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mars 2023 – ChemDigest

Mois : mars 2023

Ionic Liquid‐Mediated Approach for the Synthesis of Site‐Specific Thioether Conjugates

Par / 31 mars 2023 / Non classé
Ionic Liquid-Mediated Approach for the Synthesis of Site-Specific Thioether Conjugates

Bioconjugation methodologies have become a central part of therapeutic development. Conjugation of thiol-containing compounds is now simple with this ionic liquid-mediated reaction which is site-specific toward thiol and preserves the stereochemistry. Additionally, Cysteine-free peptides can be functionalized using the developed technique.

Abstract

Site-specific conjugation approaches are of great importance in drug discovery, notably for the synthesis of biochemical probes or molecular conjugates for targeted delivery. Herein, we report a mild ionic liquid (IL)-mediated thiolation technique that relies on the use of 1,3-ethyl-methyl imidazolium acetate, [C2mim][OAc] as a solvent and precursor to generate activated IL, as well as a solvent for the conjugation reaction. First, a focused library of active ILs was prepared for functionalizing/conjugating cysteine-containing small molecules and unprotected peptides. Interestingly, a bifunctional active IL could also be successfully employed as a linker for the conjugation of peptides lacking Cys. This study sets the ground for further investigation of the use of active ILs for modifying, labeling or conjugating larger and more complex therapeutic modalities such as proteins and antibodies.

Wiley: Chemistry – A European Journal: Table of Contents
Authors: Helal Abujubara, Jie Yang, A. Birsen Otyakmaz, Anaïs F. M. Noisier, Werngard Czechtizky, Malin Lemurell, Alesia A. Tietze
chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/chem.202203915

Bismuth Cations: Fluoride Ion Abstraction, Isocyanide Coordination, and Impact of Steric Bulk on Lewis Acidity

Par / 31 mars 2023 / Non classé
Bismuth Cations: Fluoride Ion Abstraction, Isocyanide Coordination, and Impact of Steric Bulk on Lewis Acidity

By the Bi: The bismuth cation [BiDipp2]+, stabilized by an [SbF6]− counteranion, has been synthesized, isolated and fully characterized (Dipp=2,6-iPr2-C6H3). A detailed comparison with [BiMe2(SbF6)] highlights the impact of steric bulk on bismuth-based Lewis acidity. Differences in their Lewis acidity have been rationalized, and their reactivity towards [PF6]− as well as Lewis pair formations have been studied.

Abstract

The molecular compound [BiDipp2(SbF6)], containing the bulky, donor-free bismuth cation [BiDipp2]+ has been synthesized and fully characterized (Dipp=2,6-iPr2-C6H3). Using its methyl analog [BiMe2(SbF6)] as a second reference point, the impact of steric bulk on bismuth-based Lewis acidity was investigated in a combined experimental (Gutmann-Beckett and modified Gutmann-Beckett methods) and theoretical approach (DFT calculations). Reactivity studies of the bismuth cations towards [PF6]− and neutral Lewis bases such as isocyanides C≡NR’ revealed facile fluoride ion abstraction and straightforward Lewis pair formation, respectively. The first examples of compounds featuring bismuth-bound isocyanides have been isolated and fully characterized.

Wiley: Chemistry – A European Journal: Table of Contents
Authors: Tobias Dunaj, Johannes Schwarzmann, Jacqueline Ramler, Andreas Stoy, Sascha Reith, Joel Nitzsche, Lena Völlinger, Carsten Hänisch, Crispin Lichtenberg
chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/chem.202204012

Molecular Shape, Electronic Factors, and the Ferroelectric Nematic Phase: Investigating the Impact of Structural Modifications

Par / 31 mars 2023 / Non classé
Molecular Shape, Electronic Factors, and the Ferroelectric Nematic Phase: Investigating the Impact of Structural Modifications

Molecular shape and its effects: The synthesis and characterisation of two series of low molar mass mesogens is reported comparing the effect of having a lateral alkoxy chain in the central phenyl ring versus the chain being attached to the methoxy-substituted terminal ring. Rather than the molecule being required to show a tapered shape, it is the role of the lateral chain in inhibiting anti-parallel associations that is key.

