X-ray Powder Diffraction Methods Research Articles

Long-range A-site cation disorder in NaA(MO4)2 (M = Mo, W) double scheelite oxides

Synchrotron X-ray and neutron powder diffraction methods have been used to obtain accurate long-range average structures of some double scheelite compounds of the type NaA(BO4)2 (A ​= ​La, Pr, Nd, Sm, Lu, and Bi; B = Mo, W) at room temperature. Phase pure samples were synthesized using standard solid-state methods. Rietveld refinements using combined synchrotron X-ray diffraction (SXRD) and neutron diffraction (NPD) revealed a random distribution of the Na and A-type cations regardless of the presence of 6s2 lone pairs (such as Bi3+) and the difference in oxidation states and ionic radii between the cations. The NaA(BO4)2 (A ​= ​La, Pr, Nd, Sm, Lu, and Bi) series displayed linear trends in lattice parameters and AO8 polyhedra volume with the ionic radius of the A-type cation for the lanthanoids, but a deviation from the trend was observed for A ​= ​Bi3+. The NaBi(BO4)2 structure has a smaller than expected unit cell volume than based on extrapolation from the corresponding NaLn(BO4)2 series, possibly due to short-range ordering of the 6s2 lone pair electrons.

Salt or Cocrystal? Using XRPD to Infer Proton Transfer in Three Adducts of Iodoxybenzoic Acid by Analyzing Iodine–Oxygen Bond Lengths

2-Iodoxybenzoic acid (IBX) is a versatile oxidant, which has been used for a plethora of reactions through the years. Its explosive properties and low solubility, the major limitations to a more widespread use of this reactant, have led to the search for derivatives, adducts, or mixtures with comparable oxidative properties but better characteristics. In this paper, different adducts of IBX, in particular with pyridine (PIBX), quinoline (QUIBX), and nicotinamide (B3-IBX), have been structurally characterized using state-of-the-art X-ray powder diffraction (XRPD) methods. Their oxidative properties have been tested and compared to those of pristine IBX. While generally structure determination from XRPD does not allow us to investigate the proton position, a strategy was devised based on the investigation of iodine–oxygen exocyclic bond lengths to discriminate between single and double iodine–oxygen bonds. The final aim was to attempt to use XRPD to answer an elusive question: salt or cocrystal?

Covalent organic frameworks

The first members of covalent organic frameworks (COF) have been designed and successfully synthesized by condensation reactions of phenyl diboronic acid C6H4[B(OH)2]2 and hexahydroxytriphenylene C18H6(OH)6. The high crystallinity of the products (C3H2BO)6 (C9H12)1 (COF-1) and C9H4BO2 (COF-5) has allowed definitive resolution of their structure by powder X-ray diffraction methods which reveal expanded porous graphitic layers that are either staggered (COF-1, P63/mmc) or eclipsed (COF-5, P6/mmm). They exhibit high thermal stability (to temperatures up to 500- to 600-C), permanent porosity, and high surface areas (711 and 1590 m2/g, respectively) surpassing those of related inorganic frameworks. A similar approach has been used for the design of other extended structures.

Measurements and predictions of phase equilibria in the quaternary system KBr + MgBr2 + SrBr2 + H2O at 273 K and 308 K

The underground brines in Sichuan Basin of China are rich in potassium, magnesium, strontium, bromine. Consequently, the studies of phase equilibria for the underground brines are of great significance. The phase equilibria of the quaternary system KBr + MgBr 2 + SrBr 2 + H 2 O at 273 K and 308 K are determined by the isothermal dissolution equilibrium method in this work. Firstly, the equilibrium liquid phase compositions at two temperatures were measured by chemical analysis. Secondly, the corresponding solid phases were identified by X-ray powder diffraction method. As a result, the corresponding phase diagrams were drawn based on the obtained data. The equilibrium phase diagrams all include four crystallization fields (SrBr 2 ·6H 2 O, MgBr 2 ·6H 2 O, KBr·MgBr 2 ·6H 2 O and KBr), five isothermal solubility curves and two invariant points, which present the same trend at the two temperatures. Furthermore, the mixed ion interaction parameters ( θ Mg , Sr , φ K , Sr , Br , φ Mg , Sr , Br ) of Pitzer model, which have not been reported in the literatures, were obtained by using the solubility data of the ternary system and multiple linear regression. And Pitzer equation and particle swarm optimization algorithm were used to simulate and predict the solubility of salts in the quaternary system. By comparing the calculated phase diagrams at 273 K and 308 K, some obvious deviation in crystalline phase zone of MgBr 2 ·6H 2 O and KBr·MgBr 2 ·6H 2 O at 273 K have been found. And both of them are within the reasonable deviation range. The results show that the fitted parameters and the calculated model of the mixed ion interaction are reliable, and the calculated data agree well with the experimental data.

