X-ray Powder Diffraction Patterns Research Articles

Fine-tuning the molecular conformation and packing structures of coumarin-based luminogens to achieve distinct piezochromic properties upon mechanical grinding and under hydrostatic pressures.

Organic luminogens (OLs) exhibiting piezochromic (PC) properties have drawn much attention owing to their great application potentials. Both mechanical grinding (MG) and hydrostatic pressures (HP) can induce PC behaviors of OLs, and it is highly desirable to combine the two strategies to study the PC properties of OLs for comprehensively exploring their application scopes and deeply understanding the intrinsic PC mechanisms. In this work, four coumarin derivatives with different substituents at 3- or 4-positions are designed and synthesized to investigate their PC properties by MG and under HP. By MG, two materials show PL shifts, and the PL of the other two molecules barely change. In contrast, under HP, these molecules all exhibit PL shifts, but with different pressure coefficients. In addition, they show different reversibility of PL change after releasing HP. The different molecular conformation and packing structure changing manners of the materials, indicated by single-crystal and powder X-ray diffraction patterns, and in situ PL lifetime analysis, are anticipated to induce distinct PC behaviors upon disparate force stimulus. Our study indicates that fine-tuning the functionalization position of coumarin derivatives is a powerful strategy to engineer their molecular conformation and packing structures, thus developing versatile pressure-responsive OLs.

Energy trapping to substitutional and charge compensation defects in persistent luminescent BaAl2O4:Tb3+

The holistic approach of the photoluminescence (PL), thermoluminescence (TL), and persistent luminescence properties at room temperature of BaAl2O4:Tb3+ were investigated in detail using a wide range of techniques. Materials were obtained using a solution combustion synthesis. The x-ray powder diffraction patterns of nondoped and Tb3+ doped BaAl2O4 indicated the hexagonal phase, and a Tb4O7 solid solution was observed at 4 and 5 mol% Tb doped aluminate. X-ray photoelectron spectroscopy revealed that Ba occupied one site and that Tb ions occupied this site as Tb3+ as well as TbIV. PL emission in blue, green, and red was observed under an excitation at 228 nm, that originated from the interconfigurational 4f8–4f75d1 transitions of Tb3+. Time-of-flight secondary ion mass spectroscopy, UV–vis diffuse reflectance, and PL revealed the presence of a Cr3+ impurity. The 0.5 mol% Tb3+ doped BaAl2O4 exhibited a strong TL band at 354, 437 and 598 K, which were attributed to the traps formed by Tb3+ doping and subsequent O2− charge compensation. A persistent luminescence mechanism was constructed for the Tb3+ doped BaAl2O4. After the energy was stored in thermally liberated Tb3+ in the Ba2+ substitution sites and charge compensation defects, the Tb3+ was the source of the continuous luminescence.

Energy band gap tuning of Ba-Ca hexagonal ferrite by Dy3+ ion substitution (0 ≤ x ≤ 0.2) to improve spectral, structural, dielectric and photocatalytic properties

In the present study, Dy3+ substituted M-type Ba0.5Ca0.5DyxFe12-xO19 (0.00 ≤ x ≤ 0.20) hexagonal ferrites were synthesized using sol-gel auto-combustion method with lemon extract as a fuel. The single hexaferrite phase with space group P63/mmc is revealed by the X-ray powder diffraction (XRD) patterns. The Field emission scanning electron microscopy (FESEM) exhibits the agglomeration of nanoplates with vacancies at some places. Energy dispersive X-ray photoelectron spectroscopy (EDAX) mapping confirmed the presence of Ba, Ca, Fe, O, and Dy in the hexaferrite. Fourier Transform Infrared (FTIR) spectroscopy exhibits two characteristic bands at 579 and 429 cm−1 corresponding to tetrahedral and octahedral metal ions-oxygen stretching, revealing the occurrence of the ferrite phase. The optical energy band gap calculated using the Tauc plots was found to increase with the increase in dysprosium substitution to fall within the range of 2.8–3.5 eV. The Raman spectra confirmed the Raman vibration modes and M-type structures of hexagonal ferrites (HFs). The dielectric constant values drop rapidly with increasing frequency up to a few KHz and then gradually for the further higher frequencies. The occurrence of Ba and Ca with 2+, while Dy, and Fe with 3+ oxidation states is confirmed using X-ray photoelectron spectroscopy (XPS). The HFs exhibit remarkable efficiency by degrading the Reactive Brown dye to 99.3 % in just 15 min, equivalent to a high degradation reaction rate constant (k) value of up to 0.0396 min−1. Consequently, the catalyst shows promising potential for environmental remediation.

