ChemistryEurope最新文献

Extremely sterically demanding bis(bis(trimethylsilyl)methyl)-substituted aluminum and gallium compounds are particularly suitable for applications in frustrated Lewis pair (FLP) chemistry. A selective exchange reaction between Bis₂GaBr (Bis = CH(SiMe₃)₂) and Bis₂AlH affords the previously inaccessible Bis₂GaH, a monomeric gallium hydride, in solution, as confirmed by diffusion ordered spectroscopy NMR, IR spectroscopy, quantum chemical calculations, and—indirectly—by hydrogallation of phenylacetylene. A simple one-pot route enables access to Bis₂EOP^tBu₂ FLPs (E = Al, Ga) via formal HBr adducts and subsequent deprotonation with KHMDS. As predicted for Bis₂GaOP^tBu₂, H₂ activation is favored, although it proceeds slowly and irreversibly. Surprisingly, variable-temperature NMR studies unveil a dynamic equilibrium between the H₂ adduct Bis₂Ga(H)OP(H)^tBu₂ and the free gallium hydride and phosphine oxide, shedding new light on reversible hydrogen activation in main-group FLP systems.

This study explores the synthesis and characterization of novel indium-based pentafluoroorthotellurate (teflate) derivatives. It introduces a series of indium(III) teflate mono- and trianions, including [In(OTeF₅)₄(THF)₂]^– and [In(OTeF₅)₆]^3–. The research utilizes low-temperature single-crystal X-ray diffraction, IR, and NMR spectroscopy to provide the first structural insights into these indium(III) teflate anions. The neutral Lewis acid [In(OTeF₅)₃] is successfully synthesized as its THF adduct [In(OTeF₅)₃(THF)₃] via a salt metathesis reaction with InCl₃ and AgOTeF_5. Quantum-chemical calculations and catalytic tests highlight the pronounced Lewis acidity of the indium center in these compounds.

In this Guest Editorial, the special issue of ChemistryEurope on supramolecular luminescent chemosensors (LCs) is presented, showcasing selected contributions from members of the COST Action LUCES (CA22131). LCs are a versatile means to sensitively and selectively detect pollutants and biologically relevant molecules. Recent advances in this rapidly growing field include molecular receptors and nanostructured assemblies, as well as device integration and data-driven sensing. Articles in this issue highlight a range of innovations within European collaborations fostered by LUCES, demonstrating the Action's focus on translating fundamental findings from the laboratory into real-life solutions to environmental and societal needs.

Lithium–sulfur (Li–S) batteries have garnered significant attention owing to high theoretical energy density (2600 Wh kg^–1). Their commercialization is otherwise impeded by sluggish redox kinetics and shuttle effect stemming from the generation of soluble lithium polysulfides (LiPSs). Extensive studies have indicated the introduction of light energy into Li–S systems effectively enhances the reaction kinetics of the sulfur reduction/evolution reaction while simultaneously suppressing the LiPS shuttling. Nevertheless, the realization of high-performance photoassisted Li–S batteries remains challenging, primarily because of the insufficient utilization efficiency of photoinduced carriers in redox reactions. Collectively, the field lacks a comprehensive overview elucidating the mechanisms of charge carrier separation and the photoelectrochemistry of LiPS conversion. In this review, recent advances in the design of battery configurations, photoelectrodes, and catalysts for photoassisted Li–S batteries are summarized, providing an in-depth discussion on the photoelectrochemical processes. The prevailing challenges and future prospects toward the practical viability of photoassisted Li–S batteries are also highlighted.

Sustainable agricultural systems face numerous challenges, including the need for sustainable resources, enhanced crop productivity, and improved postharvest management. Due to their unique physicochemical properties, such as tunable luminescence range, biocompatibility, ease of synthesis, facile surface functionality, water solubility, and low toxicity, carbon dots (CDs) have emerged as promising nanomaterials for sustainable agriculture. These features enable their broad application throughout the agricultural life cycle, from promoting plant growth and development to enhancing the preservation and detection of agricultural products. CDs can be synthesized from a wide variety of organic waste, including crop residues, facilitating their reintegration into a closed-loop agricultural system. Here, recent progress in the use of CDs in key stages of the crop growth cycle, including seed germination, vegetative development, and crop protection, is summarized. In addition, their role in postharvest preservation, antimicrobial activity, and safety assessment of agricultural commodities is discussed. Finally, current limitations and future directions for the application of CDs in sustainable agriculture are critically evaluated.

