivity in composites with various diamonds in connection with structural data obtained in neutron scattering experiments on dry membranes, as well as ideas about the formation of cylindrical micelles with central ion channels and shells composed of hydrophobic copolymer chains. Finally, the characteristics of the network of ion channels in the composites were found depending on the type and amount of introduced diamonds, and correlations between the structure and conductivity of the membranes were established.

Synthesis and crystal structure of bis-(9-mesityl-9,10-di-hydro-10-aza-9-borabenzo[h]quinolinato-κ2N1,N10)zinc(II).

The title compound, [Zn(C20H18BN2)2] (Zn L 2), is an overall uncharged chelate that consists of two units of an NH-deprotonated 10-aza-9-borabenzo[h]quinoline ligand (L) per ZnII center. It was synthesized in two steps by treating the protonated ligand HL with lithium bis-(tri-methyl-sil-yl)amide and further conversion with di-ethyl-zinc. Its asymmetric unit comprises one ZnL fragment; the mol-ecule is completed by application of inversion symmetry at Zn. Due to the fourfold coordination with nitro-gen atoms, the zinc(II) ion is located in a distorted tetra-hedral environment. Besides the relatively short N-Zn bonds, Zn L 2 is characterized by the significant protrusion of the central ion from the plane of the ligand backbone. The crystal structure is consolidated by intra- and inter-molecular π-π stacking inter-actions, while the polarized B-N bond is barely involved in any close atom contacts.

Structural, physicochemical characterization and antimicrobial activities of a new tris(8-quinolinolato-κ2N,O)cobalt(III) ethanol solvate [Co(C9H6NO)3].(C2H6O)

We report herein the synthesis and physicochemical characterization of a new 8-hydroxyquinoline cobalt(III) complex ethanol solvate with formula [Co(C9H6NO)3].(C2H6O). This compound was been prepared by slow evaporation at room temperature and characterized by single crystal X-ray diffraction. It crystallizes in the monoclinic system, spaces group P21/n. The central cobalt ion has a slightly distorted square bipyramidal environment, coordinated by three chelating 8-hydroxyquinoline molecules. Structural cohesion is primarily established by π-π interactions between the neighboring rings of quinoline groups and intermolecular hydrogen bonds O-H…O connecting the cobalt complex entities and uncoordinated ethanol molecules.The title compound has been characterized by the infrared (IR) and the UV–Visible (UV–Vis) spectra. Intermolecular interactions in the crystal structure were quantified by Hirshfeld surface analysis. The band gap of the complex was calculated using solid-state reflectance spectra, and the results show that the complex acts as a semiconductor. Moreover, the new compound exhibits high antibacterial and antifungal activities, as detected by the well agar diffusion against various bacterial and fungal clinical strains. The superior inhibitory effect was observed against Klebsiella pneumoniae, Candida albicans and Candida glabrata with zones inhibition of about 17.5, 17.5 and 17 mm, respectively.

Triple microenvironment modulation of zeolite imidazolate framework (ZIF) nanocages for boosting dopamine electrocatalysis

Multiple microenvironmental modulation of zeolite imidazole framework-8 (ZIF-8) is expected to solve the long-term intractable problem of low sensitivity in electrochemical sensing. Herein, the metal phthalocyanines with different central ions (PcM, M = Fe, Co, Ni and Cu) were introduced into ZIF-8 by in-situ synthesis method. Then, the hollow composite nanomaterials, HZIF-8/PcFe and HZIF-8@PcFe (HZIF-8, i.e., hollow ZIF-8) with different TA (tannic acid) coating thicknesses (∼11 nm and ∼33 nm) were successfully fabricated by carefully designed polyphenol-mediated modulation (PMM) strategy. Next, the HZIF-8@PcFe electrochemical sensor was constructed for selective and sensitive analysis by selecting dopamine (DA) as the analyte. The TA coating (superhydrophilic state), PcFe (redox properties) and hollow MOF cavity (faster mass transfer) was used as the triple microenvironment modulation of ZIF-8 to enhance the electrocatalytic performance. Under the optimum conditions (pH = 8.0), the linear correlations of 0.3 to 200 μmol/L was obtained for the peak current response, with a detection limit of 0.1 μmol/L (S/N = 3, i.e., Signal/Noise = 3). Meanwhile, the HZIF-8@PcFe electrochemical sensor exhibited excellent interference selectivity, reproducibility and stability, which enabled it to detect low abundance DA in real samples. And the F-test (homogeneity test of variance) and t-test (student's t test) statistical analyses were employed to enhance the accuracy of the actual samples' detection. This work will enlighten researchers working in the field of porous framework composites and open up new paths for the development of hollow MOFs hybrid materials in electrochemical sensing.

