Powder X-ray Diffraction Studies Research Articles

Electron-Rich Triazine-Conjugated Microporous Polymers for the Removal of Dyes from Wastewater.

Conjugated microporous polymers (CMP) as porous functional materials have received considerable attention due to their unique structures and fascinating properties for the adsorption and degradation of dyes. Herein, a triazine-conjugated microporous polymer material with rich N-donors at the skeleton itself was successfully synthesized via the Sonogashira-Hagihara coupling by a one-pot reaction. These two polymers had Brunauer-Emmett-Teller (BET) surface areas of 322 and 435 m2g-1 for triazine-conjugated microporous polymers (T-CMP) and T-CMP-Me, respectively. Due to the porous effects and the rich N-donor at the framework, it displayed a higher removal efficiency and adsorption performance compared to cationic-type dyes and selectivity properties for (methylene blue) MB+ from a mixture solution of cationic-type dyes. Furthermore, the T-CMP-Me could quickly and drastically separate MB+ and (methyl orange) MO- from the mixed solution within a short time. Their intriguing absorption behaviors are supported by 13C NMR, UV-vis absorption spectroscopy, scanning electron microscopy, and X-ray powder diffraction studies. This work will not only improve the development of porous material varieties, but also demonstrate the adsorption or selectivity of porous materials for dyes from wastewater.

Novel Red Phosphor of Gd3+, Sm3+ co-Activated AgxGd((2-x)/3)-0.3-ySmyEu3+0.30☐(1-2x-2y)/3WO4 Scheelites for LED Lighting.

Gd3+ and Sm3+ co-activation, the effect of cation substitutions and the creation of cation vacancies in the scheelite-type framework are investigated as factors influencing luminescence properties. AgxGd((2-x)/3)-0.3-ySmyEu3+0.3☐(1-2x)/3WO4 (x = 0.50, 0.286, 0.20; y = 0.01, 0.02, 0.03, 0.3) scheelite-type phases (AxGSyE) have been synthesized by a solid-state method. A powder X-ray diffraction study of AxGSyE (x = 0.286, 0.2; y = 0.01, 0.02, 0.03) shows that the crystal structures have an incommensurately modulated character similar to other cation-deficient scheelite-related phases. Luminescence properties have been evaluated under near-ultraviolet (n-UV) light. The photoluminescence excitation spectra of AxGSyE demonstrate the strongest absorption at 395 nm, which matches well with commercially available UV-emitting GaN-based LED chips. Gd3+ and Sm3+ co-activation leads to a notable decreasing intensity of the charge transfer band in comparison with Gd3+ single-doped phases. The main absorption is the 7F0 → 5L6 transition of Eu3+ at 395 nm and the 6H5/2 → 4F7/2 transition of Sm3+ at 405 nm. The photoluminescence emission spectra of all the samples indicate intense red emission due to the 5D0 → 7F2 transition of Eu3+. The intensity of the 5D0 → 7F2 emission increases from ~2 times (x = 0.2, y = 0.01 and x = 0.286, y = 0.02) to ~4 times (x = 0.5, y = 0.01) in the Gd3+ and Sm3+ co-doped samples. The integral emission intensity of Ag0.20Gd0.29Sm0.01Eu0.30WO4 in the red visible spectral range (the 5D0 → 7F2 transition) is higher by ~20% than that of the commercially used red phosphor of Gd2O2S:Eu3+. A thermal quenching study of the luminescence of the Eu3+ emission reveals the influence of the structure of compounds and the Sm3+ concentration on the temperature dependence and behavior of the synthesized crystals. Ag0.286Gd0.252Sm0.02Eu0.30WO4 and Ag0.20Gd0.29Sm0.01Eu0.30WO4, with the incommensurately modulated (3 + 1)D monoclinic structure, are very attractive as near-UV converting phosphors applied as red-emitting phosphors for LEDs.

