X-ray Powder Diffraction Patterns Research Articles

Crystal structures of two new high-pressure oxynitrides with composition SnGe4N4O4, from single-crystal electron diffraction.

SnGe4N4O4 was synthesized at high pressure (16 and 20 GPa) and high temperature (1200 and 1500°C) in a large-volume press. Powder X-ray diffraction experiments using synchrotron radiation indicate that the derived samples are mixtures of known and unknown phases. However, the powder X-ray diffraction patterns are not sufficient for structural characterization. Transmission electron microscopy studies reveal crystals of several hundreds of nanometres in size with different chemical composition. Among them, crystals of a previously unknown phase with stoichiometry SnGe4N4O4 were detected and investigated using automated diffraction tomography (ADT), a three-dimensional electron diffraction method. Via ADT, the crystal structure could be determined from single nanocrystals in space group P63mc, exhibiting a nolanite-type structure. This was confirmed by density functional theory calculations and atomic resolution scanning transmission electron microscopy images. In one of the syntheses runs a rhombohedral 6R polytype of SnGe4N4O4 could be found together with the nolanite-type SnGe4N4O4. The structure of this polymorph was solved as well using ADT.

Preparation, characterization and photocatalytic studies of defect pyrochlore, KMn0·33Te1·67O6 and its composite with g-C3N4

Skeletal materials belonging to the defect pyrochlore family have been the subject of considerable interest due to their remarkable properties. In this work, a highly efficient, stable and visible light active composite photocatalytic system consisting of defect pyrochlore of composition KMn0·33Te1·67O6 (KMnTeO) and g-C3N4 (g-CN) has been successfully prepared by simple physical mixing of pre-prepared KMnTeO and g-CN components synthesized in solid state and thermal treatment of low-cost melamine, respectively. Structural, morphological and optical properties of as-prepared catalysts were deduced from powder X-ray Diffraction (XRD), Fourier Transform Infrared (FT-IR), Raman, Field Emission Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (FESEM-EDX), Transmission Electron Microscopy-High Resolution Transmission Electron Microscopy (TEM-HRTEM), Ultraviolet–Visible Diffuse Reflectance Spectroscopy (UV–Vis DRS), X-ray Photoelectron Spectroscopy (XPS) and Photoluminescence (PL) measurements. The lattice parameter “a” of parent KMnTeO was obtained from Rietveld refinement of its powder XRD pattern. The FT-IR and Raman spectra of KMnTeO gave characteristic bands belonging to the defect pyrochlore structure. The photocatalytic activities of KMnTeO and composite KMnTeO-g-CN were evaluated by the degradation of methylene blue (MB). Scavenger experiments were carried out to identify the reactive species responsible for the degradation of MB. Furthermore, the reusability and stability of the photocatalysts were explored. The probable photocatalytic mechanism for MB degradation over the composite KMnTeO-g-CN was surmised according to the scavenger experiments. The work provides a new approach for the development of novel defect pyrochlore based composite photocatalysts to treat industrial wastewater containing organic pollutants.

Morphological studies, photocatalytic degradation of organic dyes and anticancer potential of copper sulfide nanoparticles prepared from bis(diallyl dithiocarbamato)copper(II) complex

Bis(diallyl dithiocarbamato)copper(II) complex was synthesized and characterized by single crystal X-ray crystallography. The molecular structure revealed dimeric copper(II) complex consisting of two copper(II) ions that coordinate two molecules of diallydithiocarbamato anions in bidentate chelating modes and the centrosymmetrically related diallydithiocarbamato anions bridges the S-atom of the adjacent chelating ligand to formed square pyramidal geometry around the copper(II) ions. Copper sulfide nanoparticles were prepared at 160 °C by thermolysis of the copper(II) complex in dodecylamine (DDA), hexadecylamine (HDA), and octadecylamine (ODA) to study the effect of capping agents on the structural morphologies, photocatalytic properties, and anticancer potential of the as-prepared copper sulfides nanoparticles. Powder X-ray diffraction patterns confirmed Cu9S5 digenite crystalline phases for CuS-DDA and CuS-HDA while CuS-ODA is covellite crystalline phase. HRTEM images showed spherical particles with particle sizes in the range 2–25 nm. The copper sulfide nanophotocatalysts are efficient for the degradation of bromophenol blue with the highest photocatalytic efficiency of 95.14 % for CuS-DDA followed by CuS-HDA with 94.52 % and 93.95 % for CuS-ODA. The anticancer potentials of the compounds showed that CuS-HDA is the most potent with IC50 values of 1.22 µg/mL against HEK293 and 28.78 µg/mL against HeLa.

