Angewandte Chemie International Edition

Cover image for Vol. 53 Issue 38

Editor: Peter Gölitz, Deputy Editors: Neville Compton, Haymo Ross

Online ISSN: 1521-3773

Associated Title(s): Angewandte Chemie, Chemistry - A European Journal, Chemistry – An Asian Journal, ChemistryOpen, ChemPlusChem, Zeitschrift für Chemie

Upcoming Hot Papers

Hot Papers are chosen by the Editors for their importance in a rapidly evolving field of high current interest. Many of the "Very Important Papers" (VIPs) would certainly qualify to be included here, but such a duplication is avoided.

Antimicrobial Peptides

Insect-Derived Proline-Rich Antimicrobial Peptides Kill Bacteria by Inhibiting Bacterial Protein Translation at the 70 S Ribosome

Andor Krizsan, Dr. Daniela Volke, Stefanie Weinert, Prof.Dr. Norbert Sträter, Dr. Daniel Knappe and Prof.Dr. Ralf Hoffmann

Insect-Derived Proline-Rich Antimicrobial Peptides Kill Bacteria by Inhibiting Bacterial Protein Translation at the 70 S RibosomeLost in translation: Proline-rich antimicrobial peptides (PrAMPs) inhibit bacterial protein translation by binding to the 70S ribosome of Gram-negative bacteria. This represents a novel killing mechanism for gene-encoded antimicrobial peptides. Alanine substitutions in the peptides additionally identified specific basic and hydrophobic residues as major interaction sites, which will enable the design of optimized compounds.

Read more now


 

Natural Product Synthesis

Enantioselective Divergent Syntheses of Several Polyhalogenated Plocamium Monoterpenes and Evaluation of Their Selectivity for Solid Tumors

Carl V. Vogel, Halina Pietraszkiewicz, Omar M. Sabry, Prof. William H. Gerwick, Dr. Frederick A. Valeriote and Prof. Christopher D. Vanderwal

Enantioselective Divergent Syntheses of Several Polyhalogenated Plocamium Monoterpenes and Evaluation of Their Selectivity for Solid TumorsGlyceraldehyde acetonide serves as a chiral glyoxal equivalent and a linchpin for the enantioselective synthesis of several acyclic polyhalogenated monoterpenes from the red algae Plocamium. Several of these compounds demonstrate selective toxicity towards solid-tumor cell lines over leukemia cell lines, as well as low-micromolar cytotoxicity towards the HCT-116 human colon carcinoma cell line.

Read more now


 

Carbon Nanofibers

Carbon Nanofibers Decorated with Molybdenum Disulfide Nanosheets: Synergistic Lithium Storage and Enhanced Electrochemical Performance

Fei Zhou, Dr. Sen Xin, Dr. Hai-Wei Liang, Lu-Ting Song and Prof. Dr. Shu-Hong Yu

Carbon Nanofibers Decorated with Molybdenum Disulfide Nanosheets: Synergistic Lithium Storage and Enhanced Electrochemical PerformanceCarbon nanofibers (CNFs) decorated with molybdenum disulfide sheets are fabricated by a facile hydrothermal process with low-cost, biomass-derived carbonaceous nanofibers as the supports. On reacting with lithium, the nanofibers undergo novel electrochemical processes that are triggered by a synergistic lithium storage effect, leading to enhanced cycling and rate performance of the lithium-ion battery.

Read more now


 

Antitumor Agents

A CXCR4-Targeted Site-Specific Antibody–Drug Conjugate

Dr. Sumith A. Kularatne, Dr. Vishal Deshmukh, Dr. Jennifer Ma, Dr. Virginie Tardif, Dr. Reyna K. V. Lim, Holly M. Pugh, Dr. Ying Sun, Anthony Manibusan, Aaron J. Sellers, Dr. Richard S. Barnett, Shailaja Srinagesh, Jane S. Forsyth, Dr. Wolf Hassenpflug, Dr. Feng Tian, Dr. Tsotne Javahishvili, Prof. Brunhilde Felding-Habermann, Prof. Brian R. Lawson, Dr. Stephanie A. Kazane and Prof. Peter G. Schultz

A CXCR4-Targeted Site-Specific Antibody–Drug ConjugateHitting the mark(er): A chemically defined anti-CXCR4–auristatin antibody–drug conjugate (ADC) was produced that selectively targets and eliminates CXCR4+ metastatic cancer cells in vitro and in vivo with no significant overt toxicity. Because the CXCR4 receptor is highly expressed in the majority of metastatic cancers, a CXCR4–auristatin ADC may be useful for the treatment of a variety of metastatic malignancies.

