Powder Diffraction Research Articles

An organic-organometallic CO-releasing material comprising 4,4'-bipyridine and molybdenum subcarbonyl building blocks.

Over the past two decades, following the discovery of the important biological roles of carbon monoxide (CO), metal carbonyl complexes have been intensively studied as CO-releasing molecules (CORMs) for therapeutic applications. To improve the properties of "bare" low molecular weight CORMs, attention has been drawn to conjugating CORMs with macromolecular and inorganic scaffolds to produce CO-releasing materials (CORMAs) capable of storing and delivering large payloads of the gasotransmitter. A significant obstacle is to obtain CORMAs that retain the beneficial features of the parent CORMs. In the present work, a crystalline metal-organic framework (MOF) formulated as Mo(CO)3(4,4'-bipyridine)3/2 (Mobpy), with a structure based on Mo(CO)3 metallic nodes and bipyridine linkers, has been prepared in near quantitative yield by a straightforward reflux method, and found to exhibit CO-release properties that mimic those typically observed for molybdenum carbonyl CORMs. Mobpy was characterized by powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), FT-IR, FT-Raman and diffuse reflectance (DR) UV-vis spectroscopies, and 13C{1H} cross-polarization (CP) magic-angle spinning (MAS) NMR. The release of CO from Mobpy was studied by the deoxy-myoglobin (deoxy-Mb)/carbonmonoxy-myoglobin (MbCO) UV-vis assay. Mobpy liberates CO upon contact with a physiological buffer in the dark, leading to a maximum released amount of 1.3-1.5 mmol g-1, after 1.5 h at 37 °C, with half-lives of 0.5-1.0 h (time to transfer 0.5 equiv. of CO to Mb). In the solid-state and under open air, Mobpy undergoes complete decarbonylation over a period of 42 days, corresponding to a theoretical CO-release of 7.25 mmol g-1.

A stable and regenerative TiO2/Bi2MoO6 photocatalyst for highly effective degradation of Rhodamine B and Congo Red

ABSTRACT This research unravels a facile method for synthesising TiO2/Bi2MoO6 photocatalysts and their effective applications in degrading industrial dyes. Initially, Bi2MoO6 was prepared as the substrate, followed by the addition of TiO2 to form the TiO2/Bi2MoO6 composite. The photocatalyst was characterised by powder X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray spectrometry (SEM-EDS), X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HR-TEM), photoluminescence (PL), and UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS). Its photocatalytic properties were evaluated by dye degradation under various conditions, including different dopant loading amounts, the reaction time, the initial concentration of the dye, and pH values. The results indicated that 50 mg of 15% TiO2/Bi2MoO6 achieved the highest photodegradation efficiency: 98.51% for 50 mL 10 mg L−1 Rhodamine B (RhB) within 100 min in a neutral buffer solution and 90.71% for 50 mL 10 mg L−1 Congo Red (CR) within 80 min in an aqueous solution. This material exerted effectiveness across a wide pH range, with removal rates of RhB exceeding 95.41% in both acidic and alkaline conditions. The degradation process conformed to the pseudo-first-order kinetic model. Radical trapping experiments revealed that the dye degradation mechanism involved ∙ O 2 − and h+. Notably, the synthesised TiO2/Bi2MoO6 photocatalyst demonstrated high stability and reusability, maintaining performance even after four degradation cycles. The TiO2/Bi2MoO6 photocatalyst, with TiO2 as the dopant and Bi2MoO6 as the substrate, demonstrated significant versatility and potential for practical dye degradation applications.

Preparation and Evaluation of Clarithromycin Taste-Masking Dry Suspension Using Hot Melt Extrusion Based on Solid Dispersion Technology.

