• Issue
    Volume 27, Issue 9
    2882-3186
    February 10, 2021

Cover Pictures

Free Access

Front Cover: Mimicking Photosystem I with a Transmembrane Light Harvester and Energy Transfer-Induced Photoreduction in Phospholipid Bilayers (Chem. Eur. J. 9/2021)

  • Pages: 2882
  • First Published: 14 January 2021
Description unavailable

A transmembrane dye and an energy accepting dye were implemented in lipid bilayers of liposomes and giant vesicles. Light-induced energy transfer and transmembrane arrangement can be observed with luminescence spectroscopy, dynamic light scattering and confocal microscopy, supported by time-dependent DFT calculations and molecular dynamics simulation. More information can be found in the Full Paper by A. Pannwitz, S. Bonnet, et al. on page 3013.

Free Access

Cover Feature: Efficient Imine Formation by Oxidative Coupling at Low Temperature Catalyzed by High-Surface-Area Mesoporous CeO2 with Exceptional Redox Property (Chem. Eur. J. 9/2021)

  • Pages: 2883
  • First Published: 07 December 2020
Description unavailable

The excellent performance of CeO2 for imine synthesis at low temperature is highlighted in the cover image. A template-induced homogeneous precipitation method was used to prepare high-surface-area mesoporous CeO2 that carries abundant surface oxygen vacancies attached to coordinatively unsaturated Ce3+ ions. These boost the activation of alcohol and O2, and allow superior catalytic stability and wide substrate scope with good to excellent imine yields. More information can be found in the Full Paper by W. Fang et al. on page 3019.

Free Access

Cover Feature: Double Orthogonal Click Reactions for the Development of Antimicrobial Peptide Nanotubes (Chem. Eur. J. 9/2021)

  • Pages: 2884
  • First Published: 07 December 2020
Description unavailable

Killing bacteria using supramolecular drugs based on self-assembled peptide nanotubes: The peptides are designed to interact with the bacteria membrane and to stack forming supramolecular hollow cylinders that disrupt the bacteria lipid bilayer. More information can be found in the Full Paper by J. R. Granja et al. on page 3029.

Free Access

Cover Feature: Push–Pull Bisnaphthyridylamine Supramolecular Nanoparticles: Polarity-Induced Aggregation and Crystallization-Induced Emission Enhancement and Fluorescence Resonance Energy Transfer (Chem. Eur. J. 9/2021)

  • Pages: 2885
  • First Published: 07 December 2020
Description unavailable

An organic solution with a push–pull-type fluorophore, which resembles the shape of a dragon in the cover image, exhibits aggregation-induced emission enhancement upon water addition. The cover tells the story of one dragon who strayed into the mythical world. The dragon found water, which was poured by Ganymēdēs; he showered and drank the water. He then flew away swiftly, shining like the star sign Aquarius. Upon increasing the water content of the aqueous solutions, transformations from the monomer to the crystals and the crystals to the nanoparticles were observed, accompanied by emission enhancement. More information can be found in the Full Paper by S. Karasawa et al. on page 3039.

Frontispiece

Free Access

Frontispiece: New Promises and Opportunities in 3D Printable Inks Based on Coordination Compounds for the Creation of Objects with Multiple Applications

  • First Published: 10 February 2021
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Multidisciplinary applications of 3D printing inks based on metal–organic compounds are described in the Review by N. Maldonado and P. Amo-Ochoa on page 2887.

Free Access

Frontispiece: Temperature Induced Aggregation of Organic Semiconductors

  • First Published: 10 February 2021
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Temperature is an influential parameter that determines the aggregation of solution processed organic semiconductors. In their Minireview on page 2908, Tao Wang et al. summarize the temperature-induced aggregation of organic semiconductors in solution, during solution casting and upon thermal annealing post-treatment of solid-state thin films, which in turn impacts their optoelectronic properties.

