Powder X-ray Diffraction Studies Research Articles

Two-layer compounds in rare earth-{Fe, Co, Ni, Rh, Pd, Pt}-Te systems: crystal structure and magnetic properties

The partial isothermal sections of {Gd, Ho}-Ni-Te and Gd-Co-Te systems (~40–100 ​at. % of rare earth) have been investigated at 1070 ​K by X-ray and electron microprobe analysis. The Y5Ni2Te2-type {Tb, Dy, Ho}5Fe2Te2 and {Gd, Tb, Dy, Ho}5{Co, Ni}2Te2 (space group Cmcm, No. 63, oC36), Er7Ni2Te2-type Er7Co2Te2, {Y, Dy, Ho}7Ni2Te2, Ho7{Rh, Pd}2Te2 and {Y, Gd}7Pt2Te2 (space group Imm2, No. 44, oI22), Fe2P-type Ho6NiTe2 (space group P-62m, No. 189, hP9) and Sc6PdTe2-type Ho6{Rh, Pd}Te2 and {Y, Gd}6PtTe2 (space group Pnma, No. 62, oP36) compounds have been established using powder X-ray diffraction studies. Magnetization measurements show that the Y5Ni2Te2-type {Tb, Dy, Ho}5Fe2Te2, {Gd, Tb, Dy}5Co2Te2 and {Tb, Ho}5Ni2Te2 compounds exhibit a high-temperature ferromagnetic ordering with low-temperature spin-reorientation transition for Tb-, Dy- and Ho-containing compounds. Below Curie temperature, Tb5Fe2Te2, Tb5Co2Te2 and Ho5Ni2Te2 are soft ferromagnets, while they show hard magnetic properties below spin-reorientation transition. At 2 ​K, Tb5Co2Te2 and Tb5Fe2Te2 exhibit a coercive field of 35 ​kOe and ~30 ​kOe and the residual magnetization of 17.2 μB and 22.9 μB per formula unit, leading to theoretical maximum energy product of ~620 ​kJ/m3 and ~700 ​kJ/m3, respectively. Ho5Ni2Te2 reaches a maximum magnetic entropy change of −10.0 ​J/kg⋅K and −9.4 ​J/kg⋅K for a magnetic field change of 0–50 ​kOe ​at 45 ​K and 20 ​K, respectively.

Capture and Decomposition of the Nerve Agent Simulant, DMCP, Using the Zeolitic Imidazolate Framework (ZIF-8).

Understanding mechanisms of decontamination of chemical warfare agents (CWA) is an area of intense research aimed at developing new filtration materials to protect soldiers and civilians in case of state-sponsored or terrorist attack. In this study, we employed complementary structural, chemical, and dynamic probes and in situ data collection, to elucidate the complex chemistry, capture, and decomposition of the CWA simulant, dimethyl chlorophosphonate (DMCP). Our work reveals key details of the reactive adsorption of DMCP and demonstrates the versatility of zeolitic imidazolate framework (ZIF-8) as a plausible material for CWA capture and decomposition. The in situ synchrotron-based powder X-ray diffraction (PXRD) and pair distribution function (PDF) studies, combined with Fourier transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), zinc K-edge X-ray absorption near edge structure (XANES), and Raman spectroscopies, showed that the unique structure, chemical state, and topology of ZIF-8 enable accessibility, adsorption, and hydrolysis of DMCP into the pores and revealed the importance of linker chemistry and Zn2+ sites for nerve agent decomposition. DMCP decontamination and decomposition product(s) formation were observed by thermogravimetric analysis, FT-IR spectroscopy, and phosphorus (P) K-edge XANES studies. Differential PDF analysis indicated that the average structure of ZIF-8 (at the 30 Å scale) remains unchanged after DMCP dosing and provided information on the dynamics of interactions of DMCP with the ZIF-8 framework. Using in situ PXRD and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), we showed that nearly 90% regeneration of the ZIF-8 structure and complete liberation of DMCP and decomposition products occur upon heating.