Abstract

The synthesis and characterisation of two series of low molar mass mesogens, the (4-nitrophenyl) 2-alkoxy-4-(4-methoxybenzoyl)oxybenzoates (NT3.m) and the (3-fluoro-4-nitrophenyl) 2-alkoxy-4-(4-methoxybenzoyl)oxybenzoates (NT3F.m), are reported in order to investigate the effect of changing the position of a lateral alkoxy chain from the methoxy-substituted terminal ring to the central phenyl ring in these two series of materials based on RM734. All members of the NT3.m series exhibited a conventional nematic phase, N, which preceded the ferroelectric nematic phase, NF, whereas all the members of the NT3F.m series exhibited direct NF-I transitions except for NT3F.1 which also exhibited an N phase. These materials cannot be described as wedge-shaped, yet their values of the ferroelectric nematic-nematic transition temperature, T, exceed those of the corresponding materials with the lateral alkoxy chain located on the methoxy-substituted terminal ring. In part, this may be attributed to the effect that changing the position of the lateral alkoxy chain has on the electronic properties of these materials, specifically on the electron density associated with the methoxy-substituted terminal aromatic ring. The value of TNI decreased with the addition of a fluorine atom ortho to the nitro group in NT3F.1, however, the opposite behaviour was found when the transition temperatures of the NF phase were compared which are higher for the NT3F.m series. This may reflect a change in the polarity and polarizability of the NT3F.m series compared to the NT3.m series. Therefore, it is suggested that, rather than simply promoting a tapered shape, the role of the lateral chain in inhibiting anti-parallel associations and its effect on the electronic properties of the molecules are the key factors in driving the formation of the NF phase.

Wiley: Chemistry – A European Journal: Table of Contents
Authors: Naila Tufaha, Ewan Cruickshank, Damian Pociecha, Ewa Gorecka, John M.D. Storey, Corrie T. Imrie
chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/chem.202300073

Highly Chemoselective Synthesis of Indole Derivatives

Par / 31 mars 2023 / Non classé
Highly Chemoselective Synthesis of Indole Derivatives

Chemoselective electrophilic activation of amides and enols/ketones has been achieved using either Hendrickson reagent in combination with triflic anhydride or triflic acid, which provides an efficient protocol for the divergent synthesis of polysubstituted indoles with flexible substituent patterns from α-arylamino-β-hydroxy-2-enamides, α-arylamino-β-oxo-amides or their enol-keto tautomeric mixture.

Abstract

A facile and efficient synthesis of polysubstituted indoles from α-arylamino-β-hydroxy-2-enamides, α-arylamino-β-oxo-amides, or their tautomeric mixture via electrophilic activation strategy is described. The salient feature of this methodology is the use of either combined Hendrickson reagent and triflic anhydride (Tf2O) or triflic acid (TfOH) to control the chemoselectivity in the intramolecular cyclodehydration to provide a predictable approach to these valuable indoles with flexible substituent patterns. Moreover, the mild reaction conditions, simple execution, high chemoselectivity, excellent yields, and wide range of synthetic potential of products make this protocol much attractive for academic research and practical applications.

Wiley: Chemistry – A European Journal: Table of Contents
Authors: Yu Wang, Rui Zhang, Jiacheng Li, Chitturi Bhujanga Rao, Xuebei Ye, Dewen Dong
chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/chem.202300191

Fluorescence Detection of the Persistent Organic Pollutant Chlordecone in Water at Environmental Concentrations

Par / 31 mars 2023 / Non classé
Fluorescence Detection of the Persistent Organic Pollutant Chlordecone in Water at Environmental Concentrations

Fluorescent cages allow for the detection of the persistent organic pollutant chlordecone in water at environmental concentrations. The reported method is inexpensive, easy to carry out, and of general use for generating many measurements on contaminated water samples. This provides an affordable tool to tackle the major environmental and public health issues associated with chlordecone contamination.

Abstract

Chlordecone (CLD), a Persistent Organic Pollutant, is still present in water and food chain of the French West Indies (FWI), leading to dramatical public health problems. One of the major issues is the lack of an easy, non-expensive, sensitive and robust method for the detection of chlordecone to ensure chlordecone-free water and foods for the residents of the FWI. This study reports on the development of a fluorescent molecular cage that allows a simple and convenient detection of chlordecone in water at environmental concentration. The specific structural features of chlordecone prompted the choice of hemicryptophanes as receptor. First, the size, shape of the cavity, as well as the recognition units, were optimized to identify the most efficient non fluorescent host for CLD complexation. Then, this selected compound was equipped with fluorophores at different positions in order to find the most efficient system for CLD detection by fluorescence. Among the two most promising fluorescent cages, the newly synthesized hemicryptophane with biphenyl moieties allowed the development of a fast, easy, reproducible and cheap procedure to detect CLD in water. Based on its sensitivity and scalability, with modulation of hemicryptophane, concentration, CLD concentrations were estimated over five orders of magnitude (10−2–103 μg/L) including the environmental levels of contamination and the permissible limit for drinking water in the FWI.

