ChemPlusChem最新文献

Multifunctional materials that exhibit both photoluminescence (PL) and liquid-crystalline (LC) properties, referred to as photoluminescent liquid crystals (PLLCs), have garnered considerable interest for applications in fluorescent thermometers and thermosensors. This interest is attributable to their reversible fluorescence switching behavior, driven by aggregated structural changes associated with phase transitions upon heating and cooling. The research group has developed various PLLCs by incorporating fluorescent π-conjugated mesogens into donor–π–acceptor (D–π–A)-type fluorinated tolanes, functionalized with a range of electron-donating and electron-withdrawing groups (EWGs) at the molecular terminal positions. This article introduces a novel class of D–π–A-type fluorinated tolanes featuring an imidazole ring, which functions as an EWG with both steric and electronic effects. These compounds exhibit distinct phase transition behaviors and photophysical properties depending on the chain length of the flexible alkoxy units. Furthermore, for compounds exhibiting any LC phase, the PL behavior in the mesophase is evaluated. The results reveal that phase transitions lead to changes in both the fluorescence wavelength and intensity. These findings demonstrate that nitrogen-containing heterocycles, such as imidazole, are effective EWG units with both steric and electronic contributions. As such, they hold promise for the design of PLLCs for use in PL sensing materials.

This work is devoted to the synthesis, the characterization, and the evaluation of hydroxyapatite-supported ruthenium catalysts, with or without Ba and/or Cs promotion. Thus, a series of catalysts containing Ru, Cs, and Ba was synthesized by the incipient wetness impregnation method. Such catalysts are characterized by different physicochemical methods, providing insights into their properties. These catalysts are evaluated in the ammonia synthesis reaction at 350–500 °C and 10–25 bar. Sample 1Ru/hydroxiapatite (HAP), without promoter, shows a negligible catalytic activity, due to the formation of large Ru nanoparticles, which are not favorable for the formation of ammonia. On the other hand, the addition of Cs and Ba improves the catalytic performance, and Ba is found to be better than Cs. The pretreatment of the barium-containing catalysts under Ar flow at 600 °C is also found to be crucial for the decomposition of barium nitrate into barium oxide, thereby enhancing catalytic activity.

Self-doping has emerged as an effective strategy to tailor the electronic properties of organic materials, especially for n-type semiconductors based on perylene diimide (PDI) and naphthalene diimide (NDI). This review summarizes recent progress in the molecular design and application of self-doped PDI/NDI systems. Representative self-doping groups such as amines, ammonium salts, and other anionic species are introduced and classified. The effects of doping group connecting site selection, including the imide position, aromatic core, and side substitutes, on molecular and electronic properties are then discussed. The application of self-doped PDI/NDI materials in organic electronic devices is also highlighted, covering thin-film solar cells, organic field-effect transistors, and organic thermoelectrics. These materials have shown the ability to improve charge injection, enhance device stability, and regulate interfacial processes. Overall, self-doping is a promising strategy for developing high-performance n-type organic semiconductors. With ongoing improvements in molecular design and device engineering, self-doped PDI/NDI materials are expected to contribute significantly to the advancement of next-generation electronic materials and devices.

Stimuli-responsive systems play a crucial role in biological processes. Research on supramolecular cages formed via noncovalent interactions contributes to the development of receptors that mimic these natural systems. Recently, anion-coordination-driven assembly (ACDA) employing oligourea ligands and trivalent phosphate ions (PO₄³⁻) has emerged as a promising strategy for constructing responsive supramolecular architectures. These assemblies are stabilized through multiple hydrogen bonds and are capable of undergoing structural transformations in response to external stimuli, offering a conceptual framework for understanding flexibility and environmental adaptability in biological contexts. This mini-review highlights the stimuli-responsive properties of anionic self-assemblies, with a focus on systems involving oligourea ligands and PO₄³⁻ ion. Organized by stimulus type, it discusses multistimuli responsiveness, guest-induced transformations, solvent sensitivity, and light-responsive behaviors. Current challenges and identifying future opportunities in the study of ACDA-based stimuli-responsive systems are discussed.

Two Cyanostyryl-guanidiniocarbonyl-pyrrole based amphiphiles are synthesized and examined in detail. In addition to achieving aggregation-induced emission from self-assembly, resulting in nanoparticles, it was found that the observed [2 + 2] photocycloaddition tunes the photophysical properties. The guanidiniocarbonyl-pyrrole component of these hybrid luminophores is shown to bind oxo-anions, such as pyrene-tetracarboxylate, as confirmed by fluorescence lifetime measurements. Moreover, both amphiphiles are used in bio-imaging experiments with HeLa cells, demonstrating effective cellular uptake.