Preparation, Spectroscopic Characterization, Theoretical Investigations, and In Vitro Anticancer Activity of Cd(II), Ni(II), Zn(II), and Cu(II) Complexes of 4(3H)-Quinazolinone-Derived Schiff Base

Herein, we report the synthesis and characterization of a new Schiff base ligand 3-[[(E)-(3-hydroxyphenyl)-methylidene]amino]-2-methyl-quinazolin-4(3H)-one (HAMQ) and its Cd(II), Ni(II), Zn(II), and Cu(II) complexes (C1–C4). The ligand HAMQ was synthesized by reacting 3-hydroxybenzaldehyde and 3-amino-2-methyl-4(3H)-quinazolinone in a 1:1 molar ratio. The structure of the ligand and its complexes (C1–C4) were evaluated using ultraviolet (UV)–visible (Vis) light spectroscopy, 1H-NMR, Fourier-transform infrared (FT-IR) spectroscopy, MS, elemental analysis, conductance data, and thermogravimetric analysis (TGA). The characterization results suggested that the bidentate ligand, HAMQ, coordinated to the metal center through the lactum oxygen and the azomethine nitrogen. Moreover, all the metal complexes were analyzed using powder X-ray diffraction studies, which revealed that all of them belong to a triclinic crystal system. The research was supplemented by density functional theory (DFT) studies on the IR and UV–Vis spectra, as well as the chemical reactivity of the HAMQ and its four metallic derivatives making use of conceptual density functional theory (CDFT) by means of KID (Koopmans in DFT) methodology. The synthesized complexes displayed significant in vitro anticancer activity against human cancer cell lines (HeLa and HCT-115).

Topological Strain-Induced Regioselective Linker Elimination in a Chiral Zr(IV)-Based Metal-Organic Framework

Summary Zr-carboxylate metal-organic frameworks (MOFs) are structurally robust materials, in part due to their strong coordination bonds. The regioselective Zr–O bond cleavage and formation between 3D architectures are thus challenging and are heretofore unexplored. In this work, by introducing highly flexible 18-crown-6-ether functionalities into a homochiral Zr-MOF, we report an unprecedented topology transition in which a 4,10-connected framework undergoes a rapid solid-state transition into a thermodynamically more stable 4,8-connected analog by a regioselective-linker-elimination under ambient conditions. The transition process was unambiguously unraveled by single-crystal and powder X-ray diffraction studies, and we proposed a possible transition mechanism based on various control experiments and theoretical calculations. The excellent chemical stability and substantially expanded porosity and pore apertures endowed the transformed chiral MOF with an exceptional capacity for the enantioadsorptive and solid-phase extractive separation of the racemic drug molecule of lansoprazole with 98% ee and 93% ee, respectively.

Influence of Fluorine Substitution on the Optical, Thermal, Electrochemical and Structural Properties of Carbazole-Benzothiadiazole Dicarboxylic Imide Alternate Copolymers.

In this work four novel donor-acceptor copolymers, PCDTBTDI-DMO, PCDTBTDI-8, P2F-CDTBTDI-DMO and P2F-CDTBTDI-8, were designed and synthesised via Suzuki polymerisation. The first two copolymers consist of 2,7-carbazole flanked by thienyl moieties as the electron donor unit and benzothiadiazole dicarboxylic imide (BTDI) as electron acceptor units. In the structures of P2F-CDTBTDI-DMO and P2F-CDTBTDI-8 copolymers, two fluorine atoms were incorporated at 3,6-positions of 2,7-carbazole to investigate the impact of fluorine upon the optoelectronic, structural and thermal properties of the resulting polymers. P2F-CDTBTDI-8 possesses the highest number average molecular weight (Mn = 24,200 g mol−1) among all the polymers synthesised. PCDTBTDI-DMO and PCDTBTDI-8 show identical optical band gaps of 1.76 eV. However, the optical band gaps of fluorinated copolymers are slightly higher than non-fluorinated counterparts. All polymers have deep-lying highest occupied molecular orbital (HOMO) levels. Changing the alkyl chain substituents on BTDI moieties from linear n-octyl to branched 3,7-dimethyloctyl groups as well as substituting the two hydrogen atoms at 3,6-positions of carbazole unit by fluorine atoms has negligible impact on the HOMO levels of the polymers. Similarly, the lowest unoccupied molecular orbital (LUMO) energy levels are almost comparable for all polymers. Thermogravimetric analysis (TGA) has shown that all polymers have good thermal stability and also confirmed that the fluorinated copolymers have higher thermal stability relative to those non-fluorinated analogues. Powder X-ray diffraction (XRD) studies proved that all polymers have an amorphous nature in the solid state.

