• Issue

    Chemistry – A European Journal: Volume 28, Issue 16

    March 16, 2022

Cover Pictures

Free Access

Front Cover: Tribo-Excited Chemical Reaction Using an EuIII Complex with a Stacked Anthracene Framework (Chem. Eur. J. 16/2022)

  • First Published: 03 March 2022
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Tribo-excitation in a crystalline compound is an interesting phenomenon in which a mechanical stimulus drives the compound to its excited state. We demonstrate a tribo-excited chemical reaction using trivalent europium (EuIII) and gadolinium (GdIII) complexes with stacked anthracene ligands for the development of tribo-excitation chemistry. The tribo-oxidation and -dimerization reactions in the stacked anthracene ligands occur in the EuIII and GdIII complexes, respectively. More information can be found in the Research Article by Y. Kitagawa, Y. Hasegawa et al. (DOI: 10.1002/chem.202104401).

Free Access

Cover Feature: Role of Anionic Backbone in NHC-Stabilized Coinage Metal Complexes: New Precursors for Atomic Layer Deposition (Chem. Eur. J. 16/2022)

  • First Published: 24 February 2022
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A series of new N-heterocyclic carbene (NHC) based Cu(I) and Ag(I) complexes were synthesized, analyzed, and evaluated for their potential usage in atomic layer deposition (ALD) of coinage metal thin films. Employing the same set of diketonate-type ligands for both metals did result in thermally stable Cu(I) complexes suitable for ALD, while the Ag(I) complexes exhibit an inherently unstable nature and different bonding features. More information can be found in the Research Article by Anjana Devi et al. (DOI: 10.1002/chem.202103798).

Frontispiece

Free Access

Frontispiece: Ferroelectrics in Photocatalysis

  • First Published: 16 March 2022
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Ferroelectric semiconductors are attracting more and more attention due to their unique polar nature. Herein, ferroelectrics in photocatalysis are systematically summarized to provide an overview to help breakthroughs in this field and to inspire related work involving solar conversion and ferroelectric devices. The high efficiency, selectivity and controllability of photocatalysis are covered, as are their thorough mechanisms for the synthesis and functions. For more details, see the Review by H. W. Huang and L. Z. Liu (DOI: 10.1002/chem.202103975).

Free Access

Frontispiece: Pedal to the Metal: The Homogeneous Catalysis of the Native Chemical Ligation Reaction

  • First Published: 16 March 2022
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Homogeneous nucleophilic catalysis is key to the acceleration of the native chemical ligation (NCL) reaction and thus to its application to protein semi or total synthesis and utilization in chemical biology. The concept article by V. Diemer et al. discusses the fundamental principles of NCL rate and catalysis and is presented as a guide for readers in the search for an appropriate catalyst.

Cover Profile

Free Access

Tribo-Excited Chemical Reaction Using an EuIII Complex with a Stacked Anthracene Framework

  • First Published: 07 March 2022
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We demonstrate a tribo-excited chemical reaction using trivalent europium (EuIII) and gadolinium (GdIII) complexes with stacked anthracene ligands for the development of tribo-excitation chemistry. The tribo-oxidation and -dimerization reactions in the stacked anthracene ligands occur in the EuIII and GdIII complexes, respectively.” This and more about the story behind the front cover can be found in the article at 10.1002/chem.202104401).

Reviews

Reviews Showcase

Ferroelectrics in Photocatalysis

  • First Published: 16 December 2021
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Structure, nature and future: This review classifies ferroelectric photocatalysts into perovskite, layered bismuth-based and other materials based on their crystal structure. Progress in ferroelectrics research is then summarized including photocatalytic pollution degradation, water splitting and CO2 reduction. Finally, current challenges and future prospects are provided with the purpose for presenting a deep insight and guideline for future research into ferroelectrics.

Concepts

Pedal to the Metal: The Homogeneous Catalysis of the Native Chemical Ligation Reaction

  • First Published: 19 January 2022
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Nucleophilic catalysis is key to the acceleration of the native chemical ligation (NCL) reaction and thus, to its application for protein synthesis, functionalization and utilization in chemical biology. The present concept article discusses the fundamental principles of NCL rate and catalysis with emphasis on thiol nucleophiles.