Valorization of biomass-derived chemicals into high-quality compounds and biofuels is enormously fundamental to diminish dependence on fossil-based resources. Furfural is a bio-based valuable compound which can be proficiently upgraded to 4-(2-furyl)-3-buten-2-one (FAc) and 1,4-pentadiene-3-one, 1,5-di-2-furanyl (F₂Ac) via aldol condensation of furfural with acetone. In the present work, efficient Cu-doped MgAl layered double hydroxides (LDH) nanocatalysts are fabricated by coprecipitation and are exploited for furfural conversion to obtained FAc and F₂Ac. The structure–activity relationship is scrutinized by characterizing fresh and spent nanocatalysts via numerous techniques. The good correlation between the amount of weak acidic-weak basic catalytic sites and nanocatalysts performance is established. The superior performance of Cu-0.1 nanocatalyst (Cu-content = 1.85 wt%) in aldol condensation is attributed to the presence of optimum weak acidic sites (0.21 mmol g⁻¹) and weak basic sites (0.36 mmol g⁻¹), synergistic acidic-basic effect, nano-sized Cu(OH)₂ nanoparticles (1.6 nm), high BET surface area (181 m²g⁻¹), and mesoporous architecture of material. Cu-0.1 nanocatalyst delivered 98% FAc selectivity with 100% furfural conversion at 85 °C. Furthermore, at 100 °C, the nanocatalyst gives 55% F₂Ac selectivity with 73% furfural conversion. The catalyst displays good recyclability (7 recycles) and stability. Plausible mechanistic pathway for transformation of furfural to FAc and F₂Ac is proposed.

The investigation of the intermolecular profile of F···F interactions is based on the statistical analysis of data obtained from the Cambridge Structural Database, quantum theory of atoms in molecules, and quantum-mechanical calculations. The influence of the nature of the substituents bound to the interacting fluorine atoms is also investigated. The geometric parameters used to define F···F interactions (bond length, bond angle, and torsion angle) indicate the suitability of F···F interactions for a supramolecular compromise with other interactions from the environment. Regardless of the nature of the substituent, the antiparallel orientation of the interacting groups and long distances (longer than 2.9 Å) represent the specificity of these interactions, which makes them suitable for forming a large number of simultaneous interactions with species from the environment. The shallow minima in the energy profiles, in the range from 3.0 to 3.5 Å, indicate weak noncovalent interactions, as well as the possibility of F···F interactions to easily adapt to the geometries of the surrounding interactions. Changes in the geometry and in the substituents on the aromatic ring have a significantly greater influence on the strength of F···F interactions compared to the case where the interacting fluorine atoms are bound to alkyl groups.

The increasing concentration of greenhouse gases, such as CH₄ and CO₂, in the environment is pushing the planet to the next level of global warming, where living creatures are becoming extinct one after another. The catalytic conversion of CH₄ and CO₂ together into syngas, known as dry reforming of methane (DRM), not only depletes the concentration of these gases but also provides an industrially important synthesis gas. Herein, the active sites (metallic Ni) supported over calcium-stabilized zirconia (Ni–xCaSZ; x = 8, 10, 12, 14 mol%) are investigated toward DRM reaction. Catalysts are characterized by X-ray diffraction, surface area and porosity, X-ray photoelectron spectroscopy, Raman spectroscopy, H₂-temperature-programmed reduction, and thermogravimetry. Calcium stabilizes the cubic phases of ZrO₂ and surges mixed oxide phases like cubic CaZrO₃ and monoclinic CaZr₄O₉. At high mol% of Ca, the interaction between CaO and ZrO₂ is grown, the covalence character about oxygen in MOM′ bond is raised, the surface area of catalyst is increased, and coke deposition is restricted. Upon increasing mol% of Ca from 8 to 12 mol%, the moderate-level interaction of NiO over support is established, weak interaction of NiO is declined, and overall concentration of active sites is grown. As a result, 5Ni–12CaSZ achieves the highest 66% CH₄ conversion, 73% CO₂ conversion, and 0.86 H₂/CO ratio at 700 °C reaction temperature. An excess amount of calcium (14 mol%) changes the surface composition of CaZrO_x, as well as it may also block the oxide vacancy, which may inhibit the CO₂ activation vis-à-vis catalytic activity.

The crystal structures of triphenylthiazol-3-ium-4-olates substituted with iodine atoms on different phenyl rings are investigated. Analysis of single molecule crystal structures reveals consistent torsion angles across all compounds. Specifically, excellent planarity with the mesoionic ring is achieved when the phenyl ring at the 5-position enables effective conjugation with the enolate moiety. Three types of halogen interactions are identified depending on the iodine substituent position: CO···I, π-electron···I, and I···I interactions. All crystal structures exhibited columnar stacking arrangements. Density functional theory calculations show that stacking interactions provide greater energetic stabilization than halogen bonds. Additionally, the columnar stacking arrangement is influenced by the nature of the halogen bonding.

Two beta-cyclodextrins (β-CD) modified with 2-hydroxyethyl-1,2,3-triazole or hydroxymethyl-1,2,3-triazole groups are synthesized utilizing copper catalyzed 1,3-Huisgen click cycloaddition reaction. A simple electrochemical purification process is employed to remove unwanted copper from the desired products affording up to 88% removal in 10 h. Physicochemical analysis of both purified modified β-CDs (Modβ-CDs) reveales marked differences caused just by the additional methyl group, not only between their physicochemical properties (such as melting point and hydrophilicity) but also in their capabilities to self-assemble forming aggregates at relatively low concentrations, which demonstrates to be efficient structures for encapsulating hydrophobic molecules, as it is demonstrated here with curcumin. These Modβ-CDs spontaneously formes aggregates that presented globular shapes with diameters between 100 and 400 nm (as verified by dynamic light scattering and atomic force microscopy analyses). Such type of aggregates could expand the notion of capturing larger molecules within these Modβ-CD-based structures (by not being confined just to the size of the β-CD toroidal cavity), thus increasing their performances to solubilize in a more efficient way hydrophobic compounds in aqueous solutions. This promising data suggests this simple modification could improve the ability of β-CD-based compounds to capture other large molecules of interest for the remediation of contaminated sites or for medicinal/pharmaceutical purposes.