Preparation, thermal stability and crystal structure of Li3UF7: New insights into LiF-UF4 binary phase diagram

In this manuscript the crystal structure of Li3UF7 from powder X-ray and neutron diffraction studies is reported. The existence of Li3UF7 has been debated for a long time, as it is often missed in a number of phase diagram studies. This study adopted a judicious composition of LiF and UF4, and an optimum cooling rate to prepare Li3UF7. The Li3UF7 phase could be obtained by cooling the molten LiF-UF4 with large excess of LiF at a rate of 5 K/min while slower cooling tends to form LiUF5. The crystal structures of Li3UF7 and LiUF5 in the temperature range of 300–10 K have been obtained from the powder neutron diffraction studies. At 300 K, Li3UF7 has an orthorhombic lattice with unit cell parameters: a = 8.698(2) Å, b = 8.692(2) Å, c = 12.803(1) Å, V = 968.0(4) Å3; Z = 8 (Space group: Ccca), and is isostructural to orthorhombic Li3ThF7. On cooling, the orthorhombic distortion of Li3UF7 increases but does not reveal any structural transition down to 10 K. The crystal structure of Li3UF7 is built from the defective (Li-deficient) layers of edge shared octahedral LiF6 and layers corner connected UF9 polyhedra. Analogous studies on LiUF5 have also been carried out, which has a tetragonal (Space Group: I41/a) lattice with unit cell parameters: a = 14.8882(8) Å, c = 6.5438(7) Å, V = 1450.5(2) Å3; Z = 16. The structure of LiUF5 is built from the three-dimensional sub-lattice formed by U4F30 units and the empty tunnels of the sublattice are occupied by Li4F16 clusters formed by four edge shared LiF6 octahedra. Also, the details of crystal chemistry of the compounds in LiF-UF4 systems and their thermal stabilities are discussed. The complexity in the crystal chemistry in LiF-UF4 system is manifested in multiple close by thermal events in the DTA runs which has also been discussed in the manuscript.

Synthesis and characterization of La0.7Sr0.3Fe0.7Co0.3O3±δ by Sonochemistry

AbstractAmong different possible energy sources, in the search for fossil fuel substitutes, hydrogen and fuel cells are presented as one of the most promising alternatives, with great potential, in the development of devices for the generation of clean electrical energy. Recently, lanthanum based compounds have been studied due to their interesting transport properties, which led these products to be applied as possible cathode materials in a solid oxide fuel cell. In this work, a lanthanum based material with a perovskite structure, La0.7Sr0.3Fe0.7Co0.3O3±δ (LSFC), was synthesized, from nitrates, by sonochemistry. This product was structurally characterized by powder X-ray diffraction and morphological studies were obtained by scanning electron microscopy. Results showed a nanostructured material with a crystal size in de order of 14 nm and a cubic perovskite structure with cell parameters of a = 3.8927 Å. Morphological characterization indicated a porous material formed by grains of homogeneous size, pores had an average length of 17 nm and area of 36 nm2, showing a channel shape distribution.

Growth and characterization of 4-(((4-aminophenyl)sulfonyl)oxy)-2,3-dihydroxy-4-oxobutanoic acid with Ce3+: for semiorganic nonlinear optical application

Abstract This work aims at the growth and characterization of novel semi-organometallic nonlinear optical (NLO) crystal 4-(((4- aminophenyl) sulfonyl) oxy)-2,3-dihydroxy-4-oxobutanoic acid (ASODA) with ammonium ceric (II) sulfate dehydrate (ACS). The crystal 4-(((4-aminophenyl) sulfonyl) oxy)-2,3-dihydroxy-4-oxobutanoic acid with Ce3+ (STA) was grown by slow evaporation solution growth technique using deionized water as a solvent. Crystalline system of the grown STA crystal was identified by a single crystal X-ray diffraction study and confirmed as monoclinic crystalline system with non-centrosymmetric space group P21/C. The powder X-ray diffraction study confirmed the purity and crystallinity of the crystal. The presence of functional groups and hydrogen bonds (–O–H–O–) was confirmed by FT-IR spectroscopy. UV-Vis spectra showed that the grown crystal had a low cutoff wavelength at 219 nm. The position of protons and carbons were determined by structural studies based on NMR technique. The grown crystal was thermally stable up to 130 °C and its melting point was 163 °C. The SHG studies were performed by Quanta Ray Model laser source using Kurtz powder technique. The NLO efficiency of the STA crystal was 0.5 times greater than that of standard KDP. The dielectric constant and dielectric loss of the grown crystal were studied at different temperatures. The surface morphology and the particle size of the crystal were determined by FE-SEM technique. From the mechanical studies, it was found that the grown crystal is a soft material.

