ABSTRACT Replacing conventional transition metals with main‐group elements for chemical bond activation and catalysis is of increasing interest, yet alkali metals remain largely underexplored in this context. Herein, we introduce a new strategy for alkali metal‐mediated catalysis based on metal–ligand cooperation (MLC) driven by dearomatization–aromatization of the ligand. Potassium pincer complexes bearing dearomatized picolyl ligands were synthesized and shown to activate a variety of molecules, including CO 2 , CS 2 , phenyl iso(thio)cyanates, ketones, and H 2 , thereby enabling the design of alkali metal catalysis. Notably, a dearomatized potassium complex efficiently catalyzed the hydrogenation of ketones and C─C multiple bonds, reactions that remain challenging in alkali metal catalysis. Density functional theory (DFT) calculations elucidated the electronic structures and bonding characteristics of the obtained complexes and provided mechanistic insight into the transformations. This work establishes a new paradigm in alkali metal chemistry and broadens the scope of MLC for bond activation and catalysis.

While the principles of Turing-type morphogenesis are central to understanding biological pattern formation, their rational application for the design of synthetic materials remains a significant challenge. To address this gap, we rationally design stationary reaction-diffusion patterns using a chemical reaction network (CRN) of small organic molecules bearing thiol groups - a functional handle ubiquitous in materials chemistry. The CRN features autocatalysis coupled with both rapid direct inhibition and a negative feedback loop. We report the formation of dot, line, and net patterns obtained with the assistance of numerical modeling by adjusting reactant feed rates and concentrations. The use of disulfide-crosslinked polyacrylamide hydrogels enables the modulation of thiol diffusion and subsequent derivatization of the immobilized thiols with dyes, enzymes, and crosslinkers to produce soft materials. This entire process, from out-of-equilibrium self-organization to a patterned soft material, conceptually resembles the biological process that gives rise to skin patterns. Overall, this work establishes a pathway for applying Turing-type self-organization to the structuring of synthetic matter.

Abstract Borylenes are among the most intriguing low-valent species in main group chemistry, yet their broader use in synthetic organic chemistry has remained limited by the lack of mild and modular methods for their generation. Here, we report a new class of borepin precursors that undergo aromatization-driven, redox-neutral borylene formation under synthetically practical conditions. This platform enables efficient interception of the resulting borylene intermediates by tethered alkenes through formal intramolecular [1 + 2] cycloaddition, providing direct access to previously unreported fused borirane frameworks. These strained borirane intermediates serve as valuable synthetic linchpins, enabling divergent olefin functionalization through C–B, C–O, and C–C bond-forming processes with notable regioselectivity. The synthetic utility of this platform is further highlighted by the selective functionalization of substrates containing multiple alkene units, guided by a native alcohol directing group, as well as by its application to the formal synthesis of natural products. To the best of our knowledge, this work represents the first application of borylene chemistry for the preparation of valuable building blocks relevant to natural product synthesis, establishing low-valent boron intermediates as practical tools for complex-molecule construction. Mechanistic studies combining DFT calculations, NMR analysis, and X-ray crystallography support a sequence involving Lewis-base coordination, borepin rearrangement, and concerted borylene extrusion driven by naphthalene formation. Overall, this work marks an important milestone in borylene chemistry by demonstrating that these low-valent boron species can be generated and harnessed as practical intermediates in synthetic organic chemistry, thereby opening the door to new reactivity patterns and broader applications in molecular construction.

β‐Ketosulfides are synthetic precursors for a variety of organic compounds, and can also be found among natural products and medicinally active materials. Many procedures for the synthesis of β‐ketosulfides are currently available, but they are typically inherently atom‐inefficient, requiring the use of preinstalled leaving groups or additives, and leading to the generation of chemical waste. Herein, we introduce a new method for generating β‐ketosulfides through direct coupling of readily available epoxides and thiols, which is catalyzed by an acridine‐based PNP‐type Ru(II)–pincer complex and liberates H 2 gas as a byproduct. The catalyst was found to promote both epoxide thiolysis to give a β‐hydroxysulfide intermediate, and its subsequent dehydrogenation into the β‐ketosulfide. The catalytic process exhibits product inhibition, leading to mixtures of β‐ketosulfides and β‐hydroxysulfides.