Wiley: Chemistry – A European Journal: Table of Contents
Authors: Oriane Della‐Negra, Aya Esther Kouassi, Jean‐Pierre Dutasta, Pierre‐Loïc Saaidi, Alexandre Martinez
chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/chem.202203887

Light‐Triggered Reversible Open‐Close Motion of a Chiral Molecular Plier to Modulate Guest Binding

Par / 31 mars 2023 / Non classé
Light-Triggered Reversible Open-Close Motion of a Chiral Molecular Plier to Modulate Guest Binding

Light triggered configuration change (azobenzene) of one end of a molecular plier induces an interlocking motion at the other end (porphyrin unit) of the plier accompanied by a pivotal motion around the BINOL axis. E to Z isomerization decreases the distance between two porphyrin units which could be used for selective binding of pyridine-appended guests. Guest complexation with the plier increases the isomerization efficiency of azobenzene and decreases the thermal back isomerization rate.

Abstract

A chiral molecular plier’s design, synthesis, characterisation and operations are presented. The molecular plier encompasses three units: a BINOL unit which acts as a pivot as well as a chiral inducer, an azobenzene unit, which acts as a photo-switchable component and two zinc porphyrin, acting as a reporter. E to Z isomerisation persuaded by irradiating with 370 nm light alters the dihedral angle of the pivot BINOL unit, which adjusts the distance between two porphyrin units. The plier can be switched to its initial state by exposure to 456 nm light or heating at 50 °C. NMR, CD and molecular modelling supported the reversible switching and change in dihedral angle and distance between reporter moiety, which was further exploited for binding with several ditopic guests. The longest guest was found to form the strongest complex, R,R-isomer formed a stronger complex than S,S-isomer, Z-isomer of the plier formed stronger complex than the E-isomer with the guest. Moreover, complexation also increased the E-to-Z switching efficiency and decreased the thermal back isomerisation of the azobenzene unit.

Wiley: Chemistry – A European Journal: Table of Contents
Authors: Diptiprava Sahoo, Muhsin Abdul Majeed, Aarti Lathwal, Soumen De
chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/chem.202300092

An Umpolung Approach to Acyclic 1,4‐Dicarbonyl Amides via Photoredox‐Generated Carbamoyl Radicals

Par / 31 mars 2023 / Non classé
An Umpolung Approach to Acyclic 1,4-Dicarbonyl Amides via Photoredox-Generated Carbamoyl Radicals

Photoredox catalysis is used to generate carbamoyl radicals from oxamate salts. Addition to a range of electron-poor olefins gives the 1,4-amido-carbonyl products in good yields. The reaction proceeds under mild conditions, and a transition metal or organic photocatalyst can be employed.

Abstract

A method for the generation and reaction of carbamoyl radicals from oxamate salts, followed by reaction with electron-poor olefins, is described. The oxamate salt acts as a reductive quencher in the photoredox catalytic cycle, allowing mild and mass-efficient formation of 1,4-dicarbonyl products; a challenging transformation in the context of functionalized amide formation. Increased understanding has been obtained by the use of ab initio calculations, in support of experimental observations. Furthermore, steps have been taken towards an environmentally-friendly protocol, by utilizing sodium as a cheap and low mass counterion, and demonstrating successful reactions using a metal-free photocatalyst and a sustainable, non-toxic solvent system.

Wiley: Chemistry – A European Journal: Table of Contents
Authors: Jason D. Williams, Stuart G. Leach, William J. Kerr
chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/chem.202300403

A Cyclodextrin Polymer as Supramolecular Matrix for Scalable Green Photooxygenation of Hydrophobic Substrates in Homogeneous Phase

Par / 31 mars 2023 / Non classé
A Cyclodextrin Polymer as Supramolecular Matrix for Scalable Green Photooxygenation of Hydrophobic Substrates in Homogeneous Phase

Aromatic endoperoxides were synthesized as O2 releasing agents in organic solvent upon irradiation of a photocatalyst in the presence of the precursors in mM concentration. Co-encapsulation of both reactants in a cyclodextrin polymer allowed to successfully perform the photocatalyzed oxygenation in homogeneous aqueous environment. Controlled release of O2 could be achieved upon thermolysis.