Structural and electrical studies on zinc added magnesium oxide nanoparticles

Magnesium oxide (MgO, pure) and zinc added MgO nanoparticles were synthesised by a simple microwave assisted solvothermal method. The concentrations of impurity used in the present work were 0.25 M and 0.50 M. All samples were annealed at 400°C for 1 h to improve the ordering. The prepared pure and zinc added magnesium oxide nanoparticles were characterised by powder X-ray diffraction (PXRD), energy dispersive spectroscopy (EDS) and scanning electron microscopy (SEM). PXRD studies of pure and zinc added MgO nanoparticles showed that all samples belong to crystalline nature with cubic structure. The grain size of all samples were determined from the XRD results and it belongs to nano meter scale. The EDS confirmed the presence of zinc, magnesium and oxide elements in the respective prepared samples. The scanning electron microscope images confirmed that the prepared samples possess nanometer dimensions. The electrical properties such as AC conductivity, dielectric constant and dielectric loss were measured at different temperatures in the different frequency range by involving the impedance analyser of all the prepared samples.

Optical, Electrochemical, Thermal, and Structural Properties of Synthesized Fluorene/Dibenzosilole-Benzothiadiazole Dicarboxylic Imide Alternating Organic Copolymers for Photovoltaic Applications

In this work, four donor–acceptor copolymers, PFDTBTDI-DMO, PFDTBTDI-8, PDBSDTBTDI-DMO, and PDBSDTBTDI-8, based on alternating 2,7-fluorene or 2,7-dibenzosilole flanked by thienyl units, as electron-donor moieties and benzothiadiazole dicarboxylic imide (BTDI) as electron-accepting units, have been designed and synthesized for photovoltaic applications. All polymers were synthesized in good yields via Suzuki polymerization. The impact of attaching two different alkyl chains (3,7-dimethyloctyl vs. n-octyl) to the BTDI units upon the solubilities, molecular weights, optical and electrochemical properties, and thermal and structural properties of the resulting polymers was investigated. PFDTBTDI-8 has the highest number average molecular weight (Mn = 24,900 g·mol−1) among all polymers prepared. Dibenzosilole-based polymers have slightly lower optical band gaps relative to their fluorene-based analogues. All polymers displayed deep-lying HOMO levels. Their HOMO energy levels are unaffected by the nature of either the alkyl substituents or the donor moieties. Similarly, the LUMO levels are almost identical for all polymers. All polymers exhibit excellent thermal stability with Td exceeding 350 °C. X-ray powder diffraction (XRD) studies have shown that all polymers have an amorphous nature in the solid state.

Disaccharide assisted LaAlO3:Ce3+ perovskite: Structural and optical studies suitable for display devices

Sucrose mediated LaAlO3: Ce3+ nanopowders were prepared by propellant chemistry technique. The preliminary characterizations were carried out using Powder X-Ray Diffraction (PXRD), Fourier Transform InfraRed spectra (FTIR), Scanning Electron Microscopy (SEM) and transmission electron microscopy (TEM) to analyse the structure and morphology of the prepared nanophosphors. PXRD studies showed pure rhombohedral single phase with average crystallite size of the order of 45–62 nm. SEM micrographs confirmed nanoparticles formation and the crystallite size agrees well with the TEM image. The optical band gap of LaAlO3: Ce3+ (1–2 mol%) nanophosphors was found to be in the range 4.5–4.93 eV. PL spectra showed broad intense band at 449 nm and 541 nm up on 330 nm excitation. Chromaticity studies exhibit the blue green color emission of the prepared phosphors. The intensity and color of Ce3+ doped LaAlO3 nanophosphors confirm that these phosphors can be a potential material for display and optical devices.