Read more now


 

Electrochromic Supercapacitors

Large-Scale Fabrication of Pseudocapacitive Glass Windows that Combine Electrochromism and Energy Storage

Peihua Yang, Peng Sun, Zhisheng Chai, Prof. Langhuan Huang, Dr. Xiang Cai, Prof. Shaozao Tan, Prof. Jinhui Song and Prof. Wenjie Mai

Large-Scale Fabrication of Pseudocapacitive Glass Windows that Combine Electrochromism and Energy StorageA pseudocapacitive glass window (15×15 cm2) is obtained by the deposition of WO3 on fluorine-doped tin oxide glass. Such smart pseudocapacitive glass windows show great potential in functioning as electrochromic windows and concurrently powering electronic devices, such as mobile phones or laptops.

Read more now


 

Nanoflakes

Hexagonal Transition-Metal Chalcogenide Nanoflakes with Pronounced Lateral Quantum Confinement

Dr. Pere Miró, Jae Hyo Han, Prof. Dr. Jinwoo Cheon and Prof. Dr. Thomas Heine

Hexagonal Transition-Metal Chalcogenide Nanoflakes with Pronounced Lateral Quantum ConfinementSix-sided flakes: Transition-metal dichalcogenide nanoflakes of composition MX2 (where M=Ti, Zr and Hf; X=S and Se) grow preferentially in equilateral hexagons and exhibit a pronounced lateral quantum confinement. The hexagonal shape arises from the charge location at the edges and vertices and the resulting Coulombic repulsion.

Read more now


 

Radical C[BOND]H Functionalization of Heteroarenes under Electrochemical Control

Dr. Alexander G. O'Brien, Dr. Akinobu Maruyama, Dr. Yasuhide Inokuma, Prof. Makoto Fujita, Prof. Phil S. Baran and Prof. Donna G. Blackmond

Radical C<img src="http://onlinelibrarystatic.wiley.com/undisplayable_characters/00f8ff.gif" alt="[BOND]" />H Functionalization of Heteroarenes under Electrochemical ControlElectrochemical reactions are shown to be effective for the C[BOND]H functionalization of a number of heterocyclic substrates that are recalcitrant to conventional peroxide radical initiation conditions and of interest in medicinal chemistry. Monitoring reaction progress under electrochemical conditions provides mechanistic insight into the C[BOND]H functionalization process.

Read more now


 

Carbon Dioxide

Differential Reduction of CO2 by Molybdenum and Vanadium Nitrogenases

Johannes G. Rebelein, Prof. Dr. Yilin Hu and Prof. Dr. Markus W. Ribbe

Differential Reduction of CO2 by Molybdenum and Vanadium NitrogenasesVanadium nitrogenase can reduce CO2 to CO, CD4, C2D4, and C2D6. Its ability to reduce CO2 to C2 hydrocarbons adds another important reaction to the catalytic spectrum of the vanadium nitrogenase, that is, a reaction that involves C[BOND]C coupling from CO2.

Read more now


 

Pyrrole Synthesis

Insertion of Nitriles into Zirconocene-1-aza-1,3-diene Complexes: Chemoselective Synthesis of N-H and N-Substituted Pyrroles

Shasha Yu, Meijun Xiong, Xin Xie and Prof. Yuanhong Liu

Insertion of Nitriles into Zirconocene-1-aza-1,3-diene Complexes: Chemoselective Synthesis of N-H and N-Substituted PyrrolesExercise control: N-H and N-substituted pyrroles can be prepared through the direct insertion of nitriles into zirconocene-1-aza-1,3-diene complexes and their subsequent acidic aqueous work-up. The outcome of the reaction depends on the relative stability and reactivity of the corresponding enamine–imine tautomers formed through the hydrolysis of the diazazirconacycles.

Read more now


 

Anion Complexation

Anion Complexation and The Hofmeister Effect

Ryan S. Carnegie, Corinne L. D. Gibb and Prof. Bruce C. Gibb

Anion Complexation and The Hofmeister EffectThe strength of association between the hydrophobic, concave binding site of a deep-cavity cavitand and the ClO4 ion is controlled by co-salts in a manner that follows the Hofmeister series. A competitive binding of the co-salt anion to the hydrophobic pocket and its counterion to the external carboxylate groups accounts for the observed changes in ClO4 affinity.