Mesomorphism and luminescence in coordination compounds and ionic salts based on pyridine-functionalized β-diketones. Influence of the pyridine nitrogen position

Pyridine-functionalized β-diketones with the pyridine nitrogen atom at 3 or 4 position (L3N and L4N, respectively) have been used as building blocks to obtain two new families of compounds with mesomorphic and luminescent behaviors. The N-pyridine coordination of the β-diketones to zinc(II), palladium(II) and platinum(II) metal centers has allowed to synthesize neutral coordination compounds of the type [MCl2(LZN)2] (M = Zn(II), Pd(II), Pt(II); Z = 3, 4). Particularly, coordination of L4N towards Pt(II) gives rise to the cationic species [Pt(NH3)2(L4N)2]2+. Otherwise, protonation of the pyridine moiety was strategically used to obtain a novel series of pyridinium ionic salts of the type (HLZN)nA (n = 1, A = Cl; n = 2, A = MCl4, M = Zn(II), Pd(II), Pt(II); Z = 3, 4). The neutral or ionic nature of the complexes, as well as the β-diketone ligands and the metal center in both the neutral and anionic complexes, has a great influence on the mesomorphic behavior. Thus, columnar or smectic mesophases can be selectively formed. Single-crystal and temperature-dependent powder X-ray diffraction studies have been performed to analyze the molecular packing in the crystal and the supramolecular ordering in the mesophase. All the aforementioned factors also play a key role on the luminescence properties, the Zn(II) coordination compounds and ionic salts being the best candidates as bifunctional materials.

Postsynthetic Modification of Core-Shell Magnetic Covalent Organic Frameworks for the Selective Removal of Mercury.

Core-shell magnetic covalent organic framework (COF) materials were prepared, followed by shell material functionalization with different organic ligands, including thiosemicarbazide, through a postsynthetic modification approach. The structures of the prepared samples were characterized with various techniques, including powder X-ray diffraction (PXRD), Brunauer-Emmett-Teller (BET) method, thermogravimetric analysis (TGA), photoinduced force microscopy (PiFM), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and solid 13C NMR. PXRD and BET studies revealed that the crystalline and porous nature of the functionalized COFs was well maintained after three steps of postsynthetic modification. On the other hand, solid 13C NMR, TGA, and PiFM analyses confirmed the successful functionalization of COF materials with good covalent linkage connectivity. The use of the resulting functionalized magnetic COF for selective and ultrafast adsorption of Hg(II) has been investigated. The observations displayed rapid kinetics with adsorption dynamics conforming to the quasi-second-order kinetic model and the Langmuir adsorption model. Furthermore, this prepared crystalline magnetic material demonstrated a high Langmuir Hg(II) uptake capacity, reaching equilibrium in only 5 min. Thermodynamic calculations proved that the adsorption process is endothermic and spontaneous.

Dehydration of Niclosamide Monohydrate Polymorphs: Different Mechanistic Pathways to the Same Product.

Many active pharmaceutical ingredients (APIs) can crystallize as hydrates or anhydrates, the relative stability of which depends on their internal structures as well as the external environment. Hydrates may dehydrate unexpectedly or intentionally, though the molecular-level mechanisms by which such transformations occur are difficult to predict a priori. Niclosamide is an anthelmintic drug on the World Health Organization's "List of Essential Medicines" that crystallizes in two monohydrate forms: HA and HB. Through complementary time-resolved synchrotron powder X-ray diffraction and thermogravimetric kinetic studies, we demonstrate that the two monohydrates dehydrate via distinctly different solid state pathways yet yield the same final anhydrate phase. Water loss from HA via diffusion yields an isomorphous desolvate intermediate which can rearrange to at least two different polymorphs, only one of which exhibits long-term stability. In contrast, dehydration of HB proceeds via a surface nucleation process where simultaneous water loss and product formation occur with no detectable crystalline intermediates. Comparative analysis of the two systems serves to highlight the complex relationship between lattice structure and solid state dehydration processes.

Formation of the Sub-oxide Sc4Au2O1-x and the Drastically Negative 27Al NMR Shift in Sc2Al.