Preparation and Characterization of Quinoxaline-Pyrene-Based Conjugated Copolymers for Organic Photovoltaic Devices

In this study, two novel conjugated polymers, poly(4,5,9,10-tetrakis((2-ethylhexyl)oxy]pyrene-alt-2,3-bis(3-(octyloxy)phenyl)-5,8-di(2-thienyl)-6,7-difluoroquinoxaline) (PPyQxff) and poly(4,5,9,10-tetrakis((2-ethylhexyl)oxy)pyren-alt-2,3-bis(3-(octyloxy)phenyl)-5,8-di(2-thienyl)quinoxaline) (PPyQx), consisting of quinoxaline units with and without fluorine substituents, as electron-accepting moieties and pyrene flanked with dithienyl units as electron-donating moieties were prepared via Stille polymerization reactions for use as electron donor materials in bulk heterojunction (BHJ) solar cells. PPyQxff and PPyQx were characterized by X-ray powder diffraction (XRD), gel permeation chromatography (GPC), thermogravimetric analysis (TGA), cyclic voltammetry (CV), UV−VIS absorption, and nuclear magnetic resonance (NMR) spectroscopy. PPyQxff and PPyQx revealed excellent solution processability in common organic solvents. PPyQxff and PPyQx presented decomposition temperatures above 300 °C. The inclusion of F atoms to the quinoxaline moiety made a slight reduction in the highest occupied molecular orbital (HOMO) level, relative to the unfluorinated polymer, but had no impact on the lowest unoccupied molecular orbital (LUMO) level. PPyQxff and PPyQx exhibited similar physical properties with strong and broad absorbance from 400 to 700 nm and an optical band-gap energy of 1.77 eV. The X-ray powder diffraction study indicated that PPyQxff possessed a reduced π–π stacking distance relative to PPyQx.

Selective synthesis of dioxolane biofuel additive via acetalization of glycerol and furfural enhanced by MCM-41-alanine bifunctional catalyst

Highly active and selective acetalization catalyst, viz. alanine functionalized MCM-41 (MCM-41-16Alanine), synthesized using post-grafting method is reported. The mesoporous solid is first reacted with (3-chloropropyl)triethoxysilane (CPTES) before alanine is covalently bonded onto the hybrid support as confirmed by TGA/DTG, IR and UV-Raman spectroscopy analyses. Furthermore, the meso-ordered structure of MCM-41 is also retained after surface modification as revealed by the X-ray powder diffraction (XRD) and transmission electron microscopy (TEM) studies. The resulting bifunctional catalyst bearing both acidity and basicity exhibits good catalytic performance in the acetalization of glycerol with furfural reaction where 90% conversion with 78% selective to (2-(furan-2-yl)-1,3-dioxolan-4-yl)methanol-a valuable dioxolane biofuel additive-are achieved under optimized reaction conditions. Furthermore, the excellent catalytic performance of MCM-41-16Alanine is demonstrated when it is compared to other reported catalysts thanks to its large surface area, acid-base bifunctionality and mesopore confinement that induce synergistic effects. The catalyst also displays high catalyst reusability and no significant deterioration in catalytic activity is shown after six consecutive runs, thus offering a green pathway for synthesizing dioxolane biofuel additive with high selectivity.

Investigation of Structural and Optical Properties of Pr3+-Substituted M-Type Ba–Ni Nano-Ferrites

In this study, a series of Ba0.8Ni0.2Fe(12–x)PrxO19 (0 ≤ x ≤ 0.4) ferrites was synthesized by co-precipitation route. The powder X-ray diffraction studies confirmed the formation of M-type hexaferrite structure. XRD results were used to determine the crystallite size and lattice constants of the prepared powders. The average crystallite size was found in the range of 19.88–29.19 nm and increased with increase in Pr3+ content. The FT-IR and Raman spectroscopy further confirmed the formation of M-type hexagonal structure. The optical bandgap was determined by UV-vis spectroscopy and it was found in the range of 2.80–3.44 eV. It was also observed that optical bandgap decreased when Pr3+ content increased until x = 0.3. With further increase in Pr3+ content, optical bandgap started to increase. This study demonstrates the potential of Pr-substituted Ba–Ni M-type hexagonal nanoferrites to be used in magneto-optical devices.

Structural, third-order nonlinear optical properties and optical limiting studies of novel zinc potassium aluminum sulfate nonadecahydrate single crystal

The crystal of zinc potassium aluminum sulphate nonadecahydrate (ZPASDH) was first time grown by the slow evaporation method. Powder X-ray diffraction (PXRD) study was used to evaluate the structure of ZPASDH crystal. Using Fourier transform infra-red (FTIR) analysis the functional groups were identified. The UV–Vis spectrum recorded for the grown ZPASDH crystal, from the spectrum optical cutoff wavelength is observed at 387 nm and the optical band gap was also determined. Thermo gravimetric analysis (TGA) was used for confirmation of thermal stability of grown crystal. Mechanical strength of the ZPASDH single crystal was confirmed by Vickers microhardness study. Third-order nonlinear refractive index (n2 = 1.11 × 10−9 cm2/W), nonlinear absorption coefficient (β = 5.31 × 10−5 cm/W) and optical limiting behavior of ZPASDH crystal have been determined by Z-scan technique.

