CrystEngComm最新文献

We report that the stepwise introduction of difluorophenylene as dipolar blades into triptycenes diversifies the intermolecular packing modes in crystals. Single crystal XRD studies revealed that changing the number of dipoles in triptycene tunes the intermolecular packing from two dimensional intermeshed structures to helical structures, offering a novel insight for engineering triptycene-based supramolecular materials.

Three new metal bromides functionalized with L-arginine were synthesized via a solvent evaporation approach. These compounds have different low-dimensional structures, all of which exhibit second-harmonic generation (SHG) activity. Density functional theory calculations were performed to unravel the origin of the SHG response of the as-synthesized lead bromide.

Zirconium and uranium co-doped LiNbO₃ crystals were grown by the modified Bridgman method. The co-doping simultaneously shortens the photorefractive response to 600 ms and enhances optical damage resistance to ∼10⁵ W cm⁻² at 442 nm. This dual improvement offers a promising material platform for high-power integrated LiNbO₃ photonic applications.

The effect of fluid shear on secondary nucleation has long been debated in the crystallization literature. In this work, we investigated the influence of seed polymorphism on secondary nucleation under flow conditions in the absence of mechanical impact, using a “seed-on-a-stick” technique to isolate the effect of fluid shear on secondary nucleation induced by a single glycine seed crystal in aqueous solutions. In situ imaging and particle count analysis were used to assess the impact of seed polymorphism on secondary nucleation kinetics. The presence of glycine seeds induced earlier nucleation under all conditions investigated here, as evidenced by shorter delay times compared to those for control and unseeded experiments. By seeding with either α- or γ-glycine, we found that the solid form of the seed had no significant impact on secondary nucleation rates or delay times and α-glycine consistently nucleated irrespective of the seed solid form. This indicates that cross-nucleation of metastable α-glycine can occur with γ-glycine seeds under flow conditions. We propose that fluid shear driven secondary nucleation may operate similarly to primary nucleation near a solution–solid interface, where enhancement of nucleation is due to stabilisation and aggregation of solute clusters in the interfacial solution region.

Hydroxyapatite (HAP) nanowires are promising biomaterials due to their biocompatibility and compositional/structural similarity to bone and dental tissues, yet conventional synthesis methods yield brittle, low-aspect-ratio structures limiting flexibility and functionality. Herein, we report a rapid, environmentally friendly microwave-assisted hydrothermal synthesis of flexible ultralong HAP nanowires (UHAPNWs) using β-glycerophosphate as an organic phosphorus source and calcium oleate precursor. Optimizing parameters such as the Ca/P molar ratio, hydrothermal temperature, and reaction time, we achieved UHAPNWs with lengths of several hundred micrometers and aspect ratios exceeding 10 000. These nanowires self-assemble into ordered bundles along the longitudinal direction and can be further fabricated into flexible macroscopic fibers via injection assembly. The resulting fibers exhibit superior mineralization capability in simulated body fluid, indicating potential for applications in bone regeneration and dental enamel repair. This method offers a versatile platform for developing functional HAP-based nanostructured biomaterials with enhanced flexibility and bioactivity.

The current study describes judiciously designed flavin analogues that use different metal coordination sites to engender structurally distinct, discrete flavin–copper complexes that are then utilized to generate morphologically distinct cuprous oxide nanoparticles. The ligand design encompasses a carboxylic pendant at the C7 or N10 position of the flavin core structure to bind the coordinating copper ion, resulting in distinct mononuclear dimeric flavin–copper complexes. Furthermore, the structurally distinct complexes were used to generate morphologically distinct cuprous oxide nanoparticles with different sizes. The present study offers a simpler yet elegant design strategy to create distinct complexes that can be extended to nanoparticle formation.

