CrystEngComm最新文献

The aim of this study was to prepare stable novel crystalline salts of cabozantinib, a tyrosine kinase inhibitor used to treat medullary thyroid cancer, to improve its dissolution properties and thereby reduce the positive food effect associated with its marketed salt form (L-malate). Five novel multi-component solid forms were obtained. In addition to the detailed physicochemical characterization, we report the crystal structures of the saccharinate, hydrochloride, and hydrobromide salts. The hydrobromide and hydrochloride salts of cabozantinib were chosen for further studies based on promising preliminary results from dissolution rate measurements. The potential of the hydrochloride and hydrobromide salts to be used for drug formulation was determined by testing their physical stability using hygroscopicity tests and by observing their melting properties. To investigate the impact of these salts on reducing the patient-relevant food effect, in vitro dissolution studies in stimulated fed and fasted states using biorelevant media were performed and compared to the marketed form of the drug.

Polyoxometalates (POMs) with excellent redox capacity, high negative charge properties, good structural stability and polyatomic active sites are considered excellent candidates for water splitting. In this work, the synthesis process of compounds was explored by adjusting the pH, solvent volume and reaction temperature to obtain the most suitable conditions for crystal precipitation by a one-step solution method. Single crystal X-ray diffraction tests showed that two POM compounds modified by Mn group and organic ligand were successfully synthesized, which were [{Na₁₂(H₂O)₁₁Mn₂(OH)₈}{W₁₂O₄₀}]·8H₂O (1), (Hdmap)₆[H₂W₁₂O₄₀]·3H₂O (2) (dmap = 4-dimethylaminopyridine). CCDC 2306403 and CCDC 2327916 contain the supplementary crystallographic data for this paper. Compound 1 showed a layered three-dimensional structure wrapped by 14-core sodium ions and manganese ions with a unique channel (11.73 Å × 24.71 Å). Compound 2 possessed a layered three-dimensional structure of dmap-{W₁₂}-dmap. For HER. Compound 1 exhibited the best overpotential value of 199 mV for HER at a current density of 10 mA cm⁻² and a slope of 63.95 mV dec⁻¹, which were lower than those of Na₁₀[H₂W₁₂O₄₂]·27H₂O (440 mV, 495.76 mV dec⁻¹), compound 2 (322 mV, 73.86 mV dec⁻¹) and blank carbon cloth (552 mV, 750.85 mV dec⁻¹). Compared to Na₁₀[H₂W₁₂O₄₂]·27H₂O and compound 2, compound 1 also exhibited a lower overpotential value of 398 mV and the Tafel slope of 46.24 mV dec⁻¹ for OER. Meanwhile, compound 1 offered excellent stability after 24 hours and durability after 2500 cycles for both HER and OER. Surprisingly, compound 1/CC||compound 1/NF required only 1.48 V to drive water electrolysis, which was close to the value of Pt/CC||RuO₂/NF (1.43 V). Moreover, the CP curve of compound 1/CC||compound 1/NF was controlled for 20 h, reflecting that compound 1 has considerable durability.

Fast ultrasound-assisted processes were utilized for the first time to achieve the successful synthesis of two highly crystalline Zr-based metal–organic cages, namely ZrT-1 and ZrT-1–OH. By varying the temperature and power level, the desired product was obtained after 5–8 minutes as crystalline particles with cubic shape (ca. 2–8 μm). Furthermore, ultrasound-assisted synthesized ZrT-1 and ZrT-1–OH demonstrated exceptional performance for tartrazine adsorption. Under optimal conditions, their maximum adsorption capacities were determined to be 238.6 mg g⁻¹ and 225.3 mg g⁻¹, respectively.

Using a solvent for recrystallization can lead to solvate formation, which may be undesirable or desirable. Herein, we present a statistical analysis of the deposits of the Cambridge Structural Database (CSD) aimed at assessing the frequency with which varied solvents are used for recrystallization and their propensity towards solvate formation.

Vanadium dioxide (VO₂) is a conventional semiconductor material with a phase transition, and its properties strongly depend on the preparation process. In this study, VO₂ thin films were fabricated on c-type sapphire substrates by direct current (DC) magnetron sputtering, and the deposition was conducted under different bias voltages to investigate their impacts on the microstructure, morphology, electrical properties, and optical properties of the films. Raman spectra of the films exhibited molecular bond vibrations with specific spectral peaks of VO₂ and vanadium pentoxide (V₂O₅). In situ variable temperature Raman spectroscopy revealed the characteristics of the films during the phase transition of VO₂. Scanning electron microscopy (SEM) images showed that as the bias voltage increased, the surface structure of the film gradually became dense, and the surface morphology was smoother. The thin film deposited at a bias voltage of −100 V exhibited excellent optical and electrical properties, with an optical modulation amplitude of 78.25% at 4.5 μm. The energy distribution study demonstrated that the energy provided by the bias endowed ions with more kinetic energy, thereby improving the film formation quality. Moreover, V₂O₅ was directly generated under a high bias voltage. Consequently, our results confirmed the formation of VO₂ with related structural, optical, and electrical properties under various bias conditions in the magnetron sputtering process, providing a strategy for fabricating stable and high-quality VO₂ thin films.