Free Access

Frontispiece: Synthesis of Ajoene Analogues by Novel Synthetic Strategies

  • First Published: 10 February 2021
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Garlic (Allium sativum) has a long history as a food ingredient and traditional medicine, and garlic extracts have been known for a very long time to exhibit a wide range of biological properties (some general structures of ajoene analogues are shown on the picture of the plant). In their Full Paper on page 3008, Wirth et al. describe the synthesis of three non-natural Allium analogues. These analogues were biologically evaluated in their ability to inhibit biofilm production in S. Aureus and P. Aeruginosa with promising results.

Cover Profile

Free Access

Mimicking Photosystem I with a Transmembrane Light Harvester and Energy Transfer-Induced Photoreduction in Phospholipid Bilayers

  • Pages: 2886
  • First Published: 10 February 2021
Description unavailable

In this study we designed and synthesized a transmembrane dye for light harvesting, energy and electron transfer within a biomimetic lipid bilayer. Surprising to us personally was the fact that the transmembrane orientation of the blue emitting dye was optically visible via confocal microscopy.” Read more about the story behind the cover in the Cover Profile and about the research itself on page 3013 ff. (DOI: 10.1002/chem.202003391).

Reviews

Metal–Organic Frameworks

New Promises and Opportunities in 3D Printable Inks Based on Coordination Compounds for the Creation of Objects with Multiple Applications

  • Pages: 2887-2907
  • First Published: 07 September 2020
Description unavailable

Shaping the future in 3D: Metal–organic compounds with dynamic coordination bonds as new possible 3D inks with interesting properties are reviewed. Technological advances, the combination of various printing techniques, and the properties of coordination bonds lead to the creation of surprising new printable inks and objects with highly complex shapes that will close the gap between academia and industry for research into coordination compounds.

Minireviews

Materials Science | Reviews Showcase

Temperature Induced Aggregation of Organic Semiconductors

  • Pages: 2908-2919
  • First Published: 28 June 2020
Description unavailable

Temperature plays a vital role in determining the aggregation behavior of organic semiconductors in solution, during solution casting and in solid thin films, consequently it has an impact on optoelectronic properties.

Physical Chemistry | Reviews Showcase

Quantifying the Overall Efficiency of Circularly Polarized Emitters

  • Pages: 2920-2934
  • First Published: 29 July 2020
Description unavailable

A new tool, named circularly polarized luminescence (CPL) brightness (BCPL), is introduced to evaluate the performances of CPL emitters. Beyond the dissymmetry factor, it takes into account quantum yields and extinction coefficients, allowing an easy and direct comparison of various CPL-emitters belonging to different chemical classes.

Fluorinated Compounds

Synthesis of Fluoro-, Monofluoromethyl-, Difluoromethyl-, and Trifluoromethyl-Substituted Three-Membered Rings

  • Pages: 2935-2962
  • First Published: 17 September 2020
Description unavailable

Better with three: Fluorinated three-membered rings are valuable compounds with many applications. In this Minireview, the synthesis of fluoro-, monofluoromethyl-, difluoromethyl-, and trifluoromethyl-substituted cyclopropanes, cyclopropenes, aziridines, azirines, epoxides, and thiiranes over the past decade are described.

Biosynthesis | Reviews Showcase

Enzymatic Formation of Indolactam Scaffold by C−N Bond-Forming Cytochrome P450 Oxidases in Teleocidin Biosynthesis

  • Pages: 2963-2972
  • First Published: 30 September 2020
Description unavailable

Enzymatic formation of indolactam: This minireview focuses on recent research progress on the elucidation of the molecular basis for the P450-catalyzed remarkable intramolecular C−N bond-forming reaction to generate the indolactam scaffold. In addition, precursor-directed biosynthesis led to formation of a series of unnatural novel molecular scaffolds including a sulfur-substituted indolactam, conformation of which is significantly different from that of indolactam V.