Read more now


 

Fragment-Based Drug Discovery

Exploring Weak Ligand–Protein Interactions by Long-Lived NMR States : Improved Contrast in Fragment-Based Drug Screening

Roberto Buratto, Daniele Mammoli, Dr. Elisabetta Chiarparin, Dr. Glyn Williams and Prof. Geoffrey Bodenhausen

Exploring Weak Ligand–Protein Interactions by Long-Lived NMR States : Improved Contrast in Fragment-Based Drug ScreeningLigands with an affinity for selected proteins can be screened very effectively by exploiting long-lived states (LLS) in NMR spectroscopy. This approach allows ligands with a wide range of affinities (10 nM<KD<12 mM) to be characterized. The LLS method was used to measure the dissociation constants of fragments that bind weakly to the ATP binding domain of heat shock protein Hsp90, a therapeutic target for cancer treatment.

Read more now


 

18F-Labeling

An Organotrifluoroborate for Broadly Applicable One-Step 18F-Labeling

Zhibo Liu, Maral Pourghiasian, Mark Alex Radtke, Joseph Lau, Dr. Jinhe Pan, Gemma M. Dias, Dr. Donald Yapp, Dr. Kuo-Shyan Lin, Prof. Dr. Francois Bénard and Prof. Dr. David M. Perrin

An Organotrifluoroborate for Broadly Applicable One-Step 18F-LabelingLike a postage stamp that neither alters a letter’s weight nor changes its contents or destination, a new zwitterionic trifluoroborate radiosynthon transforms complex molecules into 18F-tracers that are labeled in a single aqueous-phase step in high yield and at high specific radioactivity without HPLC purification.

Read more now


 

Natural Products

Forazoline A: Marine-Derived Polyketide with Antifungal In Vivo Efficacy

Thomas P. Wyche, Dr. Jeff S. Piotrowski, Dr. Yanpeng Hou, Doug Braun, Raamesh Deshpande, Sean McIlwain, Irene M. Ong, Chad L. Myers, Dr. Ilia A. Guzei, Dr. William M. Westler, Prof. Dr. David R. Andes and Prof. Dr. Tim S. Bugni

Forazoline A: Marine-Derived Polyketide with Antifungal In Vivo EfficacyA bit of structure: A novel antifungal natural product, forazoline A, was isolated from Actinomadura sp. The structure of forazoline A was elucidated by a combination of NMR spectroscopy, molecular modeling, and synthetic modifications. The compound demonstrated in vivo efficacy in a mouse model of Candida albicans. A chemical genomics approach suggested that forazoline A works through a new mechanism of action.

Read more now


 

Lithium-Ion Batteries

Organic Dicarboxylate Negative Electrode Materials with Remarkably Small Strain for High-Voltage Bipolar Batteries

Dr. Nobuhiro Ogihara, Tomomi Yasuda, Yoshihiro Kishida, Dr. Tetsu Ohsuna, Kaito Miyamoto and Dr. Nobuko Ohba

Organic Dicarboxylate Negative Electrode Materials with Remarkably Small Strain for High-Voltage Bipolar BatteriesCorridors of power: 2,6-Naphthalene dicarboxylate dilithium (Naph(COOLi)2), which has an organic–inorganic layered framework, shows reversible Li intercalation at a flat potential of 0.8 V. The layered framework is maintained during Li intercalation, and its volume change is only 0.33 %. An 8 V bipolar Naph(COOLi)2/LiNi0.5Mn1.5O4 cell with an Al current collector was constructed from only two cells connected in series.

Read more now


 

Carbonic Acid

Gas-Phase Preparation of Carbonic Acid and Its Monomethyl Ester

Dr. Hans Peter Reisenauer, M. Sc. J. Philipp Wagner and Prof. Dr. Peter R. Schreiner

Gas-Phase Preparation of Carbonic Acid and Its Monomethyl EsterThe matrix-isolation IR spectrum of carbonic acid generated through gas-phase pyrolysis of Boc2O (Boc=tert-butoxycarbonyl) or (tBuO)2CO unequivocally shows that the long-claimed identity of the gas phase above its α-polymorph is not carbonic acid, but rather the monomethyl ester, which was analogously prepared from MeOC(O)OtBu and identified in the gas phase for the first time.

