• Issue

    Chemistry – A European Journal: Volume 26, Issue 6

    1161-1436
    January 27, 2020

Cover Pictures

Free Access

Front Cover: Simultaneous Spin-Crossover Transition and Conductivity Switching in a Dinuclear Iron(II) Coordination Compound Based on 7,7′,8,8′-Tetracyano-p-quinodimethane (Chem. Eur. J. 6/2020)

  • Pages: 1161
  • First Published: 16 December 2019
Description unavailable

Thermally-induced simultaneous switching of magnetism and electrical conductivity has been realized by a two-dimensional supramolecular coordination assembly composed of FeII spin-crossover complexes and partially charged TCNQ (7,7’,8,8’-tetracyano-p-quinodimethane) radicals. FeII spin-crossover units are directly linked to π-stacked TCNQ columns, thus possessing strongly coupled magnetism (from localized d electrons) and electrical conductivity (from delocalized π electrons). This result was further supported by the observation of a magnetoresistance effect. More information can be found in the Full Paper by R. Ishikawa et al. on page 1278.

Free Access

Cover Feature: Tuning of Oxidation Potential of Ferrocene for Ratiometric Redox Labeling and Coding of Nucleotides and DNA (Chem. Eur. J. 6/2020)

  • Pages: 1162
  • First Published: 16 December 2019
Description unavailable

Substituted ferrocene derivatives with tuned redox potentials were tested as redox labels for electrochemical detection and coding of nucleobases in DNA. The ferrocene-linked nucleotides were enzymatically incorporated to DNA and analyzed by using capture probes on gold electrodes. Ferrocenecarboxamide and ethynylferrocene were used as tags for orthogonal ratiometric coding and analysis of cytosine and adenine in DNA. More information can be found in the Full Paper by M. Fojta, C. K. O′Sullivan, M. Hocek, et al. on page 1286.

Free Access

Cover Feature: Dual Responsive Regulation of Host–Guest Complexation in Aqueous Media to Control Partial Release of the Host (Chem. Eur. J. 6/2020)

  • Pages: 1163
  • First Published: 16 December 2019
Description unavailable

The regulation of the concentration of a wide range of small molecules is ubiquitous in biological systems to adapt to the continuous changes in the environmental conditions. The cover artwork illustrates the opportunity to tune a host concentration in aqueous media in an orchestrated manner by controlling the partial collapse of a colored host–guest synthetic polymeric system featuring both thermo- and pH responsiveness. This colored supramolecular assembly is one of the first synthetic systems providing control over the concentration of a small molecule, providing great potential as both T and pH chromic materials and as a basis to develop more complex systems with molecular communication. More information can be found in the Full Paper by H. Guo, R. Hoogenboom, P. Woisel, et al. on page 1292.

Free Access

Cover Feature: Fe-Doped CoP Flower-Like Microstructure on Carbon Membrane as Integrated Electrode with Enhanced Sodium Ion Storage (Chem. Eur. J. 6/2020)

  • Pages: 1164
  • First Published: 10 January 2020
Description unavailable

Flower-like Fe-doped CoP microstructures were obtained by hydrothermal method and in-situ phosphorization. The Fe doping and carbon membrane synergistically impact the formation of the flower-like hierarchical microstructures during the crystal-growth process. The final Fe-doped CoP, possess a different morphology with pure CoP on the carbon membrane. The Fe doping could adjust the electron structure of CoP to increase the active site for sodium storage and stabilize the phase-transition process during sodiation/desodiation. The unique hierarchical microstructure could increase the contact area between electrode and electrolyte and accommodate volume expansion during cycling. The hierarchical Fe-doped CoP directly grown on the carbon membrane could further promote the internal electron conduction in the Fe-doped CoP/CM electrode. More information can be found in the Full Paper by X. Y. Li, L. Z. Chen et al. on page 1298.

Frontispiece

Free Access

Frontispiece: Unlocking the Drug Potential of the Bryostatin Family: Recent Advances in Product Synthesis and Biomedical Applications

  • First Published: 30 January 2020
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Bryostatins, a class of naturally occurring macrocyclic lactones with eleven chiral centers, which were isolated from marine invertebrates, turned out as promising candidates for medicinal applications, including AIDS, Alzheimer's disease, and cancer. The ongoing work towards the total synthesis of bryostatins and structural analogues (bryologs) as well as the biomedical application of these compounds is summarized in the Review by J. Jiao, H. Zhang et al. on page 1166 ff.

