septembre 2022 – ChemDigest

Differential Peptide Multi‐Macrocyclizations at the Surface of a Helical Foldamer Template

Par admin / 30 septembre 2022 30 septembre 2022 / Non classé

The selective formation of different macrocycles can be implemented using Cys residues within a peptide and chloroacetamides at the surface of a foldamer helix by placing the latter at precise locations. Helix rigidity and faster formation of smaller macrocycles make the favored product largely predictable.

Abstract

Hybrid sequences comprising a peptide with several Cys residues and an aromatic foldamer helix with several chloroacetamide functions at its surface were synthesized. Such products may in principle form numerous macromulticyclic thioether products by intramolecularly combining all Cys residues and all chloroacetamide functions. However, we show that the reactive sites on the structurally defined helix can be placed at such locations that the peptide selectively stitches itself to form a series of different macrocycles within mostly one preferred product. Reactions were monitored by HPLC and products with two, three or four macrocycles were identified using LC–MS and NMR. The series of selective macrocyclizations define a sort of reaction trail where reaction sites otherwise identical are involved successively because of their precise positioning in space. The trails can be predicted to a large extent based on structural considerations and the assumption that smaller macrocycles form faster.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Sebastian Dengler, Céline Douat, Ivan Huc
onlinelibrary.wiley.com/doi/10.1002/anie.202211138

Regulating Surface Reaction Kinetics through Ligand Field Effects for Fast and Reversible Aqueous Zinc Batteries

Par admin / 30 septembre 2022 30 septembre 2022 / Non classé

The boron acid additive can alleviate the intrinsic tradeoff between Zn nucleation/dissolution kinetics and the interfacial hydrogen evolution reaction by modulating the solvation sheath. The formed solvation structure with moderate ligand field strength enables fast and highly reversible Zn deposition.

Abstract

Designing water-deficient solvation sheath of Zn²⁺ by ligand substitution is a widely used strategy to protect Zn metal anode, yet the intrinsic tradeoff between Zn nucleation/dissolution kinetics and the side hydrogen evolution reaction (HER) remains a huge challenge. Herein, we find boric acid (BA) with moderate ligand field interaction can partially replace H₂O molecules in the solvation sheath of Zn²⁺, forming a stable water-deficient solvation sheath. It enables fast Zn nucleation/dissolution kinetics and substantially suppressed HER. Crucially, by systematically comparing the ligand field strength and solvation energies between BA and the ever-reported electrolyte additives, we also find that the solvation energy has a strong correlation with Zn nucleation/dissolution kinetics and HER inhibition ability, displaying a classic volcano behavior. The modulation map could provide valuable insights for solvation sheath design of zinc batteries and beyond.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Bo Liu, Cong Wei, Zixuan Zhu, Yanyan Fang, Zenan Bian, Xin Lei, Ya Zhou, Chongyang Tang, Yitai Qian, Gongming Wang
onlinelibrary.wiley.com/doi/10.1002/anie.202212780

Big (Bio)Chemical Data Mining Using Chemometric Methods: A Need for Chemists

Par admin / 30 septembre 2022 30 septembre 2022 / Non classé

Big (Bio)Chemical Data Mining: Large and complex chemical data sets generated by modern analytical technologies have led to the so-called Big (Bio)Chemical Data era. These data sets can be produced using modern analytical instruments such as multi-dimensional chromatography, high-resolution and multi-dimensional spectroscopy, hyperspectral imaging and DNA/RNA microarrays. Chemometric methods have shown potential to analyze BBCD especially in omics sciences and chemical toxicology/drug discovery.

Abstract

This Review summarizes how big (bio)chemical data (BBCD) can be analyzed with multivariate chemometric methods and highlights some of the important challenges faced by modern analytical researches. Here, the potential of chemometric methods to solve BBCD problems that are being encountered in chromatographic, spectroscopic and hyperspectral imaging measurements will be discussed, with an emphasis on their applications to omics sciences. In addition, insights and perspectives on how to address the analysis of BBCD are provided along with a discussion of the procedures necessary to obtain more reliable qualitative and quantitative results. In this Review, the importance of “big data” and of their relevance to (bio)chemistry are first discussed. Thereafter, analytical tools which can produce BBCD are presented as well as the theoretical background of chemometric methods and their limitations when they are applied to BBCD. Finally, the importance of chemometric methods for the analysis of BBCD in different chemical disciplines is highlighted with some examples. In this work, we have tried to cover many of the current applications of big data analysis in the (bio)chemistry field.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Hadi Parastar, Roma Tauler
onlinelibrary.wiley.com/doi/10.1002/anie.201801134

Photo‐Excited Nickel‐Catalyzed Silyl‐Radical‐Mediated Direct Activation of Carbamoyl Chlorides To Access (Hetero)aryl Carbamides

Par admin / 30 septembre 2022 30 septembre 2022 / Non classé

Photoexcited nickel catalysis enabled silyl-radical-mediated activation of carbamoyl chlorides. This process provides an operationally simple and widely applicable amidation reaction of a plethora of aryl and hetero(aryl) halides. Mechanistic understanding suggests that the reaction involves an energy-transfer mechanism for aryl bromide; while a single-electron-transfer mechanism is operating for aryl chlorides.