Reviews Showcase

Interstitial Hydrides in Nanoclusters can Reduce M(I) (M=Cu, Ag, Au) to M(0) and Form Stable Superatoms

  • First Published: 22 December 2021
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The concept proposes that interstitial hydrides in high-nuclearity coinage metal nanoclusters can reduce M(I) (M=Cu, Ag, Au) to M(0) and form stable superatoms. This implies the hydride species can induce internal self-redox reactions (no external reducing agent needed) but as prerequisite the transformed clusters seem to have a similar core framework structure. These observations have implications in catalytic and energy cycles.

Research Articles

Hot Paper

Tribo-Excited Chemical Reaction Using an EuIII Complex with a Stacked Anthracene Framework

  • First Published: 01 February 2022
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A spin-selective tribo-chemical reaction using a dinuclear lanthanide complex is demonstrated for the first time. The dinuclear complex is composed of two EuIII ions, hexafluoroacetylacetonato ligands, and anthracene-based phosphine oxide bridges. Single-crystal analysis revealed a face-to-face-type anthracene dimer structure in the dinuclear EuIII complex. Mechanical stimulus on the dinuclear EuIII complex induced selective formation of oxidized anthracene. This first spin-selective tribo-chemical reaction using a EuIII complex will offer new possibilities for the development of tribo-excitation chemistry.

Open Access

Role of Anionic Backbone in NHC-Stabilized Coinage Metal Complexes: New Precursors for Atomic Layer Deposition

  • First Published: 19 January 2022
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In pursuit of new precursors for the deposition of coinage metals by atomic layer deposition (ALD), a series of new N-heterocyclic carbene (NHC)-based CuI and AgI complexes has been synthesized, analyzed, and evaluated for their potential use in ALD. One precursor was found to be particularly useful for the deposition of metallic copper when using hydroquinone as the reducing agent in a thermally driven ALD process.

Open Access

Parasitic Light Absorption, Rate Laws and Heterojunctions in the Photocatalytic Oxidation of Arsenic(III) Using Composite TiO2/Fe2O3

  • First Published: 03 February 2022
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The mechanisms that control the kinetics of arsenic(III) photocatalytic oxidation when meso-TiO2 is coupled with an Fe2O3 adsorbent phase are investigated herein. Parasitic light absorption is the primary factor, followed by changes in rate law (from disguised zero-order to first order). Charge transfer across the heterojunction in our material is negligible.

Dissolution Behavior and Varied Mesoporosity of Zeolites by NH4F Etching

  • First Published: 25 February 2022
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Based on the particularities of zeolites dissolution topology, hidden mosaic structures and zeolite microporosity are identified as interlocking factors in shaping the final dissolution behavior of zeolites and the resultant mesoporosity pattern. The size, shape, concentration, and spatial distribution of the mosaic structures predefine the size and morphology of the void space left by dissolution. The dimensions and topology of the micropores determine the dissolution preference towards single framework atoms, interior mosaic blocks, or exterior features of zeolite crystals.

Dye-Conjugated Spinach RNA by Genetic Alphabet Expansion

  • First Published: 08 February 2022
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Light emission by dye-conjugated Spinach RNA transcripts can be generated by genetic alphabet expansion. Dye-conjugated unnatural base substrates are site-specifically incorporated into Spinach RNA opposite to its unnatural base pairing partner in DNA templates by T7 transcription. The dye-conjugated Spinach RNAs or shorter versions robustly emit fluorescence.

Benchmarking of Density Functionals for the Description of Optical Properties of Newly Synthesized π-Conjugated TADF Blue Emitters

  • First Published: 02 February 2022
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Synthesis and computational guidelines based on benchmarking of DFT functionals for new π-conjugated TADF emitters are reported. The three target compounds were obtained by multistep synthesis, including metal-catalyzed reactions and functional-group transformations. The emitters feature electron donors and acceptors moderately coupled through a spacer. The importance of the treatment of long-range exchange within the functionals and their ability to balance the π-delocalization of the separate molecular fragments are explicitly outlined.

Hot Paper

Open Access

Visible-Light Switching of Metallosupramolecular Assemblies

  • First Published: 31 January 2022
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Visible-light photoswitching: A photoswitchable ligand and palladium(II) ions form a dynamic mixture of self-assembled metallosupramolecular structures. Visible-light photoswitching of the azobenzene-based ligand reversibly pumps the system away from equilibrium towards the thermodynamically unstable structure.