Lithium metal atoms fill vacancies in the germanium network of a type-I clathrate: synthesis and structural characterization of Ba8Li5Ge41.

Clathrate phases with crystal structures exhibiting complex disorder have been the subject of many prior studies. Here we report syntheses, crystal and electronic structure, and chemical bonding analysis of a Li-substituted Ge-based clathrate phase with the refined chemical formula Ba8Li5.0(1)Ge41.0, which is a rare example of ternary clathrate-I where alkali metal atoms substitute framework Ge atoms. Two different synthesis methods to grow single crystals of the new clathrate phase are presented, in addition to the classical approach towards polycrystalline materials by combining pure elements in desired stoichiometric ratios. Structure elucidations for samples from different batches were carried out by single-crystal and powder X-ray diffraction methods. The ternary Ba8Li5.0(1)Ge41.0 phase crystallizes in the cubic type-I clathrate structure (space group Pm3̄n no. 223, a ≈ 10.80 Å), with the unit cell being substantially larger compared to the binary phase Ba8Ge43 (Ba8□3Ge43, a ≈ 10.63 Å). The expansion of the unit cell is the result of the Li atoms filling vacancies and substituting atoms in the Ge framework, with Li and Ge co-occupying one crystallographic (6c) site. As such, the Li atoms are situated in four-fold coordination environment surrounded by equidistant Ge atoms. Analysis of chemical bonding applying the electron density/electron localizability approach reveals ionic interaction of barium with the Li-Ge framework, while the lithium-germanium bonds are strongly polar covalent.

The microstructural representation and fractal nature intepolation analysis of feldspar

This paper presents a comparative analysis of microstructural parameters by the powder X-ray diffraction method on a polycrystalline sample and the fractal analysis. The presented results of microstructural parameters are obtained by crystallographic programs FullProf based on the Rietveld method. The synthetic Ba/Ca-celsian sample has been used for microstructural parameters analysis. The feldspar sample has been synthesized by the thermal induction phase transformation process of ion exchange Ca-LTA zeolite with Ba cation. After the ion exchange Ba/Ca-LTA, the sample was heated at the temperature of 1300?C and the structure of Ba/Ca-feldspar was determined by the X-ray powder diffraction analysis. The X and U shape parameters that contribute to the strain have been reconstructed by fractal interpolation. Once we can reconstruct the shapes, which are quantum mechanics effects, we should provide the data for predicting desired parameters mentioned previously. We reported in this paper the successful application of this advanced and deep microstructure analysis, which confirmed original fractal copies based on the presented morphology characterization.

Tantalum doped titanium dioxide nanoparticles for efficient photocatalytic degradation of dyes

In this work, the hydrothermal method was utilized for the facile synthesis of tantalum (Ta) doped titanium dioxide (TiO2) nanoparticles. A study of structural, morphological, and optical properties was conducted using various characterizations such as powder X-ray diffraction method (XRD), Raman analysis, Fourier transform infrared (FTIR) spectroscopy, Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Energy-dispersive X-ray spectroscopy (EDS) analysis, Brunauer-Emmett-Teller (BET) measurements, Ultraviolet-Visible diffusion reflection (UV–vis-DRS) spectroscopy. The structure of as-synthesized nanoparticles was analyzed by the XRD and their phase purity was confirmed with Raman analysis. The functional groups present in the samples were verified with Fourier transform infrared (FT-IR) spectra which showed bands that are characteristic of the titanium dioxide (Ti-O-Ti) bonds. Also, it shows the presence of the Ta-O-Ta bond which confirms the presence of tantalum in TiO2. The optical band gap of as-synthesized TiO2 was slightly reduced when doped with tantalum. The morphology and nature of the samples were confirmed by transmission electron microscopy (TEM). The photocatalytic activity of the pure TiO2 and Ta-doped TiO2 was investigated by using Rhodamine B (Rh B) and Methylene Blue (MB) dyes and were confirmed with the first-order kinetics. The synthesized nanoparticles were used for the degradation of the Rh B and MB dyes under ultraviolet light irradiation for 120 minutes. Ta-doped TiO2 nanomaterials, remarkably Ta with 3 wt.% showed enhanced photocatalytic dye degradation when compared with as-synthesized TiO2.