Abstract

In the quest for new therapies targeting hypoxia, aromatic endoperoxides have intriguing potential as oxygen releasing agents (ORAs) able to free O2 in tissues upon suitable trigger. Four aromatic substrates were synthesized and the formation of their corresponding endoperoxides was optimized in organic solvent upon selective irradiation of Methylene Blue, a low-cost photocatalyst, producing the reactive singlet oxygen species. Complexation of the hydrophobic substrates within a hydrophilic cyclodextrin (CyD) polymer allowed their photooxygenation in homogeneous aqueous environment using the same optimized protocol upon dissolution in water of the three readily accessible reagents. Notably, reaction rates were comparable in buffered D2O and organic solvent and, for the first time, the photooxygenation of highly hydrophobic substrates was achieved for millimolar solutions in non-deuterated water. Quantitative conversion of the substrates, straightforward isolation of the endoperoxides and recovery of the polymeric matrix were achieved. Cycloreversion of one ORA to the original aromatic substrate was observed upon thermolysis. These results hold great potential for the launch of CyD polymers both as reaction vessels for green, homogeneous photocatalysis and as carrier for the delivery of ORAs in tissues.

Wiley: Chemistry – A European Journal: Table of Contents
Authors: Marco Agnes, Arianna Mazza, Eszter Kalydi, Szabolcs Béni, Milo Malanga, Ilse Manet
chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/chem.202300511

A Highly Active Cobalt Catalyst for the General and Selective Hydrogenation of Aromatic Heterocycles

Par / 31 mars 2023 / Non classé
A Highly Active Cobalt Catalyst for the General and Selective Hydrogenation of Aromatic Heterocycles

A highly active cobalt catalyst for the selective hydrogenation of aromatic N-, O-, and S-heterocycles was identified. The key is a simple three component catalyst synthesis permitting to optimize the ratio between N-doped carbon for embedding and the metal species to be embedded.

Abstract

Nanostructured earth abundant metal catalysts that mediate important chemical reactions with high efficiency and selectivity are of great interest. This study introduces a synthesis protocol for nanostructured earth abundant metal catalysts. Three components, an inexpensive metal precursor, an easy to synthesize N/C precursor, and a porous support material undergo pyrolysis to give the catalyst material in a simple, single synthesis step. By applying this catalyst synthesis, a highly active cobalt catalyst for the general and selective hydrogenation of aromatic heterocycles could be generated. The reaction is important with regard to organic synthesis and hydrogen storage. The mild reaction conditions observed for quinolines permit the selective hydrogenation of numerous classes of N-, O- and S-heterocyclic compounds such as: quinoxalines, pyridines, pyrroles, indoles, isoquinoline, aciridine amine, phenanthroline, benzofuranes, and benzothiophenes.

Wiley: Chemistry – A European Journal: Table of Contents
Authors: Christof Bauer, Felix Müller, Sercan Keskin, Mirijam Zobel, Rhett Kempe
chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/chem.202300561

Nickel‐Catalyzed Sulfonylation of Aryl Bromides Enabled by Potassium Metabisulfite as a Uniquely Effective SO2 Surrogate

Par / 31 mars 2023 / Non classé
Nickel-Catalyzed Sulfonylation of Aryl Bromides Enabled by Potassium Metabisulfite as a Uniquely Effective SO2 Surrogate

A nickel-catalyzed sulfonylation of aryl bromides has been developed utilizing an inexpensive, stench-free, inorganic sulfur salt (K2S2O5) as a uniquely effective SO2 surrogate. While initial mechanistic studies identified SO2 as a catalyst poison, later use of the isolated oxidative addition complex revealed that SO2 insertion occurs via dissolved SO2 slowly released upon thermal decomposition of K2S2O5.

Abstract

The development and mechanistic investigation of a nickel-catalyzed sulfonylation of aryl bromides is disclosed. The reaction proceeds in good yields for a variety of substrates and utilizes an inexpensive, stench-free, inorganic sulfur salt (K2S2O5) as a uniquely effective SO2 surrogate. The active oxidative addition complex was synthesized, isolated, and fully characterized by a combination of NMR spectroscopy and X-ray crystallography analysis. The use of the isolated oxidative addition complex in both stoichiometric and catalytic reactions revealed that SO2 insertion occurs via dissolved SO2, likely released upon thermal decomposition of K2S2O5. Key to the success of the reaction is the role of K2S2O5 as a reservoir of SO2 that is slowly released, thus preventing catalyst poisoning.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: J. Caleb Hethcox, Heather C. Johnson, Jungchul Kim, Xiao Wang, Lili Cheng, Yang Cao, Melissa Tan, Daniel A. DiRocco, Yining Ji
onlinelibrary.wiley.com/doi/10.1002/anie.202217623

Palladium‐Catalyzed Direct Carbonylation of Bromoacetonitrile to Synthesize 2‐Cyano‐N‐acetamide and 2‐Cyanoacetate Compounds

Par / 31 mars 2023 / Non classé
Palladium-Catalyzed Direct Carbonylation of Bromoacetonitrile to Synthesize 2-Cyano-N-acetamide and 2-Cyanoacetate Compounds

A new and convenient palladium-catalyzed carbonylative procedure of bromoacetonitrile has been developed. A variety of valuable 2-cyano-N-acetamide and 2-cyanoacetate compounds were obtained in good to excellent yields under mild reaction conditions. Furthermore, this transformation can be carried out under atmospheric pressure and provides an alternative route to 7 drug compounds.

