CrystEngComm最新文献

The ongoing depletion of fossil fuels and the resulting environmental degradation underscore a pressing demand for alternative energy sources. High-efficiency electrocatalytic materials are examined for their potential to enable water splitting in clean hydrogen production. A bimetallic electrocatalyst (FeRu-BDC/NF) was prepared via hydrothermal synthesis. The material's structure and composition were examined via various characterization methods, with subsequent electrochemical testing within the alkaline electrolyte. Systematic experiments revealed that the incorporation of Ru can optimize the electronic structure and conductivity of monometallic Fe-BDC. As a result, at 10 mA cm⁻², the overpotential in the hydrogen evolution reaction (HER) process on FeRu-BDC/NF was a mere 54 mV; at 50 mA cm⁻², the overpotential in the oxygen evolution reaction (OER) process was 230 mV. In the comprehensive water splitting measurement, the FeRu-BDC/NF||FeRu-BDC/NF catalyst demonstrated exceptional electrochemical stability and catalytic performance, delivering 10 mA cm⁻² current density with a cell voltage of just 1.47 V. Additionally, DFT calculations indicated that incorporating Ru into MOFs had the capacity to fine-tune the electronic configuration of the metal center. This, in turn, led to an optimized binding affinity between H₂O and H*, ultimately elevating the efficacy of electrochemical water splitting. The methodology put forth in this research offers a fresh and innovative strategy for the creation of materials that are not only efficient and stable but also economically viable.

Energetic materials are essential substances for the development of advanced aerospace technologies and welding applications. In this study, we synthesized new high-nitrogen energetic salts based on linearly linked 1,2,4-triazole, furoxan and N-hydroxytetrazole scaffolds. All the prepared substances were thoroughly characterized using multinuclear NMR spectroscopy, IR spectroscopy and X-ray diffraction analysis. The synthesized energetic compounds exhibited a wide range of thermal stability, ranging from moderately stable guanidinium-based salts (T_d: 153–173 °C) to highly stable sodium and [1,2,4]triazolo[4,3-b][1,2,4]triazolium salts, respectively (T_d: 227–236 °C). All synthesized energetic materials had high enthalpies of formation (362–1074 kJ mol⁻¹) resulting in good detonation performance (D: 6.9–8.3 km s⁻¹; P: 19–32 GPa) simultaneously retaining friction insensitivity. Overall, the proposed method for the assembly of triheterocyclic substances offers a promising avenue for the development of nitrogen-rich energetic materials.

In this work, we report the discovery of a new solvated form of metacetamol—an acetone hemisolvate—obtained through a swift cooling crystallization process. The method generated relative supersaturation levels ranging from σ = 0.03 to 2.55, enabling systematic examination of nucleation behavior. At lower supersaturation values (σ = 0.33–1.01), only the stable form I crystals nucleated, whereas higher supersaturation levels (σ = 1.09–2.55) exclusively yielded the acetone hemisolvate. Induction time decreased markedly with increasing supersaturation, confirming the strong kinetic influence of supersaturation on nucleation. The resulting crystals were characterized by in situ optical microscopy, Powder X-ray Diffraction (PXRD), Differential Scanning Calorimetry (DSC), Single Crystal X-ray Diffraction (SCXRD) and Thermo Gravimetric-Differential Thermal Analysis (TG-DTA). Hot Stage Microscopy (HSM) further revealed the thermal desolvation behavior of the hemisolvate, corroborating DSC results and confirming transformation into stable form I upon solvent loss. These findings establish the acetone hemisolvate as a novel pseudopolymorphic form of metacetamol and provide insight into its nucleation, morphology, and stability profile.

