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We present a method for the rapid assembly of highly substituted 1,4-benzodiazepin-2-ones by the addition of unsymmetrical imides to arynes, the subsequent deprotection of a protected amino functionality followed by immediate ring closure. An optimized procedure for the synthesis of diversely substituted unsymmetrical imides was developed, granting access to a large pallet of benzodiazepine precursors. This allows for the application of this protocol in a modular fashion, which is demonstrated for both the unsymmetrical imides and the benzodiazepines. Ultimately, we thereby reveal rapid access to a large variety of densely functionalized benzodiazepine cores.

Cleavage by γ-secretase within the transmembrane domain (TMD) of amyloid precursor protein (APP) generates Aβ peptides that can accumulate in amyloid plaques in Alzheimer's disease pathogenesis. How γ-secretase selects its substrates has been an enigma as they do not have a consensus sequence. In our previous study, we discussed a dynamic signature that controls internal bending/kinking and orientation of the two halves of the TMD. The extent, however, had remained ambiguous due to limitations of NOE-based NMR structure determination. To solve this question, we measured residual dipolar couplings (RDCs) of APP-TMD, using a polyethylene glycol gel-based alignment medium with TFE/water mixtures. Using ¹H¹⁵N RDCs, we analyzed the conformations of APP-TMD and two mutants, G38L and G38P, which previously had differed significantly in bend and orientation and cleavage efficiency by γ-secretase. By fitting snapshots from a molecular dynamics trajectory, we analyzed how well structures matched the measured RDC values. This indicated that G38L retained mainly its relatively straight conformation, whereas bent and—in the case of G38P—locally unfolded structures likewise contribute dynamically to the other two. The RDC selected structures thus reproduce the features of the NOE-derived structures, but show that all three TMDs retain some conformational adaptability.

High-entropy alloy (HEA) nanoparticles (NPs) have been subject to increasing interest as prospective catalyst materials. However, highly controllable synthesis methods for HEA NPs remain scarce. To address this issue, we present a systematic study of the synthesis parameter space in a simple colloidal synthesis approach where IrPdPtRuRh NPs were synthesised in triethylene glycol. We show that ultra-small (1–3 nm), single-phase HEA NPs can be synthesised through a hot-injection synthesis approach. In contrast, multiple phases are observed when a one-pot synthesis is carried out. We also show that the particle sizes and morphologies are affected by the choice of metal precursor counterion, and further investigate the dependence of metal reduction on the reaction temperature. Additionally, we present the synthesis of mixed noble/non-noble-metal IrPdPtRuNi and IrPdPtRuCo HEA NPs. By carrying out reduction kinetics experiments, we relate phase separation and compositional gradients of some of the synthesised samples to large differences in the reduction rates of the reacting metals. The individual metal reduction rates are found to vary depending on which other elements are present during particle formation. These results emphasise the importance of understanding the chemical landscape during reaction for the controlled synthesis of HEA NPs.

Fifty-four halopyridines were classified into six series based on halogen substituent positions at ortho, meta, and para to the pyridinic nitrogen. Complexation of these halopyridines with CuCl₂ and CuBr₂ from acetonitrile and ethanol resulted in 158 X-ray structures, including five mixed-ligand-Cu(II) complexes. The dataset provides generalizable insights into coordination structures governed by the halogen atom and position. Bonding and structural analysis across the six halopyridine series, considering bond lengths, angles, and coordination geometries, reveals no more than 19 distinct structural motifs. Across this diverse structural landscape, each halopyridine series adopts a maximum of six coordination structure motifs. The halogen position determines whether crystallization yields single crystals or non-crystalline solids. The ortho-halogens display unique dual properties. Their σ-hole participates in the CX···Cl/BrCu (X = F, Cl, Br, I) halogen bonding, while their electron-belt simultaneously participates in intramolecular CX···Cu interactions, influencing whether ortho-halogens adopt cis- or trans-arrangements in Cu(II) complexes. The density functional theory-computed energies of C–X···Cu interactions vary from 1 to 4 kcal mol⁻¹, depending on the halogen atom identity. Docking studies with human serum albumin reveal stabilizing protein-halopyridine-Cu(II) interactions. These findings provide a framework for the rational design of halopyridine-Cu(II) complexes for applications in materials and bioinorganic chemistry.

The properties and applications of 2D organic materials strongly depend on their structural and morphological features. Herein, under different solvothermal conditions, the reaction is demonstrated between 2,6-diaminoanthraquinone (ANQ) and mellitic trianhydride (MTA) that results in a thermodynamically-controlled, mellitic triimide (MTI) based crystalline covalent-organic framework MTI–ANQ–COF with an ABC-type interlayer packing and the kinetically-driven covalent-organic network MTI–ANQ–CON, which is amorphous. Solid-state characterization techniques and electrochemical analyses established the structural features of both materials. The symmetric supercapacitors fabricated using crystalline MTI–ANQ–COF exhibited a specific capacitance (C_sp) of 54 A g⁻¹, at a constant current density of 1 A g⁻¹ in organic electrolyte, while MTI–ANQ–CON could exhibit nearly half of it (29 A g⁻¹). Interestingly, the MTI–ANQ–COF-based symmetric supercapacitor exhibited relatively better cycling stability (92%) as compared to the MTI–ANQ–CON-based symmetric supercapacitor (55%) for 10,000 continuous charge–discharge cycles, revealing the fact that crystalline COF exhibits better performance over amorphous CON.