Abstract

Amide bonds connect the amino acids in proteins and exist as a prevalent structural motif in biomolecules. Herein, we have exploited the concept of cross-electrophile coupling by merging the photo-redox and transition-metal catalysis to construct carbamides from superabundant (hetero)aryl halides along with commercially feasible carbamoyl chlorides. The success of this method relies on the prior formation of Ni^II-aryl halide intermediates, which involves in a photoexcited Ni-halide homolysis event by energy transfer from aryl bromide and single-electron transfer from aryl chloride to assist generation of the vital carbamoyl radical. The breadth of application of this technique is demonstrated both in inter- as well as intramolecular routes for the synthesis of a plethora of (hetero)aryl carbamides with diverse functionalities, and biologically important benzolactams.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Sudip Maiti, Sayan Roy, Pintu Ghosh, Aashi Kasera, Debabrata Maiti
onlinelibrary.wiley.com/doi/10.1002/anie.202207472

Regio‐ and Stereoselective 1,2‐Oxyhalogenation of Non‐Conjugated Alkynes via Directed Nucleopalladation: Catalytic Access to Tetrasubstituted Alkenes

Par admin / 30 septembre 2022 30 septembre 2022 / Non classé

Palladium(II)-catalyzed regio- and stereoselective oxyhalogenation of unactivated internal alkynes is facilitated by a structurally tuned bidentate directing auxiliary, providing rapid access to tetrasubstitued alkenes that can be further diversified into valuable products.

Abstract

A catalytic 1,2-oxyhalogenation method that converts non-conjugated internal alkynes into tetrasubstituted alkenes with high regio- and stereoselectivity is described. Mechanistically, the reaction involves a Pd^II/Pd^IV catalytic cycle that begins with a directed oxypalladation step. The origin of regioselectivity is the preference for formation of a six-membered palladacycle intermediate, which is facilitated by an N,N-bidentate 2-(pyridin-2-yl)isopropyl (PIP) amide directing group. Selectivity for C(alkenyl)−X versus −N (X=halide) reductive elimination from the Pd^IV center depends on the identity of the halide anion; bromide and iodide engage in C(alkenyl)−X formation, while intramolecular C(alkenyl)−N reductive elimination occurs with chloride to furnish a lactam product. DFT calculations shed light on the origins of this phenomenon.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Mingyu Liu, Juntao Sun, Tao Zhang, Yi Ding, Ye‐Qiang Han, Raúl Martín‐Montero, Yu Lan, Bing‐Feng Shi, Keary M. Engle
onlinelibrary.wiley.com/doi/10.1002/anie.202209099

Boosting Bismuth(III) Complexation for Targeted α‐Therapy (TAT) Applications with the Mesocyclic Chelating Agent AAZTA

Par admin / 30 septembre 2022 30 septembre 2022 / Non classé

[Bi(AAZTA)]⁻ and derivatives have been comprehensively characterized. Fast formation, remarkable stability, strong accumulation in AR42J tumour make ²¹³Bi(AAZTA-C4-TATE)]⁻ an outstanding candidate for TAT.

Abstract

Targeted α therapy (TAT) is a promising tool in the therapy of cancer. The radionuclide ²¹³Bi^III shows favourable physical properties for this application, but the fast and stable chelation of this metal ion remains challenging. Herein, we demonstrate that the mesocyclic chelator AAZTA quickly coordinates Bi^III at room temperature, leading to a robust complex. A comprehensive study of the structural, thermodynamic and kinetic properties of [Bi(AAZTA)]⁻ is reported, along with bifunctional [Bi(AAZTA-C4-COO⁻)]²⁻ and the targeted agent [Bi(AAZTA-C4-TATE)]⁻, which incorporates the SSR agonist Tyr³-octreotate. An unexpected increase in the stability and kinetic inertness of the metal chelate was observed for the bifunctional derivative and was maintained for the peptide conjugate. A cyclotron-produced ^205/206Bi mixture was used as a model of ²¹³Bi in labelling, stability, and biodistribution experiments, allowing the efficiency of [²¹³Bi(AAZTA-C4-TATE)]⁻ to be estimated. High accumulation in AR42J tumours and reduced kidney uptake were observed with respect to the macrocyclic chelate [²¹³Bi(DOTA-TATE)]⁻.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Dávid Horváth, Adrienn Vágner, Dezsö Szikra, György Trencsényi, Nicola Demitri, Nicol Guidolin, Alessandro Maiocchi, Simona Ghiani, Fabio Travagin, Giovanni B. Giovenzana, Zsolt Baranyai
onlinelibrary.wiley.com/doi/10.1002/anie.202207120

Self‐Healing and Shape Memory Hypercrosslinked Metal‐Organic Polyhedra Polymers via Coordination Post‐Assembly

Par admin / 30 septembre 2022 30 septembre 2022 / Non classé

A type of coordination hypercrosslinked MOP (CHMOP) polymers was prepared using soluble and well-defined MOPs as high-connectivity building blocks. The introduction of MOPs constructs a coordination dynamic network that not only enhances mechanical properties but also realizes multifunctionality including self-healing, shape memory, solution processability, and 3D printing. CHMOPs provide a novel platform for expansion of the smart soft materials.