Read more now


 

Organocatalysis

Enantioselective Synthesis of Piperidines through the Formation of Chiral Mixed Phosphoric Acid Acetals: Experimental and Theoretical Studies

Dr. Zhankui Sun, Grace A. Winschel, Prof. Dr. Paul M. Zimmerman and Prof. Dr. Pavel Nagorny

Enantioselective Synthesis of Piperidines through the Formation of Chiral Mixed Phosphoric Acid Acetals: Experimental and Theoretical StudiesA rich seam: An enantioselective chiral phosphoric acid-catalyzed cyclization of unsaturated acetals has been utilized for the synthesis of functionalized chiral piperidines. The chiral enol ether products of these cyclizations undergo subsequent in situ enantioenrichment. A new computational method was utilized to elucidate the mechanism and stereoselectivity of this transformation. Cbz=benzyloxycarbonyl; S=resolution.

Read more now


 

Mussel Adhesive

In Vivo Residue-Specific Dopa-Incorporated Engineered Mussel Bioglue with Enhanced Adhesion and Water Resistance

Byeongseon Yang, Dr. Niraikulam Ayyadurai, Prof. Hyungdon Yun, Prof. Yoo Seong Choi, Dr. Byeong Hee Hwang, Jun Huang, Dr. Qingye Lu, Prof. Hongbo Zeng and Prof. Hyung Joon Cha

In Vivo Residue-Specific Dopa-Incorporated Engineered Mussel Bioglue with Enhanced Adhesion and Water ResistanceEngineered mussel glue with a very high 3,4-dihydroxyphenylalanine (Dopa) content close to that of natural protein was created through in vivo residue-specific Dopa incorporation method in Escherichia coli. This bioglue exhibited strong adhesion and water-resistance, which shows great potential in underwater applications.

Read more now


 

Catalyst Stability

Engineering Catalyst Microenvironments for Metal-Catalyzed Hydrogenation of Biologically Derived Platform Chemicals

Thomas J. Schwartz, Robert L. Johnson, Javier Cardenas, Dr. Adam Okerlund, Prof. Nancy A. Da Silva, Prof. Klaus Schmidt-Rohr and Prof. James A. Dumesic

Engineering Catalyst Microenvironments for Metal-Catalyzed Hydrogenation of Biologically Derived Platform ChemicalsThe surface properties of supported metal hydrogenation catalysts are modified by the formation of microenvironments inside the catalyst pores and surrounding the metal nanoparticles. These microenvironments are derived from poly(vinyl alcohol) (PVA), and they are used to mitigate catalyst deactivation that is due to biogenic impurities.

Read more now


 

Fischer–Tropsch Kinetics

The optimally performing Fischer–Tropsch catalyst

Ivo A. W. Filot, Prof. Dr. Rutger A. van Santen and Prof. Dr. Emiel J. M. Hensen

The optimally performing Fischer–Tropsch catalystState-of-the-art quantum-chemical reaction data were used in a microkinetics simulations study to elucidate the different fundamental kinetic regimes underlying Fischer–Tropsch activity and selectivity. Based on the nature of the rate-controlling steps, three regimes were identified: I) monomer formation, II) chain-growth termination, and III) water formation.

Read more now


 

Formic Acid Dehydrogenation

Hydrogen from Formic Acid through Its Selective Disproportionation over Sodium Germanate—A Non-Transition-Metal Catalysis System

Dr. Ruth I. J. Amos, Dr. Falk Heinroth, Dr. Bun Chan, Sisi Zheng, Prof. Brian S. Haynes, Prof. Christopher J. Easton, Prof. Anthony F. Masters, Prof. Leo Radom and Prof. Thomas Maschmeyer

Hydrogen from Formic Acid through Its Selective Disproportionation over Sodium Germanate—A Non-Transition-Metal Catalysis SystemFrom models to reality: A robust catalyst for the selective dehydrogenation of formic acid to liberate hydrogen gas has been designed computationally, and also demonstrated experimentally. This catalyst represents an important step towards the use of renewable formic acid as a hydrogen-storage and transport vector in fuel and energy applications.