Organic Electronics | Reviews Showcase

Electron-Deficient Conjugated Materials via p–π* Conjugation with Boron: Extending Monomers to Oligomers, Macrocycles, and Polymers

  • Pages: 2973-2986
  • First Published: 27 August 2020
Description unavailable

The development of π-extended organoboranes is systematically discussed from both theoretical and experimental perspectives. An analysis of the p–π* conjugation and of mutual interactions between electron-deficient boron centers across π-conjugated linkers allows for important structure–property relationships to be deduced. It is also illustrated how the unique properties of these boron-containing π-conjugated systems are exploited in the field of organic optical and optoelectronic device materials.

Communications

Drug Delivery | Hot Paper

Construction of Hyaluronic Acid-Covered Hierarchically Porous MIL-nanoMOF for Loading and Controlled Release of Doxorubicin

  • Pages: 2987-2992
  • First Published: 15 December 2020
Description unavailable

Controlled release: HACD@ADA-PA/MIL-101_NH2 (Fe)-P nanoparticle was fabricated from MIL-101_NH2 (Fe)-P nanoMOF, phosphite-modified adamantane (ADA-PA), and β-cyclodextrin (β-CD)-modified hyaluronic acid (HACD), by supramolecular and coordination interactions. The chemotherapeutic drug doxorubicin (DOX) could be loaded into the porous structure of the nanoparticle to obtain HACD@ADA-PA/MIL-101_NH2 (Fe)-P@DOX, which was stable at pH 7.2 but could release DOX in a controlled way at pH 5.7.

2D Materials | Hot Paper

Covalent Cross-Linking of 2H-MoS2 Nanosheets

  • Pages: 2993-2996
  • First Published: 24 November 2020
Description unavailable

Cross-linked nanosheets: The covalent combination of different flakes of 2D materials is relatively underexplored, in particular, in the case of transition metal dichalcogenides. This work reports a simple methodology of covalent cross-linking of MoS2 through bismaleimide reagent. The MoS2–MoS2 homostructures show preferably a vertical connection, basal plane to basal plane of different flakes.

Catalytic Mechanisms

Open Access

A Switchable Catalyst Duo for Acyl Transfer Proximity Catalysis and Regulation of Substrate Selectivity

  • Pages: 2997-3001
  • First Published: 06 October 2020
Description unavailable

Two switchable catalysts with differently sized cavities and allosteric control are reported that allow complementary size-selective acyl transfer in an on/off manner by modulating the effective local concentration of the substrates. Selective activation of one of the two catalysts in a mixture of reactants of similar reactivity enabled upregulation of the desired product.

Macrocycles

Open Access

Calcium Hydride Catalysts for Olefin Hydrofunctionalization: Ring-Size Effect of Macrocyclic Ligands on Activity

  • Pages: 3002-3007
  • First Published: 13 November 2020
Description unavailable

Macrocyclic ligands recognize ion size, but are rarely used to influence metal-centered catalytic activity. Calcium hydride cation [CaH]+ supported by the fifteen-membered NNNNN macrocycle Me5PACP (Me5PACP=1,4,7,10,13-pentamethyl-1,4,7,10,13-pentaazacyclopentadecane) catalyzes hydrogenation and hydrosilylation of unactivated olefins significantly faster than the analogous calcium catalyst containing the twelve-membered NNNN macrocycle (see figure).

Full Papers

Organic Chemistry | Hot Paper

Synthesis of Ajoene Analogues by Novel Synthetic Strategies

  • Pages: 3008-3012
  • First Published: 07 December 2020
Description unavailable

Non-natural Allium analogues of three types have been synthesised by novel synthetic strategies. Analogues have been biologically evaluated in their ability to inhibit biofilm production in S. Aureus and P. Aeruginosa with promising results.

Energy Transfer | Hot Paper

Open Access

Mimicking Photosystem I with a Transmembrane Light Harvester and Energy Transfer-Induced Photoreduction in Phospholipid Bilayers

  • Pages: 3013-3018
  • First Published: 02 August 2020
Description unavailable

Mimicking PS I: Light absorption, energy transfer and electron transfer were obtained in a supramolecular mimic of photosystem I.

