ChemistryEurope最新文献

Carbocationic rearrangements are fundamental to both biosynthetic and synthetic chemistries, yet their high reactivity and mechanistic complexity often defy intuitive prediction of outcomes. Herein, HopCat, a hybrid algorithmic platform combining rule-based transformation logic with quantum-mechanically informed kinetics, is applied to explore the rearrangement networks of acid-catalyzed terpenoid transformations. Using a series of terpenoid substrates, an array of structurally diverse and unprecedented products is obtained. It is narated how HopCat can work synergistically with a human chemist to guide product assignment, downselect product candidates based on NMR cues, and reconstruct plausible, multistep mechanistic pathways, including those involving unanticipated intermediates.

Fundamental studies of diffusion processes on solid catalysts are challenging due to the lack of appropriate characterization techniques. Herein, using NH₃ diffusion on various zeolites as an example, flow-pulse adsorption microcalorimetry (FPAM) is demonstrated capable of characterizing diffusion processes on solid catalysts. Initial adsorption heats and differential adsorption heats of NH₃ on zeolites are measured temperature-dependent arising from the diffusion of adsorbed NH₃ from the weakly adsorbed Lewis acidic sites (LAS) to the strongly adsorbed Brønsted acid sites (BAS). A model is then established to acquire the temperature-dependent distributions of NH₃ adsorbed at the LAS and BAS sites, from which the LAS-to-BAS diffusion barrier of adsorbed NH₃ is derived between 3.1 and 7.4 kJ mol⁻¹ mainly related to the binding energy of NH₃ adsorbed at the LAS. The applicability of FPAM method is further demonstrated by determing the weak adsorption site-to-strong adsorption site diffusion barriers of adsorbed NH₃ on silicalite-1 and adsorbed C₃H₆ on MOR-10 as 7.3 and 17.9 kJ mol⁻¹, respectively. The established FPAM method is a general method and will greatly enable the studies of diffusion processes on solid catalysts, a key elementary step capable of regulating their catalytic performances.

Decoration of polymers with Lewis acidic borane moieties is attractive as it enables the development of functional materials for use as powerful supported catalysts, chemical sensors, and building blocks of novel supramolecular materials. The dynamic nature of Lewis acid-base interactions is of central importance in these application fields. However, methods to access well-defined polymeric Lewis acids with tunable Lewis acid characteristics remain very limited. In this article, a flexible route to a family of norbornene-functionalized triarylboranes is reported, which can be polymerized under mild conditions using ring-opening metathesis polymerization to yield borane Lewis acid-functionalized homo- and copolymers. By varying the aryl substituents about the boron center, steric and electronic tuning of the Lewis acid moieties is achieved. The latter allows for the rational design of polymers with tunable Lewis acid strength, approaching that of the widely utilized molecular Lewis acid B(C₆F₅)₃, enhanced air-stability, and desirable luminescent characteristics. The complexation behavior, stability, and photophysical properties of the new monomers and borane polymers are investigated in depth.

The transition to sustainable energy storage solutions has become an urgent global priority, driven by the escalating demand for energy and the essential shift toward renewable sources. Carbon nanotubes (CNTs) have attracted considerable attention as a promising material in this transition, owing to their unparalleled conductivity, mechanical strength, and substantial surface area. This review examines the integration of CNTs with lithium-ion battery (LIB) technologies while emphasizing their transformative potential in enhancing LIB performance. The incorporation of CNTs into LIB anodes significantly improves charge transport and cycling stability while addressing critical challenges that persist in terms of large-scale production, seamless integration into battery systems, and cost-effectiveness. This review presents the most recent innovative solutions to these challenges while highlighting emerging research directions that could accelerate the widespread adoption of CNT-enhanced LIBs. By investigating the potential of CNTs to revolutionize the LIB landscape, this work aims to outline pathways toward the next generation of high-performance and sustainable energy storage technologies.

Intrinsically disordered regions are ubiquitous within proteins and critical for protein functions. A recent cryo-electron microscopy study reveals that a pyrene-conjugated hexalysine (Pyn-KKKKKK) and a pyrene–tyrosines (EY) motif peptide (Pyn-EYEYEY) coassemble into intrinsically disordered nanofibers through aromatic–aromatic and electrostatic interactions. To probe the sequence effects, a series of peptides is generated by mutating amino acid residues, and their assemblies are examined using negative-stained transmission electron microscopy, fluorescence, and circular dichroism spectroscopy. Homochiral and heterochiral mixtures displayed similar morphologies, indicating a role of chirality in their structures. Sequence modifications reveal that aromatic residues patterning governs self-assembly: “XZXZXZ” or “XXXXXZ” (X = charged residue, Z = aromatic residue) favor fiber formation, while “XXXZXZ” promotes pyrene excimer generation. Fiber assembly consistently correlates with an intermediate emission peak at 420–430 nm, suggesting a specific pyrene stacking geometry, particularly in sequences containing aromatic residues and in heterochiral mixtures of oppositely charged peptides. These findings highlight how sequence and chirality modulate aromatic–aromatic and electrostatic interactions in intrinsically disordered peptides, providing insights into heterotypic nanofiber formation and confirming the utility of lysine–tyrosine pair in rational design of supramolecular peptide materials that maintain both disorder and self-assembly.