Clarithromycin (CLA) is the preferred drug for treating respiratory infections in pediatric patients, but it has the drawbacks of extreme bitterness and poor water solubility. The purpose of this study was to improve solubility and mask the extreme bitterness of CLA. We use Hot Melt Extrusion (HME) to convert CLA and Eudragit® E100 into Solid Dispersion (SD). Differential scanning calorimetry (DSC) and Powder X-ray diffraction (PXRD) were used to identify the crystalline form of the prepared SDs, which showed that the crystalline CLA was converted to an amorphous form. At the same time, an increase in dissolution rate was observed, which is one of the properties of SD. The results showed that the prepared SD significantly increased the dissolution rate of crystalline CLA. Subsequently, the SD of CLA was prepared into a dry suspension with excellent suspending properties and a taste-masking effect. The bitterness bubble chart and taste radar chart showed that the SD achieved the bitter taste masking of CLA. Principal components analysis (PCA) of the data generated by the electronic tongue showed that the bitter taste of CLA was significantly suppressed using the polymer Eudragit® E100. Subsequently, a dry suspension was prepared from the SD of CLA. In conclusion, this work illustrated the importance of HME for preparing amorphous SD of CLA, which can solve the problems of bitterness-masking and poor solubility. It is also significant for the development of compliant pediatric formulations.

Gompherna globosa flower extract-driven ZnO nanoparticles for enhanced antimicrobial and photocatalytic properties

Abstract The aqueous extract of Gomphrena globosa flowers was utilized for the first time as an effective capping and reducing agent for the synthesis of zinc oxide nanoparticles (ZnO NPs). The synthesized nanoparticles were examined using X-ray powder diffraction (XRD), Scanning electron microscopy (SEM), Energy dispersive X-ray analysis (EDAX), Transmission electron microscopy (TEM) and selected area electron diffraction (SAED) and Uv-vis spectroscopy. XRD revealed the single-phase wurtzite structure of ZnO nanoparticles with a P63mc space group with an average size of 23 nm. The band gap of synthesized ZnO nanoparticles was determined as 3.16 eV from Uv-vis spectroscopy. The rod-shaped structure of the synthesized ZnO NPs was revealed by SEM. The presence of the elements Zn & O was confirmed by EDAX. TEM and SAED confirmed that the average particle size was 26 nm and that the material was polycrystalline. The bio-inspired ZnO NPs achieved outstanding degradation activity of 95.4% against Malachite Green dye after 20 min of UV illumination. The antibacterial properties of the green synthesized nanoparticles were assessed in relation to gram-positive (Staphylococcus sp., Bacillus sp.,) and gram-negative (E. coli, Klebsiella sp.) bacteria. ZnO nanoparticles possess strong antifungal property against a pathogenic fungus Aspergillus niger. This study shows that green-synthesized ZnO nanoparticles derived from Gomphrena globosa flower extract are recommended for use in anti-microbial and photocatalytic applications.

Evaluating the Impact of Sonication Process on Graphene Oxide Structural Properties

Graphene oxide (GO) is one of the members of carbon-based nanomaterials and can be featured as graphene structure decorated with various oxygenated functional groups. Recently, various methods have been found for producing carbon-based nanomaterials with enhanced efficiency in several applications. The chemical process involves oxidizing graphite to GO using a powerful oxidizing chemical. Hummers method is one of the most known and versatile method for the production of GO nanomaterials because of its ease of application, parameter controllability and high yield. This process enables graphite oxidation and exfoliation into single- or multi-layered GO sheets. Exfoliation, the separation of graphene or graphitic layers, is a critical process in GO synthesis. Since exfoliation separates multilayered graphite oxide flakes or particles, it forms single layer GO by forcing oxidizing agents or solvent molecules between layers. The sonication process can exfoliate the oxidized layers, resulting in the formation of GO structure when the exfoliated layers consist of only one or a few layers of carbon atoms. Therefore, sonication procedure is among the key parameters of Hummers method that influences the characteristics of GO-based nanomaterials. In this study, the impact of sonication duration time and power parameters on morphological and structural characteristics of GO development was examined. For this purpose, characterization studies were performed by using Scanning electron microscope (SEM), X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), UV-Vis spectroscopy and Raman spectroscopy analysis. The findings revealed that the increase in sonication power and time led to an increase in defects in the resulting GO structure.