Hen egg lysozyme polymorphs mediated by two ionic liquids during batch cooling crystallization

-Lysozyme batch cooling crystallization in the presence of two ionic liquids (ILs), 1-butyl-3-methylimidazolium chloride ([C4mim]Cl), and 1,3-dimethylimidazolium iodide ([C1mim]I). Microscopic observation demonstrated that the crystal morphology with [C1mim]I is needle-like, while that with [C4mim]Cl and no ILs is plate-like. FTIR spectroscopy revealed that new peaks in the range of 1300–400 cm−1 occur with the case of adding [C1mim]I, meaning that the microstructure of lysozyme crystals changed. Raman spectroscopy and X-ray powder diffraction (XRD) pattern further confirmed that crystal forms of lysozyme with adding [C4mim]Cl and no ILs is completely different from that of adding [C1mim]I. Thermogravimetry (TG) and Differential Scanning Calorimeter (DSC) results indicated that addition of [C1mim]I delay the thermal deformation and degradation temperature of lysozyme crystals, suggesting that lysozyme crystals with [C1mim]I possesses higher thermal stability. The change in lysozyme crystal forms can be attributed to changes in interaction among lysozyme molecules and conformation in solution, leading to different assembly mode of molecules and formation of polymorphs. These findings could offer instructions for regulating lysozyme crystal forms and gaining initial insight into screening of potential ILs for developing polymorphs of the protein and other macromolecule crystals.

Exploring the formation and diversity of secnidazole cocrystals

This study investigates the cocrystallization of secnidazole (SNZ), a potent antimicrobial drug, with several coformers, overcoming the inherent stability challenges posed by its hemihydrate form to produce novel solid states. We successfully synthesized and characterized three novel cocrystals with carvacrol (CAR), fumaric acid (FMA), and 3,5-dinitrobenzoic acid (DNZ), employing synchrotron single crystal analysis to elucidate their structures. The application of Hirshfeld surface and 2D fingerprint plots further enriched our understanding of the unique packing arrangements within these cocrystals. Moreover, preliminary powder X-ray diffraction (PXRD) patterns hinted at the emergence of additional novel solid forms with salicylic acid (SLC), oxalic acid (OXA), succinic acid (SUC), citric acid (CTR), and thymol (THY). Supported by literature and a thorough analysis of molecular interactions, we propose the existence of pharmaceutical cocrystals among these newly identified solid forms. Our findings not only augment the repertoire of SNZ based pharmaceuticals but also accentuates the strategic utilization of supramolecular synthons, offering significant advancements in the understanding of novel solid form formation, and the critical role of hydrogen bonding in these processes.

New nanometric metal complexes based on thiazole derivative as potential antitumor and antimicrobial agents: Full structural elucidation, docking simulation and biological activity studies

