Angewandte Chemie International Edition

Upcoming VIPs

The following papers are very important in the opinion of two referees. They will be published as soon as possible.

You are invited to comment on published VIPs. Please use the link given at the end of each such abstract. Scientific comments may be forwarded to the authors by the editorial office and may be posted on this page. Kindly let us know if your comments are for the editorial office only, the author, or the public as well.

 

 

Compositionally Tunable Photoluminescence Emission in Cu₂ZnSn(S_1-xSe_x)₄ Nanocrystals

Ajay Singh, Shalini Singh, Sergiu Levcenko, Thomas Unold, Fathima Laffir, and Kevin M. Ryan*

Controlling the sulfur/selenium ratio in colloidal Cu₂ZnSn(S_1-xSe_x)₄ (CZTS) nanocrystals allowed very precise band-gap tuning (0.9–1.4 eV). The nanocrystals show composition-dependent photoluminescence emission with peak shifts directly correlating with the chalcogen ratio. The size-controlled nanocrystals form in the Wurtzite crystal phase with characterization by X-ray diffraction, high-resolution TEM, Raman and X-ray photoelectron spectroscopy confirming their occurrence as single-crystal alloys for all compositions. The tunable photoluminescence emission in earth-abundant quaternary chalcogenides greatly expands their potential application in both discrete nanocrystal (Q-dot) applications and in thin-film photovoltaic devices where a defined and controllable band gap is required

Coming soon.

 

 

Structure of the Parallel Duplex of Poly(A) RNA: Evaluation of a 50-Year Old Prediction

Nozhat Safaee,* Anne M. Noronha, Dmitry Rodionov, Guennadi Kozlov, Christopher J. Wilds, George M. Sheldrick, and Kalle Gehring*

Although the molecular structure of the double-stranded poly(rA) was predicted by Rich et al. in 1961, it has taken more than 50 years to confirm this prediction. The crystal structure of the parallel duplex of (rA)11 obtained at physiological pH, solved using ab initio direct methods, and refined to 1.0 Å resolution is reported. The geometry of purine rings suggests that the adenines are not protonated. Instead, supported by our thermal denaturation studies, bound ammonium ions are complexed by the adenines, stabilizing the duplex. The self-assembly of poly(rA) is a novel feature of an abundant nucleic acid motif.

Coming soon.

 

 

Combining NHC–Cu and Brønsted Base Catalysis: Enantioselective Allylic Substitution/Conjugate Addition with Alkynyl Aluminum Reagents and Their Stereospecific Isomerization to Trisubstituted Allenes

Jennifer A. Dabrowski, Fredrik Haeffner, and Amir H. Hoveyda*

Catalytic enantioselective allylic substitution reactions that involve alkynyl nucleophiles and generate tertiary carbon stereogenic centers are presented for the first time. Transformations are promoted by a chiral N-heterocyclic carbine–Cu complex and require alkynyl aluminum reagents simply prepared in situ from an alkyne and di(iso)-butylaluminum hydride; products are obtained in up to >98 % yield, >98 % S_N2′ selectivity and 98.5:1.5 enantiomeric ratio. The enantiomerically enriched skipped enynes are then converted to trisubstituted allenes with 15–100 mol % of a common amine base (dbu) typically with complete enantiospecificity. Mechanistic experiments and DFT calculations shed light on the mechanism of stereoselective alkyne-to-allene isomerization.

Coming soon.

 

 

Evidence for Low-Temperature Melting of Mercury Due To Relativity

Florent Calvo,* Elke Pahl, Michael Wormit, and Peter Schwerdtfeger*

Among the many peculiarities of elemental metallic mercury, its liquid form at room temperature, and low melting temperature at -38.83 °C, has eluded fundamental understanding so far. Special relativity has been speculated as a possible cause for this unique state, but never was proven. Using Monte Carlo simulations, together with a diatomic-in-molecule method to simulate the many-body interactions in bulk mercury, was the key to solve this challenging problem. Relativistic and nonrelativistic calculations show that the melting temperature in bulk mercury is lowered by 105 °C due to relativistic effects. Thus, hypothetical nonrelativistic mercury remains solid under normal conditions.

Coming soon.