The process of vision begins with the absorption of light by retinal, which triggers isomerization around a double bond and, consequently, a large conformational change in the surrounding protein opsin. However, certain organisms evolved different visual systems; for example, deep-sea fishes employ chlorophyll-like antennas capable of capturing red light and sensitizing the nearby retinal molecule via an energy-transfer process. Similar to retinal, most synthetic photochromic molecules, such as azobenzenes and spiropyrans, switch by double-bond isomerization. However, this reaction typically requires shortwavelength (ultraviolet) light, which severely limits the applicability of these molecules. Here, we introduce DisEquilibration by Sensitization under Confinement (DESC) – a supramolecular approach to switch various azoarenes from the E isomer to the metastable Z isomer using visible light of desired color, including red. DESC relies on a combination of a coordination cage and a photosensitizer (PS), which act together to bind and selectively sensitize E-azoarenes. After switching to the Z isomer, the azoarene loses its affinity to—and is expelled from—the cage, which can convert additional copies of E into Z. In this way, the cage⋅PS complex acts as a light-driven supramolecular machine, converting photon energy into chemical energy in the form of out-of-equilibrium photostationary states, including ones that cannot be accessed via direct photoexcitation.

Using water as a hydrogen or oxygen source in organic synthesis has enabled various reductive and oxidative transformations, but incorporation of both hydrogen and oxygen atoms into the same molecule, representing an atom-economic and environmentally benign process, has scarcely been explored. Here we report a hydrogenative oxidation strategy using water as both a source of H2 and formal oxidant, enabling the direct synthesis of lactams from N-heteroarenes and thereby eliminating the need for additional reductants and oxidants and minimizing waste generation. The reaction can be initiated either under low H2 pressure or with a catalytic amount of H2, leading to the efficient transformation of various N-heteroarenes into lactams in excellent yield thanks to an in situ-generated, piperidine-based, ruthenium pincer complex that balances the hydrogenation and dehydrogenation processes. This study will promote the design of other hydrogenative oxidation reactions using water. Water has been used in organic synthesis as a hydrogen and oxygen source for reductive and oxidative transformations, respectively. Now water is used as both the source of H2 and formal oxidant in a ruthenium-catalysed hydrogenative oxidation strategy, enabling the synthesis of lactams from N-heteroarenes in a single synthetic step.

Hydrogen bonds in molecular crystals are often modeled as double-well potentials, yet direct evidence linking this potential form to vibrational spectroscopic features remains elusive. In this study, we investigate α-glycine, a hydrogen-bonded crystal that exhibits pronounced Raman anomalies without undergoing a structural phase transition. Through temperature- and polarization-dependent Raman spectroscopy, supported by isotope substitution and first-principles calculations, we identify two peaks whose behavior violates conventional Raman selection rules. These peaks merge and narrow anomalously with temperature, an effect that cannot be explained by harmonic models or thermal broadening. Simulated spectra based on a weakly evolving asymmetric double-well potential reproduce this merging, indicating that both peaks originate from one double-well potential. Our results establish α-glycine as a model system directly linking microscopic hydrogen-bond potentials to vibrational spectroscopic features.

Spontaneous formation of stationary chemical patterns through reaction-diffusion processes, first proposed by Alan Turing, is central to understanding biological morphogenesis. However, most existing synthetic pattern-forming systems rely on inorganic reactions with limited molecular tunability, posing challenges for exploring evolutionary and design aspects of pattern formation. Here, we developed an organic reaction-diffusion system based on a thiol-based chemical reaction network (CRN), rationally designed to generate stationary patterns. The CRN features autocatalysis coupled with both rapid direct inhibition and a negative feedback loop, employing azocarboxamides as thiol oxidants. We used disulfide-crosslinked polyacrylamide hydrogels to modulate thiol diffusion and optimized the molecular structures of reactants to finely tune their reactivity and diffusivity. Patterns formed within a 12-mm hydrogel disk supplied continuously with reactants from a well-mixed reservoir through a nanoporous membrane. The resulting dot, line, and net patterns exhibited characteristic feature sizes around 1 mm. While the membrane permeability primarily influenced the pattern type, the reactivity and diffusivity of reactants determined feature sizes. Experimental results were further validated by numerical modeling. Our findings illustrate that molecular-level design can yield complex pattern-forming CRNs from organic building blocks. By providing a tunable platform that bridges inorganic and biological systems, this study opens avenues to systematically explore the principles governing formation, evolution, and robustness of reaction-diffusion patterns.

The superior and tunable optoelectronic properties of lead halide perovskite thin films have been used to improve the device performance of solar cells, photodetectors, and light-emitting diodes. The material properties of lead halide perovskite thin films play important roles in determining the performance of optoelectronic devices. It is important to correctly understand the relationship between the material properties and device performance in order to realize optimal results.Lead halide perovskites with the general formula APbX3 [A=CH3NH3+, CH(NH2)2+ or Cs+; X =I-, Br-, or Cl-], have gained much attention as photovoltaic materials because of their high power conversion efficiency (PCE) of over 22%. We focused on the family of the lead bromide perovskites, and specifically on formamidinium lead Bromide crystals.Our study combines a high resolution single-crystal X- ray diffraction with THz-range Raman-scattering and first-principles calculations to probe the inorganic sub-lattice dynamics evolution with temperature in the range of 100 - 300 K. The study shows that formamidinium lead bromide is unique, because of its inorganic sub-lattice exhibits intrinsic local static disorder, that co-exists with a well-defined average crystal structure.

