We report a ligand-free, cerium-catalyzed decarboxylative fluorination of carboxylic acids via photoinduced ligand-to-metal charge transfer (LMCT) catalysis. This method utilizes readily available carboxylic acids as radical precursors, enabling the selective formation of alkyl fluorides under mild conditions. The protocol tolerates diverse carboxylic acids with a high functional group tolerance. Mechanistic studies confirm that the reaction proceeds via alkyl radical generation through light-induced LMCT of cerium-(IV) carboxylate followed by fluorine transfer. This efficient and cost-effective strategy provides a sustainable route to fluorinated molecules relevant to pharmaceuticals and agrochemicals.

The naturally low abundance of cysteine in proteins, combined with its propensity to undergo thiol-ene reactions, makes it a preferred amino acid for various bioconjugations. However, most of these methods rely on the use of UV radiation, radical initiators, or heavy-metal-based photocatalysts, which limits their applicability in complex biological environments. Herein, we report a photocatalyzed thiol-ene radical reaction that overcomes these limitations by employing a porphyrin-based photocatalyst and low-energy red light. This method operates under mild reaction conditions and can be expanded to a cysteinyl desulfurization reaction. As this approach proceeds in aqueous media and facilitates selective transformations of both simple free cysteine and cysteine residues within complex protein, it significantly expands the existing toolbox for cysteine bioconjugation.

The present study employs DFT calculations and the independent gradient model (IGM) approach to investigate a mechanism study of the hydroboration reaction of internal alkynes catalyzed by Ag-(I)-IMes and Cu-(I)-IMes complexes. A detailed analysis of the mechanism's steps revealed that Cu-(I)-IMes exhibits superior efficiency, showing a more favorable energy pathway than Ag-(I)-IMes. The IGM method was crucial for quantifying molecular interactions, highlighting essential differences in binding forces between catalysts and substrates throughout the catalytic steps. For Cu-(I)-IMes, the migratory insertion step (TS1) demonstrated a barrier 2.5 times lower than its Ag-(I)-IMes counterpart. Additionally, the protonation step (TS2) exhibited lower energy for Cu-(I)-IMes compared to Ag-(I)-IMes, indicating a more efficient formation of the desired β-product. The results also suggest that Cu-(I)-IMes operates on a more efficient pathway, with lower energy for the catalytic cycle. These findings, coupled with detailed analyses of molecular interactions using the IGM method, provide an enhanced understanding of the reaction mechanism, highlighting the promising efficacy of Cu-(I)-IMes as a catalyst in hydroboration reactions.

Solvent effects play a critical role in ionic chemical reactions and have been a research topic for a long time. The solvent molecules in the first solvation shell of the solute are the most important solvating species. Consequently, manipulation of the structure of this shell can be used to control the reactivity and selectivity of ionic reactions. In this work, we report extensive experimental and insightful computational studies of the effects of adding diverse fluorinated bulky alcohols with different solvation abilities to the fluorination reaction of alkyl bromides with potassium fluoride promoted by 18-crown-6. We found that adding a stoichiometric amount of these alcohols to the acetonitrile solution has an important effect on the kinetics and selectivity. The most effective alcohol was 2-trifluoromethyl-2-propanol (TBOH-F3), and the use of 3 equiv of this alcohol to fluorinate a primary alkyl bromide led to a 78% fluorination yield in just 6 h of reaction time at a mild temperature of 82 °C, with 8% of E2 yield. The more challenging secondary alkyl bromide substrate obtained 44% fluorination yield and 56% E2 yield at 18 h of reaction time. More fluorinated alcohols with six or more fluorine atoms have resulted in relatively acidic alcohols, leading to large amounts of the corresponding ethers of these alcohols as side products. The widely used hexafluoroisopropanol (HFIP) was the least effective one for monofluorination, indicating that both acidity and bulkiness are important features of the alcohols for promoting fluorination using KF salt. Nevertheless, the ether of HFIP can be easily formed with the substrate, generating a highly fluorinated ether product. Theoretical calculations predict ΔG ‡ in close agreement with the experiments and explain the higher selectivity induced by the fluorinated bulky alcohols in relation to the use of crown ether alone.

Altermagnetism was very recently identified as a new type of magnetic phase beyond the conventional dichotomy of ferromagnetism (FM) and antiferromagnetism (AFM). Its globally compensated magnetization and directional spin polarization promise new properties such as spin-polarized conductivity, spin-transfer torque, anomalous Hall effect, tunneling, and giant magnetoresistance that are highly useful for the next-generation memory devices, magnetic detectors, and energy conversion. Though this area has been historically led by the thin-film community, the identification of altermagnetism ultimately relies on precise magnetic structure determination, which can be most efficiently done in bulk materials. Our review, written from a materials chemistry perspective, intends to encourage materials and solid-state chemists to make contributions to this emerging topic through new materials discovery by leveraging neutron diffraction to determine the magnetic structures as well as bulk crystal growth for exploring exotic properties. We first review the symmetric classification for the identification of altermagnets with a summary of chemical principles and design rules, followed by a discussion of the unique physical properties in relation to crystal and magnetic structural symmetry. Several major families of compounds in which altermagnets have been identified are then reviewed. We conclude by giving an outlook for future directions.