Novel Mn(II), Ni(II), Zr(IV) and Cd(II) nanosized complexes of thiazole Schiff base derivative (HL) were synthesized for further medicinal applications. The inspected complexes were fully characterized using elemental and thermal analyses in addition to infrared spectroscopy (IR) and nuclear magnetic resonance (1HNMR). Electronic absorption spectra, X-ray powder diffraction (XRD), transmittance electron microscopy (TEM), molar conductance and magnetic moment were also measured and explained. The brought about data revealed that the ligand–metal chelation happened through the N atom of N = N group, and the ortho-dehydrogenated phenolic O atom to form the chelates where the metal binds with one molecule of the parent ligand. All applied spectroscopic and analytical techniques confirmed tetrahedral geometry in Mn(II) and Ni(II) complexes and octahedral geometry for Cd(II) and Zr(IV) complexes. The ligand, Mn(II), Ni(II), and Zr(IV) chelates' XRD patterns indicated an amorphous character where the Cd(II) complex's nature is crystalline. Transmission electron microscopy (TEM) images of the prepared compounds showed that the surface morphology is uniform and homogeneous. Also, the metal ions distribute through the complexes' surface in a nanosized nature. The metal complexes have been simulated by docking in the co-crystal structures of the liver cancer and breast cancer proteins with PDB IDs, 2JW2 and 3S7S, successively. Antibacterial, antifungal and anticancer activities for the ligand that has been produced and its complexes were achieved. The most encouraging antitumor results were acquired by Ni(II) chelate which exhibited an IC50 of 23.52 µg/ml contra MCF-7 cells (human breast cancer) which is lower than the reference 5-Fluorouracil (5-FU, IC50 = 28.00 µg/ml).

Evidence of local structural distortions and subtle thermal disorder in transparent photochromic yttrium oxyhydride

The structural properties of photochromic yttrium oxyhydride powder in its transparent state were examined using x-ray diffraction and temperature-dependent extended x-ray absorption fine structure spectroscopy (EXAFS) combined with reverse Monte Carlo (RMC) simulations. The refinement of the x-ray powder diffraction pattern, employing the Rietveld method, indicates that yttrium oxyhydride crystallizes in the nanocrystalline phase with the cubic space group Fm-3m (225), at room temperature. The lattice parameter was determined as a = 5.404(3) Å, and the nanocrystallite size was estimated at d = 16(2) nm. The partial radial distribution functions (RDFs) g(r) for Y–O, O–O, and Y–Y atom pairs were obtained from the results of the RMC simulations of the Y K-edge EXAFS spectra measured at three temperatures (10, 150, and 300 K). The analysis of the RDFs reveals a subtle impact of the thermal disorder and splitting of the second coordination shell of yttrium atoms (the Y–Y RDF), remaining at all temperatures. This observation, also supported by our density functional theory calculations, suggests the presence of local structural distortions associated with yttrium sites, which do not affect the long-range crystal order.

Gajardoite-(NH4), (NH4)As3+4O6Cl2[(Ca0.5□0.5)(H2O)5], a new mineral from the Khovu-Aksy deposit, Eastern Siberia, Russia

The new mineral gajardoite-(NH4), ideally (NH4)As3+4O6Cl2[(Ca0.5□0.5)(H2O)5], is found at the Khovu-Aksy Ni-Co deposit, Republic of Tyva, Russia. Gajardoite-(NH4) occurs as tiny lamellar coarsely hexagonal or irregular curved and divergent crystals up to 0.01 mm in size. The crystals are combined in groups, rosette-like clusters or spherulitic aggregates up to 0.2 mm, which are intimately intergrown with annabergite, arsenolite, and pharmacolite on a matrix of skutterudite, safforite, and other minerals. The new mineral is colorless, white in aggregates, transparent with a white streak and a vitreous lustre. It is brittle, with a perfect cleavage on {001}. The Mohs hardness is ~1½. The calculated density (Dcalc ) is 2.583 g/cm3.Gajardoite-(NH4) is optically non-pleochroic, uniaxial (–), ω = 1.745(10), ε = 1.558(5) (589 nm). The chemical composition determined by electron microprobe (wt. %, H2O content calculated by stoichiometry) is as follows: (NH4)2O 3.17, Na2O 0.40, K2O 1.07, CaO 5.28, As2O3 67.25, Cl 12.21, H2O 15.30, O=Cl –2.76, total 101.92. The empirical formula based on four As and 11 O atoms per formula unit is [(NH4)0.72K0.13Na0.08]Σ0.93Ca0.55As3+4O6Cl2.03(H2O)5. Gajardoite-(NH4) is hexagonal, space group P6/mmm; the unit-cell parameters are as follows: a = 5.263(3), c = 16.078(5) Å, V = 385.8(5) Å3, Z = 1. The strongest lines of the powder X-ray diffraction pattern [d, Å (I, %) (hkl)] include 16.08 (34) (001), 5.36 (34) (003), 4.565 (41) (100), 3.466 (23) (103), 2.637 (100) (110), 2.360 (25) (113). Gajardoite-(NH4) is an ammonium analog of gajardoite KCa0.5As3+4O6Cl2 • 5H2O. Their structural identity is confrmed by powder X-ray diffraction and infrared and Raman spectroscopy.