Combined Application of Dentin Noncollagenous Proteins and Odontogenic Biphasic Calcium Phosphate in Rabbit Maxillary Sinus Lifting.

Teeth can be used as a raw material for preparing bone substitutes due to their similar chemical composition to bone. The objective of our study was to evaluate the effect of odontogenic biphasic calcium phosphate (BCP) incorporating dentin noncollagenous proteins (DNCPs) on osteogenesis and stability in maxillary sinus augmentation. The composition, structure and morphology of the odontogenic BCP were tested by X-ray powder diffraction (XRD), Brunauer-Emmett-Teller, and scanning electron microscopy methods. The biocompatibility and osteoinduction of DNCPs and materials were examined in vitro and their bone regeneration capacity was verified in vivo. The results showed that the cells adhered and proliferated well on the DNCP-loaded BCP scaffold. The odontogenic BCP and DNCPs promoted osteogenic differentiation of cells, The new bone formation in the BCP groups and DNCP subgroups was significantly higher than the new bone formation in the control, and the new bone quality was better. The bone regeneration effect of odontogenic BCP was similar to the effect of deproteinized bovine bone mineral, but β-TCP did not maintain the height and volume of bone reconstruction. In conclusion, the combined application of DNCPs and odontogenic BCP is an effective strategy for tissue engineering osteogenesis in the maxillary sinus region. The biomimetic strategy could provide a new approach for patients requiring maxillary sinus lifting.

Effect of isovalent substitution on structure of the two-slab BaNd2-xSmxIn2O7 indates

The conditions of isovalent substitution of Nd atoms for Sm atoms in A-positions of the BaNd2In2O7 two-slab perovskite-like structure of the BaNd2-xSmxIn2O7 type (0 £ x £ 1.8) have determined by X-ray powder diffraction methods. Tetragonal crystal structure (space group P42/mnm) of the BaNd2-xSmxIn2O7 phases with substitution degree of Nd atoms equal to 0.5, 1.0, 1.5 and 1.8 was determined by the Rietveld method. Crystal structure of BaNd2-xSmxIn2O7 is based on the two-dimensional (infinite in the XY plane) perovskite-like blocks, consisting of two slabs of the deformed InO6 octahedra connected by vertices. Ba atoms are localized only at 4f position inside the perovskite block, while REE atoms are placed only at 8j position at the boundary of the perovskite block. The adjacent perovskite-like blocks are separated by a slab of LnO9 polyhedra and held together by - O - Ln - O - interblock bonds. It is established that the isovalent substitution of Nd atoms by smaller Sm atoms leads to a decrease in the length of the Ln - O2 distance (from 0.230(2) nm to 0.206(2) nm) and to an increase in the degree of deformation of the interblocks of LnO9 polyhedra, the inner block polyhedra BaO12, and the InO6 octahedra as well. Such structural changes destabilize the interblock "stitching" and are one of the main destruction factors of the slab perovskite-like structure of the BaNd2-xSmxIn2O7 phases at x > 1.8. Data obtained could be used for directed regulation of structure-sensitive properties of materials based on the BaNd2In2O7 indate.