 

 

Graphene Oxide Nanoribbons from the Oxidative Opening of Carbon Nanotubes Retain Electrochemically Active Metallic Impurities

Colin Hong An Wong, Chun Kiang Chua, Bahareh Khezri, Richard D. Webster, and Martin Pumera*

Graphene nanoribbons are commonly synthesized using carbon nanotubes (CNTs) as a precursor through the oxidative opening of the nanotubes into elongated ribbons. However, CNTs contain significant amounts of metallic impurities even after purification. Herein, we show that these impurities persist at parts-per-billion levels after oxidative opening of CNTs to graphene oxide nanoribbons and heavily influence the electrochemical behavior of the resulting material. This may have negative impacts on the range and effectiveness of potential applications suitable for graphene materials.

Coming soon.

 

 

Organic Semiconductor Doping: Impact of Dopant Strength and Electronic Coupling

Henry Méndez, Georg Heimel,* Andreas Opitz, Katrein Sauer, Patrick Barkowski, Martin Oehzelt, Junshi Soeda, Toshihiro Okamoto, Jun Takeya, Jean-Baptiste Arlin, Jean-Yves Balandier, Yves Geerts, Norbert Koch, and Ingo Salzmann*

The standard model for molecular electrical p-doping of organic semiconductors (OSCs) assumes integer charge transfer between OSC and dopant. Here, it is contrasted to an alternative model based on intermolecular complex formation between OSC and dopant. Systematically varying the acceptor strength of prototypical dopants in a matrix of a solution processible OSC allowed discriminating the two models. Determining the actual structure of intermolecular complexes and correlating it with the optical and electronic properties of p-doped samples clearly favored the alternative model. Consequences for chemical design strategies of more efficient molecular dopants are deduced.

Coming soon.

 

 

C–H Functionalization Logic Enables a Synthesis of (+)-Hongoquercin A and Related Compounds

Brandon R. Rosen, Leah R. Simke, Peter S. Thuy-Boun, Darryl D. Dixon, Jin-Quan Yu, and Phil S. Baran

A synthesis of the sesquiterpenoid antibiotic (+)-hongoquercin A using sequential site-specific C–H methylation and oxidation reactions is described. A key advancement toward this goal was the development of a ligand-accelerated C–H methylation reaction. This unique strategic disconnection enables the generation of a library of eight structurally diverse analogs, highlighting the utility of these reactions in the synthesis and modification of structurally complex molecules.

Coming soon.

 

 

Enantioselective Isomerization of Primary Allylic Alcohols into Chiral Aldehydes with the Tol-Binap/Dbapen–Ruthenium(II) Catalyst

Noriyoshi Arai, Keisuke Sato, Keita Azuma, and Takeshi Ohkuma*

Enantioselective isomerization of γ-substituted primary allylic alcohols into the β-substituted aldehydes is catalyzed by the [RuCl₂{(S)-tol-binap}{(R)-dbapen}]–KOH system. The reaction is conducted with a substrate-to-catalyst molar ratio in the range of 100–2000 at 25°C for 0.5–1 h. A turnover number of about 1550 is achieved in the best case. A series of (E)- and (Z)-configurated aromatic and aliphatic allylic alcohols, including a simple primary alkyl-substituted compound (E)-3-methyl-2-hepten-1-ol, is transformed to the aldehydes in at least 99% ee. The plausible mechanism for this reaction, which is promoted by the hemilability of the dbapen–Ru chelate structure, is also discussed.

Coming soon.

 

 

Deprotonation of a Borohydride: Synthesis of a Carbene-Stabilized Boryl Anion

David A. Ruiz, Gaël Ung, Mohand Melaimi, and Guy Bertrand*

Because of the higher electronegativity of hydrogen (2.20) compared to boron (2.04), hydrogen atoms bonded to boron are regarded as hydrides, and thus deprotonation does not seem feasible. The use of both an electrophilic cyclic (alkyl)(amino)carbene (CAAC) and of two electron-withdrawing nitrile groups, makes a neutral carbene-borohydride adduct acidic enough to be deprotonated by a strong base. The resulting (CAAC)-B(CN)₂^- anion is stable in the absence of air and moisture, and reacts with carbon and metal electrophiles at the boron center.

Coming soon.

