• Issue

    Chemistry – A European Journal: Volume 29, Issue 26

    May 8, 2023

Cover Pictures

Free Access

Front Cover: Antimicrobial Conjugated Oligoelectrolytes Containing Triphenylphosphonium Solubilizing Groups (Chem. Eur. J. 26/2023)

  • First Published: 04 April 2023
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Triphenylphosphonium functionalization of a conjugated oligoelectrolyte (COE) with a stilbene core improved its spectrum of activity to include ESKAPE pathogens and mycobacteria while crucially retaining the membrane-perturbing mode of action characteristic of COEs. The efficacy of the lead compound in vivo highlights the potential of the COE molecular platform for designing more effective antibiotics. More information can be found in the Research Article by G. C. Bazan and co-workers (DOI: 10.1002/chem.202203803).

Free Access

Cover Feature: Facilitating [2+2] Photocycloadditions by Promoting Oxygen Tolerance and Substrate Activation in Water (Chem. Eur. J. 26/2023)

  • First Published: 13 April 2023
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Micellar photocatalysis allows for a simple and benign reaction set-up using water as the solvent without the need for oxygen-removing protocols. Blue light (456 nm) is absorbed by the photocatalyst and allows the [2+2] photocycloaddition to occur between α,β-unsaturated carbonyl compounds and activated alkenes. The observed reactivity for α,β-unsaturated aldehydes is completely turned on by the use of a micellar solution as opposed to organic solvents. More information can be found in the Research Article by L. Næsborg and co-workers (DOI: 10.1002/chem.202300627).

Free Access

Cover Feature: Residue-Selective C−H Sulfenylation Enabled by Acid-Activated S-Acetamidomethyl Cysteine Sulfoxide with Application to One-Pot Stapling and Lipidation Sequence (Chem. Eur. J. 26/2023)

  • First Published: 13 April 2023
Description unavailable

The aromatic (C−H) sulfenylation reaction with S-acetamidomethyl cysteine sulfoxide (Cys(Acm)(O)) can be Trp- or Tyr-selective under acidic conditions. The red chloride anion team kicks the Cys(Acm)(O) ball into the Trp goal, whereas the blue trimethylsilyl team kicks the ball into the Tyr goal. The proton scoreline in the stands supports both teams. More information can be found in the Research Article by A. Otaka and co-workers (DOI: 10.1002/chem.202300799).

Frontispiece

Free Access

Frontispiece: Challenges and Strategies of Anion Exchange Membranes in Hydrogen-electricity Energy Conversion Devices

  • First Published: 08 May 2023
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Anion exchange membrane (AEM) is one of the most important components in anion exchange membrane water electrolyzer (AEMWE) and anion exchange membrane fuel cell (AEMFC). Herein, the challenges and corresponding strategies of AEM development are summarized to provide valuable predictions for the advancement of the hydrogen-electricity energy conversion devices.

Free Access

Frontispiece: Control of Selectivity in Homogeneous Catalysis through Noncovalent Interactions

  • First Published: 08 May 2023
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Noncovalent interactions are weak, but they can be used in the control of selectivity in homogeneous catalysis. In fact, overturn the selectivity from a 99 : 1 to 1 : 99 ratio of products can require only 6 kcal/mol energy difference between competing transition states. For details, see the Review by Mahmudov and Pombeiro (DOI: 10.1002/chem.202203861).

Free Access

Frontispiece: Thermally Activated vs. Photochemical Hydrogen Evolution Reactions–A Tale of Three Metals

  • First Published: 08 May 2023
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An in-depth analysis and comparison of hydrogen evolution reactions in gas phase model systems reveal five distinct mechanistic routes to form either atomic or molecular hydrogen. For more information, see the Concept by M. Beyer et al. (DOI: 10.1002/chem.202203590).

Reviews

Challenges and Strategies of Anion Exchange Membranes in Hydrogen-electricity Energy Conversion Devices

  • First Published: 10 January 2023
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The challenges and corresponding strategies of anion exchange membranes are summarized to provide valuable predictions for the advancement of hydrogen-electricity energy conversion devices, including anion exchange membrane water electrolyzer and anion exchange membrane fuel cell. Discussion is focused on membrane key properties (anion conductivity, long-term stability) and device applications (membrane-electrode interface, carbonation effect, water management).

