ChemPlusChem最新文献

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.

Methylformate (MF) and glycolaldehyde (GA) are two primogenital organic molecules detected in both cold and warm regions of the interstellar medium (ISM). Both gas-phase and grain-surface pathways have been proposed to explain their abundances, yet uncertainties remain, since prevailing grain-surface mechanisms favor the formation of GA over MF, which mismatch observations in different ISM regions. In this work, MF and GA synthetic reactions are atomistically modeled on surfaces containing variable H$$O and CO percentages (interstellar dirty ices), in which one of the reactants coming from the gas phase reacts with an icy CO, thus adopting the following two-step "radical + ice" mechanism: for MF, OCH$$ + $$ $$ COOCH$$ + H $$ HCOOCH$$; for GA, CH$$OH + $$ $$ COCH$$OH + H $$ HCOCH$$OH. Calculations show that the first step presents an energy barrier (32–38 kJ mol$$ for MF and 17–20 kJ mol$$ for GA), while the second step is nearly barrierless. Although the energetics favor GA formation, the observed abundances are better explained by desorption phenomena rather than reaction barriers are argued. Specifically, the weaker binding energies of MF (16.8–46.1 kJ mol$$) than GA (28.4–90.2 kJ mol$$) support its higher abundance in the ISM.

Molecular on-surface photochemistry recently emerged as an alternative strategy to thermal reactions to synthesize low-dimensional carbon-based nanomaterials, particularly on nonmetallic surfaces. However, there is still limited knowledge about the crucial aspects influencing photoreactivity in the context of surface chemistry, which contrasts with the fast progress in thermally activated reactions on metal surfaces. By reviewing recent developments in the on-surface photochemistry field, this minireview focuses on some key aspects crucial for the comprehension of photoreactions on surfaces: from the photoexcitation process to basic mechanistic aspects and intermediates characterization, including the molecular preorganization impact on the reaction evolution. To clarify these aspects, we rely upon well-established concepts of traditional photochemistry while highlighting the role of the surface. Finally, it is concluded with considerations on the evolution of the field.

Natural zeolites can be used to obtain effective catalysts for heterogeneous photocatalytic reactions due to their low cost and favorable physicochemical properties for water treatment. In this work, a natural clinoptilolite is modified by incorporating iron (NZ–Fe) and copper (NZ–Cu) as compensation cations through ion exchange processes. Metals incorporation and structural stability are demonstrated through X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy. DR-UV–Vis measurements are used to estimate the bandgap and predict the photocatalytic performance of both materials. Their effectiviness in heterogeneous photocatalytic systems is confirmed by evaluating the inactivation of E. coli as a model pathogen in water. The bacterial detection limit (initial ≈10⁶ CFU/mL) is reached using 1 gL⁻¹ of both catalysts, 100 ppm of H₂O₂ under visible light (410–710 nm) and near neutral pH in 2 h, with no post-treatment regrowth observed. Experimental data are analyzed according to the Chick–Watson, Weibull, and Hom disinfection kinetic models. Although more hydroxyl radicals are generated (trapping tests) and less iron leachate is observed for NZ–Fe, good reusability is attained for three disinfection cycles when NZ–Cu is used. This makes copper-exchanged clinoptilolite a suitable and low-cost photocatalyst for water disinfection through heterogeneous photo-Fenton-type processes.

Chalcogenide perovskites have emerged as a promising candidate for light harvesting applications owing to their high stability, nontoxicity, and exceptional optical and electronic properties. Research on chalcogenide perovskites is widely centered around Zr, Hf, and Ti at the B site of the ABX₃ structure. Here, we report the potential of BaTeS₃ chalcogenide perovskite with Te at the B site for optoelectronic and photoelectrochemical applications. This study comprises a detailed investigation of the material's structural, optical, and electronic properties. The material shows panchromatic light absorption with an indirect bandgap of 2.32 eV. Electrochemical studies reveal that the material is an n-type semiconductor with a band position suitable for water oxidation reactions. The photoanodes fabricated using BaTeS₃ exhibit a photocurrent density of 0.15 mA cm⁻² at 0.62 V versus Ag/AgCl (equivalent to 1.23 V vs. reversible hydrogen electrode).

Crystal engineering provides effective strategies to produce pharmaceutical cocrystals, aimed at enhancing the physicochemical properties of active pharmaceutical ingredients. Herein, the structural and energetic properties of carbamazepine cocrystals with meta-chlorobenzoic, meta-bromobenzoic, and meta-iodobenzoic acids are examined in depth, with particular focus on the influence of halogen substitution. A comparative assessment of solution-based crystallization and mechanochemical synthesis via liquid-assisted grinding provides insight into the viability of different synthetic methodologies. The crystallographic analysis reveals isostructurality among the three cocrystals, with lattice stability being modulated by the increasing atomic radius of the halogen substituent. Complementary techniques, including thermogravimetry, differential scanning calorimetry, Fourier transform infrared spectroscopy, and Hirshfeld surface analysis, further elucidate the intermolecular forces driving the formation of these crystalline phases. The lattice energy calculations offer a quantitative perspective on the role of halogen substitution in stabilization, enriching the understanding of fundamental crystal engineering principles relevant to pharmaceutical development.

The development of advanced anode electrocatalysts for direct ethanol fuel cells (DEFCs) faces key challenges related to the complete oxidation of ethanol, particularly the cleavage of the CC bond. This study investigates the impact of chemical functionalization (using HNO₃, H₂O₂, and urea) of mesoporous carbon (MC) supports on the performance of Pt and PtRe catalysts. Functionalization modifies the carbon structure, introducing nanowindows or causing wall degradation, altering conductivity and surface chemistry without significantly affecting particle size. Catalysts synthesized by the polyol method are characterized structurally, texturally, and electrochemically. The results demonstrate that Re addition enhances ethanol electrooxidation through synergistic effects with Pt, reducing onset potentials and increasing electrochemically active surface areas, particularly at an optimal Re loading of 3 wt%. Functionalized supports, especially MC-HNO₃, further improve catalyst dispersion and electrochemical performance. Prototype fuel cell tests confirm these trends, highlighting the importance of metal synergy and carbon surface functionalization.

The Front Cover reflects a potential-controlled deposition process of tin catalysts from organic solutions of a tin thiolated precursor, aiming to deposit on carbon-based substrates, for CO₂ electro-catalyzed reduction to formate. Electrochemical and structure tools are enrolled to investigate the complex deposition mechanism, exposing irregular current-potential and mass change phenomena. Disproportionation and comproportionation reactions of tin are entitled to untie the redox behavior enigma. More information can be found in the Research Article by Yaron S. Cohen and co-workers (DOI: 10.1002/cplu.202500208).

Suspension aging is critical in the synthesis of Cu/Zn-based methanol catalysts, because this process of chemical transformations includes crystallization of different phases. The evolution of these phases within the precipitate is leading along the so-called transitory tipping point to the target phase zincian malachite. More information can be found in the Research Article by Lucas Warmuth and co-workers (DOI: 10.1002/cplu.202500284).