Fabrication of Environmentally Compatible Biopolymer Films of Pullulan/Piscean Collagen/ZnO Nanocomposite and Their Antifungal Activity

Polysaccharide pullulan acts as a base matrix for the fabrication of pullulan/collagen blend film with dopant ZnO nanoparticles. From the FTIR data, it could be confirmed that there was significant interaction among the pullulan/collagen/ZnO-NPs. The weak interactions like H-bonding was evident by shift absorption band of hydroxyl groups into the lower frequency region. The powder X-ray diffraction study revealed the amorphous nature of pullulan/collagen blended film which was modified into a crystalline structure after the addition of ZnO nanoparticles. The transformation of the films into crystallinity and the presence of the Zn element was confirmed by SEM-EDAX. Further, the results of TGA revealed that the addition of nanoparticles influenced the thermal stability of the pullulan/collagen blended films. The addition of ZnO nanoparticles lead to an increase of the stiffness and mechanical resistance of the nanocomposite films; which showed an increase in their tensile strength evidenced by an increase in Young’s modulus. The fabricated films exhibited antifungal activity against Aspergillus niger with a maximum zone of inhibition of 18 mm for pullulan/collagen/ZnO-NPs (0.5%). However, the nanocomposite films easily dissolved in an aqueous medium, indicating their possible use as edible packaging films in the food industry.

Enhanced Oral Absorption of All-trans Retinoic Acid upon Encapsulation in Solid Lipid Nanoparticles.

All-trans retinoic acid (ATRA) is widely employed in the treatment of various proliferative and inflammatory diseases. However, its therapeutic efficacy is imperiled due to its poor solubility and stability. Latter was surmounted by its incorporation into a solid matrix of lipidic nanoparticles (SLNs). ATRA loaded SLNs (ATRA-SLNs) were prepared using a novel microemulsification technique (USPTO 9907758) and an optimal composition and were characterized in terms of morphology, differential scanning calorimetry (DSC), and powder X-ray diffraction studies (PXRD). In vitro release, oral plasma pharmacokinetics (in rats) and stability studies were also done. Rod-shaped ATRA-SLNs could successfully incorporate 3.7 mg/mL of ATRA, increasing its solubility (from 4.7 μg/mL) by 787 times, having an average particle size of 131.30 ± 5.0 nm and polydispersibility of 0.283. PXRD, DSC, and FTIR studies confirmed the formation of SLNs. Assay/total drug content and entrapment efficiency of ATRA-SLNs was 92.50 ± 2.10% and 84.60 ± 3.20% (n=6), respectively, which was maintained even on storage for one year under refrigerated conditions as an aqueous dispersion. In vitro release in 0.01 M phosphate buffer (pH 7.4) with 3% tween 80 was extended 12 times from 2h for free ATRA to 24 h for ATRA-SLNs depicting Korsmeyer Peppas release. Oral administration in rats showed 35.03 times enhanced bioavailability for ATRA-SLNs. Present work reports preparation and evaluation of bioenhanced ATRA-SLNs containing a high concentration of ATRA (>15 times than that reported by others). Latter is attributed to the novel preparation process and intelligent selection of components. Lay Summary: All-trans retinoic acid (ATRA) shows an array of pharmacological activities but its efficacy is limited due to poor solubility, stability and side effects. In present study its solubility and efficacy is improved by 787 and 35.5 times, respectively upon incorporation into solid lipid nanoparticles (ATRA-SLNs). Latter extended its release by 12 times and provided stability for at least a year under refrigeration. A controlled and sustained release will reduce dose related side effects. ATRA-SLNs reported presently can thus be used in treatment /prophylaxis of disorders like cancers, tuberculosis, age related macular degeneration and acne and as an immune-booster.

Versatility of Amide-Functionalized Co(II) and Ni(II) Coordination Polymers: From Thermochromic-Triggered Structural Transformations to Supercapacitors and Electrocatalysts for Water Splitting.

