Chemistry methods : new approaches to solving problems in chemistry最新文献

The Cover Feature shows multicolored LEDs emitting circularly polarized light onto double and triple heterohelicenes, thereby highlighting their tunable optoelectronic properties. These complex molecules, featuring multiple chiral axes and heteroatoms, have been synthesized through innovative short-step strategies for next-generation optoelectronic applications. For more details, see the Review by M. S. H. Salem and S. Takziawa (DOI: 10.1002/cmtd.202500018).

The Front Cover shows a magnified view of a polyoxometalate-based electrode material, highlighting the thermal activation of organic cations. This process is depicted as dancing molecules, symbolizing the dynamic rearrangement triggered by heat treatment. The work described in the Research Article by M. Giménez López and co-workers (DOI: 10.1002/cmtd.202500046) emphasizes the importance of selecting organic cations with tailored molecular structures and applying a thermal activation strategy to develop more efficient and stable energy storage systems.

The crystallization of soluble salts poses a significant challenge to mural painting conservation. While cellulose poultices are widely used to desalinate mural paintings due to their high absorption and ease of handling, their effectiveness within the porous network of wall paintings remains a complex issue. For the first time, this study explores the potential of micro-structured cellulose-based foams as an alternative to conventional poultices for desalinating fresco wall paintings. A laboratory experiment compared the efficacy of foams and poultices, using fresco wall painting mock-ups (produced with the Roman technique) that were vacuum-impregnated with salt solutions (chlorides, sulfates, and mixtures). Short and long application times were considered, and foam reusability across multiple application cycles was assessed. Micro-energy dispersive X-ray fluorescence (µ-EDXRF) imaging was employed to quantitatively evaluate salt content reduction, both superficially and throughout the mock-up stratigraphy. Results show that foams are considerably more effective than poultices, achieving a salt removal efficiency between 6 and 10 times higher. The uniform micro-porous foam network enables faster desalination, reducing treatment risks and minimizing waste while supporting circular economy principles. This study also demonstrates the utility of µ-EDXRF imaging in monitoring desalination efficacy for both surface and cross-section analyses when assessing new desalination protocols.

Carbonyl derivatives are widely present in biologically active molecules, pharmaceuticals, natural products, and materials, and their synthesis has garnered much attention. Hence, developing new, efficient, and environmentally friendly methods for synthesizing carbonylated compounds is one of the core research projects in the field of organic synthesis. In carbonylation reactions, direct carbonylation of aromatic CH bonds is an effective tool for the synthesis of carbonyl compounds. Yet, the selective carbonylation of CH bonds of aromatic hydrocarbons remains an important challenge as multiple CH bonds of a molecule have similar electronic properties and steric environments. In this regard, aryl sulfonium salts, as active reagents that can be involved in various synthetic reactions, provide an attractive solution to this challenge. In this review, the recent advances in the site-selective carbonylation transformation of arenes via aryl sulfonium salts, as well as their reaction mechanisms and synthetic applications are summarized and discussed systematically.

Over the last year, peptides have been consolidated as an important class of biomolecules, receiving increased attention from the pharmaceutical, cosmetic, and food industries. Most peptides currently used in both industrial and research modes are prepared by means of solid-phase peptide synthesis, which is based on the use of a solid polymeric support. The preparation of C-terminal amide peptides is easier than for their acid counterparts, and there are several resins available for this purpose. In contrast, the synthesis of peptides bearing a C-terminal acid is more challenging because ester formation is more difficult than amide formation, and esters show increased lability. The two main resins employed in peptide synthesis are Wang resin, which is used for the preparation of unprotected peptides, and 2-chlorotrityl chloride (CTC) resin, which can also be used to obtain side-chain protected peptides. Herein, a new solid support, 4-Methylbenzhydryl bromine resin, isdiscussed, which, although slightly more stable than CTC resin, allows the preparation of protected peptides, renders less diketopiperazine (DKP) formation than Wang resin, and does not degrade during the final global cleavage and deprotection, and is therefore exempt of back alkylation.

A red squirrel with a nut symbolizes the importance of sustainability—a core value of a continuous-flow solid-phase peptide synthesis (CF-SPPS) approach. In their Research Article (DOI: 10.1002/cmtd.202500010), I. M. Mádity and co-workers reveal how they used propylene carbonate (PC), a green solvent selected by using the GSK guide, to achieve high-yield synthesis of α- and β-peptides, including challenging sequences, even on >4 g scale. The image reflects low solvent use, reduced PMI, and the eco-friendly, scalable nature of this breakthrough CF-SPPS technology.

The Front Cover depicts copper nanoparticles with finely tuned wettability beneath a cut-away electrolyte layer, forming abundant three-phase interfaces where CO₂, protons, and electrons meet. This balance of hydrophilicity and hydrophobicity enriches local CO₂ concentration, boosting activity, selectivity, and stability. For details, see the Concept by T. W. B. Lo, J. Yin, Q. Lei, and co-workers (DOI: 10.1002/cmtd.202400080).

In this work, inverse gas chromatography at infinite dilution was used to associate the surface properties (London component, acid and basic constants, and enthalpy) of two tannic based adsorbent materials with the removal capacity against lead pollutant in contaminated water. Such materials have been prepared with same molar ratio TEOS/tannic (5/1) using p-toluene sulfonic (p-TSA) and nitric acids (NA) as catalyst. The dispersive component of the surface (London component, γ_S^D) is higher for the p-TSA material (64.7 mJ.m⁻²) than NA material (35.3 mJ.m⁻²). Identical behavior is found for enthalpy (81.2 mJ.m⁻² for p-TSA and 39.2 mJ.m⁻² for NA) and acid constant of the surface (0.25 and 0.15 for p-TSA and NA, respectively). The porous structure is not very important in the removal capacity for these materials due to the very low specific surface area and pore volume being very close for both samples. Kinetically, the adsorption of Pb(II) on p-TSA material follows a Freundlich isotherm model indicating that the surface is heterogeneous. The maximum adsorption capacity of the best TEOS/tannic sample for Pb (II) was 62 mg.g⁻¹. The results obtained in this work establishes that the surface energy also would play a very important role on the removal capacity of contaminants independent of the textural characteristics of the adsorbent.

Polyoxometalates (POM) are promising materials for electrochemical applications, such as supercapacitors. However, their stability in aqueous electrolytes is compromised due to POM cluster leaching. To mitigate this issue, POM can be combined with organic counter cations, which reduce their solubility in water and influence interactions with carbon support materials. Nevertheless, further research is needed to determine the optimal characteristics and electrode design for maximizing performance. In this work, a synergistic methodology to investigate POM compounds bearing cations with three core functionalities (ammonium, imidazolium, and pyridinium) and varying alkyl side chain lengths, is developed in order to elucidate and optimize the effects of hydrophobicity on the structure of organic–inorganic hybrid materials, electrode films, and their electrochemical performance. The results show that, although cations with long alkyl chains exhibit lower capacitance, they can be activated through molecular rearrangement in the solid state, facilitated by the flexibility of these chains within the structure. By combining thermal and electrochemical techniques, the electrode materials are optimized. These findings demonstrate that the careful selection of counter-cations with the appropriate molecular structures, followed by a thermal activation protocol, is key to developing more efficient and durable energy storage systems.