Electrochemical Activation of LiGaO2: Implications for Ga-Doped Garnet Solid Electrolytes in Li-Metal Batteries.

Ga-doped Li7La3Zr2O12 garnet solid electrolytes exhibit the highest Li-ion conductivities among the oxide-type garnet-structured solid electrolytes, but instabilities toward Li metal hamper their practical application. The instabilities have been assigned to direct chemical reactions between LiGaO2 coexisting phases and Li metal by several groups previously. Yet, the understanding of the role of LiGaO2 in the electrochemical cell and its electrochemical properties is still lacking. Here, we are investigating the electrochemical properties of LiGaO2 through electrochemical tests in galvanostatic cells versus Li metal and complementary ex situ studies via confocal Raman microscopy, quantitative phase analysis based on powder X-ray diffraction, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and electron energy loss spectroscopy. The results demonstrate considerable and surprising electrochemical activity, with high reversibility. A three-stage reaction mechanism is derived, including reversible electrochemical reactions that lead to the formation of highly electronically conducting products. The results have considerable implications for the use of Ga-doped Li7La3Zr2O12 electrolytes in all-solid-state Li-metal battery applications and raise the need for advanced materials engineering to realize Ga-doped Li7La3Zr2O12for practical use.

Selenite Stable Isotope Fractionation during Abiotic Reduction by Sodium Sulfide.

Reduction of Se(IV) by sulfur reducing bacteria (SRB) can remove Se from groundwater either by direct respiration or the production of H2S(g) and subsequent abiotic reduction. This study examined abiotic Se(IV) reduction by H2S(g) to determine the associated Se isotope fractionation. The extent of fractionation was compared to the results with studies of Se(IV) reduction in systems containing microorganisms to assess whether these processes could be distinguished. A solution containing Na2S was added in increasing concentrations to solutions containing Se(IV) as SeO32- to reduce and precipitate Se. Precipitates with three distinct colors were observed. Powder X-ray diffraction (PXRD) results yielded three distinct spectra for each of the three colors of precipitate, which corresponded to SenS8-n (orange) or Se(0) (red) and S(0) (yellow). The δ82Se values of the residual dissolved Se increased as the aqueous Se concentration decreased. The S/Se in solution affected the isotopic fractionation, with an 82ε of 10.1 ± 0.6‰ observed for solutions with S/Se < 1.7, and of 7.9 ± 0.3‰ for solutions with S/Se > 1.7.

The Halogenation Effect Induces a Variety of Switchable Phase Transition and Second-Harmonic-Generation Materials.

Halogen engineering offers a means of enhancing the physical properties of materials by fine-tuning the rotational energy barrier and dipole moment, which proved to be effective in achieving switchable phase transitions and optical responses in materials. In this work, by substituting the methyl group in ligand N-ethyl-1,5-diazabicyclo[3.3.0]octane (CH3CH2-3.3.0-Dabco) with halogen atoms X (Cl or Br) and then contining to react it with FeBr3 in a HBr aqueous solution, we successfully synthesized three kinds of organic-inorganic hybrid switchable phase-change materials, [CH3CH2-3.3.0-Dabco]FeBr4 (1), [ClCH2-3.3.0-Dabco]FeBr4 (2), and [BrCH2-3.3.0-Dabco]FeBr4 (3), which were fully characterized by single-crystal X-ray diffraction and variable-temperature powder X-ray diffraction. Compared to compound 1, compounds 2 and 3 show two pairs of reversible phase transitions, dielectric anomalies, and a second-harmonic-generation effect, which are successfully induced due to the halogen substitution. This study offers an effective molecular design strategy for the exploration and construction of iron halide organic-inorganic hybrid materials with temperature-adjustable physical properties.