Magnetic properties and linear negative magnetocapacitance in rutile like LiFe2SbO6

Abstract We report the high-temperature magnetic ordering and the observation of linear negative magnetocapacitance mediated by a low-temperature magnetic phase crossover in the compound LiFe2SbO6. The combined observations of the absence of a second harmonic generation (SHG) signal, and Rietveld refinements of X-ray and neutron powder diffraction (NPD) patterns of the sample confirm that LiFe2SbO6 crystalizes in a centrosymmetric Pnnm structure. The DC magnetization measurements reveal that an antiferromagnetic ordering sets in at high temperature (TN= 850). The magnetic anomaly in the DC magnetization at a lower temperature T = 13 K, is corroborated by AC susceptibility and the specific heat measurements. We observe a linear negative magnetocapacitance below T = 13 K, demonstrating an indirect magneto-dielectric coupling. Further, the neutron powder diffraction study reveals a collinear antiferromagnetic ordering with a wavevector k = (0, 0, 0).

Characterization and solubility measurement of synthetic uranophane and sklodowskite under oxic groundwater conditions

Naturally occurring uranyl silicates can serve as solubility-limiting solid phases (SLSPs) of U(VI) in the oxic environment of granitic groundwater, which is likely to occur in crystalline host rock media in Korea. In this study, two synthetic uranyl silicates, uranophane (Ca[UO2SiO3OH]2·5H2O) and sklodowskite (Mg[UO2SiO3OH]2·6H2O) were prepared and used to measure the U(VI) solubility in simulated groundwater (sGW), mimicking the composition of samples collected from the underground research tunnel at the Korea Atomic Energy Research Institute (KAERI). The solid- and solution-phase species involved were examined in detail using various characterization methods. According to the powder X-ray diffraction pattern and elemental analysis results, the synthetic mineral phases, which were identified as uranophane-α and sklodowskite having layered crystal structures, were retained intact in sGW; however, in 0.1 M NaClO4, emergence of other solid phases was observed. Enhanced FTIR and Raman spectroscopic data, particularly in the regions of 790–860 and 940–1020 cm−1 for the UO22+ and SiO44− ions, respectively, enable monitoring the changes in the solid phases. Ternary Ca–U(VI)-tricarbonato complexes were identified as the dominant dissolved U(VI) species in sGW using time-resolved laser-induced luminescence spectroscopy. Furthermore, the solubility constant of uranophane was calculated (log Ks,0° = 10.3 ± 0.4) and compared with the predicted values based on our geochemical modeling analysis and previously reported ones.

Preparation of pure phase silver nanoparticles: Morphological, optical, binding interactions with bovine serum albumin and antioxidant potential studies

Pure silver nanoparticles (AgNPs) were synthesized using Senecio madagascariensis plant extract and oleic acid as capping agents. The powder X-ray diffraction patterns of the silver nanoparticles were indexed to the face-centred cubic phase of Ag. TEM images of the nanoparticles revealed polydisperse spherical nanoparticles with particle size of 9 to 22 nm range. The GC-MS revealed terpenes as some phytochemicals extracted, which the FTIR bands corroborated. The results confirmed that increase in oleic acid concentration increased the size of the silver nanoparticles. The nanoparticles' optical band gaps, Eg, were 2.26 – 2.56 eV, which decreased with particle size. The AgNPs exhibited potential antioxidant activity, as demonstrated by the DPPH scavenging assay. The DPPH scavenging activity was highest, with AgNP1 at 80 % and an IC50 of 1.668 μg/mL. Fluorescence and ultraviolet (UV) titrations were used to study the interaction of the silver nanoparticles (AgNP1) with bovine serum albumin (BSA). The Kapp value of the AgNP1 was calculated to be 3.14 × 104 ± 0.02 Lmol−1, KSV calculated as 7.38 × 104 ± 0.12 M−1. In the study, AgNPs bind to BSA potentially through a static quenching mechanism with one binding site that leads to developing a ground state complex. It is proposed that AgNPs bond to BSA's surface spontaneously based on its thermodynamic characteristics and binding constants.