2-D polypseudo-rotaxane network in (4Z,N'Z)-N’-(amino(pyridine-2-yl)methyl)isonicotionhydrazonic (apminh) Pb(II) complex: Synthesis, structural and quantum computational studies

The crystal structure of [Pb(apminh)Cl2] has been analyzed, revealing its potential as a useful component in a storage device. The complex crystallizes in the P1¯space group and is composed of a central Pb ion coordinated with two chloride anions and a tridentate apminh organic ligand. The ligand forms two chelating rings with Pb using oxygen and nitrogen atoms, resulting in a trigonal bipyramidal geometry of the central metal ion. The crystal packing of the complex is characterized by distinct intra and intermolecular interactions, with hydrogen bond interactions playing a crucial role. The complex forms 2D polymeric chains with intermolecular π...π stacking, which are bridged by the lattice solvent (methanol) through hydrogen bonds, making the 2D chains more stable. Quantum chemical calculations suggest that the complex has high kinetic stability, low chemical reactivity, electron-donating ability, and high charge storage capacity, making it a promising component for storage devices. The electronic structure analysis demonstrates the insulating nature, stable electronic structure, and long-lasting properties of the complex, providing insights into the chemical properties of the bonding in the complex. Overall, our results highlight the potential of [Pb(apminh)Cl2] as a storage device component, although further experimentation and testing are necessary to determine its suitability for this application.

Development of a cobalt (II) and 1,10-phenanthroline carboxaldehyde-based fluorescent probe for the detection of cysteine

Effective cysteine (Cys) detection is extremely important for early disease monitoring and diagnosis. In this study, a fluorescent probe (PHO) comprising 1,10-phenanthroline carboxaldehyde as the ligand and cobalt as the central ion was synthesized to detect Cys. The synthesized PHO exhibited enhanced fluorescence at 603 nm in the presence of Cys in HEPES buffer. Furthermore, the probe detected Cys concentrations as low as 0.6 μmol/L, demonstrating high sensitivity. Additionally, a strong linear relationship was established between the Cys concentration and normalized intensity of fluorescence. Importantly, the high selectivity was retained even in the presence of other interfering compounds. Consequently, this method can serve as a novel approach for detecting Cys in physiological systems.

Crystal structure of bis-{3-(3,4-di-meth-oxy-phen-yl)-5-[6-(pyrazol-1-yl)pyridin-2-yl]-1,2,4-triazol-3-ato}iron(II)-methanol-chloro-form (1/2/2).