Unusual negative thermal expansion of inter-cluster –C–BC–C– bond in carbon rich boron carbide observed using in situ x-ray diffraction technique

Temperature dependent bonding behavior plays a significant role in deciding properties of high temperature ceramics like boron carbide. However, few studies to date have addressed the physical properties of this class of materials with respect to their temperature dependent bonding nature. In addition, materials with the flexibility to accommodate variations in interatomic bonding and lattice vibrations over a wide range of temperatures are less known. In this work, temperature dependent structural analyses of carbon-rich boron carbide microflakes using in situ powder x-ray diffraction techniques (up to 1000 °C) supported by transmission electron microscopy measurements reveal that while most bonds in the rhombohedral structure increase in length with temperature; there is no change in certain bond lengths. However, there is an unusual decrease in length (∼1.03%) of the inter-cluster –C–(central boron)BC–C– without any polyhedral redistribution. This is accompanied by an increase in lattice vibrations without significant alteration to the crystal structure over the wide temperature range studied. Temperature dependent micro-Raman experiments further confirmed the above observations. The above bonding behavior could be directly correlated to the trends in reported results of high temperature conductivity via the model of hole hopping through specific atomic positions of the rhombohedral framework, thus opening the scope to investigate structure–property relationships in high temperature functional materials.

Green synthesis of Vitis vinifera extract-appended magnesium oxide NPs for biomedical applications

Abstract Biologically active magnesium oxide (MgO) nanoparticles were synthesised using green reduction with an extract derived from the Vitis vinifera plant. The investigation focused on examining the structure and carbon abundance resulting from the thermal degradation of adsorbed biomolecules. It was accomplished using powder X-ray diffraction, Raman spectroscopy, and FT-IR analysis techniques. X-ray photoelectron spectroscopy studies conducted on MgO nanoparticles indicate the absence of any supplementary peaks, thereby indicating the purity of the material. The morphological characteristics, which have been examined using field emission scanning electron microscopy and TEM methodologies, demonstrate the presence of particles with a spherical shape, exhibiting minimal agglomeration and a uniform distribution across the surfaces of MgO. The porous structure, porosity, and pore volume of the MgO particles were evaluated using Brunauer-Emmett-Teller surface analysis. The experimental findings reveal that the surface area of the MgO nanoparticles is 23.8742 m2/g, while the total pore volume is 0.12528 cm3/g. Additionally, the average pore diameter is determined to be 1.7 nm. These observations collectively suggest the presence of microporous structures within the MgO nanoparticles. This article discusses the biological studies to assess the antibacterial, antifungal, anti-inflammatory, and anti-diabetic activities of the synthesised MgO nanoparticles.

CaRu2Zn10, SrRu2Zn10 and EuRu2Zn10 – new superstructure variants of ThMn12

Abstract The zinc-rich intermetallic phases CaRu2Zn10, SrRu2Zn10 and EuRu2Zn10 were synthesized by induction-melting of the elements in sealed tantalum ampoules followed by annealing to increase the crystallinity. The samples were characterized by powder X-ray diffraction and the structures were refined from single crystal X-ray diffractometer data: new type, P42/nnm, a = 894.68(14), c = 518.44(9) pm, wR2 = 0.0830, 432 F 2 values, 22 variables for CaRu2Zn10, a = 907.01(10), c = 516.35(6), wR2 = 0.0469, 445 F 2 values, 22 variables for SrRu2Zn10 and a = 902.84(9), c = 515.91(5) pm, wR2 = 0.0469, 434 F 2 values, 22 variables for EuRu2Zn10. The three structures are new ordering variants of the aristotype ThMn12. They are discussed on the basis of a group-subgroup scheme and compared to the known superstructures CaCr2Al10, ErNi10Si2 and ScFe6Ga6. The calcium atoms within the Ca@Ru4Zn16 polyhedra have flattened tetrahedral ruthenium coordination, reducing the calcium site symmetry to 4 ‾ $\bar{4}$ 2m (instead of 4/mmm in the aristotype). Electronic structure calculations show a substantial charge transfer from calcium to ruthenium and an almost neutral zinc substructure.