Free Access

Frontispiece: The Symbiotic Relationship Between Drug Discovery and Organic Chemistry

  • First Published: 30 January 2020
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Drug discovery uses both natural product sources and synthetic organic chemistry to provide suitable starting points for further optimization. Producing such compounds in a time-, quality-, and cost-efficient manner has become one of the most important applied tasks of the chemical sciences. Similarly, drug discovery has had an impact on the direction of synthetic organic chemistry. In their provide An appraisal of the relationship between synthetic chemistry and early drug discovery, along with a discussion on key concepts such as diversity-, biology-, and lead-oriented syntheses is provided in the Review article by O. Grygorenko and D. Judd et al. on page 1196 ff.

Free Access

Frontispiece: Establishing Radiolanthanum Chemistry for Targeted Nuclear Medicine Applications

  • First Published: 30 January 2020
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The image describes the radiochemical complexation of the novel radionuclides 132La and 135La for coupling with prostate cancer targeting moieties, with efficacy quantified by in vivo positron emission tomography imaging in a mouse model. For more information, see the Communication by J. J. Wilson, E. Boros, J. W. Engle, et al. on page 1238 ff.

Cover Profile

Free Access

Simultaneous Spin-Crossover Transition and Conductivity Switching in a Dinuclear Iron(II) Coordination Compound Based on 7,7′,8,8′-Tetracyano-p-quinodimethane

  • Pages: 1165
  • First Published: 16 December 2019
Description unavailable

The properties of coordination compounds can be fine-tuned through new molecular design routes and controlled through their various electronic states, which will lead to breakthroughs in science.” Read more about the story behind the cover in the Cover Profile and about the research itself on page 1278 ff. (DOI: 10.1002/chem.201903934).

Reviews

Natural Products

Unlocking the Drug Potential of the Bryostatin Family: Recent Advances in Product Synthesis and Biomedical Applications

  • Pages: 1166-1195
  • First Published: 03 September 2019
Description unavailable

Promising candidates: The development of bryostatins, a class of naturally occurring macrocyclic lactones, which might find application in the treatment of, for example, AIDS, Alzheimer's disease, and cancer is summarized, focusing on recent work on their total synthesis and biomedical applications.

Drug Discovery

The Symbiotic Relationship Between Drug Discovery and Organic Chemistry

  • Pages: 1196-1237
  • First Published: 20 August 2019
Description unavailable

Chemistry for drug discovery: All pharmaceutical products contain organic molecules, which may be sourced from natural products or be fully synthetic molecules. Thus, organic chemistry underpins both existing and upcoming pharmaceutical products. An appraisal of the relationship between synthetic chemistry and early drug discovery is given, along with a discussion on key concepts such as diversity-, biology-, and lead-oriented syntheses (see figure).

Communications

Radiopharmaceuticals

Establishing Radiolanthanum Chemistry for Targeted Nuclear Medicine Applications

  • Pages: 1238-1242
  • First Published: 19 November 2019
Description unavailable

Lanthanum revealed: The radiochemistry and first targeted in vivo application for the theranostic lanthanum radioisotope pair La-132/135 is demonstrated.

Materials Science

Open Access

Ultrasonic-Assisted Synthesis of Highly Defined Silver Nanodimers by Self-Assembly for Improved Surface-Enhanced Raman Spectroscopy

  • Pages: 1243-1248
  • First Published: 13 December 2019
Description unavailable

Made of nanostars: By the assistance of ultrasound, the violent polyol process for silver particle generation becomes controllable, enabling the self-assembly of nanostars to nanodimers. Moreover, the aggregation of nanodimers can be easily tuned by post-ultrasonic treatment, which gives a sensitive substrate for SERS.

Photochemistry

Efficient Generation and Synthetic Applications of Alkyl-Substituted Siloxycarbenes: Suppression of Norrish-Type Fragmentations of Alkanoylsilanes by Triplet Energy Transfer

  • Pages: 1249-1253
  • First Published: 08 November 2019
Description unavailable

Enhancement of the utility of alkanoylsilanes: Generation of siloxycarbenes from alkanoylsilanes by triplet energy transfer was examined by using an Ir complex and was successfully applied to C−C coupling reactions with boronates or aldehydes. This methodology efficiently suppressed undesired Norrish-type fragmentation reactions and broaden synthetic utility of alkanoylsilanes.