To the best of our knowledge, no prior reports on growth and characterization of the SbSnSe₃ crystal are available in the literature, making this study the first comprehensive investigation of its structural, optical, thermoelectric, and photoconductive properties. The SbSnSe₃ crystal was grown successfully by the vertical Bridgman technique. The orthorhombic phase of this grown crystal was confirmed through powder X-ray diffraction. Elemental assessment by EDAX reflected the near-stoichiometric composition of the grown crystal, whereas FESEM images illustrated a distinctly layered structure. The reflectance spectrum revealed a direct bandgap of about 1.48 eV, favourable for both photoresponse and thermoelectric applications. Over the range of 300–573 K, the measured Seebeck coefficient, electrical conductivity and thermal conductivity of the SbSnSe₃ crystal exhibited semiconducting behavior. Based on these thermoelectric parameters, a maximum ZT value of 0.04 was obtained. Furthermore, TG-DTG-DTA analysis carried out between 300 K and 880 K revealed a consistent two-step thermal behavior across heating rates of 10, 15, and 20 K min⁻¹, confirming the crystal's excellent thermal stability. Room temperature steady-state I–V analysis conducted under 50 mW cm⁻² illumination showed an anisotropic photoresponse in SbSnSe₃. The ⊥^r configuration exhibited a responsivity of 186.8 μA W⁻¹ and a detectivity of 10.03 × 10⁶ Jones at 10 mV bias, confirming enhanced charge transport efficiency.

The design of structurally resilient and catalytically efficient solid acid materials remains a central challenge in biomass valorization. Herein, a sulfonated MIL-101(Cr)-SO₃H framework was constructed through a post-synthetic functionalization strategy, and its structural, textural, and thermal properties were comprehensively assessed. FT-IR and XRD analyses confirmed successful functionalization while preserving the crystalline architecture of MIL-101(Cr). SEM and elemental mapping analyses revealed uniform octahedral morphology with homogeneous distribution of Cr, C, O, N, and S, whereas N₂ sorption analysis showed a decrease in surface area from 2063 to 727 m² g⁻¹ due to partial pore occupancy by grafted organic groups. The catalyst exhibited high activity toward the dehydration of fructose to 5-hydroxymethylfurfural (5-HMF), achieving a maximum yield of 98% under optimized conditions. Notably, the material retained its catalytic performance after four consecutive cycles with negligible loss of acidic sites and minimal structural alteration, as verified by post-reaction FT-IR and XRD analyses. Collectively, these findings establish MIL-101(Cr)-SO₃H as a highly robust and efficient solid acid catalyst for biomass-derived HMF production.

In this study, we examine the polymorphic control and separation of D-mannitol in a 1 : 1 (v/v) ratio of water–isopropyl alcohol solvent mixture using a swift-cooling crystallization process. This method created supersaturation (0.01 < σ < 13.18), producing obvious changes in the crystallization outcome of D-mannitol polymorphs. At low supersaturation levels, only the stable form I nucleated. Under high supersaturation conditions, metastable form II was observed, while at extremely high supersaturation levels, the metastable form III was obtained. Notably, form III converted into form I through a solution-mediated transformation, confirming its transient stability and its tendency to transform into the thermodynamically stable form. Morphological analysis was conducted through in situ optical microscopy. The structural and thermal characteristics were confirmed by powder X-ray diffraction. The crystalline phases were further verified by Le Bail profile fitting and differential scanning calorimetry. This approach effectively describes the supersaturation region governing D-mannitol polymorph formation, enabling selective crystallization of the desired metastable form with enhanced control.

CaF₂ single crystals doped with Dy³⁺ in different concentrations (1–8 at%) were grown by the Bridgman method. Their structural and spectral features were studied to realize the concentration quenching mechanisms of yellow (∼570 nm) and mid-infrared (∼3 μm) emissions. XRD and Raman analyses confirmed that all crystals retained the fluorite structure. At high doping concentrations, charge compensation and cluster formation led to lattice expansion and increased disorder. In the absorption spectra, the peak positions, absorption cross-sections, and full widths at half maximum did not change with doping concentration. The yellow emission exhibited complex concentration-dependent behavior, confirming the existence of at least two types of Dy³⁺ clusters (L-type and M/N-type) with different fluorescence lifetimes in CaF₂, which showed distinctly different yellow luminescence characteristics. In contrast, the mid-infrared emission at 2901 nm is less affected by cluster type, achieving optimal performance at a doping concentration of 6 at%, with a stable emission cross-section of approximately 3.1 × 10⁻²¹ cm². This work provides a systematic understanding of the structure–property relationships in Dy³⁺: CaF₂ crystals and offers a route for the development of dual-band yellow and mid-infrared laser materials.