The unit cell of the title compound, [Fe(C18H15N6O2)2]·2CH3OH·2CHCl3, consists of a charge-neutral complex mol-ecule, two methanol and two chloro-form mol-ecules. In the complex, the two tridentate 2-(5-(3,4-di-meth-oxy-phen-yl)-1,2,4-triazol-3-yl)-6-(pyrazol-1-yl)pyridine ligands coordinate to the central FeII ion through the N atoms of the pyrazole, pyridine and triazole groups, forming a pseudo-octa-hedral coordination sphere. Neighbouring tapered mol-ecules are linked through weak C-H(pz)⋯π(ph) inter-actions into one-dimensional chains, which are joined into two-dimensional layers through weak C-H⋯N/C/O inter-actions. Furthermore, the layers stack in a three-dimensional network linked by weak inter-layer C-H⋯π inter-actions of the meth-oxy and phenyl groups. The inter-molecular contacts were qu-anti-fied using Hirshfeld surface analysis and two-dimensional fingerprint plots, revealing the relative contributions of the contacts to the crystal packing to be H⋯H 32.0%, H⋯C/C⋯H 26.3%, H⋯N/N⋯H 13.8%, and H⋯O/O⋯H 7.5%. The average Fe-N bond distance is 2.185 Å, indicating the high-spin state of the FeII ion. Energy framework analysis at the HF/3-21 G theory level was performed to qu-antify the inter-action energies in the crystal structure.

Construction of three novel Co/Zn/Cd(II) coordination polymers based on the same ligands: Different spatial structures, electrocatalysis and photoluminescence properties

Three new metal coordination polymers with different spatial structure, namely {[Co2(H2O)6(4-PDCA)2]2·3H2O}n (SNUT-12), {[Cd(H2O)2(4-PDCA)]·2H2O}n (SNUT-13) and [Zn2(4-PDCA)2]n (SNUT-14), where H2(4-PDCA) = 1-(4-carboxyphenyl)-5-methyl-4-oxo-1,4-dihydropyridazine-3-carboxylic acid, were synthesized by changing the central ion with the same ligand under solvothermal and hydrothermal conditions, which were further characterized by single crystal X-ray diffraction, powder XRD, FT-IR and TGA. Single crystal X-ray analysis revealed that SNUT-12 exhibits a 1D infinite zigzag chains which were constructed by Cobalt(II) ion and 4-PDCA2− ligand, SNUT-13 features a 2D ladder-like structure. Meanwhile, SNUT-14 displays 2-fold 3D → 3D parallel interpenetrating frameworks. In addition, SNUT-12 exhibited high electrocatalytic oxygen evolution reaction, and SNUT-13, SNUT-14 showed strong fluorescence at room temperature.

Confocal Raman imaging reveals the impact of retinoids on human breast cancer via monitoring the redox status of cytochrome c

This paper expands the current state of knowledge on impact of retinoids on redox status of cytochrome c in cancers. Little is known how the expression of cytochromes may influence the development of cancers. We studied the effect of the redox status of the central iron ion in heme of cytochrome c. We determined the redox status of the iron ion in cytochrome c in mitochondria, cytoplasm, lipid droplets, and endoplasmic reticulum of the human breast cancer cells by Raman imaging. We incubated human breast adenocarcinoma cells (SK-BR-3) with retinoic acid, retinol and retinyl ester (palmitate) at concentration of 50 μM for 24 h. We recorded the Raman spectra and images of human breast cancer in vitro SK-BR-3 cells receiving redox stimuli by retinoic acid, retinol and retinyl ester (palmitate). The paper provides evidence that retinoic acid and retinol are pivotally important for mitochondrial energy homeostasis by controlling the redox status of cytochrome c in the electron transport chain controlling oxidative phosphorylation and apoptosis. We discussed the role of retinoids in metabolism and signaling of cancer cells. The paper provides experimental support for theoretical hypothesis how retinoic acid/retinol catalyse resonance energy transfer reactions and controls the activation/inactivation cycle of protein kinase PKCδ.