Enantioselectivity

Open Access

Catalytic Synthesis of Trifluoromethyl Cyclopropenes and Oligo-Cyclopropenes

  • Pages: 1254-1257
  • First Published: 16 October 2019
Description unavailable

Cyclopropenylation: An efficient method to produce trifluoromethyl cyclopropenes and interesting oligo-cyclopropenes is reported (see scheme).

Organocatalysis | Hot Paper

Open Access

Carbonyl Activation by Selenium- and Tellurium-Based Chalcogen Bonding in a Michael Addition Reaction

  • Pages: 1258-1262
  • First Published: 14 November 2019
Description unavailable

Make it active! Tellurium-based dicationic chalcogen bonding organocatalysts have been used to activate a carbonyl compound in the Michael addition reaction between indole derivatives and trans-crotonophenone. Up to 1000-fold rate accelerations were observed compared to the corresponding iodinated halogen bond donor. Several comparison experiments were performed to rule out other modes of activation than chalcogen bonding.

Molecular Switches

Open Access

Atomistic Insight Into the Host–Guest Interaction of a Photoresponsive Metal–Organic Framework

  • Pages: 1263-1268
  • First Published: 04 December 2019
Description unavailable

Light on interaction: Photoresponsive molecular switches embedded within metal–organic frameworks enable the modification of both the adsorption sites and the orientation of guest molecules. Atomistic simulations predict the high potential of these photoresponsive materials to change intermolecular interactions (see figure).

Organic Chemistry

Cycloaddition Reactions of an Active Cyclic Phosphane/Borane Pair with Alkenes, Alkynes, and Carbon Dioxide

  • Pages: 1269-1273
  • First Published: 18 November 2019
Description unavailable

Six-membered cyclic frustrated phosphane/borane Lewis pair adds carbon dioxide under mild conditions. Crystallization gave the unique macrocyclic tetramer with bridging CO2 between the individual cyclo-FLP units (see scheme).

Full Papers

Switchable Magnetic Semiconductors

Simultaneous Spin-Crossover Transition and Conductivity Switching in a Dinuclear Iron(II) Coordination Compound Based on 7,7′,8,8′-Tetracyano-p-quinodimethane

  • Pages: 1278-1285
  • First Published: 31 October 2019
Description unavailable

Best combination! A supramolecular coordination assembly composed of FeII ladders and partially charged TCNQ radicals undergoes thermally induced simultaneous switching of magnetism and electrical conduction (SCO=spin crossover, TCNQ=7,7′,8,8′-tetracyano-p-quinodimethane). This material also exhibits a magnetoresistance effect.

Chemical Biology

Open Access

Tuning of Oxidation Potential of Ferrocene for Ratiometric Redox Labeling and Coding of Nucleotides and DNA

  • Pages: 1286-1291
  • First Published: 14 November 2019
Description unavailable

Orthogonal redox labelling of nucleobases with substituted ferrocenes with tuned redox potential was developed for redox coding of DNA bases.

Host–Guest Systems

Dual Responsive Regulation of Host–Guest Complexation in Aqueous Media to Control Partial Release of the Host

  • Pages: 1292-1297
  • First Published: 26 September 2019
Description unavailable

Control over host concentration: A colored DNP/Blue Box synthetic PNIPAm-co-PAA polymeric system featuring both thermo- and pH responsiveness allows the host concentration in aqueous media to be tuned in an orchestrated manner by controlling the partial collapse of the dual stimuli-responsive copolymer. This supramolecular polymeric system thus shows great potential for application in both T and pH chromic materials and for the development of more complex systems with molecular communication.

Electrochemistry

Fe-Doped CoP Flower-Like Microstructure on Carbon Membrane as Integrated Electrode with Enhanced Sodium Ion Storage

  • Pages: 1298-1305
  • First Published: 12 November 2019
Description unavailable

Iron doping into CoP favors the formation of a flower-like microstructure on a carbon membrane (CM). Fe-doped CoP/CM as an integrated electrode provides more active sites and fast electron and ion transport channels for sodium storage. The Fe-doped CoP flower-like microstructure on the CM exhibits an electrochemical performance for sodium ion batteries superior to that of pure CoP/CM.

