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The shift from fossil-based to biobased feedstocks is paramount for sustainable chemical production. This work presents an efficient, catalyst-free method for synthesizing a diol-rich polyol from epoxidized castor oil. Unlike conventional acid-catalyzed methods, the presented approach minimizes undesirable side reactions, yielding a polyol with a high hydroxyl number of 6.5 per triglyceride (370 mg KOH/g) and a low oligomer content. By performing the reaction at 130°C in an overheated water–dioxane mixture, we achieved full epoxide conversion in 24 h, making the process competitive with acid-catalyzed systems. This resulting polyol, characterized by a high content of adjacent diols, was utilized to prepare novel, recyclable polyboronates with 1,4-phenylenediboronic acid. Based on NMR analysis, the stoichiometry of the reaction between the synthesized polyol and phenylboronic acid was determined. Additionally, a regioselective preference for the formation of six-membered cyclic esters with 9,10,12-trihydroxyoctadecanoates, which constitute the main fraction in the synthesized polyol, was revealed. The polymers exhibit properties of low-cross-linking-density elastomers. The dynamic covalent nature of the boronate linkages was confirmed through DMTA and stress relaxation experiments. This research establishes hydroxylated castor oil as a robust and sustainable building block for polymer materials.

Naturally occurring chromanols, such as α-tocopherol (vitamin E), exhibit diverse biological activities. Their structural complexity, arising from the conformationally labile dihydropyran ring, has prompted extensive research into their conformational behavior. α-Tocopherol O-glycosides are promising vitamin E prodrug candidates, driving research on their synthesis and molecular dynamics (MD). In this work, four chromanyl glucosides were studied. Using crystallography, dynamic nuclear magnetic resonance (DNMR), solid-state NMR (ssNMR), and computational modeling (MD simulations, CASTEP), the conformational effects induced by sugar residues at the C6 position of a vitamin E model compound (2,2,5,7,8-pentamethylchroman-6-ol) in α- and β-orientations were investigated. Despite structural similarities, significant solid-state differences were observed, particularly between the anomers of peracetylated derivative 4, where the α-anomer displayed molecular disorder absent in the β-isomer - suggesting the presence of multiple conformational states in the crystal lattice. Density functional theory calculations confirmed insignificant energy differences (<0.5 kcal/mol) among the four optimized structures of chromanyl 2,3,4,6-tetra-O-acetyl-α-D-glucopyranoside (4α), implying that the coexisting configurations are stabilized by entropy. Gauge-including projector-augmented wave NMR calculations enabled precise ssNMR peak assignments, while MD simulations indicated static crystalline disorder in 4α. This integrated approach provided a detailed structural insight into chromanyl glucosides, advancing understanding of their conformational behavior.

Covalent organic frameworks (COFs), characterized by their tunable porosity and abundance of functional moieties, offer an exceptional scaffold for the uniform dispersion and stable immobilization of metal species. Herein, we report the efficient immobilization of highly dispersed Fe(III) ions into a porphyrin-functionalized COF (AP-COF), synthesized via Schiff-base condensation between 4,4′-(ethyne-1,2-diyl)dibenzaldehyde and 5,10,15,20-tetrakis(4-aminophenyl)-21H, 23H-porphyrin. The resulting Fe@AP-COF was characterized by various techniques. High-resolution transmission electron microscopy and dark field imaging confirmed the homogeneous distribution of Fe(III) ions within the COF matrix. The Fe@AP-COF demonstrated excellent thermal robustness and high surface area, which facilitated the effective anchoring of active iron centers. This catalyst exhibited remarkable performance in promoting the one-pot synthesis of dihydropyrimidinones (DHPMs) via Biginelli multicomponent reaction under optimum conditions. Furthermore, the Fe@AP-COF showed outstanding structural integrity, minimal Fe leaching, and excellent recyclability over multiple catalytic cycles. Comparative analysis revealed its superior catalytic activity to both homogeneous and conventional heterogeneous Fe-based catalysts. These insights highlight the valuable prospects of metal-functionalized porphyrin-based COFs as adaptable and efficient platforms for advanced catalytic applications.