Abstract

Coordination-driven crosslinking networks with reversible and dynamic characteristics are gaining increasing interest in diverse application fields. Herein, we use a coordination crosslinking approach using metal-organic polyhedra (MOPs) as high-connectivity building blocks to post-assemble a class of coordination hypercrosslinked MOP (CHMOP) polymers. The introduction of 12-connected MOP nodes to the polymeric networks is critical to producing membranes that overcome the trade-off between mechanical properties and dynamic healing, and meanwhile possess multifunctionalities including shape memory, solution processability, and 3D printing. The CHMOPs can also be used for anticorrosion coating and achieve function couplings, e.g., shape memory-assisted self-healing (SMASH), which have not been achieved in the MOP-based hybrid materials yet. This work not only offers a feasible strategy to construct new multifunctional materials but also greatly expands the application scopes of MOPs.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Jinjin Liu, Jiamin Li, Shan Qiao, Zhifang Wang, Penghui Zhang, Xiangqian Fan, Peng Cheng, Yue‐Sheng Li, Yao Chen, Zhenjie Zhang
onlinelibrary.wiley.com/doi/10.1002/anie.202212253

Substrate Tumbling in a Chemisorbed Diastereomeric α‐Ketoester/1‐(1‐Naphthyl)ethylamine Complex

Par admin / 30 septembre 2022 30 septembre 2022 / Non classé

Guided by intermolecular H-bonding and adsorption forces, an α-ketoester tumbles between two prochiral states in a chemisorbed diastereomeric complex.

Abstract

Scanning tunneling microscopy (STM) data for α-ketoester/1-(1-naphthyl)ethylamine complexes on Pt(111) reveal a tumbling motion that couples two neighboring binding states. The interconversion, resulting in prochiral inversion of the α-ketoester, occurs in single complexes without breaking them apart. This is a surprising observation because the overall motion requires rotation of the α-ketoester away from the surface without branching exclusively into diffusion away from the complex or desorption. The multi-step interconversion is rationalized in terms of sequences of bound states that combine transient H-bond interactions with the chiral molecule and weakened adsorption interactions with the metal. The observation of tumbling in single long-lived complexes is of relevance to self-assembly and directed molecular motion on surfaces, to ligand-controlled surface reactions, and most directly to stereocontrol in asymmetric heterogeneous catalysis.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Yi Dong, Jean‐Christian Lemay, Yang Zeng, Michael N. Groves, Peter H. McBreen
onlinelibrary.wiley.com/doi/10.1002/anie.202210076

Conservation of Nickel Ion Single‐Active Site Character in a Bottom‐Up Constructed π‐Conjugated Molecular Network

Par admin / 30 septembre 2022 30 septembre 2022 / Non classé

The on-surface synthesis of covalent nickel tetraphenylporphyrin network on Au(111) is studied by a multitechnique approach combining local microscopic insights with space-averaging synchrotron radiation-based methods. Even though the porphyrin nanomesh is not perfectly ordered extending the π-system results in the appearance of energy-dispersive electronic features while the Ni cores remain in the characteristic single-molecule configuration.

Abstract

On-surface chemistry holds the potential for ultimate miniaturization of functional devices. Porphyrins are promising building-blocks in exploring advanced nanoarchitecture concepts. More stable molecular materials of practical interest with improved charge transfer properties can be achieved by covalently interconnecting molecular units. On-surface synthesis allows to construct extended covalent nanostructures at interfaces not conventionally available. Here, we address the synthesis and properties of covalent molecular network composed of interconnected constituents derived from halogenated nickel tetraphenylporphyrin on Au(111). We report that the π-extended two-dimensional material exhibits dispersive electronic features. Concomitantly, the functional Ni cores retain the same single-active site character of their single-molecule counterparts. This opens new pathways when exploiting the high robustness of transition metal cores provided by bottom-up constructed covalent nanomeshes.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Daniel Baranowski, Iulia Cojocariu, Alessandro Sala, Cristina Africh, Giovanni Comelli, Luca Schio, Massimo Tormen, Luca Floreano, Vitaliy Feyer, Claus M. Schneider
onlinelibrary.wiley.com/doi/10.1002/anie.202210326

Conferring BiVO4 Nanorods with Oxygen Vacancies to Realize Enhanced Sonodynamic Cancer Therapy

Par admin / 30 septembre 2022 30 septembre 2022 / Non classé

Photoetching can confer BiVO₄ with oxygen vacancies and enhance the catalytic performance of BiVO₄. The photoetched BiVO₄ can catalyze water splitting to generate oxygen and hydroxyl radicals under the mediation of ultrasound. The generated oxygen can relieve tumor hypoxia, thereby improving the sonodynamic cancer therapy performance of BiVO₄.