Trivalent dysprosium activated LaSr2AlO5 nanophosphors for NUV-excited wLEDs: Insights into structural, optical, Judd-Ofelt parameters and temperature dependent photoluminescence

Gel-combustion (GC) methodology was implemented in the present research to produce a series of single phase Dy3+ doped LaSr2AlO5 nanophosphors for the usage in wLEDs. X-ray powder diffraction patterns verified the phase purity and crystal structure of the produced materials. The XRD inspection supported the successful fabrication of tetragonal structured (I4/mcm space group) phosphors and revealed good accordance with card number 70–2197 on the JCPDS database. We collected diffuse reflectance spectra (DRS) to examine how doping affects the band gap. Furthermore, energy-dispersive X-ray (EDX) spectroscopy and transmission electron microscopy (TEM) have been employed for assessing elemental composition and surface morphology. On 349 nm excitation, LaSr2AlO5:Dy3+ phosphors produce the distinctive yellow PL emissions causedby 4F9/2→6H13/2 transition. Using excitation spectra, the Judd-Ofelt (J-O) characteristic (Ω = 2, 4, 6) have been determined. The Dy3+ transition's features show that the J-O parameters followed the trend which suggested an asymmetric environment around the ligand. The electric dipole transition predominated in the luminescence spectrum, causing the LaSr2AlO5:Dy3+ phosphor to emit a yellowish whitecolor. The fundamental mechanism for the energy transfer and concentration quenching instances among activator ions was discovered to be dipole-quadrupole interactions. Temperature dependent luminescence showed that the synthesized phosphors had thermal stability up to 523 K with activation energy of 0.1312 eV. The future prospects of the synthesized phosphor as an effective choice for near-ultraviolet-activated wLEDs are substantially supported by current comprehensive research.

Strong signature of uncompensated magnetization in frustrated cobalt manganites using x-ray magnetic circular dichroism study

The present study is focused on the investigation of the distorted tetragonal phase of mixed spinel oxides, due to their technological relevance in the field of electronics, spintronics, magnetism, catalysis, and electrochemical energy storage. Herein, we report on solgel synthesized multivalent cobalt manganites, CoMn2O4 (CMO), and subjected them to a comprehensive analysis to elucidate their physicochemical characteristics at room temperature. Analysis employing powder x-ray diffraction patterns and electron microscopy (including field-emission scanning electron microscopy and high-resolution transmission electron microscopy) results confirmed the formation of a pure and exceptionally crystalline, distorted tetragonal phase of mixed CMO. Synchrotron-based x-ray absorption spectroscopic (XAS) measurements in the total electron yield mode examined local electronic structures affirming the formation of CMO with uncompensated electronic states involving Co2+, Co3+, Mn2+, Mn3+, and Mn4+ cations. Concurrently, XAS and x-ray magnetic circular dichroism analyses revealed antiferromagnetic coupling within Co and Mn sublattices in CMO, indicating the presence of uncompensated electronic states. Vibrating sample magnetometry results demonstrated clear hysteresis behavior, explicitly indicating the coexistence of super-paramagnetic and canted antiferromagnetic characteristics in CMO, as validated through the Langevin function fitting and x-ray magnetic circular dichroism results. The noticeable absence of saturated magnetization confirmed the high degree of spin canting, primarily stemming from the presence of the Yafet–Kittel spin arrangement.

Effect of Tb3+ and Ce3+ Co-doping on the Structure and Photoluminescence Properties of Hexagonal Boron Nitride Phosphors.

