ChemPlusChem最新文献

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.

The design, synthesis, and characterization of a series of supramolecular receptors based on electron-deficient aromatic systems capable of engaging in anion–π interactions are reported. Receptors 1 and 3 combine an electron-poor aromatic scaffold with a cation-binding crown ether unit. Binding studies monitored by ¹H NMR titrations in acetonitrile revealed that these receptors exhibit enhanced affinity for bromide anions in the presence of sodium cations, indicating cooperative ion-pair recognition. Receptor 1, incorporating both nitro-substituted aromatic rings and a macrocyclic cation-binding site, demonstrated the most significant anion–π binding enhancement. In contrast, control receptor 2, lacking electron-withdrawing groups, exhibited negligible anion affinity, supporting the role of π-acidity in anion binding. Quantum chemical calculations and electrostatic potential maps further confirmed the contribution of anion–π interactions in receptor function. The incorporation of amide functionalities in receptors 3 and 4 improved binding affinity, highlighting the synergistic effect of multiple binding domains. These findings highlight the potential for developing advanced ion-pair receptors that harness anion–π interactions alongside classical noncovalent binding motifs.

Enhancing singlet oxygen generation for photosensitizers in aqueous media can markedly improve the efficacy of photochemical therapy. Herein, triblock polymers composed of pyropheophorbide a photosensitizer (PPa), polyethylene glycol, and phospholipid are synthesized. These triblock polymers, driven by hydrophilic–hydrophobic interactions, spontaneously fold into an amphiphilic structure and further self-assemble into nanomicelles. This novel nanomicelle, termed nanoPPa, provides a stable, nonpolar microenvironment for photosensitizer molecules, thereby enhancing photodynamic energy efficiency by minimizing energy loss from molecular collisions and self-aggregation. Compared to the photosensitizer PPa alone, nanoPPa exhibits a remarkable fivefold increase in singlet oxygen generation, accompanied by a substantial boost in phototoxicity. Simultaneously, an increased fluorescence emission is observed. These enhancements in phototoxicity and fluorescence signify the potential of nanoPPa for dual applications in photodynamic therapy (PDT) and photodynamic imaging (PDI). The fabrication of this nanostructure is proposed as a versatile strategy to improve the application of photosensitizers and enhance therapeutic outcomes.

This study introduces a simple signal transduction system that mimics the receptor tyrosine kinase mechanism by employing amphiphilic receptors embedded in lipid bilayers. The designed receptors carry bisphosphonate head groups and feature aggregation-induced emission enhancement (AIEE) properties. Upon addition of polyammonium messengers, they undergo ligand-induced dimerization or clustering inside the membrane. Steric restriction of intramolecular motion in the AIE luminophores sends out a fluorescence signal. Systematic comparative studies highlight the impact of receptor design, lipid environment and messenger properties on the efficiency, kinetics, and strength of signal transduction. These findings provide new insight into the interplay between receptor aggregation and membrane organization in controlling fluorescence-based signaling systems. Practical perspectives and inherent limitations are critically discussed.

Formosulfathiazole (FSTz) is a synthetic active pharmaceutical ingredient (API) prepared by condensation of sulfathiazole with formaldehyde. Originally described for the first time in 1948, it is currently used for the treatment of bacterial and protozoal infections in cattle and pets, acting as a prodrug slowly releasing the sulfamidic sulfathiazole and formaldehyde. A systematic analysis of FSTz allowed to revise the originally believed undefined polymeric structure and uncovered the intriguing cyclophane skeleton of a well-defined cyclodimeric condensation product.