Although HCN has been explored extensively as a precursor in the prebiotic synthesis of biological molecules, macroscopic system-level phenomena, originating from reactions of HCN, such as autocatalysis, oscillations, pattern formation, and phase separation have attracted less attention. Autocatalysis and phase separation are particularly interesting in the context of the origin of life because they are sources of self-replication and compartmentalization. In this work, we investigate the reaction between HCN and cysteamine in water, which exhibits both sigmoidal reaction kinetics and the formation of a distinct liquid phase. We studied the origin of the sigmoidal kinetics using NMR spectroscopy and other techniques, investigated the chemical composition of the products using single-crystal X-ray diffraction and mass spectrometry, and probed the absorption of inert additives into the second liquid phase. Our studies show that the sigmoidal kinetics arise from an autocatalytic feedback loop driven by both an increase in pH and the catalytic nature of the newly formed phase itself. Product analysis revealed co-oligomers with a backbone derived from HCN and branches from cysteamine. This composition suggests that co-oligomerization with thiols provides a route to tractable oligomers, mitigating the formation of insoluble HCN polymers. Furthermore, this second liquid phase effectively sequesters hydrophobic molecules like benzene, demonstrating its capacity to act as a primitive compartment. The phenomena that we observed may provide some insight into prebiotic chemical networks and early-stage chemical evolution.

Alcohol coupling reactions that are induced by alcohol dehydrogenation, and generate hydrogen or water as the only byproducts, have become a well-recognized way to carry out important synthetic transformations, such as esterification and alkylation, in a green and atom-economical fashion. Herein, we report a new type of alcohol-alcohol coupling reaction that involves the dehydrogenative annulation of ethylene glycol with secondary alcohols to give 1,2-cyclopentanedione derivatives in a single synthetic step. This process, which is catalyzed by a pincer complex of earth-abundant manganese, represents a new approach for constructing structurally complicated products from inexpensive, readily available alcohols.

Liquid organic hydrogen carriers (LOHCs) offer an attractive strategy for efficient hydrogen storage and release, thereby facilitating the effective use of hydrogen as a carbon-neutral energy carrier. The advancement of LOHC technology is highly dependent on the innovation of the catalysts. Herein, based on a strategy combining rigidity and flexibility in a single molecular catalyst, a novel class of PNP-pincer ligands, called long-short-arm acridine ligands, and their Ru complexes have been developed and successfully used in the LOHC system based on ethylene glycol (EG). In comparison to previously reported catalytic systems, which suffered from low conversions or insufficient H2 release due to the dual challenge of catalyst stability and catalytic activity in the acceptorless dehydrogenative coupling of EG, this new catalytic system overcomes these challenges and achieves high conversion (up to >99%) with high H2 yield (up to 96%), achieving a hydrogen storage capacity of 6.2 wt %. Mechanistic and computational studies reveal that the special coordination mode, one 5-membered metallacycle and one 6-membered metallacycle, is essential for the high reactivity and late-stage dehydrogenative coupling. Moreover, both dehydrogenation and hydrogenation can be achieved under solvent- and additive-free conditions, highlighting the robustness and application potential of this new catalytic system. This advances the promising liquid-to-liquid paired LOHC systems based on inexpensive, widely accessible, and biobased EG toward practical application.

We introduce a novel class of boranobornadiene derivatives, termed boranoanthracene, along with an in-depth study of their structures and reactivities. Using these versatile precursors, we propose a fundamentally novel mechanism for generating free oxoborane species. This pathway enables the formation of aminoxoborane species, which are rarely reported in the literature. The proposed mechanism unfolds via the coordination of an oxygen-Lewis base (dimethyl sulfoxide) to the boron center, triggering a fragmentation cascade propelled by oxidative aromatization. A detailed experimental analysis, NMR measurements, and DFT calculations provide a strong evidence supporting our findings. We explored three distinct reactivities of these species: first, the insertion of oxoborane species into B-C bonds, representing, to the best of our knowledge, the first example of this reactivity. Second, we demonstrated the [3 + 2] cycloaddition reaction of oxoboranes with nitrones, offering viable access to new boranoheterocycles. Third, we reported the first example of a [5 + 2] cycloaddition between oxoboranes and azomethine imines, leading to the formation of a seven-membered boracycle. The diverse reactivities and facile generation of aminoxoboranes highlight their immense potential as versatile tools in organic chemistry.