Open Access

Control of Selectivity in Homogeneous Catalysis through Noncovalent Interactions

  • First Published: 23 February 2023
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The selectivity directing mission of noncovalent interactions (hydrogen, halogen, chalcogen, pnictogen and tetrel bonds, as well as agostic and π-interactions) in homogeneous catalysis is highlighted. The origin of the selectivity in noncovalent catalysis has been investigated through experimental and computational methods.

Concepts

Open Access

Thermally Activated vs. Photochemical Hydrogen Evolution Reactions–A Tale of Three Metals

  • First Published: 02 February 2023
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All roads lead to hydrogen. an in-depth analysis and comparison of hydrogen evolution reactions in gas phase model systems reveal five distinct mechanistic routes to form either atomic or molecular hydrogen.

Research Articles

Antimicrobial Conjugated Oligoelectrolytes Containing Triphenylphosphonium Solubilizing Groups

  • First Published: 04 February 2023
Description unavailable

PPh3 helps protect against pathogens: Conjugated oligoelectrolytes are a modular molecular platform for the design of novel antimicrobial agents. Substituting terminal alkylammonium cationic groups with more lipophilic triphenylphosphonium counterparts enabled bactericidal activity towards ESKAPE pathogens and clinically relevant mycobacteria. In vivo efficacy was verified in a murine wound model, at clinically relevant dosages.

Open Access

Facilitating [2+2] Photocycloadditions by Promoting Oxygen Tolerance and Substrate Activation in Water

  • First Published: 02 March 2023
Description unavailable

Micellar photocatalysis enables an oxygen-sensitive energy-transfer-catalysed [2+2] photocycloaddition in water and under aerobic conditions. Micellar effects suppress undesired quenching of triplet states by molecular oxygen through low oxygen solubility and compartmentalization of the micellar reaction mixture. Additionally, activation of the substrates towards sensitization by hydrogen bonding in the Stern layer is proposed, allowing efficient triplet energy transfer from [Ru(bpy)3]2+.

Residue-Selective C−H Sulfenylation Enabled by Acid-Activated S-Acetamidomethyl Cysteine Sulfoxide with Application to One-Pot Stapling and Lipidation Sequence

  • First Published: 15 March 2023
Description unavailable

Acid test for Tyr and Trp: S-Acetamidomethyl cysteine sulfoxide (Cys(Acm)(O)) enables the residue-selective C−H sulfenylation of Tyr or Trp under appropriately selected acidic reaction conditions. The dicationic intermediate derived from the Cys(Acm)(O) selectively reacts with Tyr, whereas the S-chlorocysteine allows Trp-selective sulfenylation. The one-pot sequence of stapling and lipidation of peptides was achieved.

Hot Paper

Open Access

Can Copper(I) and Silver(I) be Hydrogen Bond Acceptors?

  • First Published: 20 February 2023
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Hydrogen bonding with metals has recently been shown to take place with gold(I) compound. With the help of gas-phase IR spectroscopy and computational chemistry, we show, that similar interactions should exist also with Silver and Copper, with equipped with suitably designed ligands.

Facile Synthesis of Tetraphenylethene (TPE)-Based Fluorophores Derived by π-Extended Systems: Opposite Mechanofluorochromism, Anti-Counterfeiting and Bioimaging

  • First Published: 06 February 2023
Description unavailable

Two unprecedented 4,5-bis(tetraphenylethene)-1H-imidazole-fused pyridine or quinoline-based fluorophores X-1 and X-2 were designed and synthesized, and X-1 and X-2, exhibit completely opposite mechanofluorochromic behavior.