Microwave-assisted synthesis of γ-alooh nanoflowers as an adsorbent for cadmium removal from domestic wastewater.

In this study, cadmium ions were effectively removed from domestic wastewaters using an adsorptive treatment strategy based on γ-AlOOH nanoflowers. A novel, rapid, and simple procedure was developed for the synthesis of the nanoflowers. Characterization studies were performed using X-ray powder diffraction patterns and scanning electron microscope images. The synthesized nanoflowers were utilized as adsorbent in the batch adsorption experiments. The influential parameters of the adsorption process were optimized, and a flame atomic absorption spectrophotometry (FAAS) system was used to determine maximum percent removal of cadmium ions. Matrix-matched calibration strategy, in which the calibration plot was developed in wastewater medium, was utilized for the accurate and precise quantification of cadmium in the effluent samples. The percentage removal efficiency values were calculated between 84 and 98% for different concentrations of cadmium ions in the wastewater samples. Equilibrium data was fitted to the four different linearization methods of the Langmuir isotherm model, as well as the Freundlich isotherm model and Elovich isotherm model. The best fitting was achieved for the Langmuir model with a high R2 value of 0.9956 and maximum adsorption capacity was calculated as 6.23mg/g.

Single crystal structure features, optimization of ultrasonic conditions, density functional theory studies, and antibacterial activity of a new organic compound

The synthesis of a novel water-soluble organic compound, N’-acetyl-4-nitrobenzohydrazide, was successfully achieved using hydrothermal and sonochemical methods. The resulting products, denoted as 1 and 2, were obtained as single crystals and powder, respectively. Characterization of the crystals through single-crystal X-ray diffraction (SC-XRD) indicated a monoclinic system with space group -P 2yn. Elemental analysis (CHN), energy-dispersive X-ray spectrometer (EDS), Fourier transform infrared spectroscopy (FT-IR), thermal analysis (TGA/DTA), and powder X-ray diffraction pattern (PXRD), were utilized to analyze the molecular structure of 1 and 2, confirming their identical nature. Furthermore, scanning electron microscopy (SEM) was employed to examine the surface morphology of compounds 1 and 2, revealing distinct morphological features and varying particle dimensions. The impact of time, temperature, and ultrasonic energy was examined to optimize the morphology and particle size of compound 2. A density functional theory (DFT) study was performed to find the role of intramolecular hydrogen bond (IHB) interactions on the capability of the different tautomers of newly synthesized organic compounds. Various properties such as total energies of tautomers, energies of the most important molecular orbitals, electronegativity, thermodynamic functions, molecular electrostatic potential (MEP) maps, electron charge densities, and aromaticity were computed. The antimicrobial activity of 1, and 2 have been evaluated against one Gram-positive (Staphylococcus aureus, ATCC 25923) and one Gram-negative (Escherichia coli, ATCC 25922) using the disc diffusion method. The analysis of the inhibition zones revealed that 2 exhibit enhanced antibacterial efficacy compared to 1. This observation suggests that particle size reduction may contribute to increased antibacterial activity, potentially due to enhanced interaction with bacterial targets.