Synthesis and physical characteristics of narrow bandgap chalcogenide SnZrSe3

Background: The development of organic/inorganic metal halide perovskites has seen unprecedent growth since their first recognition for applications in optoelectronic devices. However, their thermodynamic stability and toxicity remains a challenge considering wide-scale deployment in the future. This spurred an interest in search of perovskite-inspired materials which are expected to retain the advantageous material characteristics of halide perovskites, but with high thermodynamic stability and composed of earth-abundant and low toxicity elements. ABX3 chalcogenides (A, B=metals, X=Se, S) have been identified as potential class of materials meeting the aforementioned criteria. Methods: In this work, we focus on studying tin zirconium selenide (SnZrSe3) relevant physical properties with an aim to evaluate its prospects for application in optoelectronics. SnZrSe3 powder and monocrystals were synthesized via solid state reaction in 600 – 750 °C temperature range. Crystalline structure was determined using single crystal and powder X-ray diffraction methods. The bandgap was estimated from diffused reflectance measurements on powder samples and electrical properties of crystals were analysed from temperature dependent I-V measurements. Results: We found that SnZrSe3 crystals have a needle-like structure (space group – Pnma) with following unit cell parameters: a=9.5862(4) Å, b=3.84427(10) Å, c=14.3959(5) Å. The origin of the low symmetry crystalline structure was associated with stereochemical active electron lone pair of Sn cation. Estimated bandgap was around 1.15 eV which was higher than measured previously and predicted theoretically. Additionally, it was found that resistivity and conductivity type depended on the compound chemical composition. Conclusions: Absorption edge in the infrared region and bipolar dopability makes SnZrSe3 an interesting material candidate for application in earth-abundant and non-toxic single/multi-junction solar cells or other infrared based optoelectronic devices.

Order of osakaite–namuwite–lahnsteinite formation during alkalization of sulfate solutions

Experiments with dropwise alkalization of a 0.1 M ZnSO4 solution with 1M NaOH were carried out to establish the formation order of Zn-hydroxy-sulfate minerals (osakaite, namuwite, and lahnsteinite). During the controlled alkalization with 1M NaOH of a 0.1M ZnSO4 solution, namuwite (osakaite), lahnsteinite and wulfingite are successively formed. The obtained precipitates were characterized by powder X-ray diffraction (XRD) and SEM-EDS methods. The formation conditions and regions of stability of osakaite and namuwite are at near circumneutral pH (6.5–7), while lahnsteinite is stable at high pH (11–12). This explains the wider distribution of namuwite and osakaite in nature. The isomorphic substitution of Zn2+ cation with Cu2+ in the hydroxide layer of the Zn-hydroxy-sulfate minerals during controlled alkalization was studied using mixed 0.1M ZnSO4 + CuSO4 solution (molar ratio Zn:Cu = 4:1 and 1:1). During controlled alkalization of mixed Zn-Cu sulfate solutions, 25% copper cations are isomorphic incorporated in the namuwite (osakaite) and lahnsteinite structures. It was determined that this Cu2+ content is the upper limit of the isomorphism and corresponds to the occupation of 1/3 of octahedral positions.

Effect of crystallization conditions on modafinil substance polymorphism

The effect of the crystallization conditions of modafinil from its methanol solutions on the polymorphic state of the resulting substance was studied using the X-ray powder diffraction method. It is shown that changes in the cooling rate and the concentration of saturated solutions have an effect on obtaining samples of the modafinil substance with differences in diffractometric characteristics. Moreover, the cooling rate practically does not affect the yield of the crystalline product, which depends on the degree of saturation of crystallization solutions. It was found that the I polymorphic form of modafinil can be obtained from modafinil solutions with a concentration in the range of 0.34–0.44 M with slow cooling of solutions, mainly with a temperature gradient of 5–10 °C/hour to a temperature of 5 ± 2 °C. An increase in the cooling rate of saturated solutions and their concentration >0.44 M leads to the production of mixed polymorphic forms of modafinil crystals.

Hydrothermal Synthesis of MnO2/Reduced Graphene Oxide Composite for 4-Nitrophenol Sensing Applications

Recently, the electrochemical sensing approach has attracted materials/electrochemical scientists to design and develop electrode materials for the construction of electrochemical sensors for the detection of para-nitrophenol (4-NP). In the present study, we have prepared a hybrid composite of MnO2 and rGO (MnO2/rGO) using a hydrothermal approach. The morphological features of the prepared MnO2/rGO composite were studied by scanning electron microscopy, whereas the phase purity and formation of the MnO2/rGO composite were authenticated via the powder X-ray diffraction method. Energy-dispersive X-ray spectroscopy was also employed to analyze the elemental composition of the prepared MnO2/rGO composite. In further studies, a glassy carbon electrode (GCE) was modified with MnO2/rGO composite (MnO2/rGO/GCE) and explored as 4-nitrophenol (4-NP) sensor. The fabricated MnO2/rGO/GCE exhibited a reasonably good limit of detection of 0.09 µM with a sensitivity of 0.657 µA/µMcm2. The MnO2/rGO/GCE also demonstrates good selectivity, stability and repeatability in 50 cycles.