Synthesis and characterisation of carbon nanofiber-wrapped polyaniline and polypyrrole sensory films in polyester resin for strain sensing

ABSTRACT Nanomaterials hold promise as flexible sensor elements due to their enhanced flexibility and efficiency compared to conventional sensors. This study explores Carbon Nanofibers (CNF) in strain-sensing applications, synthesised with Polyaniline (PANI) and Polypyrrole (PPy) via a chemical oxidative technique. These composites form sensory layers on flexible Polyester resin substrates using a layer-by-layer technique. Characterisation through Fourier-Transform Infrared (FTIR) Spectroscopy and Powder X-ray Diffraction (PXRD) reveals strong interactions within CNF/PANI/Polyester and CNF/PPy/Polyester configurations, with heightened crystallinity in CNF/PANI, indicating enhanced electrical conductivity. Stress-strain analysis shows a significant 25% elongation with a corresponding 15% change in resistance across all samples. Calculated gauge factors exhibit substantial improvements: Polyester/PPy (12.96), Polyester/PANI (13.54), Polyester/CNF wrapped PPy (58.62), and Polyester/CNF wrapped PANI (95.8). Notably, CNF-wrapped PPy and CNF-wrapped PANI demonstrate superior gauge factors compared to conventional strain sensors, with Polyester/CNF-wrapped PANI displaying the highest sensitivity at 95.8%. This research underscores the potential of CNF-based composites, particularly CNF-wrapped PANI within a Polyester matrix, for advanced strain-sensing applications.

Gapless dynamic magnetic ground state in the charge-gapped trimer iridate Ba4NbIr3O12

We present an experimental investigation of the magnetic ground state in Ba4NbIr3O12, a fractional valent trimer iridate. X-ray absorption and photoemission spectroscopy show that the Ir valence lies between 3+ and 4+ while Nb is pentavalent. Combined dc/ac magnetization, specific heat, and muon spin rotation/relaxation (µSR) measurements reveal no magnetic phase transition down to 0.05 K. Despite a significant Weiss temperature (ΘW∼−15 to −25 K) indicating antiferromagnetic correlations, a quantum spin-liquid (QSL) phase emerges and persists down to 0.1 K. This state likely arises from geometric frustration in the edge-sharing equilateral triangle Ir network. Our µSR analysis reveals a two-component depolarization, arising from the coexistence of rapidly (90%) and slowly (10%) fluctuating Ir moments. Powder x-ray diffraction and Ir-L3edge x-ray absorption fine structure spectroscopy identify 8–10% Nb/Ir site-exchange, reducing frustration within part of the Ir network, and likely leading to the faster muon spin relaxation, while the structurally ordered Ir ions remain highly geometrically frustrated, giving rise to the rapidly spin-fluctuating QSL ground state. At low temperatures, the magnetic specific heat varies as γT+αT2, indicating gapless spinon excitations, and possible Dirac QSL features with linear spinon dispersion, respectively. Published by the American Physical Society 2024

Magnetic yolk-shell structured periodic mesoporous organosilica supported palladium as a powerful and highly recoverable nanocatalyst for the reduction of nitrobenzenes

A novel palladium-loaded yolk-shell structured nanomaterial with magnetite core and phenylene-based periodic mesoporous organosilica (PMO) shell (Fe3O4@YS-Ph-PMO/Pd) nanocatalyst was synthesized for the reduction of nitrobenzenes. The Fe3O4@YS-Ph-PMO/Pd was prepared through cetyltrimethylammonium bromide (CTAB) directed condensation of 1,4-bis(triethoxysilyl)benzene (BTEB) around Fe3O4@silica nanoparticles followed by treatment with palladium acetate. This nanocatalyst was characterized by using Fourier transform infrared (FT-IR) spectroscopy, thermal gravimetric analysis (TGA), low-angle and wide-angle powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM) analyses. These analyses showed a magnetic nanomaterial with high chemical and thermal stability for the designed composite. The Fe3O4@YS-Ph-PMO/Pd nanocomposite was employed as a powerful and highly recoverable catalyst in the green reduction of nitroarenes in H2O at room temperature. A variety of nitroarene derivatives were applied as substrate in the presence of 0.9 mol% of Fe3O4@YS-Ph-PMO/Pd catalyst. All nitroarenes were selectively converted to their corresponding amines with high to excellent yields (92–96%) within short reaction times (10–18 min). This catalyst was recovered and reused at least 11 times without significant decrease in efficiency and stability.