Abstract

Nitrile compounds containing ester and amide groups are important functionalized chemicals in synthetic and medicinal chemistry. In this article, an efficient and convenient palladium-catalyzed carbonylative procedure toward 2-cyano-N-acetamide and 2-cyanoacetate compounds has been developed. The reaction proceeds under mild conditions via radical intermediate which is suitable for late-stage functionalization. Gram-scale experiment was performed successfully under low catalyst loading and gave the target product in excellent yield. Additionally, this transformation can be performed under atmospheric pressure and provide alternative routes to 7 drug precursors.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Zhi‐Peng Bao, Xiao‐Feng Wu
onlinelibrary.wiley.com/doi/10.1002/anie.202301671

NIR Light‐Mediated Mitochondrial RNA Modification for Cancer RNA Interference Therapeutics

Par / 31 mars 2023 / Non classé
NIR Light-Mediated Mitochondrial RNA Modification for Cancer RNA Interference Therapeutics

Taking advantage of the well-known cyclization reaction between furan and nucleotides of nucleic acid under the ignition of 1O2, a near-infrared (NIR) light-mediated mitochondrial RNA modification (NIMiRM) strategy was herein developed for long-term NIR/PA dual-modality imaging and remarkable suppression of tumors in vivo.

Abstract

Mitochondrial RNA (mtRNA) plays a critical role in synthesis of mitochondrial proteins. Interfering mtRNA is a highly effective way to induce cell apoptosis. Herein, we report a near-infrared (NIR) light-mediated mitochondrial RNA modification approach for long-term imaging and effective suppression of tumors. A tumor-targetable NIR fluorescent probe f-CRI consisting of a cyclic RGD peptide, a NIR fluorophore IR780, and a singlet oxygen (1O2)-labile furan group for RNA modification was rationally designed and synthesized. This probe was demonstrated to dominantly accumulate in cellular mitochondria and could be covalently conjugated onto mtRNA upon 808 nm irradiation resulting in prolonged retention in tumors. More notably, this covalent modification of mtRNA by f-CRI could perturb the function of mitochondria leading to remarkable tumor suppression. We thus envision that our current approach would offer a potential approach for cancer RNA interference therapeutics.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Yali Feng, Jing Fang, Yan Zhao, Shuyue Ye, Anna Wang, Yuqi Zhang, Jinfeng Zhu, Jiachen Li, Zhengzhong Lv, Zhongsheng Zhao, Haibin Shi
onlinelibrary.wiley.com/doi/10.1002/anie.202218969

From Dinitrogen to N‐Containing Organic Compounds: Using Li2CN2 as a Synthon

Par / 31 mars 2023 / Non classé
From Dinitrogen to N-Containing Organic Compounds: Using Li2CN2 as a Synthon

A strategy for the conversion of inert N2 into various nitrogen-containing organic compounds is presented. The activated N-containing species Li2CN2 is successfully prepared in high yields from N2 gas, C and LiH. Li2CN2 can be transformed into a range of N-containing organic compounds, including cyanamides, carbodiimides, N-aryl cyanamides and 1,2,4-triazole derivatives. 15N-labeled products, including oxazolidine derivatives, have also been prepared from 15N2 gas.

Abstract

Through the synergies of a heterogeneous synthetic approach and a homogeneous synthetic methodology, N-containing organic compounds can be synthesized via activated N-containing species prepared from N2 gas and suitable carbon sources. From N2, carbon, and LiH, we have previously succeeded in the high-yield preparation of Li2CN2 as the activated N-containing species. In this work, we applied Li2CN2 as a novel synthetic synthon for constructing N-containing organic compounds. A series of reaction models, including a substitution reaction, cycloaddition reaction, and transition metal-catalyzed coupling reaction, were successfully performed using Li2CN2 under mild conditions. Various valuable cyanamides, carbodiimides, N-aryl cyanamides and 1,2,4-triazole derivatives were readily synthesized in moderate to excellent yields. With this method, the 15N-labeled products, including oxazolidine derivatives with anti-cancer activity, could also be facilely prepared from 15N2 gas.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Li‐Jun Wu, Qianru Wang, Jianping Guo, Junnian Wei, Ping Chen, Zhenfeng Xi
onlinelibrary.wiley.com/doi/10.1002/anie.202219298

Missing‐Linker‐Confined Single‐Atomic Pt Nanozymes for Enzymatic Theranostics of Tumor

Par / 31 mars 2023 / Non classé
Missing-Linker-Confined Single-Atomic Pt Nanozymes for Enzymatic Theranostics of Tumor

A self-assembled single-atomic Pt nanozyme was developed using a facile missing-linker-confined coordination strategy. The nanozyme shows superior catalase-mimicking activity for the catalytic conversion of H2O2 overproduced in tumors into localized O2 for tumor hypoxia alleviation, which leads to enhanced ROS generation from loaded photosensitizers for apoptotic cancer cell death.

