Visible‐Light‐Promoted Palladium‐Catalyzed Cross‐Coupling of Iodocarboranes with Disulfides and Phenylselenyl Chloride

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Comprehensive Summary

This work describes a general method for the synthesis of a series of sulfenylated and selenylated carboranes at room temperature using readily available iodocarboranes as starting materials via boron-centered carboranyl radicals. Such hypervalent boron radicals are generated by a visible-light-promoted Pd(0)/Pd(I) pathway. They are useful intermediates and can be trapped by disulfides and phenylselenyl chloride for the convenient construction of B-S/Se bonds.

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Aptamer‐based antibiotic electrochemical detection platform using portable plastic gold electrode and multichannel chip

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Abstract

The development of accurate, rapid and practical electrochemical sensing technology for antibiotic detection has an important application prospect in many fields such as food safety, environmental monitoring, medical and health care. In this research, kanamycin specific nucleic acid aptamer and its partially complementary short chain were self-assembled onto the surface of an integrated portable plastic gold electrode (PGE) by Au-S bond, and a simple kanamycin electrochemical biosensor interface was constructed. At the same time, the epoxy resin channel layer was designed, and the auxiliary instrument was set up independently in the laboratory, which could help to measure and analyze eight groups of samples automatically in turn. The quantitative analysis results showed that in 20 minutes, the sensor had a good linear relationship between the peak current change of square wave voltammetry and the negative logarithm of kanamycin concentration when kanamycin concentration was in the range of 1-1000 μM, and the detection limit could reach 0.40 μM. In addition, the discrimination could be achieved within 5 minutes in the real-time analysis mode. The sensor had a simple construction method, good selectivity and stability, and could be used for rapid or real-time detection of kanamycin residues in actual water samples, which provided a new direction for the practical detection of kanamycin in environmental water samples.

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Interface charge distribution engineering of Pd‐CeO2/C for efficient carbohydrazide oxidation reaction

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Carbohydrazide electrooxidation reaction (COR) is a potential alternative to oxygen evolution reaction in water splitting process. However, the sluggish kinetics process impels to develop efficient catalysts with the aim of the widespread use of such catalytic system. Since COR concerns the adsorption/desorption of reactive species on catalysts, the electronic structure of electrocatalyst can affect the catalytic activity. Interface charge distribution engineering can be considered to be an efficient strategy for improving catalytic performance, which facilitates the cleavage of chemical bond. Herein, highly dispersed Pd nanoparticles on CeO2/C catalyst are prepared and the COR catalytic performance is investigated. The self-driven charge transfer between Pd and CeO2 can form the local nucleophilic and electrophilic region, promoting to the adsorption of electron-withdrawing and electron-donating group in carbohydrazide molecule, which facilitates the cleavage of C-N bond and the carbohydrazide oxidation. Due to the local charge distribution, the Pd-CeO2/C exhibits superior COR catalytic activity with a potential of 0.27 V to attain 10 mA cm-2. When this catalyst is used for energy-efficient electrolytic hydrogen production, the carbohydrazide electrolysis configuration exhibits a low cell voltage (0.6 V at 10 mA cm-2). This interface charge distribution engineering can provide a novel strategy for improving COR catalytic activity.

Fully Conjugated Covalent Organic Frameworks: Synthesis, Structures and Applications

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Fully Conjugated Covalent Organic Frameworks: Synthesis, Structures and Applications†


Comprehensive Summary

This review presents a comprehensive examination of fully conjugated covalent organic frameworks (COFs), which constitute an emerging class of porous materials with immense potential for diverse applications. This article focuses on diversified fully conjugated COFs, including sp2 carbon-carbon linkages, pyrazine linkages, benzobisoxazole linkages, dioxin linkages, β-aminoalkenone linkages, etc. The synthesis techniques and structural attributes of these COFs are expounded upon in great detail, along with their potential applications in various fields. The review thus provides a valuable resource for researchers keen on delving into the synthesis and applications of fully conjugated COFs, thereby highlighting their potential for developing novel functional materials with distinctive properties.

Rongalite as a Versatile Reagent in Organic Synthesis

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Rongalite as a Versatile Reagent in Organic Synthesis†

This review presents the comprehensive progress in the utilization of rongalite as a versatile reagent in organic synthesis in recent years.


