CrystEngComm最新文献

Discovery of their commercial potential gave rise to a massive implementation of zeolites in industrial (petro-)chemical processes. Their robustness and molecular scale porosity in combination with acidic and/or ion exchange properties makes zeolites nearly indispensable for most of these applications. This highlight explores the origins of zeolite porosity. As microporosity is an inherent feature of the formed topology, we emphasize the link with phase selection. For zeolites, phase selection is driven by competition between water and framework elements to coordinate with extra-framework species. This competition is important in the final product, where such coordinations provide thermodynamic stability, as well as in the crystallization medium where supermolecular structrures can play a templating role. Synthesis experiments using hydrated silicate ionic liquids show that limited water availability prompts the formation of less porous (or even dense) phases, while moderate hydration supports the development of more open frameworks. Understanding these interactions is key to deepening the insight into zeolite genesis and can guide strategies for tailoring material properties for industrial applications.

The coordination properties of a previously described fluorescence active ligand (L), consisting of a coordinating unit (1H-tetrazol-1-yl) and a fluorophore (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) derivative) towards Ag(i) were investigated. Additionally, the influence of different anions (BF₄ ^-, PF₆ ^-, PF₂O₂ ^-, ClO₄ ^-, ReO₄ ^- and NO₃ ^-) and a co-ligand (CH₃CN) on the crystal structure formation and intramolecular interactions of the Ag(i) coordination compounds was studied. Beside structural investigations via single crystal X-ray diffraction, bulk characterization of the coordination compounds was conducted in both solution and solid-state, including NMR (¹H, ¹¹B, ¹⁹F, ³¹P and ¹³C), ATR-IR, UV-vis and photoluminescence spectroscopy as well as PXRD. Eleven distinct coordination compounds are reported, each falling into one of four classes: the first group (I) comprises of a mononuclear complex, whereas group (II) consists of dinuclear complexes with ligand bridged metal centers (Ag(i)) and weak intermetallic interactions (∼4 Å). Group (III) likewise includes dinuclear complexes, but the bridging mode was prevented and the Ag-Ag distance was reduced (∼3.2 Å) upon the addition of a co-ligand. Group (IV), a structurally diverse category consists of coordination polymers, which in some cases show even shorter intermetallic contacts (<3.1 Å). All investigated coordination compounds exhibit photoluminescence in the solid state, with structurally dependent emission maxima distinct from those of the ligand.

This article presents experimental, theoretical, and numerical studies of the propagation of guided ultrasonic waves in a layered epitaxial structure of garnet compounds. A microscopic model, which yields dispersion equations based on material and geometrical properties, is developed. Acoustic microscopy experiments on a YAG:Ce crystal substrate and an epitaxial structure containing LuAG:Ce single crystalline films, grown using the liquid phase epitaxy growth method onto a YAG:Ce crystal substrate, reveal distinct phase velocity behaviors. The YAG substrate exhibits consistent velocities, minimally influenced by frequency, while the epitaxial structure shows dispersion, indicating frequency-dependent phase velocities. Experimental results are compared with numerically calculated dispersion curves, showing high agreement in the low-frequency range and minor deviations at higher frequencies. An optimization procedure is developed and applied, starting with the YAG substrate and extending to the LuAG:Ce film/YAG:Ce crystal epitaxial structure. The procedure allows for the extraction of material properties, offering valuable insights into the mechanical characteristics of the all-solid-state LuAG:Ce film/YAG:Ce crystal structure. This research represents a significant advancement in understanding ultrasonic wave dynamics in layered structures, particularly unveiling previously unexplored elastic properties of LuAG:Ce single crystalline films as a well-known scintillation material.

Solvothermal secondary growth was used to fabricate zeolite MFI anti-corrosion coatings on a stainless steel plate. Four different diols, i.e., ethylene glycol, diethylene glycol, triethylene glycol, and tetraethylene glycol, were each investigated as a synthesis solvent. High-quality b-oriented MFI films each with a thickness of 400–500 nm were obtained. The evolution processes and the corresponding characteristics of the zeolite films were compared. FT-IR and XPS analysis of the zeolite surface functional groups demonstrated that the film hydrophobicity mainly originated from the reaction between the diol solvent and the hydrolyzed silica source. The uniform structure and the surface hydrophobicity of the resulting MFI coatings were found to offer good corrosion protection for stainless steel materials.