Fabrication of modified Sb2O3 nanospheres for the removal of hazardous malachite green organic pollutant and selective NO2 gas sensor

Sb2O3 and Ni modified Sb2O3 (Ni–Sb2O3) nanospheres were synthesized using low cost co-precipitation method and characterised using various instrumental methods such as X-ray Powder Diffraction (XRD), High Resolution Transmission Electron Microscopy (HR-TEM), Scanning Electron Microscopy (SEM), Energy dispersive X-ray spectroscopy (EDS), and Fourier-transform infrared (FT-IR) spectroscopy. The XRD pattern reveals cubic crystal lattice. The average size of Sb2O3 and Ni–Sb2O3 nanoparticles was calculated to be around 41 nm and 29 nm, respectively. The HR-TEM investigation of the Sb2O3 nanomaterial reveals homogeneous spherical balls with a fine dispersion. The random-shaped nanoparticles with porous surfaces and voids were revealed by SEM. EDS examination confirms the elemental composition of Sb (41.79 %) and O (58.21 %) in Sb2O3 and Sb (36.80 %), O (58.95 %), and Ni (4.25 %) in Ni–Sb2O3. Sb2O3 and Ni– Sb2O3 exhibit band gaps of 3.67 eV and 3.51 eV, respectively, according to UV–Vis analysis. The IR peaks 445.47, 642.18, and 745.18 in Sb2O3 and 438.72, 645.07, and 756.92 in Ni– Sb2O3 support the Sb–O bonding in the synthesized nanomaterials. The synthesized nanomaterials have been used for photocatalytic degradation of malachite green (MG) dye and sensing NO2, SO2, CO2, petroleum vapour and LPG gases. The MG dye was degraded 97.67 % in 120 min using Ni–Sb2O3 at optimized conditions (catalyst dose: 0.1 g/L to 0.3 g/L, pH: 7 and MG dye: 10 ppm). The gas sensing study showed that Ni–Sb2O3 sensor has greater sensitivity and selectivity for NO2 gas.

Defect tuning and its effect on conductivity, dielectric properties of combustion derived nano CeO2: A fuel dependent approach

Oxalyldihydrazide (ODH) and coffee extracted fuel (CEF) were used to synthesize Ceria (CeO2) nanoparticles by solution combustion synthesis route. The cubic fluorite structure, crystalline nature, crystallite size and particle size of ceria nanoparticles were confirmed using the powder X-ray diffraction (PXRD) and High-Resolution Transmission Electron Microscope patterns respectively. Field Emission Scanning Electron Microscope (FESEM) images were used to understand the Surface morphology of the synthesized samples. Based on XRD results the volume of coffee husk extract for the optimum phase formation is found to be 40 mL. The fluorite structure of the samples and the presence of oxygen vacancies in the samples were confirmed from the Raman spectral analysis. ESR (Electron Spin Resonance) studies confirmed formation of relatively more intrinsic defects in CEF-ceria nanoparticles compared to ODH-ceria nanoparticles. The semiconducting nature of the synthesized samples was confirmed by analysing UV–visible absorbance spectra. The functional group confirmation was obtained by analysing Fourier Transform Infrared (FTIR) spectra of both the samples. AC conductivity and dielectric relaxation studies of the samples in pellet form were carried out over a wide frequency (20Hz–10 MHz) and temperature (200–640 °C) range using a precision impedance analyser. A higher value of dielectric constant was observed for CEF-ceria nanoparticles.

Single-crystal growth, crystal structure, and molecular dynamics of organic–inorganic [NH3(CH2)2NH3]CuBr4

As part of obtaining excellent properties that can be used as lead-free hybrid solar cells, the crystal growth, crystal structure, phase transition temperature, and thermal properties for [NH3(CH2)2NH3]CuBr4 were discussed. The crystal structure at 300 K was determined to be monoclinic by single-crystal X-ray diffraction (XRD) analysis. The phase transition temperatures were determined to be 447 and 473 K, and the results were consistent with the powder XRD patterns. Thermogravimetric analysis revealed thermal stability up to ~ 460 K. The continuous changes in the 1H and 13C chemical shifts and 14N static resonance frequency with increasing temperature are related to variations in the local environment and coordination geometry. The significant differences in activation energies obtained from the 1H and 13C spin–lattice relaxation times (t1ρ) at low and high temperatures were discussed. The activation energy results suggested that the energy barrier at low temperatures was related to the reorientation of the NH3 and CH2 groups around the three-fold symmetry axis, and the energy barrier at high temperatures was related to the reorientation of the [NH3(CH2)2NH3] cation. These physical properties will be provide important insights or potential applications of this crystal.Please check and confirm that the corresponding author and their respective corresponding affiliation have been correctly identified and amend if necessary.OK !