A new catalytic protocol is reported for the selective synthesis of glutaronitrile derivatives through manganese-catalyzed heteroaddition of saturated nitriles to unsaturated ones under mild and base-free conditions.

The rapid fluctuations of metal ion levels in biological systems are faster than the time needed to map fluorinated sensors designed for the 19F-MRI of cations. An attractive modular solution might come from the activity-based sensing approach. Here, we propose a highly reactive but still ultimately specific synthetic fluorinated sensor for 19F-MRI mapping of labile Zn2+. The sensor comprises a dipicolylamine scaffold for Zn2+ recognition conjugated to a fluorophenyl acetate entity. Upon binding to Zn2+, the synthetic sensor is readily hydrolyzed, and the frequency of its 19F-functional group in 19F-NMR is shifted by 12 ppm, allowing the display of the Zn2+ distribution as an artificial MRI-colored map highlighting its specificity compared to other metal ions. The irreversible Zn2+-induced hydrolysis results in a "turn-on" 19F-MRI, potentially detecting the cation even upon a transient elevation of its levels. We envision that additional metal-ion sensors can be developed based on the principles demonstrated in this work, expanding the molecular toolbox currently used for 19F-MRI.

Calixpyrenes, calix[4]arenes incorporating one or two pyrene moieties as a part of their hydrophobic cavities, have been prepared and fully characterized. Distally di-O-propoxy diether of the calix dipyrene, which exists in the pinched cone conformation with nearly parallel pyrene moieties, demonstrates strongly enhanced binding of an organic cation (N-methylpyridinium) compared with the analogous diethers of the parent calix[4]arene.

Acridine-based PNP-type pincer ligands (AcrPNP) have previously been used for the construction of a small number of Ru(II), Mn(I), Rh(III) and Ir(III) complexes, with most attention being given to the catalytically-active ruthenium complexes. In the present work, we significantly expand the scope of known AcrPNP complexes by introducing a series of new Ir(I) and Ir(III) complexes. These were synthesized from two AcrPNP ligands differing in their P-substituents (iPr vs Ph), in conjunction with various Ir(I)-olefin precursors, through different sequences of reactions that include intramolecular CH activations and additions of H2 and NaBEt3H. The new iridium complexes, with their observed structures and reactivities, reflect the unique properties of the acridine-based PNP ligands, i.e., their inherent structural flexibility and ability to support both metal-centered reactivity (CH and HH oxidative addition) and ligand-centered reactivity (hydride- and H2-induced dearomatization).

Polyoxymethylene (POM) is a commonly used engineering thermoplastic, but its recycling by conventional means, i.e., mechanical recycling, is not practiced to any meaningful extent, due to technical limitations. Instead, waste POM is typically incinerated or disposed in landfills, where it becomes a persistent environmental pollutant. An attractive alternative to mechanical recycling is upcycling, namely, the conversion of waste POM into value-added chemicals, but this has received very little attention. Herein, we report the upcycling of POM into useful chemicals through three different reactions, all of which are efficiently catalyzed by a single pincer complex of earth-abundant manganese. One method involves hydrogenation of POM into methanol using H2 gas as the only reagent, whereas another method converts POM into methanol and CO2 through a one-pot process comprising acidolysis followed by Mn-catalyzed disproportionation. The third method utilizes POM as a reagent for the methylation of ketones and amines.

Bond activation and catalysis using s-block metals are of great significance. Herein, a series of calcium pincer complexes with deprotonated side arms have been prepared using pyridine-based PNP and PNN ligands. The complexes were characterized by NMR and X-ray crystal diffraction. Utilizing the obtained calcium complexes, unprecedented N2O activation by metal-ligand cooperation (MLC) involving dearomatization-aromatization of the pyridine ligand was achieved, generating aromatized calcium diazotate complexes as products. Additionally, the dearomatized calcium complexes were able to activate the N-H bond as well as reversibly activate H2, offering an opportunity for the catalytic hydrogenation of various unsaturated molecules. DFT calculations were applied to analyze the electronic structures of the synthesized complexes and explore possible reaction mechanisms. This study is an important complement to the area of MLC and main-group metal chemistry.

Dioxobimanes, colloquially known as bimanes, are a well-established family of N-heterobicyclic compounds that share a characteristic core structure, 1,5-diazabicyclo[3.3.0]octadienedione, bearing two endocyclic carbonyl groups. By sequentially thionating these carbonyls in the syn and anti isomers of the known (Me,Me)dioxobimane, we were able to synthesize a series of thioxobimanes, representing the first heavy-chalcogenide bimane variants. These new compounds were extensively characterized spectroscopically and crystallographically, and their aromaticity was probed computationally. Their potential role as ligands for transition metals was demonstrated by synthesizing a representative gold(I)-thioxobimane complex.