The first example of a CN σ-bond activation in tert-butyl isocyanate and isothiocyanate by a 3,5-bis(trimethylsilyl)-phosphinine-B(C₆F₅)₃ Lewis pair is reported. Despite the inherently low nucleophilicity of phosphinines, the first step of the observed reactions is the unusually facile tert-butylation of the phosphinine via an S_N1 pathway, yielding the unprecedented 1-^tBu-phosphininium cation. The high reactivity of this intermediate leads to subsequent follow-up reactions with the excess reactant as well as side-products, forming additional phosphorus compounds under mild conditions via a complex reaction network. In stark contrast, the reaction of ^tBuNCO and ^tBuNCS with a classical frustrated Lewis pair leads to simple decomposition of the iso(thio)cyanate. This work not only reveals a new mode of CN σ-bond activation in iso(thio)cyanates by compounds based on main-group elements, but also suggests a direct pathway for the selective P-functionalization of phosphinines, opening up avenues for the targeted synthesis of such otherwise inaccessible aromatic phosphorus heterocycles.

Despite being a key concept in chemistry, aromaticity and the switching thereof have only seldom been used in charge storage devices. Herein, this work explores how aromaticity switching in a tetraoxa[8]circulene derivative, named N-TOC, can be used in sodium-ion batteries and assesses the switching mechanism through computational approaches. N-TOC delivers exceptional cycling stability at 50 and 100 mA g⁻¹ over 500 cycles with a capacity retention of 91% and 89%. Supported by DFT calculations, this work investigates changes in aromatic motifs within N-TOC through changes in redox states upon charge storage, thus presenting a promising strategy for the design of organic electrodes in Na-ion batteries.

Cage-type hydrocarbons represented by cubane serve as molecular scaffolds for various useful molecules, such as pharmaceuticals and organocatalysts. However, even for the most readily available cubane, achieving regioselective substitution and controlled induction of chirality remains extremely challenging. A method to access chiral motifs using achiral 1,4-disubstituted cubanes, highly symmetric cage-type molecules, as starting materials has been developed. Through asymmetric isomerization of their molecular frameworks, these cubanes are converted into optically active 2,6-disubstituted cuneanes. Subsequently, treatment with nucleophiles, such as alcohols and 1,3-diketones, in the presence of a rhodium catalyst enables the stereoselective and enantiospecific synthesis of trisubstituted 1,3a,4,6a-tetrahydropentalenes via skeletal isomerization accompanied by nucleophilic addition. This cuneane scaffold editing strategy provides an efficient synthetic route to chiral 1,3a,4,6a-tetrahydropentalenes bearing substituents. These compounds show promise as asymmetric, cage-derived, bowl-shaped diene ligands.

Immunotherapy, despite its notable therapeutic potential in cancer and inflammatory diseases, still faces challenges in clinical efficacy due to the complexity of tumor or inflammatory microenvironment. Nanogels (NGs) have emerged as a versatile therapeutic platform, owing to their unique structural advantages, including high drug encapsulation capacity, easy surface modification, stimuli-responsiveness, and excellent biosafety, collectively addressing critical limitations of conventional immunotherapy delivery systems. Herein, the advances in functional NG design and synthesis for immunomodulation to treat cancer and inflammatory diseases are reviewed. The mechanisms of NGs in immunotherapy are mainly elucidated including immunotherapy factor delivery systems enabling precise payload release, the immune modulation through both activation and suppression, and targeting strategies at immune cell levels. Finally, the challenges and application prospects of NG-based nanoplatforms in the treatment of cancer and inflammatory diseases are briefly discussed.

The asymmetric total synthesis of myrmenaphthol A, a natural product isolated from a Hawaiian sponge of the genus myrmekioderma, has been achieved in 12 steps. The key transformation of this synthesis is a gold-catalyzed [3,3]-sigmatropic rearrangement of sulfonium, starting from a chiral sulfoxide substrate and propargyl silane. The development of the methodology includes the synthesis of benz[e]inden-2-one derivatives with quaternary centers (51–78% yield, 90%–99% ee).