Effects of Fe substitution for Mn on structural, magnetic and magnetocaloric properties of TbMn2-xFexSi2

The structural and magnetic properties of TbMn2-xFexSi2 compounds (x = 0.0–0.4) have been investigated in details by high-resolution synchrotron x-ray and neutron powder diffraction, specific heat, and dc magnetization measurements. The replacement of Fe for Mn in TbMn2-xFexSi2 does not change the crystal structure but leads to a significant contraction of the unit cell (dV/dx ∼ - 6 Å3) and modification of three magnetic phase transition temperatures – the Curie temperatures Tc1, Tc2 and the Néel temperature TN. For example, the Tc1, Tc2 and TN values of TbMn2Si2 decrease from Tc1 = 50 K, Tc2 = 64 K and TN = 500 K to Tc1 = 27 K, Tc2 = 37 K and TN = 440 K for TbMn1.6Fe0.4Si2. Detailed neutron diffraction investigations have allowed us to determine the magnetic structures and construct the magnetic phase diagram as well as confirm the presence of magnetoelastic coupling effects. The significantly different responses of Tc1 and Tc2 to applied magnetic fields (e.g. dTc1/dB = 0.52 K/T and dTc2/dB = 4.7 K/T for TbMn1.6Fe0.4Si2), leads to expansion of the temperature region (ΔT = Tc2- Tc1) for the canted ferromagnetic state Fmc-ii between Tc1 and Tc2. In the case of TbMn1.6Fe0.4Si2, ΔT increases from ΔT = 9 K for applied magnetic field B = 0.2 T to ΔT = 36 K for B = 6 T, resulting in plateau-like behaviour of magnetic entropy change and enhances the relative cooling power (RCP) in this system. Under a change of magnetic field of 0 T – 5 T, the maximum value of the magnetic entropy changes -ΔSmax and adiabatic temperature change, ΔTad are derived to be -ΔSmax = 13.1 J/kg K and ΔTad = 8.4 K with the RCP = 411 J/kg for x=0.4 sample. The plateau-like magnetocaloric effect and relatively large RCP make these materials potentially suitable for application in cryogenic magnetic refrigeration.

Synthesis, characterization and structure-property relations in mullite-type Pb2(Pb1−x Sn x )O4 solid solution

Abstract The crystal structures of both Pb2PbO4 (Pb3O4) and Pb2SnO4 at room temperature can be described using mullite-type setting in the space groups P42/mbc and Pbam, respectively. At what chemical extend the crystal structure prefers either of the space groups would be an excellent playground in the Pb2(Pb1−x Sn x )O4 solid solution. Members of the solid solutions have been prepared by solid-state reactions carried out in sealed quartz tubes. Each sample has been found to be phase pure confirmed by X-ray powder diffraction data Rietveld refinement. Samples with higher tin content require higher synthesis temperatures, and controlled decomposition of Pb3O4 serves as the source for both Pb2+ and Pb4+ cations. Since the Pb4+ cation is larger than Sn4+, the MO6 polyhedral volume decreases with increasing Sn-content. As such, each metric parameter shows a linear trend following Vegard’s rule. The concomitant contraction of the MO6 octahedra and the high stereo-chemical activity of the 6s 2 lone electron pairs of lead in the Pb2+O4 distorted pyramid results in symmetry reduction. DFT suggests dynamical instability of the tetragonal Pb3O4 while Pb2SnO4 keeps orthorhombic symmetry at low temperatures, which agrees well with the experimental findings. The global blue shift of the vibrational mode frequencies is explained by the quasi-harmonic approach. The indirect band-gap linearly increases from 2.1(1) eV (x = 0) to a maximum value of 2.5(1) eV for x = 0.8 followed by a sharp drop towards Pb2SnO4. Thermogravimetric analysis demonstrates higher thermal stability with increasing Sn-content, which is explained in terms of higher bond strength of Sn–O than that of Pb–O in the MO6 octahedra.