Ceria Catalysts | Hot Paper

Efficient Imine Formation by Oxidative Coupling at Low Temperature Catalyzed by High-Surface-Area Mesoporous CeO2 with Exceptional Redox Property

  • Pages: 3019-3028
  • First Published: 09 October 2020
Description unavailable

Mesoporous ceria catalysts: A high-surface-area mesoporous CeO2 catalyst prepared by an organic-template-induced homogeneous precipitation method shows exceptional redox properties and can boost imine formation by direct oxidative coupling of primary alcohols and anilines in air atmosphere at low temperature.

Nanotubes | Hot Paper

Double Orthogonal Click Reactions for the Development of Antimicrobial Peptide Nanotubes

  • Pages: 3029-3038
  • First Published: 28 September 2020
Description unavailable

Double clicked amphipathic cyclic peptides assemble in bacteria membranes to form polymeric supramolecular nanotubes, conferring them antimicrobial properties.

Emissive Nanoparticles | Hot Paper

Push–Pull Bisnaphthyridylamine Supramolecular Nanoparticles: Polarity-Induced Aggregation and Crystallization-Induced Emission Enhancement and Fluorescence Resonance Energy Transfer

  • Pages: 3039-3046
  • First Published: 15 September 2020
Description unavailable

Emissive bisnaphthyridylamine derivatives (BNA-X) have been prepared. In MeOH/water mixtures, the BNA-X containing alkyl groups or a phenyl ring showed aggregation-induced emission enhancement (AIEE) and crystallization-induced emission enhancement (CIEE) depending on the water content. The AIEE behavior was based on the formation of nanoparticles (NPs) with small polydispersity indices. In the presence of pyrene, the NPs showed fluorescence resonance energy transfer (FRET).

Porphyrin Chemistry | Hot Paper

Open Access

A Synthetic Strategy for Cofacial Porphyrin-Based Homo- and Heterobimetallic Complexes

  • Pages: 3047-3054
  • First Published: 18 January 2021
Description unavailable

Simple route to dimeric complexes: Three different types of covalently linked metalloporphyrin dimers were synthesized. The monomers were synthesized sequentially and can be filled with metals before linking. As a result, different heterobimetallic systems can be made. Depending on the metals M1 and M2 used (M=Mn, Fe, Ni, Cu, Zn, Pd), a wide range of potentially catalytically active species can be prepared, such as analogues of carbon monoxide dehydrogenase.

Aromaticity

Open Access

Isolation of a 16π-Electrons 1,4-Diphosphinine-1,4-diide with a Planar C4P2 Ring

  • Pages: 3055-3064
  • First Published: 20 October 2020
Description unavailable

Aromatic (I) and antiaromatic (II) C4P2 ring systems derived from an anionic dicarbene (ADC) have been reported. Electronic structures of I and II have been analyzed by NMR and X-ray diffraction studies and corroborated by computational calculations. The ACID (anisotropy of induced current density) plot of II shows that the ring current in the central C4P2 ring is paratropic (antiaromatic) whereas the peripheral C3N2 rings exhibit two local diatropic ring currents. The ACID plot of the aromatic system II unveils a global diatropic current on the periphery of the C3N2 and C4P2 rings.

Organic semiconductors

Design Approach of Lifetime Extending Thermally Activated Delayed Fluorescence Sensitizers for Highly Efficient Fluorescence Devices

  • Pages: 3065-3073
  • First Published: 13 November 2020
Description unavailable

Efficient TADF sensitizer: Three thermally activated delayed fluorescence (TADF) materials having fast reverse intersystem crossing rate were developed for TADF sensitizer. Among these, two TADF materials include tert-butyl blocking group to manage the Dexter energy transfer. TADF sensitized fluorescent devices with blocking groups show high maximum external quantum efficiencies. In addition, the device operational lifetime is extended by adding blocking groups.