MOF Encapsulated AuPt Bimetallic Nanoparticles for Improved Plasmonic-induced Photothermal Catalysis of CO2 Hydrogenation

  • First Published: 03 February 2022
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Porous UiO-66-NH2 encapsulated AuPt alloy NPs exhibit a significant enhancement in the CO2 hydrogenation under low temperature (150 °C). The outstanding performance of AuPt@UiO-66-NH2 was attributed to the synergetic effect induced by plasmonic metal Au, active metal Pt, and versatile substrate UiO-66-NH2. Importantly, the AuPt alloy structure retains both the optical behavior of plasmonic metal and the reactive behavior of catalytic metal. This construction strategy provides guidance for the preparation of high-performance plasmonic catalysts.

Silver-Promoted Radical Ring-Opening/Pyridylation of Cyclobutanols with N-Methoxypyridinium Salts

  • First Published: 09 February 2022
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An efficient silver-catalyzed radical ring-opening/pyridylation of tertiary cyclobutanol with N-methoxypyridinium salts has been achieved for the synthesis of γ-ketopyridines. The overall process is thought to occur by β-scission of the corresponding cyclobutoxy radical to generate an alkyl radical, that adds to the pyridinium salt. A wide range of tertiary cyclobutanols and N-methoxypyridinium salts are compatible with these reaction conditions.

Open Access

Asymmetric Synthesis of Heterocyclic Chloroamines and Aziridines by Enantioselective Protonation of Catalytically Generated Enamines

  • First Published: 08 February 2022
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Brønsted acid catalysis enables the synthesis of chiral vicinal chloroamines via asymmetric protonation of catalytically generated prochiral chloroenamines. The process is highly enantioselective, with the origin of asymmetry and catalyst substituent effects elucidated by DFT calculations. The method allows access to rare heterocycle-substituted vicinal chloroamines, aziridines, and vicinal diamines.

Hot Paper

Open Access

Enantioselective Total Synthesis of (+)-Eucophylline

  • First Published: 27 January 2022
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Two strategies based respectively on the free-radical carbo- and sulfonyl-cyanation of cyclopropenes and cyclobutenes were developed to achieve the total enantioselective synthesis of (+)-eucophylline, a monoterpene alkaloid isolated from Leuconotis eugenifolius.

Synthetic Antibody-Rhamnose Cluster Conjugates Show Potent Complement-Dependent Cell Killing by Recruiting Natural Antibodies

  • First Published: 01 February 2022
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A highly efficient chemoenzymatic synthesis of homogeneous antibody-rhamnose and antibody-αGal cluster conjugates is described. The synthesis was achieved through a modular antibody Fc-glycan remodeling that includes site-specific chemoenzymatic Fc-glycan functionalization and subsequent click conjugation of synthetic rhamnose- and αGal trisaccharide clusters. A comparative cell-based assay indicated that the antibody-rhamnose cluster conjugates showed potent complement-dependent targeted cancer cell killing by recruiting natural anti-rhamnose antibodies.

Open Access

One-Pot Chemical Protein Synthesis Utilizing Fmoc-Masked Selenazolidine to Address the Redox Functionality of Human Selenoprotein F

  • First Published: 02 February 2022
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The one-pot chemical synthesis of the thioredoxin-like domain of the ER human selenoprotein F using novel Fmoc-protected selenazolidine is reported. This allowed us to perform different in vitro biological characterizations, including redox potential determination, insulin turbidimetric assay, and the effect on the oxidative folding of Cys-rich protein models. Our results support that SELENOF acts as a reductase for non-native disulfide bonds in the ER.

Hot Paper

Rational Design and Integrative Assembly of Heteromeric Metalla[2]Catenanes Featuring Cp*Ir/Rh Fragments

  • First Published: 19 February 2022
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Integrative assembly of a series of heteromeric metalla[2]catenanes was realized on account of prior precise design. A new design strategy was proposed. The design strategy essentially follows the principle of shape complementarity. Based on careful rational design of the functional groups, the shape and the size of the building blocks, the integrative assembly of a series of heteromeric [2]catenanes were successfully achieved both by assembly of two pre-assembled metalla-rectangles and by one-pot three-component self-assembly.

Open Access

The Apparently Unreactive Substrate Facilitates the Electron Transfer for Dioxygen Activation in Rieske Dioxygenases

  • First Published: 24 January 2022
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A quantum chemical study of model complexes finds that reaction energies for the generation of a coordination vacancy at the Fe center of naphthalene dioxygenase through water reorientation and dioxygen binding are insensitive to the presence of naphthalene. The role of the substrate only becomes evident after Rieske cluster oxidation for the 6-coordinate Fe active site where an additional electron is likely to be first transfered to the naphthalene substrate. These results imply allosteric control of the substrate on Rieske dioxygenase reactivity.