During attempts to synthesize Sc4AuAl in the cubic Gd4RhIn-type structure, the solid solution Sc2Au0.5Al0.5 in the PbCl2-type structure formed instead. Subsequently, the solid solution Sc2Au1-xAlx was investigated with respect to its existence range along with the structure types formed for different compositions with x = 0, 0.25, 0.5, 0.75, and 1. According to X-ray powder diffraction studies, Sc2Al and nominal Sc2Au0.25Al0.75 crystallized in the hexagonal Ni2In-type structure (P63/mmc), while Sc2Au0.5Al0.5, Sc2Au0.75Al0.25, and Sc2Au were found to crystallize in the orthorhombic PbCl2-type structure (Pnma). The crystal structures of Sc2Au and Sc2Au0.59(1)Al0.41(1) were refined from single-crystal data (Sc2Au: a = 648.0(1), b = 467.2(1), c = 835.2(2) pm, wR2 = 0.0382, 535 F2 values, 25 variables; Sc2Au0.59(1)Al0.41(1): a = 632.48(5), b = 472.16(3), c = 848.67(6) pm, wR2 = 0.0484, 540 F2 values, 21 variables). Contamination with air during the synthesis of Sc2Au led to the discovery of a compound adopting the cubic W4Co2C-type structure (stuffed cubic Ti2Ni type). Using Sc2O3 as a defined oxygen source led to samples with high amounts of Sc4Au2O1-x. All intermetallic compounds exhibited Pauli paramagnetic behavior in the investigated temperature range of 2.1 to 300 K, and no superconductivity was observed at low temperatures and low fields. Sc2Au and Sc2Al were investigated by 27Al and 45Sc solid-state NMR investigations. For Sc2Al, one signal was found in the 27Al NMR spectra in line with the crystal structure; however, an extremely negative resonance shift of δ = -673 ppm was observed. In both compounds, two Sc resonances were observed, in line with the proposed crystal structure. Finally, it was observed that the stability of Sc2Au in air is limited. This was investigated via thermal analysis and (temperature-dependent) powder X-ray diffraction. DFT calculations helped in assessing charge analysis, electronic properties, and chemical bonding.

Two new lead(II) discrete complex and coordination polymer & ultrasound-assisted synthesis of their nanostructures: synthesis, characterization, crystal structure determination, thermal & X-ray powder diffraction studies

New lead(II) mononuclear complex [Pb(pyterpy)(NO3)2] (1) and coordination polymer [Pb2(μ-pyterpy)(DMSO)(μ3-Br)(μ2-Br)2(Br)]n (2) (where [pyterpy] is 4′-(3-pyridyl)-2,2′:6′,2′'-terpyridine) and their corresponding nano-structures were synthesized. Complexes 1 and 2 were fully characterized by elemental analysis, IR, NMR, UV–Vis, luminescence spectroscopy as well as single-crystal X-ray diffraction method. The coordination polyhedron for Pb atoms in 1 and 2 can be viewed as hemidirected and holodirected geometries, respectively. The new nanostructures were synthesized using a sonochemical method and characterized by IR spectroscopy, X-ray powder diffraction, and scanning electron microscopy. Moreover, the thermal behavior of complexes 1 and 2 and their nanostructures were studied.

Optical, Structural, and Magnetic Hyperthermia Properties of Yttrium Iron Garnet Synthesized by Hybrid Microwave-Assisted Hydrothermal and Sol-Gel Auto Combustion Routes.

Magnetic hyperthermia is an emerging technique used for the treatment of tumors, where the infected cells will be deactivated using the heat generated from magnetic particles. This study discusses the viability of yttrium iron garnet (YIG) in magnetic hyperthermia treatment. YIG is synthesized using hybrid microwave-assisted hydrothermal and sol-gel auto combustion techniques. The formation of the garnet phase is confirmed using powder X-ray diffraction studies. Further, the morphology and grain size of the material are analyzed and estimated with the help of field emission scanning electron microscopy. Transmittance and optical band gap are obtained using UV-visible spectroscopy. Raman scattering of the material is discussed to understand the phase and vibrational modes. The functional groups of garnet are studied using Fourier transform infrared spectroscopy. Further, the effect of the synthesizing routes on the characteristics of the materials is discussed. A relatively higher magnetic saturation value is observed in the hysteresis loop at room temperature of YIG samples, which is synthesized by a sol-gel auto combustion technique, and it confirms the ferromagnetic behavior. The colloidal stability and surface charge of the prepared YIG are evaluated by a zeta potential measurement. In addition, magnetic induction heating studies are carried out for both prepared samples. The specific absorption rates of 1 mg/mL concentration are 237 and 214 W/g at 35.33 kA/m and 316 kHz field of sol-gel auto combustion and hydrothermal methods, respectively. Due to their higher saturation magnetization of 26.39 emu/g, the sol-gel auto combustion method produced effective YIG and demonstrated superior heating efficiency than the hydrothermally prepared sample. The prepared YIG are biocompatible, and their hyperthermia properties may be explored in various biomedical applications.