While DNA-templated ligations typically rely on the sequence-specific hybridization of complementary strands to bring reactive groups into close proximity, charge-transfer assisted ligation (CTAL) is proposed as a fundamentally different strategy. Rather than depending on a DNA template for spatial organization, CTAL exploits charge-transfer interactions between reactants to promote bond formation between two noncomplementary DNA strands. The strategic placement of donor and acceptor units at the termini of DNA strands drives the colocalization of reactive functional groups, enabling efficient reactions at sub-micromolar concentrations. The versatility of the CTAL is demonstrated on CuAAC and SPAAC click reactions, allowing the formation of conjugates with 3′-5′, 3′-3′, or 5′-5′ junctions, with outstanding apparent rate constants in the 10⁴–10⁵ M⁻¹s⁻¹ range, while the nonassisted reactions are inoperative in such dilute conditions (0.5 µM). Furthermore, the potential of the CTAL is extended to RNA–RNA and siRNA–DNA aptamer ligations. Finally, a traceless strategy based on a cleavable linker is developed, which allows the removal of aromatic units after ligation under basic conditions.

Lanthanide(III) complexes are invaluable tools for probing protein structure and dynamics, enabling precise distance measurements and site-specific labeling across electron paramagnetic resonance (EPR), nuclear magnetic resonance (NMR), and luminescence-based techniques. Designing an optimal lanthanide tag requires high thermodynamic and kinetic stability, minimal linker flexibility, and rapid, quantitative reactivity under mild conditions. Herein, a short series of Ln(III) complexes developed as efficient protein tags is reported, each showing high chemoselectivity for cysteine and enabling labeling in aqueous solution under mild conditions (pH 8, 37 °C). Subtle modifications to the reactive arm of the parent Ln.L1 complex has a pronounced effect on tagging kinetics, with Tb.QuNO achieving >95% labeling of the free amino acid cysteine within 10 min. The more compact and readily synthesized Gd.PyNO also labels efficiently and exhibits a narrow EPR linewidth (3.1 mT average at Q-band across three protein-labeled samples), making it an optimal choice for many EPR applications. These findings highlight the critical role of linker design in lanthanide-based probes for EPR spectroscopy and biological imaging.

The one-step syntheses of highly luminescent Cu(I) dimetallic complexes are reported using Cu(I) salts and the commercially available dppm ligand. Three crystalline phases A–C, obtained either with PF₆⁻ (A and B: [Cu₂(μ₂-dppm)₃](PF₆)₂) or TEF⁻ (C: [Cu₂(μ₂-dppm)₃](TEF)₂) anions, display distinct conformations and crystal packings that strongly influence photophysical properties. All phases show intense solid-state thermally activated delayed fluorescence with room temperature quantum yields of nearly 100%. Emission energies and decay times are modulated by packing effects. Phases A and B exhibit pronounced mechanochromic luminescence upon gentle grinding, while phase C is mechanically insensitive, presumably due to its bulky and flexible counter-anions. Density functional calculation/time-dependent density functional calculations suggest that crystal packing impacts the structural molecular relaxation, in agreement with mechanochromic behaviors. In aerated CH₂Cl₂, these complexes generate singlet oxygen with quantum yield of up to 30%, highlighting their potential as photosensitizers.

Schizochytrium sp., a eukaryotic microalga, biosynthesizes docosahexaenoic acid (DHA; C22:6 ω3) by DHA synthase, which is composed of three subunits (OrfA to C) possessing multiple catalytic domains. The enzyme has three dehydratase (DH) domains, DH_PKS in OrfA and tandem DH_FabA (DH1_FabA and DH2_FabA) domains in OrfC. In this study, the function of each of the DH domains was investigated by in vivo heterologous expression experiments in Escherichia coli and in vitro studies with recombinant truncated OrfA containing DH_PKS and full-length OrfC, in which one of the tandem DH_FabA domains was inactivated by site-directed mutagenesis, and acyl–acyl carrier protein (ACP) intermediates. Following heterologous expression, the DH1_FabA- or DH2_FabA-inactivated enzyme produced no DHA, revealing that both domains are essential, while the DH_PKS-inactivated enzyme showed significantly reduced DHA productivity, confirming that DH_PKS is required for full production of DHA. Moreover, in vitro experiments showed that the C4-ACP substrate was accepted by all of the DHs, but DH_PKS and DH2_FabA showed higher activities than DH1_FabA. DH1_FabA catalyzed two types of reactions: (de)hydrations of C10-, C16-, and C22-ACP substrates and (de)hydrations/2-trans to 2-cis isomerization of C8-, C14-, and C20-ACP substrates. By contrast, DH2_FabA catalyzed (de)hydrations/2-trans to 3-cis isomerization of C6-, C12-, and C18-ACP substrates.

The Front Cover shows a porosity-controlled carbon fiber paper, constructed by electrospinning polyacrylonitrile (PAN) and poly(methyl 2-methacrylate) (PMMA) and carbonization, as a dual-functional electrode substrate for high-sulfur-loading cathodes (6.1 mg cm⁻²) and stabilized lean-lithium anodes (10 mA h cm⁻²). The fabricated lithium–sulfur full cell achieves stable 400 cycles with a low negative-to-positive capacity ratio under lean electrolyte conditions (electrolyte-to-sulfur ratio of 7 μL mg⁻¹). For more information, see the Research Article by C.-C. Wu and S.-H. Chung (DOI: 10.1002/ceur.202500070).