Role of Alkyl Substituent and Solvent on the Structural, Thermal, and Magnetic Properties of Binary Radical Salts of 1,2,3,5-Dithia- or Diselenadiazolyl Cations and the TCNQ Anion

The synthesis, structural, thermal, and magnetic properties of a series of simple binary organic salts based on the radical anion of 7,7,8,8-tetracyanoquinodimethane (TCNQ) and 4-(N-alkylpyridinium-3-yl)-1,2,3,5-dithiadiazolyl (DTDA), 1R (R = Et, Pr, Bu), radical cations and their heavier selenium analogues (DSDA), 2R, are described. Single-crystal X-ray structural analyses reveal that short alkyl substituents on the pyridinium moiety of DTDA/DSDA cations lead to crystallization of isostructural acetonitrile (MeCN) solvates 1Et·MeCN, 1Pr·MeCN, 2Et·MeCN, and 2Pr·MeCN with trans-cofacial DTDA radical cation and eclipsed-cofacial TCNQ radical anion dimers. A slight increase in the substituent chain length to butyl affords the solvate 1Bu·0.5MeCN or the nonsolvate 1Bu. The nonsolvate 1Bu can be exclusively isolated using propionitrile (EtCN), whereas the isostructural selenium analogue 2Bu crystallizes from MeCN. The crystal packing in 1Bu·0.5MeCN and 1Bu/2Bu is distinctively different: rare one-dimensional (1D) columnar π-stacks of evenly spaced TCNQ radical anions with periodic distortions along the vertical stacking direction and cis-cofacial DTDA dimers in 1Bu·0.5MeCN vs discrete, non-eclipsed-cofacial TCNQ dimers and trans-antarafacial DTDA/DSDA dimers in 1Bu/2Bu. The nonsolvated structure 1Pr with trans-cofacial DTDA and non-eclipsed-cofacial TCNQ dimers can be isolated from EtCN. Single-crystal and powder X-ray diffraction methods confirmed a thermally driven, irreversible, single-crystal-to-single-crystal structural transformation between 1Pr·MeCN and 1Pr. Thermogravimetric analyses of all nonsolvated salts show varied, yet robust, thermal behavior, while the thermal behavior of the solvates is consistent with more facile lattice solvent loss from structures with longer N-alkyl chains. Variable-temperature magnetic susceptibility measurements indicate that all structures are diamagnetic at low temperatures. However, thermally populated magnetic states could be observed for 1Et·MeCN, 1Et·EtCN, 1Pr·MeCN, 1Bu·0.5MeCN, 1Bu, and 2Bu at higher temperatures. This can be correlated with desolvation and structural changes that lead to the generation of weakly antiferromagnetically coupled non-eclipsed-cofacial TCNQ dimers, in agreement with results from density functional theory (DFT) calculations.

Synthesis, molecular docking, and biological studies of novel heteroleptic Cu(II) and Zn(II) complexes of natural product-based semicarbazone derivatives

In this study, we describe the synthesis of novel heteroleptic Cu(II) and Zn(II) complexes using two semicarbazone-based derivative ligands: ortho-phthalaldehyde disemicarbazone (L1) and dehydrozingerone semicarbazone (L2). The metal salts and the two ligands were used in a 1:1:1 ratio. The complexes were characterized by magnetic moment measurements, elemental analysis, SEM-EDX, liquid chromatography-mass spectrophotometer (LC-MS), thermogravimetric analysis (TGA), X-ray powder diffraction (XRD), UV-visible spectrophotometer, NMR, and FT-IR spectroscopy methods. Using the disk diffusion and DPPH procedures, the complexes' potential for scavenging free radicals and having antibacterial effects was examined. The results indicate that the ligand L1 has good mean inhibition zones on S. aureus (12.42 ± 0.23 mm) and S. pyogenes (11.64 ± 0.12 mm) bacteria. The [Cu(L1)(L2)] complex displayed higher antibacterial activities (13.67 ± 0.52 mm) against S. pyogenes bacteria, whereas [Zn(L1)(L2)] shows higher activity against P. Aeruginosa (14.22 ± 0.33 mm). Both complexes showed good antioxidant activity (63.7 % and 59.68 %). Furthermore, the docking results of the compounds against S. aureus Gyrase confirm the ligands (L1 and L2) and the complexes exhibit binding potentials of -7.39 to -11.01 kcal/mol. Higher value was obtained for the [Zn(L1)(L2)] complex (-11.01 kcal/mol). In order to enhance the biological activities of metal complexes, this study sheds light on the significance of multi-semicarbazone ligands and their corresponding complexes.