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.

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.

The relationships between the molecular structures of the racemic and meso isomers of 2,2′′-disubstituted-1,1′′-biferrocenes and their crystal packings and electrochemical properties are of interest. However, there are few studies on their structure–property relationships. In this study, we prepared and characterized the racemic (1a) and meso (1b) forms of 2,2′′-dibromo-1,1′′-biferrocene. Single-crystal X-ray structural analysis revealed that 1a possesses a twisted molecular structure with axial chirality and forms racemic crystals. In the crystal, 1a exhibited a pseudo-three-dimensional network structure constructed via Br⋯HC hydrogen bonding interactions, whereas 1b exhibited a pseudo-two-dimensional sheet structure owing to Br⋯Cp halogen bonding interactions (Cp = cyclopentadienyl). The monocations of 1a and 1b (1a⁺ and 1b⁺) showed broad intervalence charge-transfer bands at approximately 1900 nm. The reaction of 1a with iodine produced a monocation salt ([1a]I₇), and its crystal structure was determined. In the crystal, the cation moiety was contained in a cube-like polyiodide cage composed of I₃⁻ and I₂ molecules. The positive charge in the mixed-valence cation was localized to one of the two ferrocenyl units because of electrostatic interactions. Additionally, 1-bromo-2-cyanoferrocene, a byproduct of the reaction, was crystallographically characterized, revealing a helically assembled structure via intermolecular Br⋯NC halogen bonding in the crystal. The intramolecular and intermolecular interactions in these crystals are discussed based on Hirshfeld analyses and interaction energy calculations.

In this study, the solubility of 3,3′-diaminobenzidine in two mixed solvents (N,N-dimethylacetamide + water and dimethyl sulfoxide + water) was determined. The affecting mechanism of solvents and additives on the crystal behavior of 3,3′-diaminobenzidine was discussed. The interactions between 3,3′-diaminobenzidine and solvents or additives were analyzed from the aspects of crystal surface properties, diffusion coefficient, surface electrostatic potential distribution and radial distribution function. It was found that solvents and additives can significantly affect the crystal growth of 3,3′-diaminobenzidine in many ways. Hydrogen bonding and van der Waals forces play major roles in crystal packing. The interaction between solvent and crystal face can affect the growth of 3,3′-diaminobenzidine in different solvents by synergistic action. The presence of additives would affect the diffusion of molecules near the crystal surface and additive molecules are more easily adsorbed on (1 1 −1) and (1 0 0) faces. Meanwhile, the interaction between the (1 1 −1) face and additives is stronger and hence the area of the (1 1 −1) face is the largest in the final crystal habit. These findings could provide thermodynamic basis for the development of separation and purification technology for 3,3′-diaminobenzidine products, as well as theoretical guidance for regulating the crystal habit of 3,3′-diaminobenzidine crystals.

The process of producing a nanosized cocrystal employing two or more components that possess hydrogen bonds, pi–pi stacking, and van der Waals interactions is known as nanococrystallization. Because of their high surface area to volume ratio, nanococrystals are unique, similar to cocrystals in construction, but with vastly superior qualities. The surface area-to-volume ratio increases as the particle size approaches the nanoscale, which will have an impact on properties including dissolution, bioavailability, efficacy, and surface energy, benefitting their use in the pharmaceutical industry. Since nanococrystallization is a recent concept, extensive research is still being done on its potential applications. The synthesis method, particle size, and components used for every medicine that has been tested and is currently available are set out. Here, we examine the critical steps involved in generating nanococrystals on a commercial scale, the pros and cons of preparative methods, nanococrystal formation mechanisms, selection of coformers, characterization techniques, and future prospects. Furthermore, we discuss real-world applications and challenges found in nanococrystal technology, which will aid future researchers in creating successful nanococrystal formulations.