Crystal Growth & Design最新文献

Empagliflozin is a sodium-glucose cotransporter 2 (SGLT2) inhibitor that has received widespread attention in the treatment of diabetes in recent years, and it is usually prepared by solution crystallization. How to choose the appropriate crystallization solvent to obtain empagliflozin crystals with good crystal morphology and high purity is currently a key issue that urgently needs to be addressed. This paper proposes a computer-aided design/screening method for empagliflozin crystallization solvents. First, Hirshfeld surface analysis (HSA) is used to analyze the intermolecular interactions in empagliflozin crystals. Subsequently, the modified attachment energy (MAE) model is used to explore the influence of solvation on the crystal morphology of empagliflozin, and a quantitative prediction model for crystal morphology is established based on the generative adversarial network (GAN) and extreme gradient boosting (XGBoost) model. After data enhancement by GAN, the R² of the model performance can be increased from 0.4894 to 0.9454, and MAE, RMSE, and MAPE can be reduced to 0.1775, 0.2281, and 5.21% respectively. Next, the established quantitative prediction model is coupled with the computer-aided molecular design (CAMD) model, which is solved by the decomposition solution strategy. Finally, the crystallization solvents that meets all requirements are obtained.

Establishing the presence of gunshot residue (GSR) is a crucial investigative insight used by forensic scientists to place a discharged firearm in the vicinity of shooters or victims in the conduct of crime scene reconstructions. The most prevalent presumptive test for identifying GSR on objects or locations is the sodium rhodizonate test, which produces a visible red or orange coloration upon reaction with lead or barium, respectively. Despite widespread use since the 1950s, the identity of the chromophores produced when sodium rhodizonate reacts with GSR metals remains poorly characterized. This work provides new insights and solid-state structures of metal rhodizonate coordination species. Additionally, a host of new and unexpected chromophore candidates were identified, providing a more complete picture of the chemical complexity underpinning GSR testing. A multi-instrumental approach was undertaken to support the characterization of five lead, four barium, and one organic dye structures with single crystal diffraction studies, thereby linking these solid-state structures to solution-state behavior. This work assigned coloration of key solution- and solid-state reaction species using UV–visible and absorbance spectroscopy, and enabled the interpretation of solution-state reaction behavior from in situ mass spectrometry analysis of the mixtures, thereby providing unprecedented insights into the chemistry that underpins the sodium rhodizonate test for GSR.

We present a novel approach to scintillating crystal engineering through the incorporation of fluorescein molecules as a dopant into a cesium iodide (CsI) matrix. This work provides a comprehensive preparation method and characterization of the resulting hybrid material for applications in ionizing radiation detectors. Comprehensive characterization included powder X-ray diffraction (PXRD) to assess the dopant’s influence on the CsI lattice, followed by spectroscopic measurements (absorption, fluorescence, and fluorescence lifetime) to determine the optical properties and fast response time. Crucially, the quantum yield was also measured as a metric of energy conversion efficiency. The results demonstrate that the inclusion of fluorescein in the CsI matrix leads to a new scintillator, exhibiting superior properties compared to conventional materials such as CsI(Tl) or NaI(Tl). The presented research is the first step toward developing a new generation of scintillating detectors characterized by an optimal emission wavelength, high quantum yield, and fast response time, which are critical for applications in nuclear medicine, particle physics, and security systems.

A novel growth technique called “multiseed solution growth” (MSSG) was developed to increase the yield and reduce the cost of SiC production. In this work, four 1 inch P-type 4H-SiC bulk crystals were obtained in a single growth process. The high crystal quality was achieved by antiparallel flow on the entire seed surface, as the opposite directions of the step-flow and solution flow during solution growth create a smooth surface without solvent inclusions and foreign polytypes. The growth temperature distribution, flow pattern, and growth rates were predicted by a 3D numerical model, indicating its advantages in offering insights into nonaxisymmetric seed crystal settings and unidirectional solution flow. According to the surface stability on the 4° off vicinal surface, we discussed the formation of the tilted growth surface of the as-grown crystals and proposed a mechanism for macroscopic surface reconstruction of 4H-SiC. Our study confirmed the off-axis SiC growing quality under unidirectional solution flow. Scale-up of MSSG-SiC growth could be an optional technique for growing cost-effective bulk SiC crystals.

A series of quaternary rare-earth containing thiosilicates with the general formula RE₂EuSi₂S₈ (RE = Ce–Nd, Sm, Gd, Tb) has been synthesized via the flux-assisted boron chalcogen mixture (BCM) crystal growth method. High-quality single crystals were obtained, and their crystal structures were determined by single-crystal X-ray diffraction. The RE₂EuSi₂S₈ series crystallizes in the trigonal system, adopting the space group R-3c. Polycrystalline samples were employed for physical property measurements, including magnetic susceptibility measurements, UV–visible diffuse reflectance, and photoluminescent response. Magnetic data of RE₂EuSi₂S₈ (RE = Ce, Nd, and Gd) were collected over the 2–300 K temperature range. The samples were paramagnetic behavior with negative Weiss constants (θ_W = −11.05, −10.55, and −1.35 K respectively). Their thermal stability was investigated using thermogravimetric analysis (TGA). Optical band gaps, estimated from diffuse reflectance spectra, were determined to be 2.2(1) eV for Ce₂EuSi₂S₈, 1.8(1) eV for Nd₂EuSi₂S₈, and 1.7(1) eV for Gd₂EuSi₂S₈ respectively. Photoluminescence measurements were collected on Ce₂EuSi₂S₈ and Tb₂EuSi₂S₈ single crystals.