Read more now


 

π Interactions

Anion–π and Cation–π Interactions on the Same Surface

Dr. Kaori Fujisawa, Dr. César Beuchat, Marie Humbert-Droz, Dr. Adam Wilson, Prof. Tomasz A. Wesolowski, Dr. Jiri Mareda, Dr. Naomi Sakai and Prof. Stefan Matile

Anion–π and Cation–π Interactions on the Same SurfaceIt takes two to tango: Theoretical and experimental evidence shows that anion–π and cation–π interactions can occur simultaneously on the same aromatic surface. The resulting ion pair–π interactions shift the absorption of push–pull chromophores to the red.

Read more now


 

Hot-Electron Transfer

Hot-Electron-Transfer Enhancement for the Efficient Energy Conversion of Visible Light

Sungju Yu, Yong Hwa Kim, Su Young Lee, Hyeon Don Song and Prof. Jongheop Yi

Hot-Electron-Transfer Enhancement for the Efficient Energy Conversion of Visible LightA core–shell nanostructure with three distinct components enables the efficient production of H2 from water and significant electron harvesting under visible-light irradiation because of enhanced hot-electron injection, the formation of a Schottky junction, and high-performance electron filtering. The electron transfer pathway is elucidated through steady-state and time-resolved photoluminescence spectroscopy.

Read more now


 

Bioorthogonal Chemistry

Super-Resolution Imaging of Plasma Membrane Glycans

Sebastian Letschert, Dr. Antonia Göhler, Christian Franke, Nadja Bertleff-Zieschang, Elisabeth Memmel, Priv.-Doz. Dr. Sören Doose, Prof. Dr. Jürgen Seibel and Prof. Dr. Markus Sauer

Super-Resolution Imaging of Plasma Membrane GlycansGlycan spotting: Click chemistry and super-resolution imaging was used to visualize and quantify ManNAc-, GalNAc-, and O-GlcNAc-modified glycans in the plasma membrane of mammalian cells with single-molecule sensitivity (see image). The data demonstrate that a single cell may easily contain more than ten million glycans, which are homogeneously distributed and do not form clusters or nanodomains.

Read more now


 

Ruthenium Pincer Complexes

Direct Catalytic Olefination of Alcohols with Sulfones

Dr. Dipankar Srimani, Dr. Gregory Leitus, Yehoshoa Ben-David and Prof. Dr. David Milstein

Direct Catalytic Olefination of Alcohols with SulfonesThe one-step olefination of alcohols with sulfones for the direct synthesis of terminal and internal olefins is catalyzed by ruthenium pincer complexes. Furthermore, performing the reaction with dimethyl sulfone under mild hydrogen pressure provides a one-step method for the replacement of alcohol hydroxy groups by methyl groups.

Read more now


 

Bioconjugation

Dialdehydes Lead to Exceptionally Fast Bioconjugations at Neutral pH by Virtue of a Cyclic Intermediate

Pascal Schmidt, Dr. Linna Zhou, Kiril Tishinov, Kaspar Zimmermann and Prof. Dr. Dennis Gillingham

Dialdehydes Lead to Exceptionally Fast Bioconjugations at Neutral pH by Virtue of a Cyclic IntermediateFor aldehydes, 1+1=500: Dialdehydes react with O-alkylhydroxylamines at rates of 500 M−1 s−1 at neutral pH values in the absence of catalysts. The key to these conjugations is an unusually stable cyclic intermediate, which ultimately undergoes dehydration to yield an oxime. The application of this method in bioconjugations and a mechanistic interpretation are outlined.

Read more now


 

Electrocatalysis

Controlling Selectivity in the Chlorine Evolution Reaction over RuO2-Based Catalysts

Kai S. Exner, Josef Anton, Timo Jacob and Herbert Over

Controlling Selectivity in the Chlorine Evolution Reaction over RuO2-Based CatalystsBeing selective: The selectivity in the industrially important Chlor-Alkali process has been elucidated on the microscopic level through a combination of DFT calculations and volcano plots. A single layer of TiO2(110) grown on RuO2(110) increases the selectivity between the chlorine and oxygen evolution reactions (CER and OER, respectively) by several orders of magnitude, while keeping the high activity for CER practically constant.