Electrocatalysis

ZnO-Templated Selenized and Phosphorized Cobalt-Nickel Oxide Microcubes as Rapid Alkaline Water Oxidation Electrocatalysts

  • Pages: 1306-1313
  • First Published: 05 November 2019
Description unavailable

Selenized and phosphorized cobalt-nickel oxide microcubes formed by a novel strategy using a sacrificial ZnO spherical template are employed as an oxygen evolution reaction (OER) electrocatalyst. The selenized samples manifest desirable and robust OER performance, with comparable overpotential at 10 mA cm−2 (312 mV) as RuO2 (308 mV) and better activity when the current reaches 13.7 mA cm−2.

Electrochemistry

Open Access

Tuning PtII-Based Donor–Acceptor Systems through Ligand Design: Effects on Frontier Orbitals, Redox Potentials, UV/Vis/NIR Absorptions, Electrochromism, and Photocatalysis

  • Pages: 1314-1327
  • First Published: 28 November 2019
Description unavailable

Outcomes of ligand design: A series of platinum-based donor–acceptor complexes is presented. The effect of the donor ligands on the frontier orbitals, redox potentials, redox-induced isomerism, and photocatalysis is probe.

Enzyme Catalysis

Selenocysteine as a Substrate, an Inhibitor and a Mechanistic Probe for Bacterial and Fungal Iron-Dependent Sulfoxide Synthases

  • Pages: 1328-1334
  • First Published: 23 September 2019
Description unavailable

Sulfoxide synthases: Bacterial and fungal iron-dependent sulfoxide synthases are distinguished by their different abilities to catalyze oxidative carbon–selenium bond formation.

Coordination Chemistry

Open Access

Non-Oxido-Vanadium(IV) Metalloradical Complexes with Bidentate 1,2-Dithienylethene Ligands: Observation of Reversible Cyclization of the Ligand Scaffold in Solution

  • Pages: 1335-1343
  • First Published: 13 November 2019
Description unavailable

A rare species: In this work, the redox active ligand 1,2-bis(2,5-dimethylthiophen-3-yl)ethane-1,2-dione is described. Chelation of a vanadium metal center gives rise to an en-diolate motif in two five-membered VIV metallacycles with hexatriene DTE backbones bearing axial chirality. Two non-oxido VIV atropisomeric complexes with metalloradical character were isolated. Their dynamic behavior (reversible cyclization) in solution was studied in a CW EPR spectroscopic study.

Chiral Resolution

On the Effect of Secondary Nucleation on Deracemization through Temperature Cycles

  • Pages: 1344-1354
  • First Published: 20 November 2019
Description unavailable

Enhanced deracemization: Crystallization-enhanced rapid and complete deracemization of a chiral isoindolinone was achieved by fast microwave-assisted temperature cycling. The crucial role of stereoselective secondary nucleation in this process was elucidated in a targeted parametric study, which showed that optimization of this phenomenon leads to maximization of the deracemization rate (see figure).

Metal–Organic Frameworks | Hot Paper

Highest and Fastest Removal Rate of PbII Ions through Rational Functionalized Decoration of a Metal–Organic Framework Cavity

  • Pages: 1355-1362
  • First Published: 22 November 2019
Description unavailable

Highest and fastest Pb removal: TMU-56, exhibits high performance in removal of toxic PbII metal ions from aqueous solutions. The existence of abundant strong chelating sites, along with large enough pore size, lead not only to the highest uptake capacity for PbII ions of 1130 mg g−1, but also the fastest removal rate that has ever been reported for functionalized metal–organic frameworks (MOFs), which occurred in just 20 s (see figure).

Photocatalysis | Hot Paper

Open Access

One Amine–3 Tasks: Reductive Coupling of Imines with Olefins in Batch and Flow

  • Pages: 1363-1367
  • First Published: 28 November 2019
Description unavailable

One amine–3 tasks: Gamma-aminobutyric acid derivatives could easily be synthesized by the visible-light photoredox-catalyzed coupling of imines with olefins. The reaction works well for a range of substrates and tolerates many functional groups. A continuous-flow strategy considerably improved the efficiency of this methodology.