Size-dependent polymeric arrays of heterometallic Cs+–Ln3+ β-diketonates

A series of alkali–lanthanide heterometallic systems such as Cs+–Ln3+ β-diketonate complexes [Ln(TFPB)4Cs]n (Ln = La (1), Pr (2), Eu (3), Y (4), Yb (5), Lu (6) and TFPB = 4,4,4-trifluoro-1-phenyl-1,3-butanedione) were prepared and structurally explored. The complexes exist only in polymeric forms while both monomeric and polymeric structures are found in the previously reported Na+–Ln3+ congeners. Tuning the sizes of the central rare earth ions from La3+ to Lu3+ results in three types of infinite Cs+–Ln3+ chains which are helical, two-step zigzag and single zigzag patterns. Nonetheless, the Na+–La3+ and Na+–Eu3+ complexes (1-Na and 3-Na) are isomorphous polymers. The size variation of the Ln3+ ions can also alter the degree of π interactions of the Cs+ ions with β-diketonate fragments and phenyl rings. Interestingly, multiple interactions are detected in the complexes with small rare earth ions (5 and 6). Photoluminescence measurements reveal much brighter red emission of 3 than that of 3-Na. It is assumed that the Cs+ ions have more appropriate size than the Na+ ions toward the binding with [Eu(TFPB)4]– anions via oxygen and fluorine atoms, alleviating the energy dissipation of the excited states.

Amyloid Fibrils Formed by Short Prion-Inspired Peptides Are Metalloenzymes.

Enzymes typically fold into defined 3D protein structures exhibiting a high catalytic efficiency and selectivity. It has been proposed that the earliest enzymes may have arisen from the self-assembly of short peptides into supramolecular amyloid-like structures. Several artificial amyloids have been shown to display catalytic activity while offering advantages over natural enzymes in terms of modularity, flexibility, stability, and reusability. Hydrolases, especially esterases, are the most common artificial amyloid-like nanozymes with some reported to act as carbonic anhydrases (CA). Their hydrolytic activity is often dependent on the binding of metallic cofactors through a coordination triad composed of His residues in the β-strands, which mimic the arrangement found in natural metalloenzymes. Tyr residues contribute to the coordination of metal ions in the active center of metalloproteins; however, their use has been mostly neglected in the design of metal-containing amyloid-based nanozymes. We recently reported that four different polar prion-inspired heptapeptides spontaneously self-assembled into amyloid fibrils. Their sequences lack His but contain three alternate Tyr residues exposed to solvent. We combine experiments and simulations to demonstrate that the amyloid fibrils formed by these peptides can efficiently coordinate and retain different divalent metal cations, functioning as both metal scavengers and nanozymes. The metallized fibrils exhibit esterase and CA activities without the need for a histidine triad. These findings highlight the functional versatility of prion-inspired peptide assemblies and provide a new sequential context for the creation of artificial metalloenzymes. Furthermore, our data support amyloid-like structures acting as ancestral catalysts at the origin of life.

Synthesis, structure and Hirshfeld surface analysis of a coordination compound of cadmium acetate with 2-amino-benzoxazole.

A first coordination compound of 2-amino-benzoxazole (2AB), namely, bis-(2-amino-benzoxazole-κN 3)bis-(acetato-κ2 O,O')cadmium(II), [Cd(CH3COO)2(2AB)2], has been synthesized from ethanol solutions of Cd(CH3(COO)2 and 2AB. In the monoclinic crystals with the space group C21/c, the cadmium ions coordinate two neutral 2AB mol-ecules in a monodentate fashion through the oxazole N atom, while two acetate ligands are coordinated through the O atoms in a bidentate manner. The coordination polyhedron of the central ion is substanti-ally distorted octa-hedral. There are two relatively strong intra-molecular hydrogen bonds in the complex mol-ecule. Additionally, two inter-molecular hydrogen bonds associate complex mol-ecules into columns running in the [10] and [110] directions. The Hirshfeld surface analysis shows that 45.7% of the inter-molecular inter-actions are from H⋯H contacts, 24.7% are from O⋯H/H⋯O contacts and 18.8% are from C⋯H/H⋯C contacts, while other contributions are from N⋯H/H⋯N and O⋯O contacts.

Chloroplast magnesium transporters play essential but differential roles in maintaining magnesium homeostasis.