Halide perovskites are emerging as promising scintillating materials for X-ray imaging. High-quality X-ray imaging typically requires a short scintillation decay time and high spatial resolution. Herein, a CsPbBr_3.03@poly(methyl methacrylate) (PMMA) composite film scintillator, which, using a strategy via overdoping bromine and a polycrystal-polymer composite film preparation method, was designed to achieve fast scintillation and high-resolution X-ray imaging. Excessive doping with bromine shortens the decay time of CsPbBr_3.03 powder to a level of subnanoseconds (192.4 ps). In addition, the prepared scintillator has an exciton binding energy of up to 161.75512 ± 10.45011 meV, and exhibits not only a short scintillation decay time of 26.901 ns but also a high spatial resolution of >30 lp·mm^–1. This work provides a low-cost and efficient approach for the design of halide perovskite@organic glass composite scintillators, paving the way for the further development of high-resolution X-ray imaging scintillators.

Here, we investigated photoreactivity and photosalient effects of isotypical Zn(II) paddle wheel complexes through a new difluoro-substituted 4-styrylpyridine (4spy). Interestingly, substitution of F at 4spy showed a tremendous change in photoreactivity as well as the rate of photoresponsive nature. For two different [Zn₂(benzoate)₄L₂] complexes, 1 = [Zn₂(benzoate)₄(35F-4spy)₂], 2 = [Zn₂(benzoate)₄(23F-4spy)₂], solid-state [2 + 2] cycloaddition reaction studies are discussed in detail. 4spy ligands are aligned in a head-to-tail fashion and can result in a photosalient effect, leading to the formation of 1D CPs. An overall increase in the percentage cell volume of 15% and 16% for 1 and 2, respectively, during the photoreaction appears to indicate a significant anisotropic expansion is responsible for the photomechanical effects and finally the photosalient effect (PSE). At molecular level F atom increase of the ligand and a suitable crystal structure to attain [2 + 2] CAR, photosalient effect are studied in detail with different size and shape of crystals. Based on our current study and results of the crystal PSE, we are able to order the PSE nature of these isotypical complexes: 2 > 1.

In this work, we report the design and characterization of two novel lithium ionic cocrystal (ICC) hydrates, formulated with p-coumaric acid (p-CA) or vanillic acid (VA) and l-proline (LPCA and LPVA). Single-crystal X-ray diffraction revealed distinct hydration modes: in LPCA, water molecules were incorporated into the lattice, whereas in LPVA, water directly coordinated with lithium cations. Complementary analyses, including FT-IR spectroscopy, Hirshfeld surface analysis, differential scanning calorimetry, thermogravimetric analysis, and powder X-ray diffraction, confirmed that water molecules played a critical role in stabilizing the crystal frameworks and modulating intermolecular interactions. Both ICCs exhibited remarkable solubility enhancements compared with their parent phenolic acids, with 448-fold and 88-fold increases for p-CA and VA, respectively. Furthermore, LPCA and LPVA demonstrated significantly improved antioxidant activities in DPPH, ABTS, and FRAP assays, consistent with synergistic effects arising from ionic assembly and hydrogen-bonding networks. These findings highlight the potential of lithium ICC hydrates as promising solid forms that combine structural novelty with enhanced physicochemical and functional properties, offering prospects for safer and more effective lithium-based therapeutics.

Olanzapine is among the drugs with notoriously elusive polymorphs that are challenging to prepare in their phase-pure form. A first solution to this problem is offered in the present work using the ability of water to compete with organic solvent for inclusion in the drug crystal lattice and the ability of solvate-hydrates with an optimal composition to give a solvent-free amorphous olanzapine and its phase-pure polymorph II upon desolvation. In the screening performed, saturation of the drug solid forms with solvent vapors was used to select an organic solvent that could be partially or completely replaced by vapors of water in the solvate. Besides, water vapors were found to be passive enough in comparison with vapors of other studied solvents in their ability to change the polymorphic state of olanzapine or be included by its stable form. The conditions used for preparation of the amorphous olanzapine form are mild enough to prevent its partial thermal decomposition. These conditions also create phase restrictions that stop the desolvation of solvate-hydrate on the intermediate Ostwald stage of polymorph II that is phase-pure above the sensitivity level of powder X-ray diffractometry and thermal analysis.

AlScN thin films were grown via metal–organic chemical vapor deposition (MOCVD), showing controllable incorporation of scandium (Sc) into the AlN lattices. Systematic variation of growth parameters demonstrated an obvious influence on Sc incorporation, with X-ray photoelectron spectroscopy analysis indicating Sc composition up to ∼13% when (MCp)₂ScCl was used as the precursor. AlScN/AlN/GaN heterostructures grown on GaN templates exhibited the formation of a two-dimensional electron gas (2DEG) channel at the AlScN/AlN/GaN interface, confirming their potential use in high electron mobility transistor device technologies. Variation in the AlScN/AlN barrier thickness within the heterostructures showed that thicker barriers yield higher sheet charge densities from both Hall and capacitance–voltage (C–V) measurements. With an AlScN/AlN barrier thickness of ∼30 nm, a sheet charge density of 5.22 × 10¹² cm^–2 was extracted from C–V. High-resolution scanning transmission electron microscopy (S/TEM) further confirmed Sc incorporation and revealed the wurtzite crystalline structure of the films and heterostructures. These results establish the MOCVD growth of AlScN as a promising and compatible material for advancing III-nitride heterostructures in high-performance electronics and potentially in ferroelectrics.