The new 2D coordination polymers (CPs) [M(L)2(H2O)2]n [M = CoII (1) and NiII (2); L = 4-(pyridin-3-ylcarbamoyl)benzoate] were synthesized from pyridyl amide-functionalized benzoic acid (HL). They were characterized by elemental, Fourier transform infrared, thermogravimetric, powder X-ray diffraction (PXRD), and single-crystal X-ray diffraction (XRD) structural analyses. Single-crystal XRD analysis revealed the presence of a 2D polymeric architecture, and topological analyses disclose a 2,4-connected binodal net. A thermochromic effect leads to the production of two new CPs, 1' and 2', by heating at ca. 220 °C, accompanied by a color change from orange to purple in the case of 1 and from blue to green in the case of 2. The transformation of 1 to 1' takes place through an intermediate (1a) with a different twist of the L- ligand, leading to the formation of a 1D polymeric architecture, as proven by single-crystal XRD analysis. The addition of water or keeping 1' or 2' in air for several days leads to regeneration of 1 or 2, respectively. The thermochromic-triggered structural transformations of 1 and 2 were further substantiated by PXRD and UV-vis ground-state diffuse-reflectance absorption studies. The supercapacitance ability of the CPs 1 and 2 and a Ni-Co composite (made from mixing the CPs 1 and 2) was investigated by electroanalytical techniques, such as cyclic voltammetry and electrochemical impedance spectroscopy. The CP 2 exhibits the highest specific capacity of 273.8 C g-1 at an applied current density of 1.5 A g-1. These newly developed CPs further act as electrocatalysts for the water-splitting reaction.

Synthesis of Vinylene‐Linked Two‐Dimensional Conjugated Polymers via the Horner–Wadsworth–Emmons Reaction

In this work, we demonstrate the first synthesis of vinylene‐linked 2D CPs, namely, 2D poly(phenylenequinoxalinevinylene)s 2D‐PPQV1 and 2D‐PPQV2, via the Horner–Wadsworth–Emmons (HWE) reaction of C 2‐symmetric 1,4‐bis(diethylphosphonomethyl)benzene or 4,4′‐bis(diethylphosphonomethyl)biphenyl with C 3‐symmetric 2,3,8,9,14,15‐hexa(4‐formylphenyl)diquinoxalino[2,3‐a:2′,3′‐c]phenazine as monomers. Density functional theory (DFT) simulations unveil the crucial role of the initial reversible C−C single bond formation for the synthesis of crystalline 2D CPs. Powder X‐ray diffraction (PXRD) studies and nitrogen adsorption‐desorption measurements demonstrate the formation of proclaimed crystalline, dual‐pore structures with surface areas of up to 440 m2 g−1. More importantly, the optoelectronic properties of the obtained 2D‐PPQV1 (Eg=2.2 eV) and 2D‐PPQV2 (Eg=2.2 eV) are compared with those of cyano‐vinylene‐linked 2D‐CN‐PPQV1 (Eg=2.4 eV) produced by the Knoevenagel reaction and imine‐linked 2D COF analog (2D‐C=N‐PPQV1, Eg=2.3 eV), unambiguously proving the superior conjugation of the vinylene‐linked 2D CPs using the HWE reaction.

Metallic Tungsten Nanoparticles That Exhibit an Electronic State Like Carbides during the Carbothermal Reduction of WCl6 by Hydrogen.

Carbothermal hydrogen reduction (CHR) is a unique dry chemical process used to fabricate metals and carbides on carbon supports. In this study, a stepwise CHR of WCl6 on a graphite support is demonstrated for the first time. Powder X-ray diffraction studies revealed that, at 773 K, metallic tungsten nanoparticles are produced, whereas, at 1073 K, the metastable W2C phase is generated rather than the thermodynamically stable WC phase. X-ray photoelectron spectroscopy and X-ray absorption near edge structure studies showed that the chemical state of the W nanoparticles simultaneously exhibits metallic W(∼0) and carbide W(δ+) character. The obtained results suggest that, although electronic interactions exist between the metallic W atoms and the graphite support, the body-centered cubic structure of the metallic tungsten is maintained, confirmed by the extended X-ray absorption fine structure. In addition, high-resolution scanning transmission electron microscopy observations revealed that the W nanoparticles exhibit a thin flattened shape on the support. These results support the notion that the mechanism for the formation of the W nanoparticles during the CHR is influenced by the electronic interactions between the W nanoparticles and the graphite support. Our work thus suggests that the combination of early-transition-metal atoms and carbon-based supports would afford modulatable electronic systems though the electronic interactions.