 

 

A Strategy for Separating and Recycling Solid Catalysts Based on the pH-Triggered Pickering Emulsion Inversion

Hengquan Yang,* Ting Zhou, and Wenjuan Zhang

A conceptually novel method for performing in situ separation and recycling of submicrometer-sized solid catalysts has been explored, which is based on the pH-triggered Pickering emulsion inversion. This method enables solid catalysts to be recycled 36 times without significant loss of activity. The developed method is distinguished from the conventional methods in respect of time and energy consumption, catalyst separation, and recycling effectiveness.

Coming soon.

 

 

Light-Regulated Stapled Peptides to Inhibit Protein–Protein Interactions Involved in Clathrin-Mediated Endocytosis

Laura Nevola, Andrés Martín-Quirós, Kay Eckelt, Nuria Camarero, Sébastein Tosi, Artur Llobet, Ernest Giralt,* and Pau Gorostiza*

Photoswitchable inhibitors of protein–protein interactions have been applied to photoregulate clathrin-mediated endocytosis (CME) in living cells. These peptides, named traffic lights because they act as "stop" and "go" signals for membrane traffic, constitute a novel tool to control cell signaling in spatiotemporally defined patterns. Traffic light peptides can be used to dissect the role of CME in receptor internalization and in cell growth, division, and differentiation.

Coming soon.

 

 

Stepwise-Resolved Thermodynamics of Hydrophobic Self-Assembly: A New Experimental Concept

Alina Grego, Achim Müller,* and Ira A. Weinstock*

Despite over a century of numerous investigations on the very important hydrophobic effect, direct observation of the evolving roles of the different related contributions during multi-step hydrophobic assembly processes has remained experimentally inaccessible. This challenging problem was now addressed by using an unprecedented type of experiment based on the step-wise growth of a structurally well-defined organic aggregate within a water-soluble porous metal-oxide nanocapsule. Detailed thermodynamic data obtained reveal an evolving spectrum of different types of hydrophobic effects acting in context with sequential growth steps, which finally lead to the formation of a beautiful "micelle"-like n-butyrate-ion assembly with a practically water-free central cavity.

Coming soon.

 

 

Photoinduced Curling of Organic Molecular Crystal Nanowires

Taehyung Kim, Muhanna K. Al-Muhanna, Salem D. Al-Suwaidan, Rabih O. Al-Kaysi,* and Christopher J. Bardeen*

Molecular crystal nanowires composed of an anthracene-9-(1,3-butadiene) derivative exhibit a rapid transition from straight to highly coiled structures when exposed to a pulse of visible light. The curling does not depend on the direction of the light illumination and occurs for nanowires composed of either the (E) or (Z) isomer. The shape change is driven by an E⇌Z photoisomerization reaction that generates a mixture of isomers within a single nanowire.

Received March 19, 2013, published online May 16, 2013, DOI: 10.1002/anie.201302323 – read now.

Did you read this article? Was it important to you? Let us know...

 

 

Enantiopure Water-Soluble Fe₄L₆ Cages: Host–Guest Chemistry and Catalytic Activity

Jeanne L. Bolliger, Ana M. Belenguer, and Jonathan R. Nitschke*

Chiral bis(diimine) ligands (derived from chiral diamines and pyridine-2-aldehyde) enantioselectively self-assemble with iron(II) sulfate to form the new enantiopure tetrahedral cage molecule ΔΔΔΔ-[Fe₄L₆] or its enantiomer, ΛΛΛΛ-[Fe₄L₆]. These versatile water-soluble capsules are capable of binding a wide range of organic guests in their large hydrophobic cavities and, additionally, are able to distinguish between the enantiomers of chiral organic guests. Furthermore, the ΔΔΔΔ-[Fe₄L₆] coordination capsule also serves as a competent supramolecular catalyst for the hydrolysis of the neurotoxic organophosphate dichlorvos.

Coming soon.

 

 

Electrochemical Synthesis of One-Dimensional Mesoporous Pt Nanorods Using Surfactant–Micelle Assembly in Confined Space

Cuiling Li, Takaaki Sato, and Yusuke Yamauchi*

A general way is reported to synthesize novel self-supported one-dimensional mesoporous Pt nanorods with high density of mesopores by using electrochemical micelle assembly in confined space of polycarbonate membrane. The mesoporous structures with around 6–8 nm pore size and thin wall thickness are well developed over the entire area. The obtained 1D motifs show high activity and CO tolerance in the methanol oxidation reaction and also exhibit superior electrochemical activity in the oxygen reduction reaction. The all-wet approach is highly reproducible and widely applicable to other metal and alloy systems, which will be very useful for the development of future electrocatalysts.