Polyoxometalate inhibition of SOX2-mediated tamoxifen resistance in breast cancer

BackgroundIncreased cancer stem cell (CSC) content and SOX2 overexpression are common features in the development of resistance to therapy in hormone-dependent breast cancer, which remains an important clinical challenge. SOX2 has potential as biomarker of resistance to treatment and as therapeutic target, but targeting transcription factors is also challenging. Here, we examine the potential inhibitory effect of different polyoxometalate (POM) derivatives on SOX2 transcription factor in tamoxifen-resistant breast cancer cells.MethodsVarious POM derivatives were synthesised and characterised by infrared spectra, powder X-ray diffraction pattern and nuclear magnetic resonance spectroscopy. Estrogen receptor (ER) positive breast cancer cells, and their counterparts, which have developed resistance to the hormone therapy tamoxifen, were treated with POMs and their consequences assessed by gel retardation and chromatin immunoprecipitation to determine SOX2 binding to DNA. Effects on proliferation, migration, invasion and tumorigenicity were monitored and quantified using microscopy, clone formation, transwell, wound healing assays, flow cytometry and in vivo chick chorioallantoic membrane (CAM) models. Generation of lentiviral stable gene silencing and gene knock-out using CRISPR-Cas9 genome editing were applied to validate the inhibitory effects of the selected POM. Cancer stem cell subpopulations were quantified by mammosphere formation assays, ALDEFLUOR activity and CD44/CD24 stainings. Flow cytometry and western blotting were used to measure reactive oxygen species (ROS) and apoptosis.ResultsPOMs blocked in vitro binding activity of endogenous SOX2. [P2W18O62]6− (PW) Wells-Dawson-type anion was the most effective at inhibiting proliferation in various cell line models of tamoxifen resistance. 10 µM PW also reduced cancer cell migration and invasion, as well as SNAI2 expression levels. Treatment of tamoxifen-resistant cells with PW impaired tumour formation by reducing CSC content, in a SOX2-dependent manner, which led to stem cell depletion in vivo. Mechanistically, PW induced formation of reactive oxygen species (ROS) and inhibited Bcl-2, leading to the death of tamoxifen-resistant cells. PW-treated tamoxifen-resistant cells showed restored sensitivity to tamoxifen.ConclusionsTogether, these observations highlight the potential use of PW as a SOX2 inhibitor and the therapeutic relevance of targeting SOX2 to treat tamoxifen-resistant breast cancer.

Visible/near-infrared luminescence and concentration effects of Pr3+-doped Sr2Al2GeO7 downconversion phosphors

The Pr3+ ion has been widely doped into various materials as a red and near-infrared (NIR) emitting center for applications in lighting and solar spectrum downconversion. Herein, the preparation of a new library of Pr3+-doped Sr2Al2GeO7 phosphors was proved by powder x-ray diffraction patterns and Rietveld refinements and characterized by a scanning electron microscope with energy-dispersive x-ray spectrometry. The Sr2Al2GeO7:Pr3+ sample strongly absorbs blue photons over 420–500 nm and yields intense visible emissions with dominant peaks around 490 nm from the Pr3+ 3P0 → 3H4 transition, as well as robust NIR emission bands over 800–1200 nm. In addition to the typical transitions of 1D2 → 3F2 at 880 nm, 1G4 → 3H4 at 1000 nm, and 1D2 → 3F3,4 at 1070 nm, the distinguishable NIR emission at 929 nm was demonstrated from the 3P0 → 1G4 transition via static and dynamic spectroscopic analysis. Most interestingly, for the 3P0 blue-excited state, a considerably elevated concentration of about 10%Pr3+ was optimal for the visible/NIR emissions, in stark contrast to the diluted optimal 1%Pr3+ for the 1D2 state. The relevant cross-relaxation from the 3P0 and 1D2 states between Pr3+ was comprehensively treated by theoretical speculations and experimental results. Such concentrated Pr3+ blue activators would significantly facilitate the blue-to-NIR downconversion through a desired two-step sequential transition from the 3P0 initial state to the 1G4 intermediate level for quantum efficiency exceeding unity. The current results would consolidate the basis of concentrated Pr3+ donors to promote the novel Pr3+/Yb3+ codoping downconversion for greatly increasing Si solar cell efficiency.