Magnesium (Mg2+) is essential for photosynthesis in the chloroplasts of land plants and algae. Being the central ion of chlorophyll, cofactor and activator of many photosynthetic enzymes including RuBisCO, magnesium-deficient plants may suffer from leaf chlorosis symptoms and retarded growth. Therefore, the chloroplast Mg2+ concentration is tightly controlled by magnesium transport proteins. Recently, three different transporters from two distinct families have been identified in the chloroplast inner envelope of the model plant Arabidopsis thaliana: MGT10, MGR8, and MGR9. Here, we assess the individual roles of these three proteins in maintaining chloroplast Mg2+ homeostasis and regulating photosynthesis, and if their role is conserved in the model green alga Chlamydomonas reinhardtii. Phylogenetic analysis and heterologous expression revealed that the CorC-like MGR8 and MGR9 transport Mg2+ by a different mechanism than the CorA-like MGT10. MGR8 and MGT10 genes are highest expressed in leaves, indicating a function in chloroplast Mg2+ transport. MGR9 is important for chloroplast function and plant adaptation in conditions of deficiency or excess of Mg2+. Transmission electron microscopy indicated that MGT10 plays a differential role in thylakoid stacking than MGR8 and MGR9. Furthermore, we report that MGR8, MGR9, and MGT10 are involved in building up the pH gradient across the thylakoid membrane and activating photoprotection in conditions of excess light, however the mechanism has not been resolved yet. While there are no chloroplast MGR-like transporters in Chlamydomonas, we show that MRS4 is a homolog of MGT10, that is required for photosynthesis and cell growth. Taken together, our findings reveal that the studied Mg2+ transporters play essential but differential roles in maintaining chloroplast Mg2+ homeostasis.

Synthesis and demulsification mechanism of an ionic liquid with four hydrophobic branches and four ionic centers

Stable emulsions can have numerous negative impacts on both the oil industry and the environment. This study focuses on the synthesis of two ionic liquids (via. PPBD and PPBH) with four hydrophobic branches and four ionic centers that can effectively treat oil-water emulsions at a low temperature of 40 °C. Their chemical structure was explored using Fourier-transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance hydrogen spectra (1H NMR). The effect of temperature, PPBD and PPBH concentration, oil-water ratio, salinity and pH value on the demulsification efficiency (DE) of W/O emulsion was studied detailly and several commercial demulsifiers were also used for comparison. Results revealed that by adding 250 mg/L of PPBH in an E30 emulsion and leaving it for 120 min at 40 °C, the DE could reach 96.34%. Meanwhile, in an E30 emulsion (oil-water mass ratio of 3:7) with 250 mg/L of PPBD, the DE of 95.23% could be obtained at 40 °C for 360 min. Especially, the DE of PPBH could reach 100% in an E70 emulsion (oil-water mass ratio of 7:3) at the same conditions. Additionally, the demulsifier (PPBH) exhibited excellent salt resistance and outperformed some commonly used commercial demulsifiers. Several methods were utilized to investigate the potential demulsification mechanism, including measuring interfacial tension (IFT), three-phase contact angle (CA), droplet contact time, zeta potential, and observing samples under optical microscopy.

Green Ultrasound-Assisted Synthesis of Rare-Earth-Based MOFs.