Beyond the ionic radii: A multifaceted approach to understand differences between the structures of LnNbO4 and LnTaO4 fergusonites

Synchrotron X-ray powder diffraction methods have been used to obtain accurate structures of the lanthanoid tantalates, LnTaO4, at room temperature. Three different structures are observed, depending on the size of the Ln cation: P21/c (Ln = La, Pr), I2/a (Ln = Nd-Ho), and P2/c (Ln = Tb-Lu). BVS analysis indicated that TaV is six-coordinate in these structures, with four short bonds and two longer bonds. Synchrotron X-ray powder diffraction methods were also used to observe the impact of Ta doping on the orthoniobates, Ln(Nb1-xTax)O4 (Ln = Pr, Nd, Sm, Gd, Tb, Dy, Ho, Yb, and Lu). Where both the niobate and tantalate oxide were isostructural (fergusonite structure, space group I2/a), complete solid solutions were prepared. In these solid solutions, the unit cell volume decreases as the Ta content increases. The subtle interaction evident between the LnO8 and BO6 sublattices in the fergusonite-type oxides was not observed in the related pyrochlore oxides. A combined synchrotron X-ray and neutron powder diffraction study of the series Ho(Nb1-xTax)O4 was used to determine accurate atomic positions of the anions, and hence, bond lengths. This revealed a change in the (Nb/Ta)-O bond lengths, reflective of the difference in the valence orbitals of Nb(4d) and Ta(5d). Examination of the partial density of states demonstrates differences in the electronics between Nb and Ta, leading to a difference in the bandgap. This study highlights the importance of the long B-O contacts in the fergusonite structures, and its potential impact on the I2/a to I41/a phase transition.

МЕТАЛООРГАНІЧНІ МАГНЕТИКИ НА ОСНОВІ КОМПЛЕКСІВ ЗАЛІЗА З 1-НІТРОЗО-2-НАФТОЛОМ

Providing macroscopic magnetism in organic materials is a very complex but quite promising scientific problem. The need to create an organic magnet is due to a number of expected advantages, such as lightness, transparency, flexibility, ability to switch under the influence of light (magneto-optics), or chemical influences (sensors), creation of modern toners for digital printing, materials for chemical power sources etc. To understand the mechanism of biological processes, in particular, human thinking and DNA functioning may help to study the state of spin glass, biomagnetism, the mechanism of action of paramagnetic probes in living tissues and others. In the present paper the peculiarities of the structure and magnetic behavior of the iron complex with 1-nitroso-2-naphthol Na[Fe(C10H6(NO2)3] have been studied. The powder X-ray diffraction method determined that the crystal structure of the complex is monoclinic with the space group P2/1. According to cyclic voltammetry, the electrochemical behavior of the complex anion Fe(C10H6(NO2)3] is characteristic of reversible electrochemical systems with one electron transfer. Optical absorption bands are observed in the electronic spectra of the complex at 389, 690, and 763 nm. The dependences of the magnetic susceptibility of the complex on the temperature, frequency and magnetic field strength in the temperature range 1.5–200 K in the external magnetic field up to 90 kE and in the frequency range from 95 to 2000 Hz are obtained and analyzed. At low temperatures, the peculiarities of magnetic behavior characteristic of the state of spin glass are revealed. The EPR spectrum of the complex is a superposition of two lines, the behavior of which is opposite when the temperature changes in the range of 4–293 K, which indicates the unusual dynamics of the molecular surrounding the Fe3+ ion. Such features may be due to the presence of two structurally inhomogeneous magnetic centers that exhibit opposite spin dynamics with changing temperature. The presence of this dynamic can have a significant impact on the properties of the substance.

Strontium Substituted β-Tricalcium Phosphate Ceramics: Physiochemical Properties and Cytocompatibility.