An efficient electrocatalytic cycloaddition approach for the construction of a lactone- or lactam-fused quinoline framework is documented. Diverse arrays of functionalities are well-compatible under this metal-free, mild, and scalable electro-redox protocol. Mechanistic studies indicate an iodide-mediated electro-oxidation of secondary amines to their corresponding imines and consequent [4 + 2] cycloaddition, fabricating C-C bonds followed by rapid aromatization leading to the six-membered core structure.

In recent years, mechanochemistry has become an innovative and sustainable alternative to traditional solvent-based synthesis. Mechanochemistry rapidly expanded across a wide range of chemistry fields, including diverse organic compounds and active pharmaceutical ingredients, coordination compounds, organometallic complexes, main group frameworks, and technologically relevant materials. This Review aims to highlight recent advancements and accomplishments in mechanochemistry, underscoring its potential as a viable and eco-friendly alternative to conventional solution-based methods in the field of synthetic chemistry.

Bipyridines and azaarenes are an important class of ligands that impart unique and tunable properties to transition metal complexes and catalysts. While some derivatives are commercially available, noncommercial analogues are often challenging to prepare and purify. Herein, we report a general nucleophilic aromatic substitution reaction that converts cationic trimethylaminated bipyridines into a series of functionalized bipyridines. Our method showcases a series of C-O, C-S, and C-F bond-forming reactions as well as a selective monodemethylation that converts the electron-deficient trimethylammonium to an electron-rich dimethylamine. The approach was further applied to diversification of pharmaceuticals and natural products and was applied to the total synthesis of Graveolinine and the preparation of Graveolinine derivatives.

Linear monoterpenes, versatile reaction biosubstrates, are bound and subsequently converted to various cyclic monomers and oligomers with excellent selectivity and efficiency, only in natural enzymes. We herein report bioinspired functions of synthetic polyaromatic cavities toward linear monoterpenes in the solution and solid states. The cavities are provided by polyaromatic coordination capsules, formed by the assembly of Pt(II) ions and bent bispyridine ligands with two anthracene panels. By using the capsule cavities, the selective binding of citronellal from mixtures with other monoterpenes and its preferential vapor binding over its derivatives are demonstrated in water and in the solid state, respectively. The capsule furthermore extracts p-menthane-3,8-diol, with high product- and stereoselectivity, from a reaction mixture obtained by the acid-catalyzed cyclization of citronellal in water. Thanks to the inner and outer polyaromatic cavities, the catalytic cyclization-dimerization of vaporized citronellal efficiently proceeds in the acid-loaded capsule solid and product/stereoselectively affords p-menthane-3,8-diol citronellal acetal (∼330% yield based on the capsule) under ambient conditions. The solid capsule reactor can be reused at least 5 times with enhanced conversion. The present study opens up a new approach toward mimicking terpene biosynthesis via synthetic polyaromatic cavities.

In order to prevent the current unsustainable waste handling of the enormous volumes of end-of-use organic polymer material sent to landfilling or incineration, extensive research efforts have been devoted toward the development of appropriate solutions for the recycling of commercial thermoset polymers. The inability of such cross-linked polymers to be remelted once cured implies that mechanical recycling processes used for thermoplastic materials do not translate to the recycling of thermoset polymers. Moreover, the structural diversity within the materials from the use of different monomers as well as the use of such polymers for the fabrication of fiber-reinforced polymer composites make recycling of these materials highly challenging. In this Perspective, depolymerization strategies for thermoset polymers are discussed with an emphasis on recent advancements within our group on recovering polymer building blocks from polyurethane (PU) and epoxy-based materials. While these two represent the largest thermoset polymer groups with respect to the production volumes, the recycling landscapes for these classes of materials are vastly different. For PU, increased collaboration between academia and industry has resulted in major advancements within solvolysis, acidolysis, aminolysis, and split-phase glycolysis for polyol recovery, where several processes are being evaluated for further scaling studies. For epoxy-based materials, the molecular skeleton has no obvious target for chemical scission. Nevertheless, we have recently demonstrated the possibility of the disassembly of the epoxy polymer in fiber-reinforced composites for bisphenol A (BPA) recovery through catalytic C-O bond cleavage. Furthermore, a base promoted cleavage developed by us and others shows tremendous potential for the recovery of BPA from epoxy polymers. Further efforts are still required for evaluating the suitability of such monomer recovery strategies for epoxy materials at an industrial scale. Nonetheless, recent advancements as illustrated with the presented chemistry suggest that the future of thermoset polymer recycling could include processes that emphasize monomer recovery in an energy efficient manner for closed-loop recycling.