Facile Biogenic synthesis of Europium doped lanthanum silicate nanoparticles as novel supercapacitor electrodes for efficient energy storage applications

In this work, we demonstrated for the first time, use of Europium doped lanthanum silicate nanoparticles (LS NPs) as electrodes for supercapacitor applications. Europium (Eu3+) doped (5 mol%) LS NPs were synthesized by green solution combustion method using Mexican mint leaf extracts. Various analytical techniques such as High-Resolution Transmission Electron Microscopy (HRTEM), Selected Area Diffraction (SAED), Powder X-ray Diffraction (PXRD), Fourier Transform Infra-Red Spectroscopy (FTIR) and Diffuse Reflectance Spectroscopy (DRS) techniques were used to confirm the morphological and structural characteristics of the synthesized nanoparticles. The HRTEM and SAED patterns confirms the formation of NPs having agglomerated structure with a particle size less than 50 nm. The PXRD patterns reveals crystalline cubic structure for the NPs. Further, the FT-IR spectra reveal the successful doping of Europium in Lanthanum Silicate NPs. The DRS (Diffuse Reflectance Spectroscopy) studies confirm the reduced band gap for Europium (Eu3+) doped (5 mol%) LS NPs. Cyclic voltametric and electrochemical impedance spectroscopy experiments were performed in an alkaline medium to compare the electrochemical activity of Eu3+ doped LS NPs with that of their undoped counterpart. The Eu3+ doped (5 %) LS NPs electrodes attained a specific capacitance of 373.3 Fg-1 at a current density of 0.5 Ag-1 in comparison to pure LS NPs which is about 267 Fg-1. The long-term stability of the Eu3+ doped (5 %) LS NPs electrodes show excellent stability up to 4000 cycles of operation in comparison pure LS NPs electrodes. Doping of Eu3+ had a favourable effect on the conductivity and electrochemical activity of LS NPs. Due to favourable green combustion synthesis, superior electrochemical performance, these Eu3+ doped LS NPs could be potential materials for new generation supercapacitors in energy storage applications.

Colloidal nanoparticles of a β-cyclodextrin/L-Tryptophan inclusion complex for use as Pickering emulsion stabilizers

Inclusion complexes of β-cyclodextrin (β-CD) and tryptophan (Trp) were synthesized using an antisolvent approach, and fully characterized. Scanning electron microscope images proved the formation of the β-CD/Trp nanoparticles (NP) and the powder X-ray diffraction pattern indicated the formation of a crystalline channel-like structure for the β-CD/Trp NPs (NPs). The NPs of a β-CD/Trp inclusion complex were used as a natural stabilizer at the oil/water interface of a Pickering emulsion. Pickering emulsions with an oil to water ratio of 1:1 (v:v) were obtained under high-speed homogenization and different mass ratios of the β-CD to Trp (1:0, 1:0.1, 1:0.25, 1:0.5, 1:1), and at different pH levels (3, 5, 7, 9). At pH 9, when the β-CD:Trp mass ratio was 1:0.1, the β-CD/Trp NPs were hydrophilic, and the oil-in-water Pickering emulsions stabilized by those nanoparticles showed the highest storage stability: 180 days at room temperature. In contrast, when the emulsions were prepared at pH 5 with the weight ratios of either 1:0.1 or 1:1, β-CD:Trp, the nanoparticles were hydrophobic and could be used to stabilize water-in-oil Pickering emulsions.