Abstract

Owing to the high depth of tissue penetration, non-invasiveness, and controllability, ultrasound (US)-mediated sonodynamic therapy (SDT) has shown broad application prospects for tumor treatment. However, the electron-hole separation inefficiency of sonosensitizers and the tumor hypoxia remain two major challenges limiting the effect of SDT. Here, ultrafine photoetched bismuth vanadate (BiVO₄) nanorods modified with DSPE-PEG₂₀₀₀ (PEBVO@PEG NRs) were fabricated to achieve in situ self-supply of oxygen (O₂) and reactive oxygen species (ROS) for hypoxic tumor therapy. The photoetching approach could enhance the charge separation by inducing enriched oxygen vacancies on the surface of BiVO₄, thereby improving the generation efficiency of ROS and O₂. The PEBVO@PEG overcome the main obstacles of traditional sonosensitizers in the SDT process and show promising sonodynamic therapeutic effects, thus providing new strategies for improving the performance of sonosensitizer and hypoxic tumor elimination.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Zhuang Yang, Meng Yuan, Bin Liu, Wenying Zhang, Aziz Maleki, Baolin Guo, Ping’an Ma, Ziyong Cheng, Jun Lin
onlinelibrary.wiley.com/doi/10.1002/anie.202209484

Direct Acquisition of the Gap Height of Biological Tissue‐Electronic Chemical Sensor Interfaces

Par admin / 30 septembre 2022 30 septembre 2022 / Non classé

A pair of nanopores was integrated at the electrochemical sensor plane and used to measuring the ion conductance between them providing a versatile strategy to directly determine the gap height during exocytotic release from tissues. Direct cooperative measurement of the gap height and exocytotic release at the same sensor can be used to address the long-term question of the influence of diffusional filtering on the exocytotic spike.

Abstract

Interfacing biological tissues with electronic sensors offers the exciting opportunity to accurately investigate multiple biological processes. Accurate signal collection and application are the foundation of these measurements, but a long-term issue is the signal distortion resulting from the interface gap. The height of the gap is the key characteristic needed to evaluate or model the distortion, but it is difficult to measure. By integrating a pair of nanopores at the electronic sensor plane and measuring the ion conductance between them, we developed a versatile and straightforward strategy to realize the direct cooperative evaluation of the gap height during exocytotic release from adrenal gland tissues. The signaling distortion of this gap has been theoretically evaluated and shows almost no influence on the amperometric recording of exocytosis in a classic “semi-artificial synapse” configuration. This strategy should benefit research concerning various bio/chemical/machine interfaces.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Xin‐Wei Zhang, Amir Hatamie, Andrew G. Ewing
onlinelibrary.wiley.com/doi/10.1002/anie.202210224

Regioselective Access to Vicinal Diamines by Metal‐Free Photosensitized Amidylimination of Alkenes with Oxime Esters

Par admin / 30 septembre 2022 30 septembre 2022 / Non classé

A metal-free, photosensitized regioselective diamination of alkene is reported. The keys to this advance are: 1) rational design of bifunctional diamination reagent, 2) simultaneous generation of long-lived iminyl radical and transient amidyl radical with significantly differed reactivities, and 3) involvement of photoinduced energy transfer reaction mode.

Abstract

A metal-free photosensitized protocol for regioselective diamination of alkene feedstocks over a single step was developed based on the rationally designed bifunctional diamination reagent, thus affording a range of differentially protected 1,2-diamines in moderate to high yields. Mechanistic studies reveal that the reaction is initiated with a triplet-triplet energy transfer between thioxanthone catalyst and diamination reagent, followed by fragmentation to simultaneously generate long-lived iminyl radical and transient amidyl radical. The excellent regioselectivity presumably stems from the large reactivity difference between two different N-centered radical species. This protocol is characterized by excellent regioselectivity, broad functional group tolerance, and mild reaction conditions, which would enrich the diversity and versatility of facilitate the diversity-oriented synthesis of 1,2-diamine-containing complex molecule scaffolds.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Yu Zheng, Zhu‐Jun Wang, Zhi‐Peng Ye, Kai Tang, Zhen‐Zhen Xie, Jun‐An Xiao, Hao‐Yue Xiang, Kai Chen, Xiao‐Qing Chen, Hua Yang
onlinelibrary.wiley.com/doi/10.1002/anie.202212292

Ultrastable Anti‐Acid “Shield” in Layered Silver Coordination Polymers

Par admin / 30 septembre 2022 30 septembre 2022 / Non classé

Acid resistance (12 M HCl) was made possible for two isomorphic two-dimensional silver-based coordination polymers. Protection is provided by a hydrophobic organic shell and a dynamic proton buffer layer via a thiolate-thione tautomerism of 2-thiobenzimidazole ligands. Thus, these ligands are promising surface inhibitors, acting as a dual protective shield against metal corrosion.