Rare-earth (RE)-based metal organic frameworks (MOFs) are quickly gaining popularity as flexible functional materials in a variety of technological fields. These MOFs are useful for more than just conventional uses like gas sensors and catalyst materials; in fact, they also show significant promise in emerging technologies including photovoltaics, optical, and biomedical applications. Using yttrium and europium as ionic host centres and dopants, respectively, and 1,3,5-benzenetricarboxylic acid (H3-BTC) as an organic linker, we describe a simple and green approach for the fabrication of RE-MOFs. Specifically, Y-BTCs and Eu-doped Y-BTCs MOFs have been synthesised in a single step using an eco-friendly method that makes use of ultrasound technology. To establish a correlation between the morphological and structural properties and reaction conditions, a range of distinct reaction periods has been employed for the synthetic processes. Detailed analyses of the synthesised samples through powder X-ray diffraction (PXRD), field emission scanning electron microscopy (FE-SEM), and Fourier-transform infrared spectroscopy (FT-IR) have confirmed the phase formation. Furthermore, thermal analyses such as thermogravimetric analysis (TGA) have been employed to evaluate the thermal stability and structural modifications of the Y-BTC and Eu-doped Y-BTC samples. Finally, the luminescent properties of the synthesised samples doped with Eu3+ have been assessed, providing an evaluation of their characteristics. As a proof of concept, an Eu-doped Y-BTC sample has been applied for the sensing of nitrobenzene as a molecule test of nitro derivatives.

Isotope dependence of transport in ST40 hot ion mode plasmas

The ST40 compact, high-field spherical tokamak, operating at 2.1 T and with 1.8 MW of neutral beam heating, achieved central carbon impurity ion temperatures in excess of 10 keV, surpassing their business milestone of 100 M ∘C (8.6 keV). The high temperature discharges were in the hot ion mode, with , and they were achieved in both hydrogen and deuterium plasmas with deuterium neutral beam injection. In order to achieve the high temperature scenarios, careful wall conditioning and scenario optimization was carried out in , , and finally in plasmas. The TRANSP transport code was employed to study the dependence of confinement and transport on isotopic mass, and the conditions that led to the high measured central ion temperatures in the and plasmas. The kinetic profiles input into TRANSP were inferred from line-of-sight and limited radial measurements as well as consistency with a number of other experimental constraints. The TRANSP results first showed that the main species central ion temperature was only 0.5–1 keV lower than the measured carbon impurity temperature, and thus in the high performance plasmas also surpassed the 100 M ∘C level. TRANSP also showed that while the electron thermal conduction loss was dominant, reductions in central ion transport, and an effective decoupling of the ions from the electrons, led to an increase in central ion temperatures with increasing plasma mass. In fact, the associated confinement times exhibited a strong dependence on the isotopic mass of the thermal plasma. These preliminary results are foundations for dedicated experiments with full kinetic profile measurements on ST40 in the next run campaign.

Synthesis and characterization of phenoxy-bridged copper(II) complexes: Structural features, magnetic, thermal and redox properties, and theoretical studies

Three phenoxy-bridged Cu(II) complexes, atrinuclear partial cubane type Cu(II) complex [Cu3(L1)3(µ3-OH)](ClO4)2 (1) (where L1H = (E)-2-(((2-aminoethyl)imino)methyl)-5-(diethylamino) phenol) and two dinuclear Cu(II) complexes, [Cu(L2)(MeOH)(OMe)]2 (2)and [Cu(sal)(bipy)(ClO4)]2 (3) (where L2H = (E)-N'-(5-bromo-2-hydroxybenzylidene) benzohydrazide), sal = 5-Bromo salicylaldehyde, bipy = 2,2-Bipyridine) were synthesized via in-situ reaction and have been successfully characterized both experimentally and computationally. In an in-situ reaction, the Schiff base formed (L1H/L2H) behaves as tridentate ligands having ONO donor sites. The structures of Cu(II) complexes(1)-(3)were established by X-ray crystallography. In the trinuclear Cu(II) complex(1), the three phenoxy oxygen atoms of ligand L1 bridge the Cu(II) center ions in µ3-fashion, while in dinuclear Cu(II) complexes (2)and(3), the phenoxy oxygen bridges the Cu(II) center ionsin µ2-fashion. The temperature dependence magnetic susceptibility, thermal gravimetric analysis (TGA) and cyclic voltammetry analysis were performed for Cu(II) complexes(1)-(3). Hirshfeld surface analysis and 2D fingerprint plots have also been explored in the crystal structure of complexes.