Read more now


 

Aldehyde-Assisted Ruthenium(II)-Catalyzed C[BOND]H Oxygenations

M. Sc. Fanzhi Yang, Karsten Rauch, M. Sc. Katharina Kettelhoit and Prof. Dr. Lutz Ackermann

Aldehyde-Assisted Ruthenium(II)-Catalyzed C<img src="http://onlinelibrarystatic.wiley.com/undisplayable_characters/00f8ff.gif" alt="[BOND]" />H OxygenationsThe weakest link: Challenging aryl C[BOND]H oxygenations with very weakly coordinating aldehydes proceed chemoselectively in the presence of versatile ruthenium(II) catalysts under mild reaction conditions. This transformation features an ample substrate scope and excellent positional selectivity.

Read more now


 

Boride Magnets

Unexpected Synergy between Magnetic Iron Chains and Stacked B6 Rings in Nb6Fe1−xIr6+xB8

Dipl.-Chem. Mohammed Mbarki, M.Sc. Rachid St. Touzani and Priv.-Doz. Dr. Boniface P. T. Fokwa

Unexpected Synergy between Magnetic Iron Chains and Stacked B6 Rings in Nb6Fe1−xIr6+xB8A mutual dependency between ferromagnetic iron chains and stacked B6 rings (see picture) is found in the new ferromagnetic material, Nb6Fe1−xIr6+xB8 (TC=350 K) by combining experiment and density functional theory (DFT). The strong magnetic Fe–Fe interactions found in the iron chains induce an unexpected strengthening of the B–B interactions in the B6 rings.

Read more now


 

Trifluoromethylation

Vanadium-Catalyzed Solvent-Free Synthesis of Quaternary α-Trifluoromethyl Nitriles by Electrophilic Trifluoromethylation

Natalja Früh and Prof. Dr. Antonio Togni

Vanadium-Catalyzed Solvent-Free Synthesis of Quaternary α-Trifluoromethyl Nitriles by Electrophilic TrifluoromethylationNot only copper! Oxovanadium(IV) complexes catalyze the trifluoromethylation of silyl ketene imines with hypervalent iodine reagents to form quaternary α-trifluoromethyl nitriles under solvent-free conditions. The products, formed in up to 93 % yield, may be further transformed into useful synthetic building blocks for organofluorine chemistry.

Read more now


 

CO2 Utilization

Ruthenium-Catalyzed Reductive Methylation of Imines Using Carbon Dioxide and Molecular Hydrogen

Dr. Kassem Beydoun, Ghazi Ghattas, Katharina Thenert, Prof. Dr. Jürgen Klankermayer and Prof. Dr. Walter Leitner

Ruthenium-Catalyzed Reductive Methylation of Imines Using Carbon Dioxide and Molecular HydrogenTertiary N-methyl amines were obtained in good to excellent yields through the reductive methylation of imines (used as such or formed in situ from amines and aldehydes, see scheme). Apart from the well-defined [Ru(triphos)(tmm)] catalyst, CO2 was used as C1 source, and H2 as reducing agent. This method enabled the preparation of the antifungal agent butenafine in one step with no apparent waste, thus increasing the atom efficiency of its synthesis.

Read more now


 

Contrast Agents

Phosphonated Near-Infrared Fluorophores for Biomedical Imaging of Bone

Dr. Hoon Hyun, Dr. Hideyuki Wada, Dr. Kai Bao, Dr. Julien Gravier, Dr. Yogesh Yadav, Dr. Matt Laramie, Dr. Maged Henary, Dr. John V. Frangioni and Dr. Hak Soo Choi

Phosphonated Near-Infrared Fluorophores for Biomedical Imaging of BoneBifunctional molecules with high-affinity binding to bone minerals as well as bright near-infrared fluorescence were obtained by attaching low-affinity pendant groups to the non-delocalized backbone of polymethines. These agents enable the noninvasive assessment of bone development over the course of weeks in living animals.

Read more now


 

Nanoparticle Architectures

Planet–Satellite Nanostructures Made To Order by RAFT Star Polymers

Christian Rossner and Prof. Dr. Philipp Vana

Planet–Satellite Nanostructures Made To Order by RAFT Star PolymersSmall world: Gold nanoparticles decorated with RAFT star polymers of different molecular weights can be used as scaffolds for the attachment of functional units at defined distances from the central core. This approach can result in planet–satellite nanostructures.