In the paper, we have successfully prepared hexagonal boron nitride (h-BN:Tb3+, Ce3+) phosphors with melamine as the nitrogen source. The X-ray powder diffraction patterns confirm that the sample possesses a hexagonal crystal structure within the P m2 space group. It is interesting that the co-doping combination of Tb3+ and Ce3+ can markedly enhance the threshold concentration of doped activators within the limited solid solution of h-BN phosphors. Under 302nm excitation, the h-BN:Ce3+ phosphors exhibit broadband blue light emission at 406nm. In h-BN:Tb3+, Ce3+ phosphors, the co-doping of Ce3+ not only ensures high phase purity but also results in strong green light emission. The energy transfer efficiency from Ce3+ to Tb3+ is about 55%. The fluorescence lifetime increases with the increase of Ce3+ and Tb3+ concentration, and the fluorescence lifetime of h-BN:0.025Tb3+, 0.05Ce3+ phosphor reached 2.087ms. Additionally, the h-BN:0.025Tb3+, 0.05Ce3+ phosphor exhibits excellent thermal performance with an activation energy value of 0.2825eV. Moreover, the photoluminescence quantum yield of the sample exceeds 52%. Therefore, the h-BN:Tb3+, Ce3+ samples can be used as green phosphors for solid state lighting and fluorescent labeling.

Mckelveyite group minerals – Part 4: Alicewilsonite-(YLa), Na2Sr2YLa(CO3)6 ⋅ 3H2O, a new lanthanum-dominant species from the Paratoo mine, Australia

Abstract. The new mckelveyite group mineral, alicewilsonite-(YLa), Na2Sr2YLa(CO3)6 ⋅ 3H2O, was found together with kamphaugite-(Y), paratooite-(Y), bastnäsite-(La), and decrespignyite-(Y) coating along fractures in dolomite at the Paratoo copper mine, South Australia, Australia. It occurs as pale pink to colourless pseudohexagonal tabular crystals up to 150 µm in size. The streak is white; the lustre is vitreous. The mineral has no cleavage. Dcalc is 3.37 g cm−3. Alicewilsonite-(YLa) is optically biaxial (−), α = 1.556(2), β= 1.582(2), γ= 1.592(2), 2V (meas.) = 60(2)°, 2V (calc.) = 63° (589 nm). The IR spectrum is reported. The composition (wt %, average of seven analyses) is Na2O 7.43, CaO 2.00, SrO 18.43, BaO 1.64, Y2O3 9.59, La2O3 11.74, Pr2O3 1.29, Nd2O3 5.74, Sm2O3 0.44, Eu2O3 0.09, Gd2O3 0.95, Dy2O3 1.15, Ho2O3 0.25, Er2O3 0.89, Yb2O3 0.29, CO2 29.78, H2O 6.18, total 97.88. The empirical formula calculated on the basis of six cations with 3 H2O molecules is as follows: Na2.10Ca0.31Sr1.56Ba0.10Y0.74La0.63Pr0.07 Nd0.30Sm0.03Eu0.01Gd0.04Dy0.05Ho0.01Er0.04 Yb0.01(CO3)5.92(H2O)3. The mineral is triclinic, P1, a= 8.9839(2), b= 8.9728(3), c= 6.7441(2) Å, α= 102.812(2)°, β= 116.424(2)°, γ= 60.128(2)°, and V= 422.17(2) Å3 and Z= 1. The strongest reflections of the powder X-ray diffraction pattern [d,Å(I)(hkl)] are 6.03(43)(001), 4.355(100)(11‾0, 2‾1‾1, 120), 4.020(30)(1‾11, 210, 1‾2‾1), 3.188(29)(2‾1‾2, 11‾1, 121), 2.819(96)(002, 1‾12, 211, 1‾2‾2), 2.592(40)(3‾01, 030, 3‾3‾1), 2.228(33)(2‾21, 4‾2‾1, 2‾4‾1). 2.011(36)(2‾22, 003, 420, 2‾4‾2), 1.9671(32)(3‾03, 301, 03‾2, 032, 3‾3‾3, 331). The crystal structure was solved and refined from single-crystal X-ray diffraction data (R1= 0.058).

