CrystEngComm最新文献

Tautomerism is a phenomenon where a compound may exist in two or more interconvertible structural isomers (known as tautomers) that are generally different in terms of the relative position of one hydrogen atom. Tautomeric pharmaceuticals have more potential solid forms, thereby expanding the range of options for modulating their physicochemical properties in the solid state. All crystal structures of topiroxostat (TOP) polymorphs solved previously and in this contribution reveal that the TOP molecule monotonically exists in the 2H-tautomeric form. After salt formation with hydrochloric acid (TOP–HCl–H₂O) or sulfuric acid (TOP–H₂SO₄ form I and form II), the protonated 3H-tautomeric form was observed. Compared with TOP, all three salt forms demonstrated improved dissolution performance and TOP–HCl–H₂O also displayed satisfactory moisture stability. It is noteworthy that hydrochloric acid and sulfuric acid are the most commonly used salt formers for commercial pharmaceuticals. The proven safety of the counterions and improved pharmaceutical performance of TOP salts highlight their potential for further pharmaceutical applications.

We report the Dy:CaWO₄ and Dy,Tb:CaWO₄ crystals grown by the Czochralski method, and their structural and optical properties are studied. Raman spectra, polarization absorption spectra, polarization emission spectra, and fluorescence lifetime are obtained. The Judd–Ofelt intensity parameters (Ω_t, t = 2, 4, 6), the fluorescence branching ratios, and the radiative lifetimes of the ⁴F_9/2 level are calculated based on the Judd–Ofelt theory. The emission cross-sections are calculated using the Füchtbauer–Ladenburg method, showing large emission cross-sections at 573 nm: 9.86 × 10⁻²¹ cm² (π polarization) and 8.11 × 10⁻²¹ cm² (σ polarization) for Dy:CaWO₄, and 9.09 × 10⁻²¹ cm² (π polarization) and 7.69 × 10⁻²¹ cm² (σ polarization) for Dy,Tb:CaWO₄, respectively. In addition, under 450 nm excitation, the crystals emit ideal white light, with CIE coordinates (0.3258, 0.3191) and a correlated color temperature of 6000 K. Therefore, Dy:CaWO₄ and Dy,Tb:CaWO₄ crystals are promising materials for white light-emitting diode (LED) applications.

In this study, the humidity stability of ethyl gallate (EG) was improved by a co-crystallization method. Through a combination of COSMO-RS virtual screening and liquid-assisted grinding assay (LAG) screening, 14 new solid phases out of 25 candidate coformers were identified and a single crystal of the ethyl gallate (EG)-2-methylimidazole (2MIE) 1 : 1 cocrystal, EG-2MIE, was obtained. The cocrystal was characterized by single crystal X-ray diffraction, powder X-ray diffraction, differential scanning calorimetry and Fourier-transform infrared spectroscopy. The ternary phase diagram (TPD) of EG-2MIE in ethanol was constructed at 298.15 K, 303.15 K and 308.15 K. The dissolution behavior of EG-2MIE in ethanol was also investigated and the thermodynamic parameters of cocrystal formation were also estimated. The results showed that EG and 2MIE were congruently dissolved, which can provide a theoretical guide for the large-scale preparation of the EG-2MIE cocrystal. The accelerated stability tests showed that EG-2MIE exhibited better stability than the original EG at 40 °C and 75% relative humidity. The dissolution behavior and humidity stability were explained by comparing the strength of intermolecular interactions by calculating the Hirshfeld surface (HS), molecular electrostatic potential surface (MEPs), atoms in molecules (AIM) analysis, and lattice energy analysis.

Industrial wastewater containing organic dye pollutants poses significant environmental challenges, necessitating cost-effective and eco-friendly solutions. Coordination polymers (CPs), with their structural regularity and stability, present a promising approach for efficient solar-driven photodegradation of such contaminants. Herein we report two new 1D-Cu(I) coordination polymers, namely [Cu₂(μ₂-I)₂(μ₂-DTP)₂]_nCP1 and [Cu₂(μ₂-Br)₂(μ₂-DTP)₂]_nCP2 achieved from the self-assembly of 3-(1,3-dithian-2-yl)pyridine (DTP) ligand with CuI and CuBr, respectively. The polymeric chain in both CPs consists of a Cu₂X₂ secondary building unit. Both CPs display excellent photocatalytic efficiency in degrading organic dyes under sunlight using a minimal amount of catalyst and H₂O₂. CP1 surpassed CP2 in performance due to its narrower energy band gap, achieving an impressive 96% degradation of methylene blue (MB) within 15 minutes. The mechanism of the dye degradation was established by several experiments, including XPS analysis, which suggests the involvement of a Fenton-like Cu(I)/Cu(II) redox cycle during the photocatalytic process. The exceptional photocatalytic properties, recyclability and facile synthesis of these CPs underscore their potential for practical environmental remediation applications.

The low temperature and high pressure behavior of Ca₁₀Ni_0.5(VO₄)₇, with a structure of the whitlockite-β-TCP type, was characterized by performing X-ray powder diffraction experiments. Ca₁₀Ni_0.5(VO₄)₇ was studied between 4(1) and 292(1) K (at ambient pressure), and independently under high pressure up to 19.7(1) GPa (at room temperature). The temperature and pressure dependent structural data obtained by the Rietveld method were used to determine (i) the evolution of lattice parameters and volumetric thermal expansion coefficients, (ii) the Debye temperature, and (iii) the equation of state parameters, in particular the bulk modulus of 68(2) GPa and isothermal compressibility coefficients.