Read more now


 

Photocatalysis

Harvesting Solar Light with Crystalline Carbon Nitrides for Efficient Photocatalytic Hydrogen Evolution

Dr. Manas K. Bhunia, Dr. Kazuo Yamauchi and Prof. Kazuhiro Takanabe

Harvesting Solar Light with Crystalline Carbon Nitrides for Efficient Photocatalytic Hydrogen EvolutionTrying out triazine: Crystalline carbon nitrides are synthesized by employing supramolecular aggregation and ionic melt polycondensation. The triazine-based carbon nitride exhibits the excellent hydrogen evolution reaction rate at visible light and apparent quantum yield reaches approximately 7 % at 420 nm.

Read more now


 

Oxygen Reduction Reaction

Oxygen Reduction Reaction in a Droplet on Graphite: Direct Evidence that the Edge is More Active than the Basal Plane

Anli Shen, Yuqin Zou, Prof. Qiang Wang, Prof. Robert A. W. Dryfe, Prof. Xiaobing Huang, Shuo Dou, Prof. Liming Dai and Prof. Shuangyin Wang

Oxygen Reduction Reaction in a Droplet on Graphite: Direct Evidence that the Edge is More Active than the Basal PlaneOn the cutting edge: To study the oxygen reduction reaction (ORR), an air-saturated electrolyte solution droplet with a diameter of approximately 15 μm was deposited at a specified position on the edge (see picture) or on the basal plane of highly oriented pyrolytic graphite. Electrochemical measurements suggest that the edge sites are catalytically more active than basal-plane sites towards the ORR.

Read more now


 

Natural Products

One-Pot Enzymatic Synthesis of Merochlorin A and B

Dr. Robin Teufel, Dr. Leonard Kaysser, Matthew T. Villaume, Dr. Stefan Diethelm, Mary K. Carbullido, Prof. Dr. Phil S. Baran and Prof. Dr. Bradley S. Moore

One-Pot Enzymatic Synthesis of Merochlorin A and BAssembly line: The biosynthetic pathway to merochlorins A and B was fully reconstituted in vitro and involves only four enzymes. The assembly route starts from the common metabolites dimethylallyl diphosphate, geranyl diphosphate, and malonyl CoA, which are transformed into an unusual polyketide-terpene hybrid intermediate. Oxidative chlorination and terpene cyclization complete the remarkably short pathway to the merochlorins.

Read more now


 

H2 Activation

Metal-Free Hydrogenation Catalyzed by an Air-Stable Borane: Use of Solvent as a Frustrated Lewis Base

Daniel J. Scott, Dr. Matthew J. Fuchter and Dr. Andrew E. Ashley

Metal-Free Hydrogenation Catalyzed by an Air-Stable Borane: Use of Solvent as a Frustrated Lewis BaseReduced frustration: THF solutions of the boranes B(C6Cl5)x(C6F5)3−x (x=0–3) activate H2 and effect catalytic hydrogenation of unsaturated substrates through a mechanism in which the solvent acts as a “frustrated” Lewis base. In particular, weakly basic substrates, such as N-tosyl imines, and pyrrole and furan derivatives (a new substrate family for frustrated Lewis pair (FLP) hydrogenations), are reduced under relatively mild conditions using air-stable B(C6Cl5)(C6F5)2.

Read more now


 

Organocatalysis

A New Class of Organocatalysts: Sulfenate Anions

Mengnan Zhang, Tiezheng Jia, Haolin Yin, Patrick J. Carroll, Prof. Eric J. Schelter and Prof. Patrick J. Walsh

A New Class of Organocatalysts: Sulfenate AnionsSulfenates take center stage: Sulfenate anions are known as highly reactive species in the organic arena. Now they premiere as organocatalysts: A sulfoxide/sulfenate (1–10 mol %) promotes the transformation of benzyl halides into trans-stilbenes under basic conditions (up to 99 % yield). CPME=cyclopentyl methyl ether.

Read more now


 

Methylidene Complexes

Mononuclear and Terminal Zirconium and Hafnium Methylidenes

Dr. Masahiro Kamitani, Balazs Pinter, Dr. Chun-Hsing Chen, Dr. Maren Pink and Prof. Dr. Daniel J. Mindiola

Mononuclear and Terminal Zirconium and Hafnium MethylidenesThe photolysis of zirconium or hafnium complexes with one aryloxide and two methyl ligands induces α-hydrogen abstraction and results in the formation of mononuclear complexes with terminal methylidene ligands. These unique systems have been fully characterized, including the determination of the solid-state structure in the case of the zirconium complex.