Hot Paper

Open Access

Assessing Combinations of B(C6F5)3 and N2-Derived Molybdenum Nitrido Complexes for Heterolytic Bond Activation

  • First Published: 20 February 2023
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Dinitrogen-derived nitrides have been explored as Lewis base component for frustrated Lewis pair type heterolytic bond splitting with B(C6F5)3 as the Lewis acid. d0 and d2 molybdenum nitrides both form stable adducts with B(C6F5)3. If Si−H bond splitting could be achieved, B−H bond activation of HB(C6F5)2 was not observed, this borane entering in competition with B(C6F5)3 to pair with the nitride without any further reactivity.

Chalcogen Bonding Catalysis of the Cloke-Wilson Rearrangement

  • First Published: 17 February 2023
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Conventionally, the Cloke-Wilson rearrangement is facilitated by strong Lewis acids, Brønsted acids and Lewis bases. Herein, a chalcogen bonding catalysis approach to the Cloke-Wilson rearrangement is established, affording dihydrofurans with moderate to good yields.

Photo-Induced In Situ Generation of Brønsted Acid for Catalytic Friedel–Crafts Alkylation of Indoles

  • First Published: 22 February 2023
Description unavailable

A photo-induced indole 2-alkylation reaction using unactivated, sterically congested alkenes as the Friedel–Crafts alkylation reagent gives a variety of 2-branched alkylated indole molecules in generally good efficiencies, with a broad scope of functional groups well tolerated.

CoNi2S4 Electrode with High Mass-Loading for High-Energy-Density Supercapacitor: Role of S-Containing Anions Exchange

  • First Published: 13 February 2023
Description unavailable

S-containing anion exchange process as a rational post-treatment route to realize the capacitive enhancement of CoNi2S4 nanoparticle arrays grown on carbon cloth (CC) with high mass-loading. The roles of anion exchange include the evolution in the surface morphology of nanoparticles, the enhancement of the crystallinity and resistance nature, and the improved durability stability.

Open Access

Biohybrid Microswimmers for Antibiotic Drug Delivery Based on a Thiol-Sensitive Release Platform

  • First Published: 09 February 2023
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Green kills. Antibiotic-loaded microswimmers kill bacteria after being triggered by a chemical stimulus. The design was based on thiol-responsive self-immolative linkers, vancomycin, and green algae as natural microbots.

Hot Paper

Open Access

Chemo-Enzymatic Synthesis of Long-Chain Oligosaccharides for Studying Xylan-Modifying Enzymes

  • First Published: 15 February 2023
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Xylan biosynthesis: Starting from dixylosides, chemo-enzymatic syntheses of xylan dodecasaccharides using glycosynthase-mediated coupling reactions between glycosyl fluoride donors and thioglycoside acceptors were performed. These long-chain xylan oligosaccharides were incubated with xylan-modifying enzymes from plants, i. e., three glycosyltransferases and one acetyltransferase, and the reaction products were analyzed by MALDI-MS.

Functionalized Benzothiadiazole Non-Fused A−D−A’−D−A Small Molecules for Effective Electron Mobilities and Metal-free Photocatalysis

  • First Published: 03 February 2023
Description unavailable

Electron mobility: Three non-fused A−D−A’−D−A π-conjugated small molecules BT-IT1, BT-IBT2 and BT2F-IBT3, with absorption in the range of 325–600 nm in solutions, were synthesized. They showed low-lying HOMO-LUMO energy levels and narrow bandgaps of (EgCV) ∼1.79 eV. Appreciable electron mobilities of 4.56×10−3 and 1.12×10−3 cm2 V−1 s−1 for compounds BT-IBT2 and BT2F-IBT3, respectively, were obtained. High photocatalytic performances and high selectivity in the oxidation of thioanisole to desired sulfoxides was observed.

Hot Paper

The Tunable and Efficient Nanoporous CuAg Alloy Catalysts Toward Methanol Oxidation Reaction Synthesized by Electrochemical Dealloying of Metallic Glassy Precursors

  • First Published: 25 February 2023
Description unavailable

Three-dimensional nanoporous CuAg alloy catalysts with various Cu/Ag ratios are prepared by electrochemical dealloying of metallic glassy precursors. The NPCu1.75Ag catalyst presents the best methanol electro-oxidation properties, including a high current density and good operation stability. The designed electrodes are expected to be promising catalysts for alkaline direct methanol fuel cell applications.