Ofloxacin (OFX), a potent antibacterial agent widely used in clinical practice, is commonly employed to treat various bacterial infections. However, its overuse has raised significant concerns due to its adverse effects on human health and environmental safety, particularly in terms of antibiotic resistance and environmental contamination. To address this issue, a novel dual-nuclear terbium complex, [Tb₂(DMOAP)₂(DMF)₄Cl₄] (DMOAP = 4-hydroxy-3,5-dimethoxybenzaldehyde), was synthesized as a highly sensitive luminescent probe for OFX detection. Experimental results demonstrated a notable decrease in the fluorescence intensity of complex 1 upon the addition of OFX, indicating a strong fluorescence quenching effect. Quantitative analysis revealed a fluorescence quenching constant of 3.3 × 10⁴ M⁻¹ and a detection limit of 0.3 μM for OFX, showcasing the excellent performance of this complex as a fluorescence probe for OFX detection. In practical applications, the probe successfully detected OFX in purchased drugs with high accuracy, demonstrating its potential in real-world environmental monitoring.

Amino-1,2,4-triazole- and amino-1,3,4-oxadiazole-substituted 1-hydroxytetrazole derivatives were synthesised via a simple method. These compounds exhibited excellent detonation performance and stability owing to their high density and heat of formation, extensive hydrogen bonding network, and π-electronic stacking. Notably, as a new energetic co-crystal, ATTO-N₂H₄ exhibited superior energy performance (D_v = 9306 m s⁻¹, P = 31.3 GPa) compared to 1,3,5,7-tetranitro-1,3,5,7-tetranitro-heterocycle (HMX) and exhibited excellent thermal stability (T_d = 329.0 °C). This study provides a new perspective on the design and preparation of insensitive high-energy compounds.

To enhance the solubility and study the anticancer activity of the drug bilastine (BLN), a European Medicines Agency-approved second-generation antihistamine drug, seven new salts were prepared with acid counterions, namely hydrochloric acid (HCl), hydrobromic acid (HBr), nitric acid (HNO₃), sulphuric acid (H₂SO₄), and orthophosphoric acid (H₃PO₄). All the prepared salts crystallize as hydrates except phosphate salt which crystallises as a methanol solvate. Anhydrous BLN⁺-H₂PO₄⁻ was prepared by the slurry method and was confirmed by ¹H NMR and TGA analysis. A di-salt of HCl and H₃PO₄ (BLN²⁺-H₂PO₄⁻-Cl⁻-3H₂O) was obtained as a single crystal from the residue after a solubility study. The salts, namely BLN⁺-Cl⁻-3H₂O, BLN⁺-Br⁻-H₂O, BLN²⁺-NO₃²⁻-H₂O, and BLN⁺-H₂PO₄⁻ were reproduced in the bulk scale and thoroughly characterized. The solubility study revealed that all the prepared salts showed improvement in solubility nearly 3 to 6 times higher than that of the parent BLN in pH 1.2 buffer medium, while in pH 6.8 buffer, the solubility is comparable to that of the parent BLN. The dissolution profile in pH 1.2 buffer showed similar drug release to BLN, whereas in pH 6.8 buffer, sustained drug release was noticed in the salts. Further, in vitro anticancer studies revealed that the prepared BLN salts exhibited excellent growth inhibitory activity against skin cancer by generating ROS and inducing apoptosis in B16F10 cells. Western blot analysis shows that BLN salts downregulate caspase 1, IL6, and IL-1β and upregulate Bax, p53 and p21, indicating that treatment of BLN salts induces apoptosis in skin cancer.

This work examined the effects of annealing temperature and time on the performance of lanthanide electrocatalysts for the oxygen evolution reaction. Results indicate that HEO particles with multilayer pore structures have more flaws, which can enhance the catalyst's active centre. Meanwhile, the naturally chaotic phase can produce many “dangling bonds”, which offer numerous active sites with unsaturated electrical structures. Among the prepared nanostructures, HEO-250AR-3H exhibited the best OER performance, reaching a low overpotential of 320 mV at 50 mA cm⁻² and maintained a stable potential for over 72 h.

A polymorph of K₂Zn₃Se₄ (1) adopting a quadrilateral network induced by the presence of deficient zinc sites is discovered in the ThCr₂Si₂-type lattice. Upon quenching the synthetic reaction at 630 °C, this lattice crystallizes into a higher symmetry and reduced cell in 1·T. DFT calculations explain a coexistence of two pseudo-enantiomeric forms with an equal energy that favors such a flexible network stabilized in 1. With the partial substitution of Zn²⁺ ions by Mg²⁺ ions, one form is then trapped in K₂Mg_0.5Zn_2.5Se₄ (2). For the two ZnSe layered wide bandgap semiconductors, photoluminescence (PL) and X-ray excited optical emission (XEOL) measurements reveal a prominent broad defect emission centered at ∼610 nm relative to the emission position observed in the benchmark ZnSe crystal.