Read more now


 

Asymmetric Organocatalysis

N-Heterocyclic Carbene Catalyzed Formal [3+2] Annulation Reaction of Enals: An Efficient Enantioselective Access to Spiro-Heterocycles

Dr. Chang Guo, Michael Schedler, Constantin G. Daniliuc and Prof. Dr. Frank Glorius

N-Heterocyclic Carbene Catalyzed Formal [3+2] Annulation Reaction of Enals: An Efficient Enantioselective Access to Spiro-HeterocyclesRing, ring: A highly enantioselective formal [3+2] annulation of α,β-unsaturated aldehydes with azaaurones or aurone is catalyzed by an N-heterocyclic carbene (NHC) and generates spiroheterocycles. The protocol represents a unique NHC activation-based approach to access spiro-heterocyclic derivatives bearing a quaternary stereogenic center with high optical purity.

Read more now


 

NMR spectroscopy

Visualizing an Ultra-Weak Protein–Protein Interaction in Phosphorylation Signaling

Qiong Xing, Peng Huang, Ju Yang, Jian-Qiang Sun, Dr. Zhou Gong, Dr. Xu Dong, Dr. Da-Chuan Guo, Shao-Min Chen, Yu-Hong Yang, Yan Wang, Prof. Ming-Hui Yang, Dr. Ming Yi, Prof. Yi-Ming Ding, Prof. Mai-Li Liu, Prof. Wei-Ping Zhang and Prof. Chun Tang

Visualizing an Ultra-Weak Protein–Protein Interaction in Phosphorylation SignalingPhosphorylation signaling takes place between two bacterial enzymes EI and EIIAGlc that has a binding affinity of only 25 mM (see picture). The structure of the ultra-weak fleeting complex was determined to atomic resolution by novel paramagnetic NMR technique, and it shows that electrostatic repulsion largely accounts for the low affinity between the two proteins.

Read more now


 

Temporary Protecting Groups

Carbon Dioxide as a Protecting Group: Highly Efficient and Selective Catalytic Access to Cyclic cis-Diol Scaffolds

Victor Laserna, Dr. Giulia Fiorani, Dr. Christopher J. Whiteoak, Dr. Eddy Martin, Eduardo Escudero-Adán and Prof. Dr. Arjan W. Kleij

Carbon Dioxide as a Protecting Group: Highly Efficient and Selective Catalytic Access to Cyclic cis-Diol ScaffoldsProtective Carbon: Aminotriphenolate complexes of FeIII and AlIII are highly efficient and selective catalysts for the conversion of functional (multi)cyclic oxiranes into the corresponding cis carbonates. Basic hydrolysis of the latter provides a series of useful cyclic cis-diol scaffolds in high yield. In this process, CO2 acts as both a temporary protecting group and an oxygen donor.

Read more now


 

ortho Alkylation

Iron-Catalyzed C(sp2)[BOND]H Alkylation of Carboxamides with Primary Electrophiles

Brendan M. Monks, Erin R. Fruchey and Prof. Silas P. Cook

Iron-Catalyzed C(sp2)<img src="http://onlinelibrarystatic.wiley.com/undisplayable_characters/00f8ff.gif" alt="[BOND]" />H Alkylation of Carboxamides with Primary ElectrophilesThe direct­ ortho­ alkylation of 8-aminoquinoline-based aryl amides was achieved with primary alkyl bromides in high yields in the presence of an iron catalyst, 1,2-bis(diphenylphosphino)ethane (dppe), and PhMgBr in 2-MeTHF.

Read more now


 

NMR Spectroscopy

Ultra-Low-Field NMR Relaxation and Diffusion Measurements Using an Optical Magnetometer

Paul J. Ganssle, Hyun D. Shin, Dr. Scott J. Seltzer, Dr. Vikram S. Bajaj, Dr. Micah P. Ledbetter, Prof. Dmitry Budker, Dr. Svenja Knappe, Dr. John Kitching and Prof. Alexander Pines

Ultra-Low-Field NMR Relaxation and Diffusion Measurements Using an Optical MagnetometerPortable NMR: NMR relaxometry and diffusometry can be highly effective in applications where high-resolution NMR spectroscopy is unnecessary or impractical, as is the case in the emerging field of portable chemical characterization. A proof-of-concept experiment is presented demonstrating the use of high-sensitivity optical magnetometers as detectors for ultra-low-field NMR relaxation and diffusion measurements.

Read more now


 

SEARCH

SEARCH BY CITATION