Very Important Paper

Surface-Stabilized CsPbI3 Nanocrystals with Tailored Organic Polymer Ligand Binding

  • First Published: 13 February 2023
Description unavailable

Stable black-phase γ-CsPbI3 nanocrystals capped with a new organic polymer ligand, HO-PS-N3, have been synthesized by hot-injection method with significantly improved resistance to moisture and light.

Stereoselective Synthesis of Tetraarylethylenes Enabled by Reductive anti-1,2-Dimetallation of Alkynes

  • First Published: 20 February 2023
Description unavailable

A palladium-catalyzed anti-1,2-diarylation of diarylacetylenes is described. The key intermediates, trans-1,2-dizincioalkenes, are prepared by sodium-promoted reductive anti-1,2-dimagnesiation of alkynes and the subsequent transmetallation to zinc. The present reaction enables the stereoselective synthesis of tetraarylethylenes which have been difficult to prepare according to the conventional methods.

Open Access

Scaffold Remodelling of Diazaspirotricycles Enables Synthesis of Diverse sp3-Rich Compounds With Distinct Phenotypic Effects

  • First Published: 01 February 2023
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Structural and functional diversity from simple precursors: an efficient entry into a diverse sp3-rich compound library was achieved by scaffold remodelling (ring cleavage, expansion and addition) of readily-prepared spirotricyclic ureas. The resulting library shows significant scaffold diversity despite the common precursors, while individual compounds demonstrate distinctive phenotypic effects in the cell-painting assay, suggesting the library is also functionally diverse.

Hot Paper

Open Access

Heterocyclic Hemipiperazines: Water-Compatible Peptide-Derived Photoswitches

  • First Published: 15 February 2023
Description unavailable

Photoswitching in presence of water: decoration of cyclic dipeptides with heteroarylidene substituents produces novel biocompatible molecular photoswitches. They show high thermal stability, and are operational under aqueous conditions with an organic co-solvent. Extended heteroaromatic system enables bidirectional switching with visible light.

Open Access

The Boekelheide Rearrangement of Pyrimidine N-oxides as a Case Study of Closed or Open Shell Reactions - Experimental and Computational Evidence for the Participation of Radical Intermediates

  • First Published: 13 February 2023
Description unavailable

Heterocycles: The rearrangement of a model pyrimidine N-oxide with carboxylic acid anhydrides provides the acyloxymethyl-substituted compounds as major products. In addition, other compounds derived from radical intermediates are formed in considerable amounts under certain conditions. By comprehensive experimental and quantum-chemical calculations, a rationale for the apparently competing mechanisms is proposed. The pathways via closed shell and open shell intermediates are compared.

Unexpectedly Large Structural Variations in Benzyl-Substituted Sila[1]ferrocenophanes

  • First Published: 17 February 2023
Description unavailable

Four related silicon-bridged [1]ferrocenophanes show large variations of the tilting of Cp rings in the crystal lattice. While the measured tilt angles range from 16.6 to 21.5°, calculated values range from 19.6 to 20.8°. With the help of DFT calculations, the unexpected experimental results are rationalized and placed into the contexts of known outliers of the sila[1]ferrocenophane family.

Very Important Paper

Mitochondria-Targeted Gene Silencing Facilitated by Mito-CPDs

  • First Published: 20 February 2023
Description unavailable

Mitochondria-Targeted Gene Silencing: We report a mitochondria-targeted cell-penetrating poly(disulfide)s (Mito-CPDs), which is not only compatible with commercially available gene-silencing reagents without the need of chemical or genetic modifications, but also capable of transporting siRNA and ASO into mitochondria and thereby silencing mtDNA specifically.

Co2+ to Al3+ Substitution Induced Dual-Site Synergistic Catalysis to Friedel-Crafts Alkylation Reactions

  • First Published: 15 February 2023
Description unavailable

A simple Co2+ to Al3+ substitution in Al4B6O15 lattice leads to the dual-site synergistic catalysis, that is the Friedel-Crafts alkylation reaction between β-nitrostyrene adsorbed and activated at the Lewis acidic site (unsaturated Co2+) and the indole molecule, which is activated by an adjacent reactive oxygen species.