In this work, highly spherical and porous ammonium dinitramide (ADN) crystals were prepared using the solvent–antisolvent crystallization method. To explore the growth mechanism of ADN crystals in different solvent environments, we adjusted the supersaturation of the solution by varying the stirring speed and flow rate. The growth process and internal morphology of the particles reflected the crystal growth mechanism: small ADN particles followed the traditional nucleation and growth process, while larger ADN particles underwent particle aggregation, filling-in-growth and wearing into spherical shapes. By combining the crystal growth mechanism of this method, iron oxide (Fe₂O₃) was introduced during the ADN crystallization process, successfully constructing ADN@Fe₂O₃ composite microparticles with the inorganic host crystal encapsulating the guest. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to verify the structure of ADN@Fe₂O₃, and the results showed that Fe₂O₃ was successfully encapsulated in ADN particles without affecting the crystal structure of ADN. The thermal decomposition behavior of the composite microparticles was compared with that of the physical mixture using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), confirming the superior catalytic effect of Fe₂O₃ in this composite form. The apparent activation energy at the initial stage of decomposition decreased from 194.39 kJ mol⁻¹ to 174.76 kJ mol⁻¹. The crystal growth mechanism revealed in this work can be extended to the preparation of other spherical crystal materials and provides a general and effective new approach for constructing composite energetic particles with unique structures and excellent decomposition performance.

Crystal structures that form with more than one molecule in the asymmetric unit (Z′ > 1) are a fascinating and important, if overlooked, aspect of crystal engineering. With the recent publication of the results of the ‘seventh blind test of crystal structure prediction’ the challenges that these structures present and the questions they provoke for the prediction and design of crystalline solids are brought sharply into focus. This article documents developments in the study of high Z′ structures over the last ten years and shines a spotlight on the most extreme and intriguing examples from recent publications. The lessons learned from these studies will inform future crystal engineering and design efforts as strides are made to work around the computational expense inherent in the prediction of structures with large asymmetric units.

Thermoelectric generators (TEGs) can directly convert low-grade thermal energy into electrical energy, possessing numerous benefits, including noise-free operation, pollution-free energy conversion, and long service life. Flexible TEGs can not only fit various curved surfaces but also withstand bending and twisting. This character makes them particularly suitable for wearable power generation technologies and raises considerable interest among people. Silver-based chalcogenide compounds, known for their excellent near-room-temperature thermoelectric properties and ductility, are considered ideal materials for constructing high-performance flexible or wearable TEGs. This study reviews the latest research on flexible thermoelectric materials derived from silver chalcogenides, focusing primarily on Ag–S, Ag–Se, and Ag–Te-based compounds and their composites. Among them, this review pays more attention to pure Ag₂Se and Ag₂Se-based materials because their performance is outstanding. Additionally, the key challenges hindering the enhancement of thermoelectric performance in these materials have also been discussed. Finally, the prospects for the development and application of silver chalcogenide-based flexible thermoelectric materials have been outlined.

Yb:CaGdAlO₄ (Yb:CALGO) single crystals having a series of Yb³⁺ concentrations (0.5, 1.7, 2.5, 5.0, 7.2, and 8.0 at%) were grown using the Czochralski method. X-ray powder diffraction (XRD), polarized absorption, fluorescence spectra, and Raman spectra were measured for the synthesized crystals to investigate the influence of the doping concentration of Yb³⁺ on the structure and spectral properties. The results indicate that Yb³⁺ doping concentrations within the tested range induce a negligible change in the structure but a significant change in the absorption and fluorescence features. Both polarized absorption and emission intensity in the π and σ-polarization increase with the increment of Yb³⁺ concentration. The fluorescence lifetimes, determined using the powder concentration dilution method, varied from 0.454 ms to 0.527 ms. Various spectral cross-sections of Yb:CALGO crystals were calculated and analyzed. Moreover, within the examined range, Yb³⁺ concentration exhibits negligible impact on the positions of the primary peaks observed in the Raman spectra. However, a notable intensity difference was observed at 311 cm⁻¹ in the Raman spectra measured along the a- and c-directions, which can be attributed to variations in the linkage of AlO₄⁵⁻ groups. This work provides a basis for the Yb:CALGO femtosecond laser experiments by optimizing the Yb³⁺ concentrations.