Comparing Microcrystal Electron Diffraction (MicroED) and X-ray crystallography as methods for structure determination of Oseltamivir phosphate

Oseltamivir phosphate is a pharmaceutical used in the treatment of influenza viruses. Panče Naumov et al. took two years of dedicated single crystal cultivation and successfully obtained low-quality single crystals through a diffusion method. Cultivation of Oseltamivir phosphate single crystals was proved to be difficult and can extend over several months or more. We employed microcrystalline electron diffraction (MicroED) for direct powder measurements, eliminating the need for lengthy single-crystal cultivation, and the time to obtain the molecular structure of Oseltamivir phosphate was shortened from several months to five hours. Comparative analyses of single crystal (Crystal 1) and MicroED (Crystal 2) results revealed equivalent crystal structures, with minimal differences in hydrogen bond distances, identical powder X-ray diffraction patterns, and negligible variations in Hirshfeld surface analysis. The differential scanning calorimetry (DSC) analysis showcased a higher melting point of Oseltamivir phosphate (206.0 °C) than Oseltamivir (110.7 °C), indicating that Oseltamivir phosphate had high temperature stability, and may result in the selection of Oseltamivir phosphate as a formulation form. The study establishes and verifies a congruence between MicroED detection and traditional single-crystal detection methods and may be applied in the elucidation of compound structures and the surveillance of drug polymorphism.

Enhancing thermoelectric behavior of Bismuth Selenide crystal via substitution of Sulfur and Tellurium

Sulfur and Tellurium substituted Bismuth Selenide (Bi2Se3-x-ySxTey, x = y = 0, 0.1, 0.15, 0.2) quaternary alloy crystals were synthesized by using vertical Bridgman technique. Energy dispersive analysis of X-rays confirmed elemental composition and purity of the grown crystals. Field emission scanning electron microscopy showed that the growth of crystals has occurred by layer growth mechanism. Rhombohedral crystal structure is validated through analysis of powder X-ray diffraction pattern. Thermoelectric parameters such as electrical conductivity, Seebeck coefficient and thermal conductivity were calculated from 303 K to 773 K and from that power factor as well as figure of merit have been determined for all grown crystals. Electrical conductivity significantly increased due to Sulfur and Tellurium incorporation and maximum value obtained is 147.72 S/cm at 503 K for Bi2Se2.6S0.2Te0.2. Seebeck coefficient and thermal conductivity showed decrement with incorporation of Sulfur and Tellurium. Reduction in thermal conductivity and enhancement in electrical conductivity resulted in the improvement of figure of merit. Sulfur and Tellurium substitution showed considerable improvement in ZT from 0.31 (533 K) for pristine Bi2Se3 to 1.28 (523 K) for Bi2Se2.6S0.2Te0.2.

Synthesis, spectroscopic and biological characterizations of platinum(IV), ruthenium(III) and iridium(III) theophylline complexes

This study used micro-analyses, (FTIR, UV-Vis) spectra, magnetic, thermogravimetric, X-ray powder diffraction (XRD) patterns, and transmittance electron microscopy (TEM) techniques to characterize three synthesized theophylline (TPH) complexes with ruthenium(III), platinum(IV), and iridium(III) metal ions. The metal ions indicated above were found to align with the TPH drug chelate as a mono-dentate ligand via the deprotonated NH group at the nitrogen atom position N7, as verified by FTIR measurements. Additionally, the complexes conductivity and magnetic susceptibility were examined. The octahedral geometry for the synthesized complexes was proposed by the current data. Except for the iridium(III) complex, which has a non-electrolytic nature due to the presence of a chlorine atom inside the chelation sphere, the molar conductivity of the complexes in DMSO solution was electrolyte in nature. Theophylline complexes with a (metal: ligand) stoichiometry of 1:2 were produced. The TPH complexes have also been tested in vitro against G(+) bacteria (Bacillus subtilis and Staphylococcus Aureus) and G(-) bacteria (Pseudomonas aeruginosa and Escherichia coli) to evaluate their antibacterial efficacy. Human breast and liver cancer cell lines were used as a test for the TPH complexes in vitro anti-cancer properties.
 KEY WORDS: Theophylline, Metal ions, Chelation, Octahedral, Spectral analysis, Nano-particles, Biological evaluation
 Bull. Chem. Soc. Ethiop. 2024, 38(3), 725-738. 
 DOI: https://dx.doi.org/10.4314/bcse.v38i3.14