Water-Induced Single-Crystal to Single-Crystal Transformation of Ionic Hydrogen-Bonded Organic Frameworks with Enhanced Proton Conductivity

  • First Published: 20 February 2023
Description unavailable

Single crystal to single crystal transition: This study reports the synthesis of two hydrogen-bonded organic frameworks (HOFs) and the transformation of iHOF-10 to iHOF-11. The results show that water molecules induce the single crystal to single crystal transition process, as well as increase the proton conductivity.

Structural Engineering of Red Luminogens to Realize High Emission Efficiency through ACQ-to-AIE Transformation

  • First Published: 20 February 2023
Description unavailable

Two “V-shaped” red-to-NIR organic luminogens, FITPA and FIMPA, were developed. The “V-shaped” configurations have been demonstrated to enhance the transition dipole moments. Moreover, the ACQ-to-AIE transformation from FITPA to FIMPA is induced by a methoxy-substitution strategy. The enhanced transition dipole moment and AIE behavior endow FIMPA intense luminescence in the solid state. Furthermore, the promising cell-imaging performance verified the great potential of FIMPA in biological applications.

Nanolobatone A, An Unprecedented Diterpenoid and Related New Casbanoids from the Hainan Soft Coral Sinularia nanolobata

  • First Published: 21 February 2023
Description unavailable

A novel antibacterial diterpenoid: The chemical investigation of Hainan soft coral Sinularia nanolobata, has led to the isolation and characterization of a novel antibacterial diterpenoid, Nanolobatone A, featuring an unprecedented tricyclo[10.3.0.01,2]pentadecane carbon skeleton, along with eight new casbane-type diterpenoids.

Very Important Paper

Revealing the Crystal Phase-Activity Relationship on NiRu Alloy Nanoparticles Encapsulated in N-Doped Carbon towards Efficient Hydrogen Evolution Reaction

  • First Published: 20 February 2023
Description unavailable

The crystal phase-activity relationship of NiRu nanoparticles is studied employing the N-doped carbon shell coated NiRu nanoparticles with different phase contents. The hcp phase NiRu has better HER performance, and the NiRu@NC (mix) with rich (∼70 %) hcp phase presented outstanding performance with an overpotential of only 27 mV @ 10 mA ⋅ cm−2 and a low Tafel slope of 42 mV ⋅ dec−1.

Open Access

Access to Amide-Linked Organic Cages by in situ Trapping of Metastable Imine Assemblies: Solution Phase Bisamine Recognition

  • First Published: 13 January 2023
Description unavailable

The majority of shape-persistent self-assembled organic cages are accessed via precipitation and studied in the solid state. Herein, we show that metastable imine cages (unsuitable for precipitation) can be trapped directly by in situ Pinnick oxidation conditions, yielding soluble, robust amide cages. Unlike the by-passed imine cages, the resulting cages are tolerant of hydrolysis conditions to unmask internal carboxylic acids, which undergo 2-point binding with amines (unsuitable guests for imine cages).

Hot Paper

Open Access

ACTIVE-BAPO – A Versatile Transfer Agent for Photoactive Bis(acyl)phosphane Oxide Units

  • First Published: 14 February 2023
Description unavailable

Active BAPO - An NHS ester substituted bis(acyl)phosphane oxide (BAPO) is synthesized by phospha-Michael addition and used as the first versatile transfer agent for the grafting of photoactive BAPO units. Amino acids, porcine skin, and poly(amido)amine (PAMAM) dendrimers were functionalized with the photoactive units and used for the synthesis of thermosets with a different degree of crosslinking.

Expedient Synthesis of Dihaloalkenynes via Pd-Catalyzed Haloalkynylation Reaction

  • First Published: 16 February 2023
Description unavailable

A robust and regioselective PdII-catalyzed haloalkynylation of haloalkynes has been established under ligand-free and oxidant-free conditions. Careful selection of the haloalkyne starting material, with respect to electron densities of the alkyne, allows for strong control of the order and selectivity of the halide atoms in the coupled product.