In this manuscript, we report the synthesis and X-ray characterization of a series of solvates and co-crystals involving triaryltelluronium salts and different Lewis bases. In some cases, the triaryltelluronium cation is able to interact with acceptor atoms simultaneously through its three σ-holes and through a “pocket” formed by the three electron-deficient aromatic rings linked to tellurium. The latter interaction involves an acceptor atom that shows close contacts with both the ortho-hydrogens of two aromatic rings and the electron-deficient π-system of the third ring. Interestingly, the co-crystal formed between the triaryltelluronium cation and ditopic nitrile ligands provides three-dimentional supramolecular networks that combine Te⋯N chalcogen bonds, C_Ar–H⋯N hydrogen bonds and N lone pair⋯π interactions.

Nanoporous gallium nitride (NP-GaN) possesses several advantages, including a large specific surface area, abundant surface active sites, a tunable bandgap, and high light extraction efficiency. It has been used in light-emitting devices, photocatalytic applications, laser emitters, and energy storage systems. This paper reviews three primary preparation methods for NP-GaN: electrochemical etching (ECE), photoassisted electrochemical etching (PECE), and annealing. The pore-forming mechanisms and key influencing factors of each method are detailed. In ECE and PECE, porous structures are formed through the oxidation of GaN by holes generated under applied voltage or illumination. The pore morphology can be controlled by the doping density of the GaN sample, the voltage applied to the GaN sample and electrolyte composition. The annealing method relies on the preferential decomposition of GaN at defect sites under elevated temperatures to form porous structures. The pore size and distribution are influenced by annealing temperature and duration. Furthermore, this paper summarizes the applications of NP-GaN in light-emitting diodes (LEDs), photocatalysis, distributed Bragg reflectors (DBRs), epitaxial lift-off, and electrode materials. By comparing the merits and limitations of these preparation techniques, this review provides valuable insights for the future development and practical application of NP-GaN.

As a representative wide-bandgap semiconductor material, silicon carbide (SiC) is widely used in the fabrication of high-temperature, high-frequency, and high-power devices due to its excellent electronic properties, high thermal conductivity, and extraordinary physicochemical stability. In the manufacturing process of SiC semiconductor devices, substrate slicing serves as a critical link connecting ingots to subsequent processes. For 8-inch SiC ingots, the control difficulty of key parameters—including surface shape accuracy, surface damage, and surface roughness—significantly increases with the enlarged size during slicing. These parameters directly determine the material removal efficiency of subsequent grinding and polishing processes, the global planarization effect of chemical mechanical polishing (CMP), and may even lead to increased defects or device failure if not properly controlled. Therefore, achieving efficient and low-damage slicing of SiC substrates is of great importance. Laser slicing and wire saw slicing are the main processing methods for SiC ingot slicing currently. However, due to the fundamental difference in their processing mechanisms (non-contact vs. contact), the substrate quality resulting from these two methods exhibits significant discrepancies. In this study, 8-inch n-type 4H-SiC ingots were selected as the research object. Characterizations including atomic force microscopy (AFM), high-resolution X-ray diffraction (HR-XRD), scanning electron microscopy (SEM), and Raman spectroscopy were employed to systematically compare the surface shape parameters, crystal integrity, and surface morphology of substrates sliced by the two processes. Furthermore, the evolution law of substrate quality throughout the entire process of “slicing – rough grinding – fine grinding – mechanical polishing (MP) – CMP” was tracked. The research results demonstrate that laser slicing exhibits remarkable advantages over wire saw slicing. This study provides crucial theoretical support and process references for the development of large-scale, low-damage processing technology for third-generation semiconductor substrates.