Electrodeposited NiFe2O4/Cu2O heterostructure thin films with enhanced photocurrent generation

In comparison with single-phase materials, heterostructures have been known for superior water splitting applications. In this study, Cu2O and NiFe2O4 are chosen to fabricate thin film heterostructures. Cu2O is electrodeposited at 60 °C for 5 min on ITO-coated glass substrates using three-electrode system. After deposition, the phase formation is confirmed using powder x-ray diffraction studies. The NiFe2O4 (NFO) thin films are deposited using RF sputtering method at room temperature for 2 h on Cu2O/ITO substrates to obtain NFO/Cu2O/ITO Type-II heterostructure. The scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) cross-sectional images show that the thickness of NFO layer is 120 nm and Cu2O layer is 1.5 µm. The photocurrent density of Cu2O on ITO is 0.08 ± 0.002 mA/cm2, and it increased to 0.12 ± 0.002 mA/cm2 after adding NFO layer on Cu2O film due to Type-II heterojunction formation.

Large Degree of Variation in Sorption Properties within a System of Isoreticular, Mixed-Ligand Ni- and Co-Based 2-Periodic Metal–Organic Frameworks

Two Ni-based and two Co-based mixed-ligand metal–organic frameworks (MOFs), which are all isoreticular with each other, are shown to have a large variation in nitrogen, carbon dioxide, hydrogen, and water vapor sorption properties, despite their similar structures. The MOFs have 1,2-bis(4-pyridyl)ethane (bpe) as the common ligand with the second ligand being either 2-nitroterephthalate (2-nta) or 2-bromoterephthalate (2-bta) for the Ni-based MOFs or 2-nta or 2-aminoterephthalate (2-ata) for the Co-based MOFs. The four MOFs have the formula [Ni(2-nta)(bpe)(H2O)2]n·2(DMA)n (1), [Ni(2-bta)(bpe)(H2O)2]n·2.8(DMF)n (2), [Co(2-nta)(bpe)(H2O)2]n·2(DMA)n (3), and [Co(2-ata)(bpe)(H2O)2]n·3(DMA)n·(H2O)n (4), respectively, where DMA = N,N′-dimethylacetamide and DMF = N,N′-dimethylformamide. Variable-temperature powder X-ray diffraction (VT-PXRD) studies indicate that the activated MOF structures are different from those of the as-synthesized MOFs, showing that the 2-periodic layers are dynamic upon desolvation. For the same metal ion, the MOF involving the 2-nta ligand has higher sorption, while sorption for the Ni-based MOFs is higher than for the Co-based MOFs. MOF 1 has the highest sorption within the isoreticular series and also has the highest sorption (the highest for water vapor) compared to other MOFs with the same or related ligands.

SYNTHESIS OF SILVER NANOPARTICLES USING LEAF EXTRACT OF ZINGIBER ZERUMBET (L.) SMITH AND THEIR ANTIBACTERIAL ACTIVITY STUDIES

Silver nanoparticles (AgNPs) were synthesized using the leaf extract of a medicinal plant, Zingiber zerumbet (L.) Smith. Characterization of the particles was done by Uv-visible spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and powder X-ray diffraction (PXRD) studies. TEM analysis shows the presence of spherical and quasi-spherical shaped particles with the maximum of size distribution curve passing through 24 nm. The selected area x-ray diffraction (SAED) pattern and the diffraction pattern from PXRD spectrum indicate that the silver in their nanoparticles crystallize in to face centred cubic (FCC) structure. Bactericidal effect of the synthesized AgNPs against the spreading of gram-negative bacteria, Escherichia coli (E. coli) and gram-positive bacteria, Staphylococcuus aureus (S. aureus) were determined. The bactericidal effect was determined in terms of minimum inhibitory concentration (MIC) in nutrient agar media, and the MICs are found to be 13.75 ×10−5 g/mL against E. coli and 16.50 ×10−5 g/mL against S. aureus bacteria. The antibacterial effect exhibited by these AgNPs against both the bacteria is superior compared to that exhibited by the reference compound, ciprofloxacin selected for the study.