Abstract

Surface passivation technology provides noble-metal materials with limited chemical stability, especially under highly acidic condition. To design effective strategy to enhance stability of noble-metal particles, an understanding of their surface anticorrosion mechanism at the atomic level is desirable by using two-dimensional (2D) noble-metal coordination polymer (CP) as an ideal model for their interfacial region. With the protection of 2-thiobenzimidazole (TBI), we isolated two Ag-based 2D CPs, {Ag₁₄(TBI)₁₂X₂}_n (S−X, where S denotes sheet and X=Cl or Br). These compounds exhibited excellent chemical stability upon immersion in various common solvents, boiling water, boiling ethanol, 10 % hydrogen peroxide, concentrated acid (12 M HCl), and concentrated alkali (19 M NaOH). Systematic characterization and DFT analyses demonstrate that the superior stability of S−X was attributed to the hydrophobic organic shell and dynamic proton buffer layer acting as a double protective “shield”.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Peipei Sun, Mo Xie, Lin‐Mei Zhang, Jia‐Xing Liu, Jin Wu, Dong‐Sheng Li, Shang‐Fu Yuan, Tao Wu, Dan Li
onlinelibrary.wiley.com/doi/10.1002/anie.202209971

Closed‐Loop Recycling of Poly(Imine‐Carbonate) Derived from Plastic Waste and Bio‐based Resources

Par admin / 30 septembre 2022 30 septembre 2022 / Non classé

Upcycling of polycarbonate (BPA-PC) with a bio-based vanillin derivative into novel dialdehyde monomer DVEC is shown. DVEC was further polymerized by using primary amines into high-performance poly(imine-carbonate)s. These modular polymers are reprocessable and chemically recyclable under acidic and energy-efficient conditions, thereby enabling a closed-loop recycling scheme.

Abstract

Closed-loop recycling of polymers represents the key technology to convert plastic waste in a sustainable fashion. Efficient chemical recycling and upcycling strategies are thus highly sought-after to establish a circular plastic economy. Here, we present the selective chemical depolymerization of polycarbonate by employing a vanillin derivative as bio-based feedstock. The resulting di-vanillin carbonate monomer was used in combination with various amines to construct a library of reprocessable poly(imine-carbonate)s, which show tailor-made thermal and mechanical properties. These novel poly(imine-carbonate)s exhibit excellent recyclability under acidic and energy-efficient conditions. This allows the recovery of monomers in high yields and purity for immediate reuse, even when mixed with various commodity plastics. This work provides exciting new insights in the design of bio-based circular polymers produced by upcycling of plastic waste with minimal environmental impact.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Keita Saito, Fabian Eisenreich, Tankut Türel, Željko Tomović
onlinelibrary.wiley.com/doi/10.1002/anie.202211806

Orthogonal Charge Transfer by Precise Positioning of Silver Single Atoms and Clusters on Carbon Nitride for Efficient Piezocatalytic Pure Water Splitting

Par admin / 30 septembre 2022 30 septembre 2022 / Non classé

Ag−C₂N₂ single-sites and Ag clusters are co-confined on carbon nitride (CN). The enhanced in-plane piezoelectric polarization by Ag single atoms and rapid out-of-plane charge transfer between Ag clusters and CN collectively contribute to the excellent piezocatalytic pure water splitting.

Abstract

Developing efficient piezocatalytic systems for two-electron water splitting (TEWS) with producing H₂ and H₂O₂ shows great promise to meet the industrial demand. Herein, Ag single atoms (SAs) and clusters are co-anchored on carbon nitride (Ag_SA+C−CN) to serve as the multifunctional sites for efficient TEWS. The Ag SAs enhance the in-plane piezoelectric polarization of CN that is intimately modulated by the atomic coordination induced charge redistribution, and Ag clusters afford strong interfacial electric field to remarkably promote the out-of-plane migration of piezoelectrons from CN. Moreover, Ag_SA+C−CN yields a larger piezoresistive effect that elevates carrier mobility under strain. Consequently, a superior H₂ and H₂O₂ evolution rate of 7.90 mmol g⁻¹ h⁻¹ and 5.84 mmol g⁻¹ h⁻¹ is delivered by Ag_SA+C−CN, respectively, far exceeding that of the previously reported piezocatalysts. This work not only presents the SAs decoration as an available polarization enhancement strategy, but also sheds light on the superiority of multi-sites engineering in piezocatalysis.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Cheng Hu, Jingcong Hu, Zijian Zhu, Yue Lu, Shengqi Chu, Tianyi Ma, Yihe Zhang, Hongwei Huang
onlinelibrary.wiley.com/doi/10.1002/anie.202212397

A Versatile Strategy for Multi‐Stimuli‐Responsive Fluorescent Material Based on Cross‐Linking‐Induced Emission: Applications in Encryption

Par admin / 30 septembre 2022 30 septembre 2022 / Non classé

An adaptable strategy toward a multi-stimuli-responsive fluorescent material with stage-by-stage responsive behavior was developed. This strategy ensures the compatibility of different stimuli-responses and the adjustability of stimulus-response behavioral logic. These multi-stimuli-responsive fluorescent materials exhibited strong accessibility and adaptability for information encryption.