Karlleuite Ca2MnO4 – a first mineral with the Ruddlesden-Popper type structure from Bellerberg volcano, Germany

AbstractKarlleuite, ideally Ca2MnO4, is a newly approved accessory mineral found in the xenolith sample within the basaltic lava from the Caspar quarry, Bellerberg volcano, Eifel, Germany. It usually occurs as thin tabular/plate crystals, which range from 40 to 80 μm in diameter, and is associated with other members of the perovskite supergroup such as srebrodolskite, brownmillerite, sharyginite, perovskite, and lakargiite distributed within rock-forming minerals represented by reinhardbraunsite, fluorellestadite, fluorapatite, larnite, gehlenite, and several hydrated Ca aluminosilicates. Karlleuite crystals are brown with sub-metallic lustre, a light brown streak, and a good cleavage along (001). It is non-fluorescent, brittle and has an uneven fracture, a Mohs hardness of 3.5 and calculated density Dx = 3.79 g/cm3. The empirical formula of the holotype karlleuite calculated based on O = 4 atoms per formula is (Ca1.97Ce3+0.06)2.03(Mn4 + 0.39Ti0.36Fe3+0.19Al0.09)1.03O4, which shows that it is a multicomponent phase characterised by various substituents at the octahedral site. Karlleuite is tetragonal I4/mmm (no. 139), with a = 3.7683(2) Å, c = 11.9893(8) Å, V = 170.254(17) Å3, and Z = 2. The calculated strongest lines in the X-ray powder diffraction pattern are [d in Å (I) hkl]: 5.995 (43), 2.742 (100), 2.665 (91), 2.023 (25), 1.998 (28), 1.884 (61), 1.553 (38), 1.371 (24). The new mineral is the first natural phase which exhibits a first order of Ruddlesden-Popper type structure, which indicates a modular nature and consists of Ca(Mn, Ti, Fe, Al)O3 perovskite layers, packed between CaO rock-salt layers arranged along the c-axis. Raman spectroscopy supports the interpretation of the chemical and structural data. Mineral association, structural data, as well as the study of the synthetic Ca-Mn-O system suggest that karlleuite could form under high-temperature conditions, above 1000˚C.

Preparation of SrVO3 by annealing of Sr2V2O7 in a reducing atmosphere

This study focuses on the synthesis of SrVO3 through the reduction of Sr2V2O7 by annealing in a reducing atmosphere. The effects of annealing temperature and annealing duration on Sr2V2O7 were investigated. The X-ray powder diffraction pattern showed that stoichiometric changes to Sr2V2O7 were achieved only at an elevated annealing temperature of 1000 °C in a reducing atmosphere, and that the desired SrVO3 was obtained only after 144 h of annealing. Further investigation of SrVO3 was performed using X-ray photoelectron spectroscopy, which confirmed that the reduction of V5+ found in Sr2V2O7 to V4+ found in SrVO3 was achieved.

Hybrid Organic-Inorganic Copper and Cobalt Complexes for Antimicrobial Potential Applications

Background/Aims: The naturally occurring phenolic chemical curcumin (CUR), which was derived from the Curcuma longa plant, has a variety of biological actions, including anti-inflammatory, antimicrobial, antioxidant, and anticancer activities. Curcumin is known for its restricted bioavailability due to its hydrophobicity, poor intestinal absorption, and quick metabolism. To boost the biological effects of these bioactive molecules, it is necessary to raise both their bioavailability and their solubility in water. Aim: The aim of this study is to synthesize and characterize hybrid organic-inorganic complexes of copper and cobalt, and to evaluate their antimicrobial potential against a range of pathogenic microorganisms. Methods: The synthesis of metal curcumin complexes (Cu-CUR and Co-CUR) was achieved by mixing curcumin with copper acetate monohydrate. The solid residue was isolated, filtered, and dried in an oven. X-ray diffraction analysis was used to identify the structure and phase of the prepared samples. FTIR spectra were recorded using a Shimadzu 2200 module. The antimicrobial activity of the prepared complexes was evaluated against four bacterial strains and two Candida species. The chemical materials were dissolved in DMSO to a final concentration of 20%, and the plates were incubated at 37°C for 24 hours. The results showed that the prepared complexes had antimicrobial activity against the tested microorganisms. Results: The study compared the Powder X-ray diffraction (XRD) patterns of prepared copper and cobalt complexes to pure curcumin, revealing new, isostructural complexes. The FTIR analysis showed that the Cu-CUR and Co-CUR complexes varied in their inhibitory effect against microorganisms, with Co-CUR being more effective. The results are consistent with previous studies showing the cobalt-curcumin complex was effective against various bacterial genera, with inhibition activity varying depending on the species and strains of microorganisms. Conclusion: Copper and cobalt curcumin complexes, synthesized at room temperature, exhibit high crystallinity and antimicrobial activity. Co-CUR, with its superior antibacterial potential, outperforms pure curcumin in inhibiting microbes. Further investigation is needed to understand their interaction mechanisms with bacteria and fungi.