La-doped LiMnPO4/C cathode material for Lithium-ion battery

LiMnPO4 and LiMn1-xLaxPO4 (0.01 ≤ x ≤ 0.1) nanostructures with in-situ carbon coating are synthesized by low temperature solvothermal method using Glycerol: Water (2:1) ratio as solvent. Powder X-ray diffraction (XRD) studies confirmed the orthorhombic crystal structure of LiMnPO4 and LiMn0.99La0.01PO4. X-ray diffraction shows that up to 1% La3+ ion doping into manganese sites does not affect the crystal structure of LiMnPO4. Field emission scanning electron microscopy (FESEM) of LiMnPO4 and LiMn0.99La0.01PO4 depicts the formation of nanosized particles with spherical morphology. Electrochemical properties of LiMnPO4 and LiMn0.99La0.01PO4 are investigated by galvanostatic charge discharge tests. The present studies show that 1% La3+ ion doped LiMnPO4 could be a promising cathode material that can improve the performance of Lithium-ion cell by increasing the electrochemical stability at higher C-rate.

Structural and optical properties of a new structural modification of Na3+3xYb2−x(PO4)3:1% Eu phosphate, where x = 0,1-0,5 and prospective thermometric applications of the compound

The powders of Na3+3xYb2-x(PO4)3: 1% Eu3+ (where x = 0.1, 0.2, 0.3, 0.4 and 0.5) have been synthesized using thermal method in solid state. Their structural and spectroscopic properties were investigated by powder X-ray diffraction, microcalorimetric method (DSC), Raman, infrared, absorption and luminescence studies. It was find that the studied materials belong to the NASICON-type compounds and crystallize in rhombohedral or monoclinic type of structure. Photoluminescence of investigated samples presents typical emission of Eu3+ ions with the dominance of electric dipole transitions and near-infrared bands attributed to Yb3+ ions. Efficient red and infrared emissions under the excitation of 395 nm can be attractive for LED lighting. The highest Yb3+ emission intensity has been registered for the sample with the Na3.9Yb1.7(PO4)3: 1% Eu3+ composition (x=0.3). Ytterbium excited level can be populated by the energy transfer from the Eu3+ ions and can be enhanced by sample heating. Due to the non-radiative processes, the Eu3+ luminescence decay times monitored at 619 nm were bi-exponental. Because of the strong influence of temperature on emission intensities, obtained compounds can be useful for non-contact temperature readout, especially in the high-temperature region (above 600 K). The maximum value of relative sensitivity Sr is equal 2.91%K-1 at 855 K for the sample Na3+3xYb2-x(PO4)3: 1% Eu3+ (x=0.3).

Anomalous oxidation state of europium in the Sr3(PO4)2-type phosphors doped with alkaline cations

A series of new phosphors Sr2.98Eu0.01M0.01(PO4)2 (SEMP), M = Li+, Na+, K+ have been synthesized by high temperature solid state reaction. Powder X-ray diffraction study reveals that SEMP samples are isostructural to palmierite-type Sr3(PO4)2 phosphate. The anomalous reduction Eu3+ → Eu2+ in nonreduction media in Sr3(PO4)2 host has been reported for the first time. The blue emission from Eu2+ (∼425 nm) corresponding to the 4f65d1→4f7(8S7/2) transitions and red emission from Eu3+ (550–750 nm), corresponding to the 4f–4f transitions 5D0 → 7FJ (J = 0−4) were observed. The highest Eu3+ luminescence intensity was observed for Li+-doped host both at 296 K and at 10 K. The results show that the synthesized samples with tunable blue/red-orange emission can be considered for thermal sensing application.

Monitoring the Local Structure and Magnetic Properties of the Dinuclear Cu2-Paddle Wheel Nodes in the Mesoporous Metal–Organic Framework, DUT-49(Cu), upon Adsorption-Induced Breathing Transitions