Green route to prepare zinc oxide nanoparticles using Moringa oleifera leaf extracts and their structural, optical and impedance spectral properties

This article investigates biosynthesis of zinc oxide (ZnO) nanoparticles (NPs) from Moringa oleifera leaves extract using an eco-friendly preparation method. The crystalline structure, optical properties, morphology and impedance characteristics of ZnO NPs were analyzed using impedance spectroscopy, powder X-ray diffraction (XRD), scanning electron microscopy, Fourier transform infrared spectroscopy (FTIR) and ultraviolet spectroscopy (UV-vis). The powder XRD pattern confirmed the crystallinity of the prepared samples as well as enabled determining their crystallite size and pure phase portion. The FTIR study confirmed the presence of functional groups responsible for reduction metal ions into ZnO NPs. UV-vis absorption spectra contained the absorption peak corresponding to ZnO NPs. Impedance spectroscopy of the prepared ZnO NPs revealed the grain boundaries in them and confirmed their semiconducting nature.

CHARACTERISATION, EVALUATION AND DENSITY FUNCTIONAL ANALYSIS OF CILNIDIPINE-NICOTINAMIDE COCRYSTALS DEVELOPED BY LIQUID ASSISTED GRINDING TECHNIQUE: A SUSTAINABLE APPROACH FOR ENHANCED SOLUBILITY

Objective: Improving the solubility of poorly water-soluble drugs has always been a challenge in drug development. This study aimed to enhance the aqueous solubility of a poorly water-soluble drug, Cilnidipine, by cocrystallisation method using liquid-assisted grinding (LAG) technique with Nicotinamide as the coformer. The study also aimed to understand the mechanism of cocrystal formation by quantum mechanical calculations. Methods: The Cilnidipine-Nicotinamide cocrystals were prepared in various stoichiometric ratios using the liquid-assisted grinding (LAG) technique. The cocrystals obtained were characterised by vibrational spectroscopy, thermal methods such as differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD) and surface morphology by field emission scanning electron microscopy (FE-SEM). The cocrystals were evaluated for saturation solubility, and the mechanistic study of cocrystal formation was performed using the Gaussian 09 software package. Results: FT-IR spectra of the formulated cocrystal indicated the intermolecular hydrogen bond formation between-N-H of Nicotinamide and the nitro group of Cilnidipine. DSC analysis showed a single endotherm at 96.76 °C, PXRD patterns were different from that of the reactants, and FE-SEM analysis revealed the changes in the surface morphology of the obtained cocrystal. The prepared cocrystal showed a 26.36-fold enhancement in the aqueous solubility of Cilnidipine. The DFT study demonstrated the formation of a strong intermolecular hydrogen bonding between the nitro-oxygen atom of Cilnidipine and the amide hydrogen atom of Nicotinamide in cocrystal formed. Conclusion: This study highlights the potential of the liquid-assisted grinding method for preparing cocrystals as a sustainable and reliable approach to address the challenges posed by poorly water-soluble drugs.

Perchiazziite, Co2(CO3)(OH)2, a New Member of the Rosasite–Malachite Group from the Monte Ramazzo Mine, Italy