Abstract

A versatile strategy for smart fluorescent materials is lacking due to their diverse responding mechanisms and incompatibility of responsive behaviors. Herein an adaptable strategy is presented toward a multi-stimuli-responsive fluorescent material with stage-by-stage responsive behavior by blending linear polymers modified with different stimulus-responsive moieties and AIE cross-linker. Under stimuli, the linear polymer can cross-link with the cross-linker to form networks, which intrinsically restrict the intramolecular rotation of the AIE molecule to induce strong emission. A unified stimuli-responsive mechanism is involved in that various stimuli are transferred through the organized “stimulus-crosslink-emission” process. This strategy ensures the compatibility of different stimuli-responses and the adjustability of stimulus-response behavioral logic. These multi-stimuli-responsive fluorescent materials exhibited strong accessibility and adaptability for information encryption.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Yu Jiang, Jiahui Ma, Ziyu Ran, Huiqing Zhong, Daohong Zhang, Nikos Hadjichristidis
onlinelibrary.wiley.com/doi/10.1002/anie.202208516

Salting‐Out Aldehyde from the Electrooxidation of Alcohols with 100 % Selectivity

Par admin / 30 septembre 2022 30 septembre 2022 / Non classé

Selective electrocatalytic oxidation of alcohols to aldehydes has significant challenges, for example, it cannot realize the preparation of aldehydes selectively in alkaline aqueous solutions. By tuning the local microenvironment over the electrocatalyst, and thus selectively salting-out the aldehyde at the gas|electrolyte interface, the electrocatalytic synthesis of aldehydes was achieved in an efficient and green way.

Abstract

Selective electrocatalytic oxidation of alcohols to value-added aldehydes has attracted increasing attention. However, due to its higher reactivity than alcohol, the aldehyde is easily over-oxidized to acid in alkaline electrolytes. Herein we realize the selective electrooxidation of alcohol to aldehyde on NiO by tuning the local microenvironment to salt out the aldehyde from the reaction system. The origin of the high selectivity was found to be the inhibition of the hydration of aldehydes, which is the result of the decreased alkalinity and the increased cation and substrate concentration. This strategy could salt out the aldehyde at the gas|electrolyte interface from the electrooxidation of alcohol with 100 % selectivity and be easily extended to other selective oxidation reactions, such as 5-hydroxymethyl furfural (HMF) to 2,5-furandicarboxaldehyde (DFF) and amine to an imine.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Leitao Xu, Zhifeng Huang, Ming Yang, Jingcheng Wu, Wei Chen, Yandong Wu, Yuping Pan, Yuxuan Lu, Yuqin Zou, Shuangyin Wang
onlinelibrary.wiley.com/doi/10.1002/anie.202210123

Iron‐Catalyzed Alkoxycarbonylation of Alkyl Bromides via a Two‐Electron Transfer Process

Par admin / 30 septembre 2022 30 septembre 2022 / Non classé

A distinct alkoxycarbonylation pattern via an in situ generated Fe²⁻ catalyst is reported. This low-valent iron catalyst activates alkyl halides via a two-electron transfer (TET) process, unlike previous reports where alkyl halides underwent a single electron transfer (SET). This reaction provides easy and efficient access to esters, and its mechanism will provide new ideas for the activation of alkyl halides in the field of carbonylation.

Abstract

Transition metal-catalyzed carbonylative cross-coupling reactions are some of the most widely used methods in organic synthesis. However, despite the obvious advantages of iron as an abundant and low toxicity transition metal catalyst, its practical application in carbonylation reaction remains largely unexplored. Here we report our recent study on Fe-catalyzed alkoxycarbonylation of alkyl halides. Mechanistic studies indicate that the reaction is catalyzed by an in situ generated Fe²⁻ complex. This low-valent iron species activates alkyl bromides via a distinctive two-electron transfer (TET) process, whereas it proceeds via a single electron transfer (SET) process for alkyl iodides which is consistent with literature.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Han‐Jun Ai, Benedict N. Leidecker, Phong Dam, Christoph Kubis, Jabor Rabeah, Xiao‐Feng Wu
onlinelibrary.wiley.com/doi/10.1002/anie.202211939

sp2 to sp3 Hybridization Transformation in Ionic Crystals under Unprecedentedly Low Pressure

Par admin / 30 septembre 2022 30 septembre 2022 / Non classé

To promote the sp²-to-sp³ hybridization transformation in ionic crystals, the realization of internal-lattice stress-transfer from ionic groups to covalent groups is proposed. It is demonstrated in a crystal of LiBO₂ which undergoes the transformation at unprecedentedly low pressure of only 2.85 GPa.