DUT-49(Cu) is a well-studied representative of flexible mesoporous frameworks, in particular, famous for long-lived overloaded metastable states in the presence of a variety of gases at defined temperatures, leading to “negative gas adsorption” transitions. Important mechanistic insights into these transitions in DUT-49 were obtained via in situ powder X-ray diffraction (PXRD) studies conducted in parallel to gas physisorption. However, for strongly X-ray absorbing probe molecules, such as xenon, such studies are not feasible, even if synchrotron radiation is used. Here we employ in situ electron paramagnetic resonance spectroscopy (EPR), PXRD, and adsorption isotherm measurements to explore the phase transformations in DUT-49(Cu) in the presence of xenon and compare its properties with the corresponding adsorption/desorption behavior of ethylene for this material. The antiferromagnetically coupled CuII–CuII dimers in the paddle-wheel (PW) units of this pillared layer MOF serve as local magnetic probes in the in situ EPR measurement. These experiments allowed us to monitor the op ↔ cp phase transformations during the xenon physisorption through the structural changes at the PW units encoded in the zero-field splitting parameters of the S = 1 state of the CuII dimers. The EPR data indicates an expansion of the unit cell for the cp phase in the presence of xenon. This novel EPR-derived insight into the phase transformation phenomena of the xenon-loaded DUT-49(Cu) could be validated by combined in situ EPR, PRXD, and adsorption isotherm measurements for ethylene adsorption over the same MOF material in a comparable temperature range.

Noncryogenic Air Separation Using Aluminum Formate Al(HCOO)3 (ALF)

Separating oxygen from air to create oxygen-enriched gas streams is a process that is significant in both industrial and medical fields. However, the prominent technologies for creating oxygen-enriched gas streams are both energy and infrastructure intensive as they use cryogenic temperatures or materials that adsorb N2 from air. The latter method is less efficient than the methods that adsorb O2 directly. Herein, we show, via a combination of gas adsorption isotherms, gas breakthrough experiments, neutron and synchrotron X-ray powder diffraction, Raman spectroscopy, and computational studies, that the metal-organic framework, Al(HCOO)3 (ALF), which is easily prepared at low cost from commodity chemicals, exhibits substantial O2 adsorption and excellent time-dependent O2/N2 selectivity in a range of 50-125 near dry ice/solvent (≈190 K) temperatures. The effective O2 adsorption with ALF at ≈190 K and ≈0.21 bar (the partial pressure of O2 in air) is ≈1.7 mmol/g, and at ice/salt temperatures (≈250 K), it is ≈0.3 mmol/g. Though the kinetics for full adsorption of O2 near 190 K are slower than at temperatures nearer 250 K, the kinetics for initial O2 adsorption are fast, suggesting that O2 separation using ALF with rapid temperature swings at ambient pressures is a potentially viable choice for low-cost air separation applications. We also present synthetic strategies for improving the kinetics of this family of compounds, namely, via Al/Fe solid solutions. To the best of our knowledge, ALF has the highest O2/N2 sorption selectivity among MOF adsorbents without open metal sites as verified by co-adsorption experiments..

Experimental synthesis of double perovskite functional nano-ceramic Eu2NiMnO6: Combining optical characterization and DFT calculations

We reported on the synthesis of the pure double perovskite Eu2NiMnO6 in nano ceramic forms by two different methods solvotermal and sol-gel routes without europium and magnesium nitrate. Room temperature X-ray powder diffraction study of the compound revealed a monoclinic P21/n structure. The particle size was determined by the Williamson–Hall and Scherrer formula and found around 43 and 59 nm for the average size. The chemical, homogeneous and optical properties of nanoparticles were confirmed by SEM, UV–vis absorbance and FTIR spectra. The Eu2NiMnO6 has an energy band gap 1.32 eV determined by Heyd-Scuseria Ernzerhof (HSE06) from density-functional theory (DFT) calculations close to the value found experimentally 1.01 eV.

Nature of magnetic transitions and evidence for magnetoelastic coupling in the biskyrmion-host hexagonal compound MnNiGa