Gene Silencing

Gapmer Antisense Oligonucleotides Containing 2′,3′-Dideoxy-2′-fluoro-3′-C-hydroxymethyl-β-d-lyxofuranosyl Nucleotides Display Site-Specific RNase H Cleavage and Induce Gene Silencing

  • Pages: 1368-1379
  • First Published: 04 November 2019
Description unavailable

A novel class of 2′-deoxy-2′-fluoro-3′-C-hydroxymethyl-β-d-lyxo-configured nucleotides has been synthesized and incorporated into antisense oligonucleotides for the first time. Experiments on exonuclease degradation showed improved nucleolytic stability relative to the unmodified control.

Chemical Probes | Hot Paper

Highly Selective, Amine-Derived Cannabinoid Receptor 2 Probes

  • Pages: 1380-1387
  • First Published: 21 January 2020
Description unavailable

The design and synthesis of CB2R-selective cannabinoids along with their in vitro pharmacological characterization (binding and functional studies) is reported. Chimeric ligands emerge as potent CB2R agonists with high selectivity over the closely related cannabinoid receptor 1 (CB1R).

Cluster compounds | Hot Paper

Atomically Precise Lanthanide-Iron-Oxo Clusters Featuring the ϵ-Keggin Ion

  • Pages: 1388-1395
  • First Published: 11 November 2019
Description unavailable

Keggin: A series of atomically precise lanthanide-iron-oxo nanoclusters featuring magnetite structure were obtained by introducing lanthanide ions as stabilizers and trans-4-Hydroxyl-l-proline (Hyp) and triethanolamine (TEOA-H3) as protecting ligands to control the hydrolysis of iron ions.

Coordination Chemistry | Hot Paper

Open Access

Shedding Light on the Interactions of Hydrocarbon Ester Substituents upon Formation of Dimeric Titanium(IV) Triscatecholates in DMSO Solution

  • Pages: 1396-1405
  • First Published: 18 November 2019
Description unavailable

A stabilizing effect: Clear trends can be found in the seemingly chaotic distribution of dimerization constants of hierarchically assembled helicates in DMSO, revealing the stabilizing effect of solvent-supported London dispersion effects.

Cycloaddition

Enantioselective Synthesis of Complex Fused Heterocycles through Chiral Phosphoric Acid Catalyzed Intramolecular Inverse-Electron-Demand Aza-Diels–Alder Reactions

  • Pages: 1406-1413
  • First Published: 29 October 2019
Description unavailable

Coming together: A highly efficient intramolecular inverse-electron-demand aza-Diels–Alder (IEDADA) reaction catalyzed by a chiral phosphoric acid has been developed (see figure). Various angular fused heterocycles were obtained in high yields with excellent diastereo- and enantioselectivities. DFT calculations provide a better insight into the mechanistic features of the chiral Brønsted acid catalyzed aza-Diels–Alder reaction.

Anion Coordination | Hot Paper

Anion-Coordination-Assisted Assembly of Supramolecular Charge-Transfer Complexes Based on Tris(urea) Ligands

  • Pages: 1414-1421
  • First Published: 24 November 2019
Description unavailable

Charge transfer (CT) complexes, formed by noncovalent bonding between electron-rich and -deficient molecules, have attracted much attention for a variety of applications. It was shown that anion coordination can provide an alternative strategy to promote the formation of π stacks with CT interactions between tris(urea) ligands and viologen cations, through infinite ⋅⋅⋅DADA⋅⋅⋅ or finite DAD π-stacking interactions.

Fluorescent Dyes

Open Access

Two π-Electrons Make the Difference: From BODIPY to BODIIM Switchable Fluorescent Dyes

  • Pages: 1422-1428
  • First Published: 27 November 2019
Description unavailable

Imidazole-based dyes: The chromophoric 12 π-electron system in BODIPY fluorescent dyes is modified to give a 14 π-electron core. The novel BODIIM fluorescent dye shows surprising properties, which are complementary to BODIPY dyes.

Chiral Ligands

A Chiral Macrocyclic Tetra-N-Heterocyclic Carbene Yields an “All Carbene” Iron Alkylidene Complex

  • Pages: 1429-1435
  • First Published: 01 December 2019
Description unavailable

The first chiral NHC macrocycle and its associated complexes are reported. The macrocyclic ligand supports both diazoalkane and alkylidene complexes on iron.