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Hydrogen bonding is prevalent in biological systems, dictating a myriad of life-sustaining functions in aqueous environments. Leveraging hydrogen bonding for molecular recognition in water encounters significant challenges in synthetic receptors on account of the hydration of their functional groups. Herein, we introduce a water-soluble hydrogen bonding cage, synthesized via a dynamic approach, exhibiting remarkable affinities and selectivities for strongly hydrated anions, including sulfate and oxalate, in water. We illustrate the use of charge-assisted hydrogen bonding in amide-type synthetic receptors, offering a general molecular design principle that applies to a wide range of amide receptors for molecular recognition in water. This strategy not only revalidates the functions of hydrogen bonding but also facilitates the effective recognition of hydrophilic anions in water. We further demonstrate an unconventional catalytic mechanism through the encapsulation of the anionic oxalate substrate by the cationic cage, which effectively inverts the charges associated with the substrate and overcomes electrostatic repulsions to facilitate its oxidation by the anionic MnO4–. Technical applications using this receptor are envisioned across various technical applications, including anion sensing, separation, catalysis, medical interventions, and molecular nanotechnology. 

The complex distribution of functional groups in carbohydrates, coupled with their strong solvation in water, makes them challenging targets for synthetic receptors. Despite extensive research into various molecular frameworks, most synthetic carbohydrate receptors have exhibited low affinities, and their interactions with sugars in aqueous environments remain poorly understood. In this work, we present a simple pyridinium-based hydrogen-bonding receptor derived from a subtle structural modification of a well-known tetralactam macrocycle. This small structural change resulted in a dramatic enhancement of glucose binding affinity, increasing from 56 M−1 to 3001 M−1. Remarkably, the performance of our synthetic lectin surpasses that of the natural lectin, concanavalin A, by over fivefold. X-ray crystallography of the macrocycle–glucose complex reveals a distinctive hydrogen bonding pattern, which allows for a larger surface overlap between the receptor and glucose, contributing to the enhanced affinity. Furthermore, this receptor possesses allosteric binding sites, which involve chloride binding and trigger receptor aggregation. This unique allosteric process reveals the critical role of structural flexibility in this hydrogen-bonding receptor for the effective recognition of sugars. We also demonstrate the potential of this synthetic lectin as a highly sensitive glucose sensor in aqueous solutions. 

By employing well-defined isoguanosine self-assembled pentamer formation and post-assembly modification, covalently tethered isoG-star through olefin metathesis was prepared as a recyclable receptor for selective cesium separation. 

Abstract Achieving selective molecular recognition of hydrophilic anions in water remains a formidable challenge due to the competitive nature of water and the high hydration energies of target anions such as sulfate. Here, we report the design, synthesis, and characterization of a simple dicationic tetralactam macrocycle (BPTL²⁺·2Cl⁻) capable of binding highly hydrated anions in water via charge‐assisted hydrogen bonding. Structural, spectroscopic, thermodynamic, and computational studies reveal that BPTL²⁺ exhibits a strong binding affinity for sulfate (K_a = 2892 M⁻¹), driven primarily by entropic gain from water release and reinforced by electrostatic and hydrogen bonding interactions. Single‐crystal X‐ray diffraction and DFT‐optimized structures confirm the formation of directional [N─H•••O] and [C─H•••O] hydrogen bonds. Comparative studies with a control macrocycle (6Na⁺•HCTL⁶⁻) that has a charge‐neutral binding cavity underscore the essential role of cationic charge in overcoming desolvation enthalpic penalties. The receptor displays anti‐Hofmeister selectivity, preferentially binding more hydrophilic anions. This work provides fundamental insights into the mechanisms of anion recognition in water. It establishes charge‐assisted hydrogen bonding as a powerful strategy for developing next‐generation receptors for sensing, separation, sequestration, transport, and catalysis in aqueous environments. 

The styryl dehydro-Diels–Alder reaction with a conjugated diyne is reported. While typical alkyne–styrene condensation requires elevated temperatures (>160 °C), the application of a conjugated diyne allowed for effective transformation under milder conditions (80 °C). The thermally stable triazole–gold (TA–Au) catalyst further improved the reaction yields (up to 95%), producing the desired alkynyl–naphthalene in a single step with molecular oxygen as the oxidant. Sequential alkyne activation resulted in various polyaromatic hydrocarbons (PAHs) in excellent yields, highlighting the efficiency of this new strategy for the preparation of PAHs with good functional group tolerance and structural diversity. 

A new class of stable four-coordinated benzotriazole-borane compounds was developed via gold-catalyzed alkyne hydroboration. The application of polymeric (BH 2 CN) n reagent gave the formation of cyano-amine-boranes (CAB) complexes with less basic N-heterocyclic amines and anilines. Various new CABs were investigated in catalytic hydroboration to synthesize N–B cycles. The 1,2,3-benzotriazoles were identified as the only feasible N-source, giving the four coordinated borane N–B cycles (BTAB) in excellent yields (up to 90%) with good functional group tolerability. This new class of polycyclic N–B compounds showed excellent stability toward acid, base, high temperature, and photo-irradiation. The facile synthesis, excellent stability, strong and tunable fluorescence emission make BTAB interesting new fluorescent probes for future chemical and biological applications. 

Abstract The one‐step synthesis of tetra‐substituted benzenes was accomplished via gold‐catalyzed diyne‐ene annulation. Distinguished from prior modification methods, this novel strategy undergoes formal [3+3] cyclization, producing polysubstituted benzenes with exceptional efficiency. The critical factor enabling this transformation was the introduction of amides, which were reported for the first time in gold catalysis as covalent nucleophilic co‐catalysts. This interesting protocol not only offers a new strategy to achieve functional benzenes with high efficiency, but also enlightens potential new reaction pathways within gold‐catalyzed alkyne activation processes.