Abstract

Under cold pressure sp¹/sp²-to-sp³ hybridization transformation has been exclusively observed in covalent or molecular crystals overwhelmingly above ≈10 GPa, and the approaches to lower the transition pressure are limited on external heat-treatment and/or catalyzers. Herein we demonstrate that, by internal-lattice stress-transfer from ionic to covalent groups, the transformation can be significantly prompted, as shown in a crystal of LiBO₂ under 2.85 GPa for the first case in ionic crystals. This unprecedentedly low transformation pressure is ascribed to the enhanced localized stress on covalent B−O frames transferred from ionic Li−O bonds in LiBO₂, and accordingly the corresponding structural feature is summarized. This work provides an internal structural regulation strategy for pressure-reduction of the s-p orbital hybridization transformation and extends the sp¹/sp²-to-sp³ transformation landscape from molecular and covalent compounds to ionic systems.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Xingxing Jiang, Maxim S. Molokeev, Naizheng Wang, Yonggang Wang, Ting Wen, Zhichao Dong, Youquan Liu, Wei Li, Zheshuai Lin
onlinelibrary.wiley.com/doi/10.1002/anie.202208247

Rationally Designing Efficient Electrocatalysts for Direct Seawater Splitting: Challenges, Achievements, and Promises

Par admin / 30 septembre 2022 30 septembre 2022 / Non classé

This Review provides an overview of electrocatalysts designed for the direct splitting of seawater. The mechanism of seawater splitting is introduced before the primary principles for designing catalysts (noble metal, noble metal free, and metal-free) for seawater splitting are analyzed in terms of both the hydrogen and oxygen evolution reactions. The future development of electrocatalysts for clean hydrogen generation is also discussed.

Abstract

Directly splitting seawater to produce hydrogen provides a promising pathway for energy and environmental sustainability. However, current seawater splitting faces many challenges because of the sluggish kinetics, the presence of impurities, membrane contamination, and the competitive chloride oxidation reaction at the anode, which makes it more difficult than freshwater splitting. This Review firstly introduces the basic mechanisms of the anode and cathode reactions during seawater splitting. We critically analyze the primary principles for designing catalysts for seawater splitting in terms of both the hydrogen and oxygen evolution reactions, including with noble metal, noble metal free, and metal-free catalysts. Strategies to design effective catalysts, such as active site population, synergistic effect regulation, and surface engineering, are discussed. Furthermore, promises, perspectives, and challenges in developing seawater splitting technologies for clean hydrogen generation are summarized.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Jianyun Liu, Shuo Duan, Hao Shi, Tanyuan Wang, Xiaoxuan Yang, Yunhui Huang, Gang Wu, Qing Li
onlinelibrary.wiley.com/doi/10.1002/anie.202210753

Greatly Enhanced Accessibility and Reproducibility of Worm‐like Micelles by In Situ Crosslinking Polymerization‐Induced Self‐Assembly

Par admin / 30 septembre 2022 30 septembre 2022 / Non classé

Greatly enhanced accessibility of worm-like micelles (W) is realized by in situ crosslinking polymerization-induced self-assembly (PISA), leading to significantly improved reproducibility of worm-like micelles. The reliability of the methodology has been demonstrated in various in situ crosslinking PISA systems with different formulations of monomers, macro RAFT agents, crosslinkers, solvents, and polymerization temperatures.

Abstract

Worm-like micelles have attracted great interest due to their anisotropic structures. However, the experimental conditions for obtaining worm-like micelles are very restricted, which usually causes seriously poor reproducibility. In this work, significantly enhanced accessibility of worm-like micelles is realized by in situ crosslinking polymerization-induced self-assembly (PISA). The reproducibility of worm-like micelles is greatly improved due to the significantly enlarged experimental windows of worm-like micelles in the morphology diagram. Moreover, the reliability of the methodology to enhance the accessibility of worm-like micelles has been demonstrated in various in situ crosslinking PISA systems. The greatly enhanced accessibility and reproducibility of worm-like micelles is undoubtedly cost-effective especially in scale-up production, which paves the way for further application of worm-like micelles with various compositions and functionalities.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Wen‐Jian Zhang, Zi‐Xuan Chang, Wei Bai, Chun‐Yan Hong
onlinelibrary.wiley.com/doi/10.1002/anie.202211792

Surface Diffusion Aided by a Chirality Change of Self‐Assembled Oligomers under 2D Confinement

Par admin / 30 septembre 2022 30 septembre 2022 / Non classé

We demonstrate a new functional molecular system with a combination of several advanced features, including a self-assembled oligomer, surface chirality, chirality switching, and finally their motion on the surface. Our results suggest that nonchiral molecules may be designed to induce switchable enantiomeric surface assemblies, relevant for heterogeneous catalysts.