Comprehensive Summary

This review provides a comprehensive summary of progress to date in the utilization of rongalite as a versatile reagent in organic synthesis, with a focus on recent researches. The contents have been organized according to the functions exhibited by rongalite. Reaction mechanisms are provided, demonstrating the multifaceted roles of this compound in various transformations, including as a sulfone, C1 or masked proton source and as a single electron donor or reducing agent.

Light‐Induced Domino and Multicomponent Reactions: How to Reach Molecular Complexity without a Catalyst

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Light-Induced Domino and Multicomponent Reactions: How to Reach Molecular Complexity without a Catalyst

Is it possible to build up molecular complexity without the help of a catalyst? Yes, it is! With the suitable starting-materials, a domino or multicomponent reaction can be initiated just turning on the right light.


Abstract

Achieving high molecular complexity can be not trivial, but the exploitation of domino reactions provides an atom- and step-economical method to reach this target. Over the past decades, a lot of efforts have been put on the development of photocatalytic cascades employing both metal-based and purely organic catalysts. Despite the effectiveness of these protocols, catalyst- and additive-free light-induced domino reactions are gaining momentum thank to their efficiency, operational simplicity and sustainability. The increasing number of papers published on this field in the last years is a proof of the appeal of these transformations. In this Review, we discuss domino and multicomponent reactions mediated by light with a focus on photocatalyst- and additive-free processes. The most recent advances in the synthesis of complex nitrogen-, oxygen-, sulphur- and selenium-heterocycles together with multicomponent cascades are analysed with an emphasis on both experimental and mechanistic studies.

Counter‐Anions Rendered Weak‐Interactions Perturb the Stability of Tyrosinase‐Mimicked Peroxo‐Dicopper(II) Active Site: Unraveling Computational Indicators

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Counter-Anions Rendered Weak-Interactions Perturb the Stability of Tyrosinase-Mimicked Peroxo-Dicopper(II) Active Site: Unraveling Computational Indicators

Counter-anions (PhCO2 −, CF3SO3 −, TsO−, and SbF6 −) perturb the stability of the tyrosinase's biomimetic model (PT ). In this work, we showcase that the Gibbs energies, Cu2O2 and counter-anion distances, IGMH-based δGPair values, orbitals overlap between Cu2O2 and counter-anion, Cu2O2 bending angles, and distortion-interaction energies are computational indicators to predict the stability of PT in presence of counter anions.


Abstract

It has been observed in literature that the stability of tyrosinase-mimicked μ-η2:η2-peroxo-dicopper(II) (P) can be perturbed in presence of counter-anions (CAs) such as PhCO2 −, CF3SO3 −, TsO− and SbF6 −. In this work, we unravel computational indicators using density functional theory to screen and study the stability of P in experimentally-reported cases. These indicators are Gibbs energies, geometrical parameters such as distances and angles, independent gradient model based on Hirshfeld partition (IGMH) generated data, orbitals’ overlap, and distortion-interaction (DI) energies. Our DFT computed Gibbs energies indicate that P is stable in case of PhCO2 − and TsO−. CF3SO3 − allows P and its isoelectronic species bis-μ-oxo-dicopper (O) to coexist. SbF6 − shows that O is in excess. Our indicators reveal that the stability of P in case of PhCO2 − and TsO− is due to the better placing of P and its CA, thus leading to better interactions and overlap of orbitals. Other indicator displays that the plane of Cu2O2 core in P is more bend in PhCO2 − and TsO− cases as compared to the plane in the other two cases. In addition, the IGMH-based indicator displays higher values in the case of PhCO2 − and TsO− than the other CAs.

Eco‐friendly Synthesis of Silver Nanoparticles and its Application in Hydrogen Photogeneration and Nanoplasmonic Biosensing

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Eco-friendly Synthesis of Silver Nanoparticles and its Application in Hydrogen Photogeneration and Nanoplasmonic Biosensing

Silver NPs between 7.0 and 12.8 nm in size are prepared in diluted aqueous solutions containing only radish extracts or honey by microwave irradiation. The AgNPs are assembled in a nanoplasmonic biosensor chip for biomarkers detections and used as co-photocatalyst (TiO2@AgNPs) for hydrogen generation using UV or visible light.