Phase Transitions

Large-Amplitude Thermal Vibration-Coupled Valence Tautomeric Transition Observed in a Conductive One-Dimensional Rhodium–Dioxolene Complex

  • Pages: 3074-3084
  • First Published: 11 November 2020
Description unavailable

Vibronic interaction has the potential to create new fields on dynamic electronic states arising from the mixing of different electronic states by nuclear displacements. A one-dimensional rhodium-dioxolene complex undergoes drastic changes in properties with the phase transition, which are ascribable to the appearance of the mixed-valence state due to the metal–ligand electron transfer coupled with a large-amplitude vibration of Rh−Rh bonds.

Photocatalysis

Proton-Functionalized Graphitic Carbon Nitride for Efficient Metal-Free Destruction of Escherichia coli under Low-Power Light Irradiation

  • Pages: 3085-3090
  • First Published: 02 December 2020
Description unavailable

Water, water everywhere: The efficiency of graphitic carbon nitride (g-C3N4) in photocatalytic water disinfection is plagued by its rapid charge recombination and sluggish electron-transfer kinetics. Protonation of g-C3N4 can enhance its conductivity and provide a “highway” for the delocalization of electrons. Consequently, protonated g-C3N4 demonstrated 100 % destruction of E. coli within 4 h under low-power household light irradiation.

Aromatic Claisen Rearrangement

Aromatic Aza-Claisen Rearrangement of Arylpropargylammonium Salts Generated in situ from Arynes and Tertiary Propargylamines

  • Pages: 3091-3097
  • First Published: 17 November 2020
Description unavailable

An unprecedented aromatic aza-Claisen rearrangement of arylpropargylammonium salts, generated in situ from arynes and tertiary propargylamines, has been established, delivering structurally diverse 2-propargylanilines. These further cyclize in the presence of aluminum chloride to afford multisubstituted indoles.

Molecular Recognition | Hot Paper

In Vitro and In Vivo Sequestration of Phencyclidine by Me4Cucurbit[8]uril

  • Pages: 3098-3105
  • First Published: 18 November 2020
Description unavailable

Be my guest: We report the binding affinity of CB[8] and its water soluble analogue Me4CB[8] toward a panel of 10 drugs of abuse by isothermal titration calorimetry. The Me4CB[8]⋅PCP complex is particularly tight with Kd=2 nm in 20 mm NaH2PO4 buffered H2O at pH 7.4. Me4CB[8] is well tolerated according to the results of in vitro cytotoxicity assays and in vivo (mice) maximum tolerated dose studies. The hyperlocomotion of swiss webster mice dosed with PCP can be controlled by the (pre)treatment with Me4CB[8].

Biosynthesis

Open Access

Chemical and Genetic Studies on the Formation of Pyrrolones During the Biosynthesis of Cytochalasans

  • Pages: 3106-3113
  • First Published: 04 November 2020
Description unavailable

Curiouser and curiouser: The long-proposed intermediacy of 1,5-dihydro pyrrol-2-ones, which are required during cytochlasan biosynthesis, is called into question. An enzyme involved in this formal Knoevenagel step (PyiE) is identified and a potential mechanism suggested.

Imaging Agents

Rational Design of High-Relaxivity EuII-Based Contrast Agents for Magnetic Resonance Imaging of Low-Oxygen Environments

  • Pages: 3114-3118
  • First Published: 23 November 2020
Description unavailable

Rigid, but relaxed: EuII-containing complexes have potential use as responsive imaging agents for hypoxia. A rigid, dimetallic EuII-containing cryptate was investigated as a high-efficiency contrast agent for magnetic resonance imaging. NMR dispersion studies indicate that this agent exhibits higher relaxometric efficiency than either a flexible dimetallic agent or analogous small-molecule agents.

Supramolecular Chirality

Effect of Stereochemistry on Chirality and Gelation Properties of Supramolecular Self-Assemblies

  • Pages: 3119-3129
  • First Published: 22 November 2020
Description unavailable

Mirror images: For C2-symmetrical dipeptide-based derivatives bearing various amino acid sequences and different chiralities, their supramolecular chirality is only determined by the amino acid adjacent to the benzene core and is irrespective of the absolute configuration of the C-terminal amino acid.