Abstract

Conventional nanozymes often possess low active site density. Pursuing effective strategies for constructing highly active single-atomic nanosystems with maximum atom utilization efficiency is exceptionally attractive. Herein, we develop a facile “missing-linker-confined coordination” strategy to fabricate two self-assembled nanozymes, i.e., conventional nanozyme (NE) and single-atomic nanozyme (SAE), which respectively consist of Pt nanoparticles and single Pt atoms as active catalytic sites anchored in metal–organic frameworks (MOFs) with encapsulated photosensitizers for catalase-mimicking enhanced photodynamic therapy. Compared to a Pt nanoparticle-based conventional nanozyme, a Pt single-atomic nanozyme shows enhanced catalase-mimicking activity in generating oxygen for overcoming tumor hypoxia, thus exhibiting a more efficient reactive oxygen species generation and high tumor inhibition rate.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Dongdong Wang, Lei Zhang, Changlai Wang, Zhiyu Cheng, Wei Zheng, Pengping Xu, Qianwang Chen, Yanli Zhao
onlinelibrary.wiley.com/doi/10.1002/anie.202217995

A Hydrazine‐Nitrate Flow Battery Catalyzed by a Bimetallic RuCo Precatalyst for Wastewater Purification along with Simultaneous Generation of Ammonia and Electricity

Par / 31 mars 2023 / Non classé
A Hydrazine-Nitrate Flow Battery Catalyzed by a Bimetallic RuCo Precatalyst for Wastewater Purification along with Simultaneous Generation of Ammonia and Electricity

This work reports a new and general electrochemical redox strategy for spontaneous and simultaneous decontamination of wastewater and generation of both fuels and electricity at low cost. Using hydrazine and nitrate effluents as a demonstration, the bimetallic RuCo precatalyst can efficiently catalyze both the hydrazine oxidation and nitrate reduction reactions so as to assemble a hydrazine-nitrate flow battery with electricity and ammonia generation.

Abstract

The traditional technologies for industrial and agricultural effluent treatment are often energy-intensive. Herein, we suggest an electrochemical redox strategy for spontaneous and simultaneous decontamination of wastewater and generation of both fuels and electricity at low cost. Using hydrazine and nitrate effluents as a demonstration, we propose a hydrazine-nitrate flow battery (HNFB) that can efficiently purify the wastewater and meanwhile generate both ammonia fuel and electricity with the assistance of our developed bimetallic RuCo precatalyst. Specifically, the battery delivers a peak power density of 12 mW cm−2 and continuously operates for 20 h with an ammonia yield rate of ca. 0.38 mmol h−1 cm−2 under 100 mA cm−2. The generated electricity can further drive a hydrazine electrolyzer to produce hydrogen fuel. Our work provides an alternative pathway to purify wastewater and generate high value-added fuels at low cost.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Weijie Zhu, Xiaoyi Zhang, Fen Yao, Runping Huang, Yue Chen, Chaolong Chen, Jiawei Fei, Yunqing Chen, Zhoucheng Wang, Hanfeng Liang
onlinelibrary.wiley.com/doi/10.1002/anie.202300390

Catalytic Chemo‐ and Regioselective Radical Carbocyanation of 2‐Azadienes for the Synthesis of α‐Amino Nitriles

Par / 31 mars 2023 / Non classé
Catalytic Chemo- and Regioselective Radical Carbocyanation of 2-Azadienes for the Synthesis of α-Amino Nitriles

A mild and broadly applicable method for the construction of complex α- and β-functionalized α-amino nitrile derivatives through a novel cascade strategy is presented. Alkyl radicals are generated by the photo-mediated reductive decarboxylation of redox-active esters, captured by 2-azadienes to provide 2-azallyl radicals and cyanized by a copper catalyst.