Abstract

Environmentally friendly methods for silver nanoparticles (AgNPs) synthesis without the use of hazardous chemicals have recently drawn attention. In this work, AgNPs have been synthesized by microwave irradiation using only honey solutions or aqueous fresh pink radish extracts. The concentrations of honey, radish extract, AgNO3 and pH were varied. AgNPs presented mean sizes between 7.0 and 12.8 nm and were stable up to 120 days. The AgNPs were employed as co-catalyst (TiO2@AgNPs) to increase the hydrogen photogeneration under UV-vis and only visible light irradiation, when compared to pristine TiO2 NPs. The prepared photocatalyst also showed hydrogen generation under visible light. Additionally, AgNPs were used to assemble a nanoplasmonic biosensor for the biodetection of extremely low concentrations of streptavidin, owing to its specific binding to biotin. It is shown here that green AgNPs are versatile nanomaterials, thus being potential candidates for hydrogen photogeneration and biosensing applications.

Protocell Communication through the Eyes of Synthetic Organic Chemists

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Protocell Communication through the Eyes of Synthetic Organic Chemists

In this Concept, the bio-derived signal transduction machineries utilised for protocell communication are reviewed and categorised into enzyme cascades, DNA strand displacement, and gene-mediated systems. Future opportunities for synthetic chemists to develop new bio-inspired and fully synthetic alternatives to these bio-derived machineries in the form of synthetic enzymes or “synzymes” are highlighted.


Abstract

The bottom-up fabrication of synthetic cells (protocells) from molecules and materials, is a major challenge of modern chemistry. A significant breakthrough has been the engineering of protocells capable of chemical communication using bio-derived molecules and ex situ stabilised cell machineries. These, however, suffer from short shelf-lives, high costs, and require mild aqueous conditions. In this Concept Article we analyse the chemistry at the heart of protocell communication to highlight new opportunities for synthetic chemists in protocell engineering. Specifically, we (i) categorise the main bio-derived chemical communication machineries in enzyme cascades, DNA strand displacement, and gene-mediated communication; (ii) review the chemistries of these signal transduction machineries; and (iii) introduce new types of bio-inspired, fully synthetic artificial enzymes to replace their natural counterparts. Developing protocells that incorporate synthetic analogues of bio-derived signal transduction machineries will improve the robustness, stability, and versatility of protocells, and broaden their applications to highly strategic fields such as photocatalysis and fine chemicals production.

Multienzymatic Synthesis of γ‐Lactam Building Blocks from Unsaturated Esters and Hydroxylamine

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Multienzymatic Synthesis of γ-Lactam Building Blocks from Unsaturated Esters and Hydroxylamine

N-hydroxy-γ-lactams are produced through an enzymatic sequence combining a lipase-catalyzed hydroxylamidation with an oxidase/peroxidase-induced ene-type cyclization. This methodology provides a mild and scalable access to N-heterocyclic building blocks from basic γ,δ-unsaturated esters and aqueous hydroxylamine, and its utility is illustrated by the formal total synthesis of the tetracyclic alkaloid cephalotaxine.


Abstract

The assembly of enzymatic cascades and multi-step reaction sequences represents an attractive alternative to traditional synthetic-organic approaches. The biocatalytic reaction mediators offer not only mild conditions and permit the use of environmentally benign reagents, but the high compatibility of different enzymes promises more streamlined reaction setups. In this study, a triple-enzymatic strategy was developed that enables the direct conversion of γ,δ-unsaturated esters to N-hydroxy-γ-lactam building blocks. Hereby, a lipase-catalyzed hydroxylaminolysis generates hydroxamic acid intermediates that are subsequently aerobically activated by horseradish peroxidase and glucose oxidase to cyclize in an intramolecular nitroso ene reaction. Utilizing the hydroxylaminolysis/ene-cyclization sequence for the preparation of an aza-spirocyclic lactam, the multi-enzymatic methodology was successfully employed in the synthesis of key intermediates en route to alkaloids of the Cephalotaxus family.