The electrocatalytic synthesis of urea by coreduction of NO₃⁻ and CO₂ provides the basis to replace the energy-intensive Bosch–Meiser process; however, such systems are inherently limited by competing reactions and urea selectivity. Scanning electrochemical cell microscopy (SECCM) with a cosputtered Co-Cu alloy thin-film materials library is used for the high-throughput investigation of element composition-dependent electrochemical activity for the coreduction of CO₂ and NO₃⁻ to urea. A NO₃⁻ containing electrolyte is provided in the SECCM capillary while CO₂ is offered through the gas phase. Comparison of linear sweep voltammograms in presence and absence of CO₂ is the basis for finding Co-Cu compositions which exhibit an increased overpotential for NO₃⁻ reduction for matching the potentials for CO₂ reduction, thus allowing the presence of the intermediates of both reactions in close vicinity at the catalytic sites. The most promising Co-Cu element ratio for urea synthesis is synthesized as a powder catalyst and investigated in a model flow-through electrolyzer concerning urea synthesis. These findings provide guidance for the rational design of Co-Cu (Co_xCu_100−x) catalysts, the optimization and the identification of optimal working potentials as well as electrolyte compositions to facilitate CN coupling to urea with minimal loss caused by competing reactions.

Catalytic cracking, one of the core processes of the refining of crude oil, is gaining industrial adoption to convert hard-to-recycle polyolefin plastics back into hydrocarbon feedstocks. While structure–composition–performance relationships for converting shorter hydrocarbons over solid acid catalysts, including zeolite-based materials, have been studied extensively, studies focusing on utilizing polyolefins are only now emerging. In this work, the effect of the catalyst pore size distribution in the catalytic cracking of polypropylene is isolated. This is achieved by preparing a set of amorphous silica–alumina (ASA) materials with close to identical external acidity (≈30 µmol g⁻¹) from silica supports of pore diameters ranging from 7 to 75 nanometers and particle sizes ranging from 1 to 40 µm. Surprisingly, it is observed that the mesopore pore size has only a minor effect on cracking activity, as measured by ramped thermogravimetric analysis at high PP:catalyst ratio. The results are rationalized by conducting a simplified simulation of pore intrusion utilizing the Lucas–Washburn equation of capillary flow, which suggests that pore filling can occur before the reaction onset in ramped experiments. The findings indicate that in optimization of plastic cracking catalysts high external acidity and small particle size will play a significantly larger role compared to mesopore size.

The Cover Feature perfectly embodies the meaning of the Research Article by A. Leyva-Pérez and co-workers (DOI: 10.1002/ceur.202500217). In the centre is a zeolite with an oasis inside it. In this oasis, a benzyl cation lies in a hammock, relaxing and sunbathing, since even such an unstable cation is stable inside the zeolite. Outside the zeolite, several tropilium ions are ready to enter and become stable as the benzyl cations on the inside.

The Cover Feature shows how the reaction path of CO₂ radical anion addition to N-Ac-enamide was explored by using automated reaction path search methods. Analysis revealed that β-position addition is both kinetically and thermodynamically favored over α-position addition, leading to the selective formation of β-amino acids. This computational prediction was further supported by experimental validation. More information can be found in the Research Article by S. Maeda, T. Mita and co-workers (DOI: 10.1002/ceur.202500184).

The Cover Feature illustrates the cooperation between Bangkok and Regensburg: the silhouettes of both cities represent the exchange, while the aziridine ring above the maps symbolizes the desired connection. A centrally placed copper catalyst refers to the underlying process, and selected example products highlight the results of the collaboration. More information can be found in the Research Article by C. Kuhakarn, O. Reiser and co-workers (DOI: 10.1002/ceur.202500218). Artwork by Kathrin Strunk.