Abstract

α-Amino nitriles are versatile structural motifs in a variety of biologically active compounds and pharmaceuticals and they serve as valuable building blocks in synthesis. The preparation of α- and β-functionalized α-amino nitriles from readily available scaffolds, however, remains challenging. Herein is reported a novel dual catalytic photoredox/copper-catalyzed chemo- and regioselective radical carbocyanation of 2-azadienes to access functionalized α-amino nitriles by using redox-active esters (RAEs) and trimethylsilyl cyanide. This cascade process employs a broad scope of RAEs and provides the corresponding α-amino nitrile building blocks in 50–95 % yields (51 examples, regioselectivity >95 : 5). The products were transformed into prized α-amino nitriles and α-amino acids. Mechanistic studies suggest a radical cascade coupling process.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Shengzu Duan, Ya Du, Lingling Wang, Xun Tian, Yujin Zi, Hongbin Zhang, Patrick J. Walsh, Xiaodong Yang
onlinelibrary.wiley.com/doi/10.1002/anie.202300605

High‐Performance and Self‐Powered X‐Ray Detectors Made of Smooth Perovskite Microcrystalline Films with 100 μm Grains

Par / 31 mars 2023 / Non classé
High-Performance and Self-Powered X-Ray Detectors Made of Smooth Perovskite Microcrystalline Films with 100 μm Grains

Dense, smooth, substrate-integrated, large-area and thickness-controlled perovskite microcrystalline films are prepared. They are used as self-powered microcrystalline X-ray detectors with an impressive sensitivity of 6.1×104 μC Gyair−1 cm−2 and a low detection limit of 1.5 nGyair s−1, leading to high-contrast X-ray imaging at an ultra-low dose rate of 67 nGyair s−1, which may further reduce the X-ray radiation risk to patients.

Abstract

Perovskite single crystals and polycrystalline films have complementary merits and deficiencies in X-ray detection and imaging. Herein, we report preparation of dense and smooth perovskite microcrystalline films with both merits of single crystals and polycrystalline films through polycrystal-induced growth and hot-pressing treatment (HPT). Utilizing polycrystalline films as seeds, multi-inch-sized microcrystalline films can be in situ grown on diverse substrates with maximum grain size reaching 100 μm, which endows the microcrystalline films with comparable carrier mobility-lifetime (μτ) product as single crystals. As a result, self-powered X-ray detectors with impressive sensitivity of 6.1×104 μC Gyair−1 cm−2 and low detection limit of 1.5 nGyair s−1 are achieved, leading to high-contrast X-ray imaging at an ultra-low dose rate of 67 nGyair s−1. Combining with the fast response speed (186 μs), this work may contribute to the development of perovskite-based low-dose X-ray imaging.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Ning Li, Yuyang Li, Shengdan Xie, Jinming Wu, Nianqiao Liu, Yuan Yu, Qinglian Lin, Yang Liu, Shuang Yang, Gang Lian, Yanjun Fang, Deren Yang, Zhaolai Chen, Xutang Tao
onlinelibrary.wiley.com/doi/10.1002/anie.202302435

Ruthenium/TiO2‐Catalyzed Hydrogenolysis of Polyethylene Terephthalate: Reaction Pathways Dominated by Coordination Environment

Par / 31 mars 2023 / Non classé
Ruthenium/TiO2-Catalyzed Hydrogenolysis of Polyethylene Terephthalate: Reaction Pathways Dominated by Coordination Environment

The coordination environment of Ru in Ru/TiO2 dictates the reaction pathway for polyethylene terephthalate hydrogenolysis. Under-coordinated Ru sites favor the formation of arenes through a desired binding orientation of aromatic adsorbates, which discourages ring hydrogenation and ring-opening reactions.

Abstract

Polyethylene terephthalate (PET) hydrogenolysis can produce benzene, toluene, and xylene (BTX), where the selectivity control is challenging. We report a reaction pathway dictated by the Ru coordination environment by examining the binding geometries of adsorbates on differently coordinated Ru centers and their evolution during PET hydrogenolysis. A BTX yield of 77 % was obtained using a Ru/TiO2 with a Ru coordination number of ca. 5.0 where edge/corner sites are dominant, while more gas and saturated products were formed for Ru/TiO2 containing primarily terrace sites. Density functional theory and isotopic labelling revealed that under-coordinated Ru edge sites favor “upright” adsorption of aromatic adsorbates while well-coordinated Ru sites favor “flat-lying” adsorption, where the former mitigates ring hydrogenation and opening. This study demonstrates that reaction pathways can be directed through controlled reactant/intermediate binding via tuning of the Ru coordination environment for efficient conversion of PET to BTX.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Mingxing Ye, Yurou Li, Zhirong Yang, Chang Yao, Weixiao Sun, Xiangxue Zhang, Wenyao Chen, Gang Qian, Xuezhi Duan, Yueqiang Cao, Lina Li, Xinggui Zhou, Jing Zhang
onlinelibrary.wiley.com/doi/10.1002/anie.202301024