Ziziphus nummularia leaves extract mediated CuO nanostructures for photocatalytic degradation of Methylene Blue

In this study, Ziziphus nummularia leaves extract was applied for the synthesis of CuO nanostructures. The material was characterized by various techniques such as Infrared (IR) spectroscopy, X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray (EDX) and scanning electron microscope (SEM) analysis. The characteristic peaks in powder XRD pattern of nanostructured of CuO at 2θ of 32.33, 35.57, 38.71, 46.11, 48.80, 51.50, 58.22, 61.58, and 68.08◦, correspond to (110), (−111), (111), (−112), (−202), (112), (202), (−113), and (220), respectively, match with diffraction patter of standard monoclinic phase of CuO (JCPDS: 01–080-1916). Tauc plot was plotted and band gap energy was calculated, and found to be 2.4 eV. The material was tested as photocatalyst for degradation of MB, and worked well at optimum parameters such as dosage of catalyst 25 mg, concentration of MB 20.0 mg L−1, pH 7 and time 120 min. The proposed method worked very well on synthetic solutions with degradation efficiency (%) ≥ 83.51 and an RSD (%) of ≤ 4.0.

Synthesis and crystal structure of new Mn (III) complex; a target catalyst for direct conversion of thiols after heterogenization

In this study, we are interested in the synthesizing of a new water-soluble complex of Mn (III) formulated as [Mn(pzo)(dipic)(H2O)2]2·3H2O; hereafter referred to as complex 1 where pzo− = pyrazonate and dipic2− = pyridine-2,6-dicarboxylate, under hydrothermal conditions. The molecular structure of complex 1 is primarily determined by single crystal X-ray diffraction (SC-XRD) which shows two mono-nuclear complexes of Mn (III) with three lattice water molecules. According to SC-XRD, complex 1 crystallizes in space group P1¯ of a triclinic system. The center of Mn (III) is seven-coordinated with a distorted pentagonal-bipyramidal geometry with three oxygen atoms and two nitrogen atoms in the equatorial plane. Two oxygen atoms of two water molecules are coordinated in the axial positions. In addition, the structure of complex 1 has been studied by elemental analysis (CHN), Fourier-transform infrared spectroscopy (FT-IR (, thermogravimetric analysis/differential thermal analysis/differential thermogravimetry (TGA/DTA/DTG). Complex 1 has been immobilized on the silica-coated Fe3O4 nanoparticles to produce an efficient and recyclable heterogeneous catalyst formulated as Fe3O4@SiO2@1; hereafter referred to as catalyst 1. Catalyst 1 was characterized by inductively coupled plasma optical emission spectrometry (ICP-OES), energy-dispersive X-ray spectrometer (EDS), FT-IR, scanning electron micrograph (SEM), powder X-ray diffraction pattern (PXRD), and Brunner-Emmet-Teller (BET). 1 was used as a new heterogeneous catalyst for the oxidative coupling of thiols to their corresponding disulfides using 30 % H2O2. Under optimum reaction conditions, catalyst 1 exhibited high catalytic activity. 1 can be recovered by a magnet and reused for at least 7 consecutive cycles without significant loss of catalytic performance.