ABSTRACT Perchiazziite, ideally Co2(CO3)(OH)2, is a new mineral discovered at the Monte Ramazzo Mine, Genova Province, Liguria, Italy. It occurs as globular aggregates up to 0.1 mm in diameter, composed of very thin fibers. These develop on a matrix composed mostly of goethite and magnetite, in association with calcite and Co-bearing malachite. Aggregates of perchiazziite are pale orange-pink on their outer surfaces but white in thin section. It is translucent with white streak, silky luster, brittle tenacity, and uneven fracture. No cleavage and parting are observed. The Mohs hardness is ∼4. Dcalc. = 3.970 g/cm3. The mean refractive index calculated using the Gladstone-Dale equation is 1.77. The main bands in the Raman spectrum are at 154, 511, 707, 1085, 1526, 3304, aXnd 3479 cm−1. The chemical composition (by electron microprobe; CO2 and H2O by stoichiometry) of perchiazziite is (in wt.%): MgO 1.81, CaO 0.41, MnO 0.32, FeO 0.12, CoO 32.45, NiO 4.02, CuO 5.40, ZnO 25.60, CO2 20.63, H2O 8.42, total 99.18. The empirical formula calculated on the basis of 5 O apfu is: (Co0.93Zn0.67Cu0.15Ni0.12Mg0.10Ca0.02Mn0.01)Σ2.00(CO3)(OH)2. The crystal structure was refined by the Rietveld method. Perchiazziite is monoclinic, space group P21/a, a = 12.1832(16) Å, b = 9.3187(16) Å, c = 3.1570(3) Å, β = 97.165(15)°, V = 355.62(8) Å3, and Z = 4. The strongest lines of the X-ray powder diffraction pattern [d, Å (I, %) (hkl)] are 6.040 (22) (200), 5.073 (38) (210), 3.694 (53) (220), 2.599 (100) (021), 2.535 (26) (420), 2.480 (27) (221̄), 2.140 (26) (231̄), 1.561 (25) (202̄). Perchiazziite is a new member of the rosasite–malachite group.

Ho3+ -doped BaGd2 ZnO5 green-emitting phosphor for solid-state lighting: synthesis, characterization, and photoluminescence properties.

In this work, we present the synthesis of a green-emitting series of BaGd2 ZnO5 :xHo3+ (0.5-3mol%) phosphors using a high-temperature solid-state reaction method. Phase purity and crystal structure information were evaluated through X-ray powder diffraction patterns. Optical properties were examined through diffuse reflectance spectra, revealing that the prepared phosphor exhibited a band gap of 4.65 eV. The effect of Ho3+ doping on the morphology and ion distribution on the surface was assessed using scanning electron microscopy and time-of-flight secondary ion mass spectrometry techniques, respectively. The excitation spectra of the synthesized phosphor exhibited a charge transfer band and strong absorption transitions. The emission spectra displayed typical holmium emission characteristics, featuring a strong green emission band associated with f-f transitions from 5 F4 + 2 S2 → 5 I8 . Decay dynamics of the synthesized phosphor exhibited a single-exponential decay pattern, with lifetimes ranging from 0.103 to 0.053 ms. The intrinsic radiative lifetime, calculated through Auzel's fitting was determined to be 0.14 ms. Using the emission spectra, colorimetric behaviour was analyzed, revealing that the Commission Internationale de l'éclairage (CIE) coordinates exclusively lay within the green region at (0.285, 0.705), with an impressive colour purity of 99.6%. Given these marked properties, the synthesized phosphor exhibits great potential for a wide range of green-emitting applications, including displays, white light-emitting diodes, and security signage.

Determination of two structures of the solvent 3-hydroxypropionitrile crystallized at low temperatures

The title compound, 3-hydroxypropionitrile, was crystallized repeatedly in situ inside a quartz capillary using a liquid nitrogen cryostream. The X-ray powder diffraction patterns obtained indicated the presence of two distinct crystalline phases. The cleanest datasets for each of the phases were used to solve the crystal structures via simulated annealing, followed by refinement and optimization via dispersion-corrected density functional theory (DFT) calculations, with a final Rietveld refinement against the experimental data. The two structures appear to correspond to those proposed in a 1960s literature vibrational spectroscopy paper, one being the more stable with a gauche molecular conformation and the second metastable phase more complex with mixed conformations. Dispersion-corrected DFT computation using lattice parameters for both phases obtained from a single 84 K dataset with co-existing phases shows the stable and metastable phases to differ in energy by less than 0.5 kJ mol−1. A comparison of experimental far infrared spectra published in the 1960s with those calculated from the proposed crystal structures provides some independent supporting evidence for the proposed structures.