Cooperative Proton and Li‐ion Conduction in a 2D‐Layered MOF via Mechanical Insertion of Lithium Halides

Par / 31 mars 2023 / Non classé
Cooperative Proton and Li-ion Conduction in a 2D-Layered MOF via Mechanical Insertion of Lithium Halides

A high ionic conductivity (>10−2 S cm−1) was observed in the 2D-Ti-dobdc MOF after Li salt intercalation, which improved the H2O affinity of the frameworks, facilitating Li+ and H+ diffusion. Furthermore, the ion diffusion evaluated by PFG NMR indicates the counter anion effect. It was demonstrated that the moderate covalent/ionic character of LiBr and the high H2O uptake are crucial factors in efficient ionic conductors.

Abstract

Ionic conduction in highly designable and porous metal–organic frameworks has been explored through the introduction of various ionic species (H+, OH−, Li+, etc.) using post-synthetic modification such as acid, salt, or ionic liquid incorporation. Here, we report on high ionic conductivity (σ>10−2 S cm−1) in a two-dimensionally (2D)-layered Ti-dobdc (Ti2(Hdobdc)2(H2dobdc), H4dobdc: 2,5-dihydroxyterephthalic acid) via LiX (X=Cl, Br, I) intercalation using mechanical mixing. The anionic species in lithium halide strongly affect the ionic conductivity and durability of conductivity. Solid-state pulsed-field gradient nuclear magnetic resonance (PFG NMR ) verified the high mobility of H+ and Li+ ions in the temperature range of 300–400 K. In particular, the insertion of Li salts improved the H+ mobility above 373 K owing to strong binding with H2O. Furthermore, the continuous increase in Li+ mobility with temperature contributed to the retention of the overall high ionic conductivity at high temperatures.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Marvin K. Sarango‐Ramírez, Masaki Donoshita, Yukihiro Yoshida, Dae‐Woon Lim, Hiroshi Kitagawa
onlinelibrary.wiley.com/doi/10.1002/anie.202301284

Going beyond Binary: Rapid Identification of Protein–Protein Interaction Modulators Using a Multifragment Kinetic Target-Guided Synthesis Approach

Par / 31 mars 2023 / medchem

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Journal of Medicinal Chemistry

Journal of Medicinal Chemistry: Latest Articles (ACS Publications)
Authors: Katya Nacheva, Sameer S. Kulkarni, Mintesinot Kassu, David Flanigan, Andrii Monastyrskyi, Iredia D. Iyamu, Kenichiro Doi, Megan Barber, Niranjan Namelikonda, Jeremiah D. Tipton, Prakash Parvatkar, Hong-Gang Wang, and Roman Manetsch
dx.doi.org/http://dx.doi.org/10.1021/acs.jmedchem.3c00108

Targeted Biomolecule Regulation Platform: A Split-and-Mix PROTAC Approach

Par / 31 mars 2023 / Non classé

TOC Graphic

Journal of the American Chemical Society

Journal of the American Chemical Society: Latest Articles (ACS Publications)
Authors: Fenfang Yang, Qinhong Luo, Yuechen Wang, Huiting Liang, Yaqi Wang, Zhanfeng Hou, Chuan Wan, Yuena Wang, Zhihong Liu, Yuxin Ye, Lizhi Zhu, Jianlong Wu, Feng Yin, and Zigang Li
dx.doi.org/https://doi.org/10.1021/jacs.2c12824

“Electron Transport Chain Interference” Strategy of Amplified Mild-Photothermal Therapy and Defect-Engineered Multi-Enzymatic Activities for Synergistic Tumor-Personalized Suppression

Par / 31 mars 2023 / Non classé

TOC Graphic

Journal of the American Chemical Society

Journal of the American Chemical Society: Latest Articles (ACS Publications)
Authors: Shuming Dong, Yushan Dong, Zhiyu Zhao, Jing Liu, Shikai Liu, Lili Feng, Fei He, Shili Gai, Ying Xie, and Piaoping Yang
dx.doi.org/https://doi.org/10.1021/jacs.2c09608

Stereoselective Synthesis of Monofluoroalkenylphosphine Oxides via Photoinduced Decarboxylative Coupling of α‑Fluoroacrylic Acids with P(O)H Compounds

Par / 31 mars 2023 / Non classé

Organic Letters: Latest Articles (ACS Publications)
Authors: Xiao-Yu Lu, Hong-Ye Pan, Rui Huang, Kang Yang, Xiang Zhang, Zi-Zhen Wang, Qian-Qian Tao, Gui-Xian Yang, Xiao-Juan Wang, and Hai-Pin Zhou
dx.doi.org/https://doi.org/10.1021/acs.orglett.3c00631