Drug Design | Very Important Paper

Discovery of a Pyrimidinedione Derivative with Potent Inhibitory Activity against Mycobacterium tuberculosis Ketol–Acid Reductoisomerase

  • Pages: 3130-3141
  • First Published: 20 November 2020
Description unavailable

On target: A compound (NSC116565) from the National Cancer Institute Developmental Therapeutic Program (NCI-DTP) chemical library shows strong inhibition of Mycobacterium tuberculosis (Mtb) ketol–acid reductoisomerase (KARI), a potential target for antituberculosis agents. NSC116565 competitively binds to the active site of KARI in the absence or presence of the NADPH cofactor and inhibits the growth of virulent and avirulent Mtb.

Bacterial Sialidases

Polyvalent Transition-State Analogues of Sialyl Substrates Strongly Inhibit Bacterial Sialidases

  • Pages: 3142-3150
  • First Published: 05 November 2020
Description unavailable

Band of brothers: Conjugation of the transition-state analogue 2-deoxy-2,3-didehydro-N-acetylneuraminic (DANA) to polymeric scaffolds leads to highly potent inhibitors of bacterial sialidases. Each clustered DANA on the polymers sees its inhibitory potency for S. pneumoniae or B. thetaiotaomicron sialidases improved by more than four orders of magnitude. This extends the multivalent concept to this important class of enzymes.

Donor–Acceptor Systems | Hot Paper

Modulating the Electron-Donating Ability of Acridine Donor Units for Orange–Red Thermally Activated Delayed Fluorescence Emitters

  • Pages: 3151-3158
  • First Published: 25 November 2020
Description unavailable

Full color palette: By fusing a benzothiophene unit to a diphenylacridine donor unit, a new donor moiety for orange–red thermally activated delayed fluorescence (TADF) emitters is achieved. Organic light-emitting diode devices based on the resulting orange–red TADF emitter show good performance over a wide range of concentrations.

Amide Ligands | Hot Paper

Open Access

A Xanthene-Based Mono-Anionic PON Ligand: Exploiting a Bulky, Electronically Unsymmetrical Donor in Main Group Chemistry

  • Pages: 3159-3165
  • First Published: 17 November 2020
Description unavailable

The application of a sterically demanding mono-anionic PON ligand in gallium chemistry has been probed, revealing a highly unsymmetrical donor profile towards GaI and structural features reminiscent of one-coordinate gallium amides. Oxidation at the metal leads to a marked increase in the donor capabilities of the phosphine donor, although the transient gallanone formed by O-atom transfer still undergoes facile C−H activation across the Ga−O bond.

Medicinal Chemistry

An Aldehyde Responsive, Cleavable Linker for Glucose Responsive Insulins

  • Pages: 3166-3176
  • First Published: 10 November 2020
Description unavailable

463 Million people live with diabetes of which approximately 10 % have type 1 diabetes. A glucose responsive insulin that responds to fluctuations in blood glucose concentrations has remained an elusive goal for decades. Here we describe the chemical development of hydrazones and thiazolidines that are cleavable in glucose concentration dependent manner. These were used to construct unprecedented glucose responsive insulins.

Selectivity Control | Hot Paper

Open Access

Selectivity of Rh⋅⋅⋅H−C Binding in a σ-Alkane Complex Controlled by the Secondary Microenvironment in the Solid State

  • Pages: 3177-3183
  • First Published: 28 October 2020
Description unavailable

Importance of microenvironment: By using solid-state molecular organometallic (SMOM) techniques, the σ-alkane complex [Rh(tBu2PCH2CH2CH2PtBu2)(η22-C7H12)][BArF4], in which the alkane binds through two exo-C−H⋅⋅⋅Rh interactions, is synthesized and structurally characterized. This is different from the analogous complex with PCy2 groups. Subtle differences in the microenvironment, as encoded by the diene precursor complex, are shown to determine the selectivity of alkane binding.

Corrigenda