Memory is the backbone of modern computing systems, enabling efficient data storage and functionality. Among emerging nonvolatile memories, resistive random-access memory (RRAM) has garnered significant attention due to its fast switching speed, high scalability, low power consumption, and CMOS compatibility, which makes it suitable for neuromorphic architectures. RRAM operation relies on the history-dependent modulation of resistance in a dielectric layer in response to external stimuli. Recent developments have focused on the wide array of memory-active materials, particularly inorganic and organic compounds, each offering distinct operational modes, tunable switching characteristics, and pathways toward multilevel, low-power, and neuromorphic memory devices. This review summarizes the latest advances in oxide-based RRAM devices, a foundational platform that has driven critical breakthroughs from the initial memristor concept to modern filamentary switching mechanisms. It compares these developments with conventional memory technologies and discusses current challenges and future prospects. Furthermore, we highlight its emerging role in neuromorphic computing, underscoring its potential to revolutionize brain-inspired hardware.

A potential impact of archival storage materials that seems to be of increased concern is the volatile organic compounds (VOCs) emitted from such materials. In this study, VOC emissions from cardboard and polypropylene were analyzed using thermal desorption gas chromatography–mass spectrometry (GC–MS) and ion chromatography (IC), with particular attention given to acetic and formic acids, and their impact was evaluated using Oddy tests. While the latter revealed that some nonarchival grade packaging materials could represent a risk to both metal and paper, which can be explained by VOC emissions measured using GC–MS, acid emissions measured at room temperature provided a different picture. Equilibrium acid concentration was modeled in archival boxes, which turned out to be insignificant in comparison with the current standards for archival air quality. This suggests that even nonarchival quality boxes do not significantly contribute to the degradation of paper, which emits its own VOCs, including organic acids. With suitable air exchange rates, the concern about box materials significantly contributing to VOC-induced degradation of paper stored within is thus not justified. Additionally, Oddy tests and other emission tests at elevated temperatures need to be re-evaluated in relation to their value to preventive conservation of organic materials.

The rise of antifungal resistance threatens public health and agriculture. Iturin A, a cyclic lipopeptide produced by Bacillus species, is known for its antifungal activity against various pathogens. In this study, three novel trifluoromethylated analogues of iturin A were synthesised as potential ¹⁹F NMR probes and to compare their bioactivity with the natural compound. Trifluoromethylation targeted the D-tyrosine and iturinic acid residues, which are critical for antifungal activity. Fluorinated building blocks were prepared via oxidative radical trifluoromethylation for D-tyrosine and, notably, via electrophilic trifluoromethylation combined with a chiral auxiliary-based approach for the iturinic acid, marking the first synthesis of a terminally trifluoromethylated long-chain β-amino fatty acid. Peptide assembly was achieved through solid-phase synthesis followed by on-resin cyclisation, alongside a high-yielding late-stage aromatic trifluoromethylation method. Bioactivity assays revealed that the mono-trifluoromethylated tyrosine analogue exhibited slight activity loss against Candida albicans and greater loss against Fusarium graminearum. The bis-trifluoromethylated tyrosine analogue lost activity against both fungi, while the alkyl-trifluoromethylated analogue retained full activity against C. albicans and showed a minor activity loss against F. graminearum. These analogues provide insights into site-specific trifluoromethylation effects, can serve as valuable ¹⁹F NMR probes, and can be a platform for further iturin A analogue development.

Cyanines are versatile polymethine dyes used in imaging, sensing, and photonics. Functionalizing their polymethine chain is a powerful yet underexplored way to modulate their properties. This review covers recent advances in chain-substituted cyanines, from synthesis to applications, highlighting how substituents on their polymethine chain affect their spectroscopic properties. More information can be found in the Review by Peter Šebej, Rebecca Strada, and David Dunlop (DOI: 10.1002/cplu.202500279).