Exploring metal carbamates as precursors for the synthesis of metal-organic frameworks.

In the synthesis of metal-organic frameworks (MOFs), the choice of the metal precursor plays a key role because of the influence that it can exert on the crystallization kinetics. The present work explores the use of metal-carbamato complexes for the synthesis of benchmark MOFs, namely HKUST-1 and UiO-66. Cu2(O2CNEt2)4·2NHEt2 and Zr(O2CNEt2)4, prepared using straightforward CO2 fixation reactions starting from the corresponding metal chlorides and diethylamine, were employed as metal precursors for MOF formation. The synthesis conditions, including the solvent, temperature, and ligand protonation degree, were systematically investigated, revealing metal carbamates as highly reactive precursors due to their prompt release of CO2 and amine upon reaction with protic species, i.e., the polycarboxylic linkers. This property of metal carbamates allowed us to identify room temperature protocols to achieve MOFs with comparable properties to those obtained using traditional metal precursors. Subsequent optimization of the reaction conditions led to the design of a one-pot synthetic strategy for HKUST-1, starting directly from copper(II) chloride and diethylamine under a CO2 atmosphere. The MOFs were characterized using various techniques, including powder X-ray diffraction, N2 sorption analysis, 1H nuclear magnetic resonance spectroscopy, and CHN elemental analysis, and compared to reference samples prepared according to literature procedures.

Biphenyl tetracarboxylic acid-based metal-organic frameworks: a case of topology-dependent thermal expansion.

The large inherent flexibility and highly modular nature of metal-organic frameworks (MOFs) make them ideal candidates for the study of negative thermal expansion (NTE). Among diverse organic ligands, the biphenyl unit, which can unrestrictedly rotate along its C-C single bond, can largely enhance the structural flexibility. Herein, we explored the thermal expansion behaviors of four indium biphenyl tetracarboxylates (BPTCs). Owing to the different dihedral angles of BPTC ligands and coordination mode of In3+, they show distinct topologies: InOF-1 (nti), InOF-2 (unc), InOF-12 (pts) and InOF-13 (nou). Intriguingly, it is found that the thermal expansion is highly dependent on the specific topology. The MOFs featuring mononuclear nodes show normal positive thermal expansion (PTE), and the magnitudes of coefficients follow the trend of InOF-2 < InOF-12 < InOF-13, inversely related to averaged molecular volumes. In contrast, the InOF-1, composed of a 1D chain of corner-shared InO6 octahedrons, shows pronounced NTE. Detailed high-resolution synchrotron powder X-ray diffraction and lattice dynamic analyses shed light on the fact that NTE in the InOF-1 is a synergy effect of the spring-like distortion of the inorganic 1D helical chain and twisting of the BPTC ligands. The present work shows how the topological arrangement of building blocks governs the thermal expansion behaviors.

Potential nanomedicinal applications and physicochemical nature of Hyphaene thebaica-reduced nano-samaria.

