ChemPlusChem最新文献

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).

New H-bonded supramolecular assembliesare obtained using the polyfluorobiphenyl H-donor derivatives and 18-crown-6 ether. Cocrystals of octafluorobenzidine with 18-crown-6 of 1:1 stoichiometry belong to the enantiomorphous space groups P6₅ and P6₁. The helical self-assembly of these achiral molecules is achieved due to the interplanar angle of the bis-aryl molecule (≈60°), which is fixed by directed N–H···O_cr H-bonds between two H_amino atoms with two O_cr atoms at both ends of the molecule. Cocrystallization of octafluorobiphenol results in the formation of a crystalline hydrate based on the water-mediated H-bond Ar-O-H···O(H)-H···O_cr. Flexible water linker eliminates the effect of the H-donor coformer structure and makes this cocrystal achiral. The hydrogen bonding details between octafluorobenzidine and 18-crown-6 within a unit cell are investigated through a combination of vibrational spectroscopy and quantum mechanical calculations. An oxygen atom in 18-crown-6 is identified as a chiral center, as a result of intermolecular interactions involving this atom and hydrogen atoms bonded to its α and β carbon atoms. The unique interaction patterns of 18-crown-6 with acetone and chloroform, along with scanning electron microscopic images, reveal the role of solvent molecules in determining the chirality of the self-assembly.

Photoreforming of biomass presents a promising approach for sustainable H₂ production by utilizing renewable solar energy under ambient conditions. However, its application is often limited by the poor solubility of biomass-derived substrates. Herein, this challenge is addressed by synthesizing hydrophilic, electron-rich pyridine-based glycopolymers via reversible addition-fragmentation chain transfer polymerization, followed by deacetylation of glucose- and maltose-based segments. The polymers and CdS nanorods are thoroughly characterized using various spectroscopic and thermal analyses. The resulting deacetylated glycopolymers exhibit enhanced aqueous solubility and are employed as biomass replacement for photoreforming. The as-prepared CdS nanorods with P4VP-b-PMDG significantly improve glucose photoreforming, achieving an efficient hydrogen evolution rate of up to 1685  μ mol h⁻¹ g⁻¹ with an apparent quantum yield of 4.10% under alkaline conditions (10 M NaOH). The CdS nanorods' stability is investigated through a photocatalytic recyclability test, representing a regeneration efficiency of 94.36% in the fourth cycle. This work highlights the potential of tailored hydrophilic polymers to overcome solubility limitations and enhance the efficiency of biomass photoreforming systems.

Surfactants adsorb at interfaces and reduce the interfacial tension. In technical applications, they are typically used as complex mixtures rather than monodisperse systems. These mixtures often include ionic and non-ionic surfactants, with the non-ionic components comprising various monodisperse species. Such complexity influences adsorption behavior significantly. In this study, we therefore investigated how different monodisperse components within a technical surfactant system affect adsorption kinetics, characterized through dynamic interfacial tension measurements. We focused on blends of the anionic biosurfactant di-rhamnolipid and technical alkyl ethoxylates. Our results show that increasing the di-rhamnolipid ratio enhances the adsorption rate at interfaces logarithmically compared to ethoxylates, which is especially relevant for applications requiring rapid adsorption. Moreover, we observed partitioning effects of the ethoxylates’ hydrophobic moieties when comparing adsorption at the oil/water and air/water interfaces. These differences explain why more hydrophilic ethoxylates are often preferred in practice. Overall, our findings deepen the understanding of adsorption behavior in mixed surfactant systems and provide a basis for tailoring formulations by adjusting the component ratio for specific application needs.