Native mass spectrometry (MS) of ribonucleic acids (RNA) is a developing technique for the study of RNA structure and interactions that can provide important information on binding stoichiometry and binding motifs. However, the stabilities of key structural elements of RNA, including G-quadruplex structures, during and after desolvation are not well understood. Efforts to improve our understanding of RNA structures in the gas phase are complicated by the fact that the most common technique for transferring RNA from solution to the gas phase, electrospray ionization (ESI), typically produces ions with a relatively wide distribution of net charges. Here, we have studied two tetramolecular RNA G-quadruplexes with very different stabilities in solution by native MS. For both K⁺ and ⁺NH₄ as central cations, we found that the ratio of quadruplex to monomer ions in the ESI spectra was higher for the RNA G-quadruplex that exhibited higher stability in solution, regardless of ion net charge. These data for native MS of RNA in negative ion mode contrast with data from native MS of proteins in positive ion mode, for which lower and higher net charge is often associated with folded and unfolded structures, respectively. We next probed the stabilities of the gaseous RNA G-quadruplex ions using collisionally activated dissociation (CAD). For quadruplex ions with K⁺ as central cations, we observed a steady decrease in stability with increasing net charge, consistent with Coulombic repulsion weakening the hydrogen bonding networks and the interactions between the central cations and the nucleobases forming the central channel of the quadruplex. Importantly, for quadruplex ions with the same net charge and for both K⁺ and ⁺NH₄ as central cations, the RNA G-quadruplex that exhibited higher stability in solution also demonstrated higher stability in the gas phase. Furthermore, we demonstrate that for quadruplexes with lower net charge and K+ as central cations, covalent bond cleavage occurs at lower energies available for dissociation than strand separation.

Singlet oxygen (¹O₂), a nonradical reactive oxygen species, has shown great potential for driving redox reactions. Electron paramagnetic resonance (EPR) spectroscopy has become a widely utilized tool for identifying the adducts formed by ¹O₂ with sterically hindered amines and indirectly determining the concentrations of ¹O₂. However, the characteristic 1:1:1 triplet EPR signal of ¹O₂ adduct can arise from other molecules and impurities. In this work, we demonstrate the presence of N-oxyl impurities in commercial 2,2,6,6-tetramethylpiperidine (TEMP) derivatives can lead to overestimation of ¹O₂ in redox systems. Additionally, the relatively low water solubility of TEMP may cause underestimation of ¹O₂ in aqueous media, while more soluble 4-substituted derivatives (4-amino, 4-oxo, and 4-hydroxy TEMP) undergo untargeted oxidation, forming products besides their corresponding N-oxyl derivatives. This study proposes vacuum distillation of TEMP to minimize paramagnetic impurities and recommend the combined use of EPR and mass spectrometry (MS) for accurate identification of N-oxyl adducts, particularly for 4-substituted TEMP in aqueous media. Our findings on the solubility and oxidation behavior of TEMP derivatives provide an improved and robust detection and quantification strategy of singlet oxygen (¹O₂) in aqueous environment.

The DNA-binding properties of four Ru^II–hydrazine complexes [{RuCl(η⁶-p-cymene)}₂(μ-Cl)(μ-L¹-κ²N,N′)]Cl (1, L¹: 3,4-dimethylphenylhydrazine) and [RuCl₂(η⁶-p-cymene)(L¹⁻³-κN)] complexes (2, L¹; 3, L3: 3-chlorophenylhydrazine; 4, L³: 3-nitrophenylhydrazine) were explored through a combination of fluorescence spectroscopy, molecular docking, and Our own N-layered Integrated molecular Orbital and Molecular Mechanic (ONIOM)-based quantum mechanics/molecular mechanics (QM/MM) simulations. Ethidium bromide (EtBr) displacement assays revealed that all compounds interact with DNA, with calculated quenching constants (K_SV) ranging from 2.44 to 4.79 × 10⁴M. The results led to the conclusion that all complexes interact with DNA with similar strength, although subtle differences were explained by the present structural groups and molecular electrostatic potential (MEP) maps. The presence of nitro and chloro substituents was important for the weak interactions with DNA, leading to partial removal of EtBr. Computational studies supported the experimental findings. Molecular docking confirmed minor groove binding for all four complexes, with favorable interaction geometries and binding energies. Complex 3 stood out, with the most negative docking score (ΔG_bind = –38.2 kJ mol⁻¹). The docking simulations with RNA, triplex DNA/RNA, and quadruplex DNA/RNA additionally proved that the size of the complex and the presence of substituents were determinants of selectivity. Further refinement using ONIOM-based QM/MM calculations yielded interaction energies with DNA that matched previous results, identifying compound 3 as the most stable DNA-binding species (ΔE = –532.7 kJ mol⁻¹). The correlation between spectroscopic and theoretical results highlights the role of Ru^II-hydrazine ligand structure in modulating DNA affinity. Complex 3, bearing electron-donating hydrazine functionality and favorable spatial orientation, emerged as a promising candidate for further development in DNA-targeted therapies.