Establishing the mechanism of the influence of the electric field on the bioconjugation and crystallization of peptide (PT) composites with gold nanoparticles (NPs) on solid surfaces is of great scientific and practical importance. In aqueous solutions, leaching of the mica surface leads to the formation of an adsorption layer of K⁺ and Si⁺ ions and the emergence of an internal natural electric field with fixed polarity. This field changes the character of PT conjugation with gold NPs. Unlike gold substrate, this electric field changes the mechanism of crystallization and growth of the solid layers of the PT composites. As a result, the carboxyl functional groups of PT molecules are replaced by the amine groups. Thus, the structure of the crown around the gold NPs changes significantly, and on the mica surface, the initially neutral surface of the gold NPs becomes negatively charged. The electric field also affects the secondary structure of PT molecules and reduces the number of allowed conformations. In addition to the deamination of the amino group of lysine with the formation of CH₃, the leaching of the mica surface leads to the formation of new compounds, namely, KOH and Si₃N₄. The obtained results have important scientific significance in establishing the mechanism of the formation of the protein corona around NPs. They can be used especially in pharmacology and medicine for the development of new nanomedical platforms and for the study of their therapeutic functionality in vivo. This may also increase the pharmacological efficacy of both existing and developing drugs.

A new copper-based coordination polymer, [Cu(bib)₃(MeOH)₂](BF₄)₂ (bib = 1,4-bis(imidazol-1-yl)benzene), was isolated and structurally characterized by single-crystal X-ray diffraction. This novel phase, herein denoted as UdP-7·2MeOHα, undergoes a series of single-crystal-to-single-crystal (SC–SC) transformations upon thermal treatment, yielding three new crystalline phases: UdP-7·2MeOHβ, UdP-7·MeOH, and UdP-7. Each transition is associated with discrete structural rearrangements driven by the progressive loss of coordinated methanol and supramolecular reorganization, leading from a 1D coordination polymer to an extended 2D layered architecture. While the α-to-β transition is fully reversible and maintains most of the structural features, the subsequent transformations involve significant shifts in Cu–N interactions and chain proximity, culminating in the formation of a new layered framework in UdP-7 [Cu(bib)₃](BF₄)₂. This study highlights the rich structural adaptability of bib-based copper polymers and provides a detailed crystallographic insight into their temperature-induced evolution.

Today, machine learning (ML) and crystal structure prediction (CSP) are principal tools in computational materials discovery. In this study, CSP of the pharmaceutical compound avadomide is presented, utilizing a workflow that combines the evolutionary algorithm USPEX, machine learning potentials in moment tensor potential (MTP) formulation, and crystal engineering concepts. Our study begins with the optimization of stable molecular conformations of avadomide using DFT, followed by the generation of likely crystal structures with the evolutionary algorithm USPEX. The optimization and ranking of structures based on ML potentials—trained on the subset of DFT data—were further refined through iterative improvements via active learning. The ML potentials employed in this study are currently constrained to local atomic environments and primarily captured short-range interatomic interactions. To address this limitation, the top-ranked structures were analyzed using crystal engineering concepts and found to contain synthons similar to those in experimental structures of related compounds in the CSD database. Using the synthon approach, two potential crystal structures were proposed for avadomide.

The pursuit for the discovery of photoswitchable materials is of great interest due to the growing demand for smart stimuli-responsive materials. Thereby, (E)-4-((4-alkoxyphenyl)diazenyl)benzonitrile derivatives, AZN-n (n = 3–12) were synthesized and characterized by FTIR and NMR (¹H and ¹³C) spectroscopies and PXRD. The structural analysis by SCXRD suggests the involvement of weak hydrogen bonds and π⋯π contacts in the crystal packing. The various interactions present and their contribution to the total interactions were described by the Hirshfeld surface as well as its 2D fingerprint plot. The energy framework analysis revealed the major contribution of the dispersion component to the total interaction energies. In addition, the nature of the short π⋯π contacts, as well as the hydrogen bonds and the charge transfer in the intermolecular interactions were well illustrated by NCI, QTAIM and NBO calculations. Furthermore, the liquid crystalline (LC) characteristics were examined by DSC and hot-stage POM analysis, revealing the appearance of a nematic phase, with the occurrence of the smectic A phase as the alkoxy chain lengthens. Again, the reversible fast photo-switching nature of these derivatives in solution as well as in the LC state was demonstrated using light irradiation of suitable wavelengths, showing their potential in the fabrication of light-controlled devices.