Herein we described the biofabrication of samarium oxide nanoparticles (HT-Sm2O3 NPs) by applying the aqueous fruit extract of Hyphaene thebaica was utilized as an eco-friendly chelating agent. The prepared NPs were subjected to various physicochemical properties and potential in biomedical applications. X-ray Diffraction (XRD) pattern revealed sharp peaks that corroborated with the Joint Committee on Powder Diffraction Standards (JCPDS) card no. 00-042-1464. Crystallite size obtained from Debye-Scherrer approximation and Williamson-Hall (W-H) plot was 28.73 and 69.3 nm, respectively. Optical bandgap was calculated by employing Kubelka-Munk (K-M) function and was found to be ~4.58 eV. Raman shift was observed at 121, 351, 424-, and 561 cm-1. Photoluminescence (PL) spectra revealed two major peaks positioned at 360 and 540 nm. The high-resolution transmission electron microscopy (HR-TEM) analysis of HT-Sm2O3 nanoparticles (NPs) showed that they predominantly have spherical to cuboidal shapes. Additionally, the selected area electron diffraction (SAED) pattern presented spotty rings, indicating a high level of crystallinity in these NPs. The potential nanomedicine applications were studied using diverse bioassays using different treatments. The antioxidant activity demonstrated 45.71% ± 1.13% inhibition at 1000 μg/mL. Brine shrimp lethality assay revealed the highest cytotoxicity of 46.67% ± 3.33% at 1000 μg/mL and LC50 value of 1081 μg/mL. HT-Sm2O3 NPs exhibited inhibition of angiogenesis (20.41% ± 1.18%) at of 1000 μg/mL. MTT assay results indicated that HT-Sm2O3 NPs exhibit inhibitory effects on cell lines. Specifically, these NPs showed an IC50 value of 104.6 μg/mL against 3T3 cells. Against MCF-7 cells, the NPs demonstrated an IC50 value of 413.25 μg/mL. Additionally, in the inhibition of acetylcholinesterase (AChE), the newly synthesized NPs showed an IC50 value of 320 μg/mL. The antidiabetic assessment through α-glucosidase and α-amylase inhibition assays revealed, an IC50 value of 380 μg/mL for α-glucosidase and 952 μg/mL for α-amylase was calculated. Overall, our study suggested that the Sm2O3 NPs possess moderate anticancer, cholinesterase inhibition, and antidiabetic potential, however, needs further assessment. RESEARCH HIGHLIGHTS: In this work, nano-samaria is synthesized using an eco-friendly and green approach. The nanoparticles were characterized using techniques such as Raman, HR-TEM, FTIR, DRS, XRD, and so on, and the applications were studied using multiple in vitro bioassays for Diabetes, Alzheimer, and Cancer. The nano-samaria revealed good potential for potential biomedical applications.

Odd-even trends in the series of new bis(α,ω-alkanediamine)dibromocadmium(II) coordination polymers: Crystal structure and thermal decomposition

In this paper, organic-inorganic coordination polymers of the CdBr2(H2N-(CH2)n-NH2) general formula, where n = 4 – 10 and 12, were studied. All the materials were synthesized as very fine powders from metal salt and diamine solutions following an analogous simple procedure. Scanning electron microscopy (SEM) images and recorded powder X-ray diffraction patterns (PXRD) allowed for the assessment of the purity and crystallinity of the products. Based on the collected diffraction data, lattice parameters and symmetry were determined. For five of the synthesized compounds (n = 4, 6, 7, 8, and 12) that were of relatively high purity and sufficient crystallinity, crystal structure models were determined and refined. It was found that the structure symmetry depends on the parity of the number of carbon atoms in the diamine molecules. Structures of the investigated compounds belonging to the even series are centrosymmetric while the ones from the odd series are not (P21 space group). Structures’ symmetry of compounds based on even diamines decreases from P2/m to P1¯ with increasing length of the organic molecules. Diamine molecules are aligned parallel to the diagonals of the (010) faces of the unit cell and there is an almost perfectly linear correlation between the value of a lattice parameter and the number of C atoms. There are, however, separate trends for even or odd series. Differential scanning calorimetry (DSC) and non-ambient PXRD measurements provided information about the thermal decomposition of the materials. The temperature of decomposition decreases with the growing length of diamine molecules and achieves the lowest value (176 °C, 449 K) for the compound with 1,12-diaminododecane (the longest diamine among the studied ones) while the sample with 1,4-diaminobutane is the most stable one (up to around 284 °C, 557 K). The studied compounds also show odd-even separate trends concerning the decomposition temperature. The compounds with even diamines start to decompose at relatively higher temperatures than the ones belonging to the odd series.