Abstract

Chirality switching of self-assembled molecular structures is of potential interest for designing functional materials but is restricted by the strong interaction between the embedded molecules. Here, we report on an unusual approach based on reversible chirality changes of self-assembled oligomers using variable-temperature scanning tunneling microscopy supported by quantum mechanical calculations. Six functionalized diazomethanes each self-assemble into chiral wheel-shaped oligomers on Ag(111). At 130 K, a temperature far lower than expected, the oligomers change their chirality even though the molecules reside in an embedded self-assembled structure. Each chirality change is accompanied by a slight center-of-mass shift. We show how the identical activation energies of the two processes result from the interplay of the chirality change with surface diffusion, findings that open the possibility of implementing various functional materials from self-assembled supramolecular structures.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Abhijit Bera, Stefan Henkel, Joel Mieres‐Perez, Yetsedaw Andargie Tsegaw, Elsa Sanchez‐Garcia, Wolfram Sander, Karina Morgenstern
onlinelibrary.wiley.com/doi/10.1002/anie.202212245

An Atypical Acyl‐CoA Synthetase Enables Efficient Biosynthesis of Extender Units for Engineering a Polyketide Carbon Scaffold

Par admin / 30 septembre 2022 30 septembre 2022 / Non classé

A new acyl-CoA synthetase (ACS, UkaQ) with broad substrate specificity and an unusual catalytic mode was identified. Its stability and catalytic activity were remarkably improved by protein engineering, enabling it to synthesize a large variety of acyl-CoAs. In combination with permissive carboxylases, diverse extender units were synthesized and used to engineer the polyketide carbon scaffold of antimycin.

Abstract

Acyl-CoAs are key precursors of primary and secondary metabolism. Their efficient biosynthesis is often impeded by the limited substrate specificity and low in vivo activity of acyl-CoA synthetases (ACSs) due to regulatory acylation of the catalytically important lysine residue in motif A10 (Lys-A10). In this study, we identified an unusual ACS (UkaQ) from the UK-2A biosynthetic pathway that naturally lacks the Lys-A10 residue and exhibits extraordinarily broad substrate specificity. Protein engineering significantly improved its stability and catalytic activity, enabling it to synthesize a large variety of acyl-CoAs with highly robust activity. By combining it with permissive carboxylases, we produced a large array of polyketide extender units and obtained six novel halobenzyl-containing antimycin analogues through an engineered biosynthetic pathway. This study significantly expands the catalytic mode of ACSs and provides a potent tool for the biosynthesis of acyl-CoA-derived natural products.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Mengmeng Zheng, Jun Zhang, Wan Zhang, Lu Yang, Xiaoli Yan, Wenya Tian, Zhihao Liu, Zhi Lin, Zixin Deng, Xudong Qu
onlinelibrary.wiley.com/doi/10.1002/anie.202208734

Programmable Assembly of Multivalent DNA‐Protein Superstructures for Tumor Imaging and Targeted Therapy

Par admin / 30 septembre 2022 30 septembre 2022 / Non classé

Programmable multivalent DNA nanomaterials are designed through the biomimetic assembly of DNA with Food and Drug Administration-approved protamine, providing biocompatible and stable drug carriers with high avidity in a simpler method. This practical approach achieves sensitive tumor imaging and targeted cancer therapy, and offers new clinical translation opportunities.

Abstract

Programmable DNA materials hold great potential in biochemical and biomedical researches, yet the complicated synthesis, and the low stability and targeting efficacy in complex biological milieu limit their clinical translations. Here we show a one-pot assembly of DNA-protein superstructures as drug vehicles with specifically high affinity and stability for targeted therapy. This is achieved by biomimetic assembly of programmable polymer DNA wire into densely packed DNA nanosphere with an alkaline protein, protamine. Multivalent DNA nanostructures encoded with different types and densities of aptamers exhibit high affinity to targeted cells through polyvalent interaction. Our results show high cancer cell selectivity, reduced side effect, excellent therapeutic efficacy, and sensitive tumor imaging in both subcutaneous and orthotopic non-small-cell lung cancer murine models. This biomimetic assembly approach provides practical DNA nanomaterials for further clinical trials and may advance oligonucleotide drug delivery.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Zhen Xu, Tianhui Shi, Fengye Mo, Wenqian Yu, Yu Shen, Qunying Jiang, Fuan Wang, Xiaoqing Liu
onlinelibrary.wiley.com/doi/10.1002/anie.202211505

Pseudo‐heterolepticity in Low‐Symmetry Metal‐Organic Cages

Par admin / 30 septembre 2022 30 septembre 2022 / Non classé

Heteroleptic metal-organic cages are prized for their structural complexity and multi-functionality. Controlling integrative self-sorting processes necessary to achieve defined self-assembly of these supramolecular hosts is a significant design challenge. In this work, ligand-tethering strategies are described that allow access to metal-organic cages with highly anisotropic cavities described by two inequivalent, unsymmetrical ligand scaffolds.

Abstract

Heteroleptic metal-organic cages, formed through integrative self-assembly of ligand mixtures, are highly attractive as reduced symmetry supramolecular hosts. Ensuring high-fidelity, non-statistical self-assembly, however, presents a significant challenge in molecular engineering due to the inherent difficulty in predicting thermodynamic energy landscapes. In this work, two conceptual strategies are described that circumvent this issue, using ligand design strategies to access structurally sophisticated metal-organic hosts. Using these approaches, it was possible to realise cavity environments described by two inequivalent, unsymmetrical ligand frameworks, representing a significant step forward in the construction of highly anisotropic confined spaces.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: James E. M. Lewis
onlinelibrary.wiley.com/doi/10.1002/anie.202212392

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