Sr2+-substituted β-tricalcium phosphate (β-TCP) powders were synthesized using the mechano-chemical activation method with subsequent pressing and sintering to obtain ceramics. The concentration of Sr2+ in the samples was 0 (non-substituted TCP, as a reference), 3.33 (0.1SrTCP), and 16.67 (0.5SrTCP) mol.% with the expected Ca3(PO4)2, Ca2.9Sr0.1(PO4)2, and Ca2.5Sr0.5(PO4)2 formulas, respectively. The chemical compositions were confirmed by the energy-dispersive X-ray spectrometry (EDX) and the inductively coupled plasma optical emission spectroscopy (ICP-OES) methods. The study of the phase composition of the synthesized powders and ceramics by the powder X-ray diffraction (PXRD) method revealed that β-TCP is the main phase in all compounds except 0.1SrTCP, in which the apatite (Ap)-type phase was predominant. TCP and 0.5SrTCP ceramics were soaked in the standard saline solution for 21 days, and the phase analysis revealed the partial dissolution of the initial β-TCP phase with the formation of the Ap-type phase and changes in the microstructure of the ceramics. The Sr2+ ion release from the ceramic was measured by the ICP-OES. The human osteosarcoma MG-63 cell line was used for viability, adhesion, spreading, and cytocompatibility studies. The results show that the introduction of Sr2+ ions into the β-TCP improved cell adhesion, proliferation, and cytocompatibility of the prepared samples. The obtained results provide a base for the application of the Sr2+-substituted ceramics in model experiments in vivo.

Membranes Based on Polyvinylidene Fluoride and Radiation-Grafted Sulfonated Polystyrene and Their Performance in Proton-Exchange Membrane Fuel Cells.

Proton-exchange membranes based on gamma-irradiated films of PVDF and radiation-grafted sulfonated polystyrene with an ion-exchange capacity of 1.8 meq/g and crosslinking degrees of 0 and 3% were synthesized. A solvent-free, environmentally friendly method of styrene grafting from its aqueous emulsion, with a styrene content of only 5 vol.% was used. Energy dispersive X-ray mapping analysis showed that the grafted sulfonated polystyrene is uniformly distributed throughout the membrane thickness. The obtained materials had a proton conductivity up to 132 mS/cm at 80 °C and a hydrogen permeability of up to 5.2 cm2/s at 30 °C, which significantly exceeded similar values for Nafion®-212 membranes. The resulting membranes exhibited a H2/O2 fuel cell peak power density of up to 0.4 W/cm2 at 65 °C. Accelerated stability tests showed that adding a crosslinking agent could significantly increase the stability of the membranes in the fuel cells. The thermal properties and crystallinity of the membranes were investigated through differential scanning calorimetry and X-ray powder diffraction methods. The conductivity, water uptake, and mechanical properties of the membranes (stress–strain curves) were also characterized.

5-Hydroxyisophthalic acid and neocuproine containing copper(II) complex as a promising cytotoxic agent: Structure elucidation, topology, Hirshfeld surface, DFT calculations, and molecular docking analysis

We aimed to synthesize a new copper(II) complex, namely [Cu(H2IPA)(NC)(Cl)]⋅H2O (1) (where, H3IPA = 5-hydroxy isophthalic acid and NC = 2,9-dimethyl-1,10-phenanthroline or Neocuproine) as a promising chemotherapeutic agent. Complex 1 was structurally characterized by single-crystal X-ray diffraction (SCXRD), UV-Visible, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and powder X-ray diffraction (PXRD) methods. Single crystal diffraction analysis reveals that Cu(II) ion exists in a distorted square pyramidal geometry, with the ligation of a chloride ion, two oxygen atoms, and two nitrogen atoms. Topological structural simplification of complex 1 shows ins as an underlying net. The prominent intermolecular interactions and their quantitative contributions in complex 1 were investigated using Hirshfeld Surface (HS) analysis. The DFT calculations were also performed to validate the experimental results (XRD, FTIR, and UV-Visible). In vitro cytotoxicity of complex 1 was performed against acute myeloid leukemia (THP-1), colorectal (SW480), and prostate cancer (PC-3) cell lines by utilizing MTT assay. The result shows that complex 1 has the ability to inhibit the growth of cancer cells at a lower concentration. The morphological changes that occur during apoptosis were carried out with acridine orange/ethidium bromide (AO/EB) staining methods on THP-1 and SW480 cancer cell lines. Additionally, comprehensive molecular docking studies were performed to understand the potential binding interactions of complex 1 with target protein and DNA double helix.