The hexagonal compound MnNiGa with Ni2In-type structure has emerged as an important biskyrmion-host system in which these textures are super-stable over a wide temperature range extending from 16 K to the Curie temperature TC ∼350 K under moderate fields. Both the intensity of the external magnetic field and the presence of magnetoelastic coupling are known to play key role in the stability of the skyrmionic textures. Here we present the results of the first comprehensive investigation of the order of the phase transitions and its field dependence along with magnetoelastic (i.e., spin-lattice) coupling using a combined magnetization and high-resolution synchrotron x-ray powder diffraction (SXRPD) study of MnNiGa. The temperature dependence of the magnetization M(T) exhibits a paramagnetic to collinear ferromagnetic (FM) transition at TC (∼347 ± 0.5 K) with thermal hysteresis and negative slope in the Arrott plots across the TC suggesting its first order character. The M(T) plot in the collinear FM phase exhibits an anomalously decreasing behaviour after reaching its peak value at 300 K followed by a step-like change below 210 K due to an additional spin reorientation transition (SRT) to a non-collinear FM phase with TSRT∼200 ± 1 K. The SRT also shows thermal hysteresis characteristic of a first order phase transition. Our field dependent studies reveal stabilization of the collinear FM phase to higher temperatures and destabilization of the SRT transition setting an upper limit on the magnetic field for the observation of biskyrmions in this system. The Rietveld analysis of the SXRPD data reveals anomalies in the unit cell parameters at TC and TSRT without any change in the crystal symmetry. The modelling of the temperature dependence of the unit cell volume in terms of the Debye-Grüneisen equation reveals significant deviation from phonon contributions and the presence of the quadratic spin-lattice coupling below the FM TC, in the precursor SRT regime as well as below TSRT. The present results on the magnetoelastic coupling in the hexagonal MnNiGa may provide the necessary insight towards understanding the extreme sensitivity of the magnetic skyrmionic textures to external stresses.

Effect of neodymium (Nd) doping on the photocatalytic organic dye degradation performance of sol-gel synthesized CoFe2O4 self-assembled microstructures

Trivalent Neodymium doped CoFe2O4 was investigated as the potent photocatalyst for wastewater treatment. The CoFe2O4 and Nd-doped CoFe2O4 with various concentrations, such as 5, 10, and 15%, were prepared to employ the sol-gel technique. Structural characterization of the synthesized materials was done by powder X-ray Diffraction and Raman studies. The optical UV–Visible spectroscopy provides the optical properties of CoFe2O4 and Nd-doped CoFe2O4 and the XPS spectra, which identify the constituting elements with their oxidation states, confirm the incorporation of Nd into the CoFe2O4 lattice. SEM was performed to investigate their surface morphology, showing the self-assembled microstructures of CoFe2O4. The dye degradation process was investigated for the synthesized samples with methylene blue dye using UV–Visible spectroscopy, which reveals the photocatalytic performance of pure CoFe2O4 and Nd doped CoFe2O4 by measuring the absorbance of methylene blue at the same interval of time. The 5% Nd doped CoFe2O4 exhibits enhanced photocatalytic activity with a degradation efficiency of 72% within 4 h, which is higher than the pure sample. Outcomes indicates that the synthesized material can be useful in wastewater treatment.

Enhanced biopharmaceutical performance of brick dust molecule nilotinib via stabilized amorphous nanosuspension using a facile acid-base neutralization approach.

"Brick dust" compounds have high lattice energy as manifested by the poor aqueous solubility and suboptimal bioavailability. Nilotinib being a weakly basic brick dust molecule exhibits erratic and limited absorption during gastrointestinal transit, attributed to pre-absorptive factors like pH-dependent solubility, poor dissolution kinetics, and post-absorptive factors including P-gp-mediated drug efflux. In our study, these problems are addressed holistically by the successful fabrication of amorphous nanosuspension by an acid-base neutralization approach. The nanosuspension was obtained via rapid precipitation of nilotinib in an amorphous form and the generated in situ sodium chloride salt assisted in stabilizing the drug-loaded nanosuspension in a cage of salt and micellar stabilizer. Soluplus® and hypromellose acetate succinate (HPMCAS) were employed as a novel combination of stabilizers. Systematic optimization was carried out by employing the I-optimal method using Design Expert®software with a concentration of HPMCAS and Soluplus®as independent variables and evaluating them for responses viz particle size, polydispersity index (PDI), and zeta potential. The resultant nanosuspension showed a mean particle size of 130.5 ± 1.22nm with a PDI value of 0.27 ± 0.01, and a zeta potential of - 5.21 ± 0.91mV. The nanosuspension was further characterized for morphology, dissolution, and in vivo pharmacokinetics study. X-ray powder diffraction study of the nano-formulation displayed a halo pattern revealing the amorphous form. Stability studies showed that the nanosuspension remained stable at 40°C ± 2°C and 75% RH ± 5% RH for a period of three months. In vitro drug release and solubility study showed threefold and 36-fold enhancement in dissolution and solubility of the nanosuspension. Furthermore, an in vivo pharmacokinetic study in Sprague-Dawley rats following oral administration displayed a 1.46-fold enhancement in the relative bioavailability of the nanosuspension in contrast to neat nilotinib.