Coming soon.

 

 

A Cyclic Silylone ("Siladicarbene") with an Electron-Rich Silicon(0) Atom

Yun Xiong, Shenglai Yao, Shigeyoshi Inoue, Jan-Dirk Epping, and Matthias Driess*

By using a neutral bidentate bis-NHC ligand (NHC=1,3-bis(2,6-diisopropylphenyl)imidazole-2-ylidene), an unprecedented bis-carbene chlorosilyliumylidene complex could be isolated, in which both HOMO and LUMO are mainly represented on the silicon(II) atom according to DFT calculations. Remarkably, dechlorination of the latter complex by sodium naphthalenide led to the first isolable cyclic siladicarbene with a bent geometry (C–Si–C angle: 89.1°) and average Si–C distances of 1.869 Å. According to the DFT calculations, the latter compound bears a single Si(0) atom with strikingly high basicity as predicted by the calculated first and second proton affinities and is hence best described as a silylone.

Coming soon.

 

 

Strongly Luminescent Gold(III) Complexes with Long-Lived Excited States: High Emission Quantum Yields, Energy Up-Conversion, and Nonlinear Optical Properties

Wai-Pong To, Kaai Tung Chan, Glenna So Ming Tong, Chensheng Ma, Wai-Ming Kwok, Xiangguo Guan, Kam-Hung Low, Chi-Ming Che*

Strongly emissive gold(III) complexes which display phosphorescence in the visible region and with emission quantum yields and lifetimes up to 58% and 305 µs, respectively, could be achieved using chelating cyclometalated ligands having fluorene substituent(s). These gold(III) complexes can sensitize energy up-conversion with a quantum yield Φ_UC up to 9.8% and display rich two-photon absorption properties.

Received February 08, 2013, published online May 16, 2013, DOI: 10.1002/anie.201301149 – read now.

Did you read this article? Was it important to you? Let us know...

 

 

Regioselectively Functionalized Pyridines from Sustainable Resources

Stefan Michlik and Rhett Kempe*

The pyridine heterocycle is an important structural motif that can be found in many natural products, drugs, herbicides, and fungicides. Here, a sustainable iridium-catalyzed pyridine synthesis is introduced. Alcohols and γ-amino alcohols are deoxygenated and selectively linked through C–N and C–C bond formation steps. The starting materials can be obtained from renewable resources. Three equivalents of hydrogen gas are eliminated in the course of the reaction. The synthesis protocol tolerates a large variety of functional groups and significantly extents the scope of existing pyridine syntheses. The new chemistry is not just sustainable it also can be impressive in scope.

Coming soon.

 

 

Photosensitization of DNA by a 5-Methyl-2-Pyrimidone Deoxyribonucleoside: The (6–4) Photoproduct as a Trojan Horse

Victoria Vendrell-Criado, Gemma M. Rodríguez-Muñiz, M. Consuelo Cuquerella, Virginie Lhiaubet-Vallet,* and Miguel A. Miranda*

An interesting feature of (6–4) photoproducts is their relatively long-wavelength absorption, which could extend the active fraction of sunlight. Surprisingly, their potential role as intrinsic DNA photosensitizers has not been addressed yet. This appealing question has been tackled here by model studies with a 5-methyl-2-pyrimidone deoxyribonucleoside, the main chromophore of (6–4) photoproducts. The results reveal photosensitized formation of oxidation products and cyclobutane thymine dimers. Overall, this raises the issue of a possible aggravation of the photomutagenicity of (6–4) lesions, acting as Trojan horses.

Received March 14, 2013, published online May 09, 2013, DOI: 10.1002/anie.201302176 – read now.

Did you read this article? Was it important to you? Let us know...

 

 

Tetrameric Cyclic Double Helicates as a Scaffold for a Molecular Solomon Link

Jonathon E. Beves, Christopher J. Campbell, David A. Leigh,* and Robin G. Pritchard

The one-pot synthesis of a molecular Solomon link assembles four iron(II) cations, four bis-aldehyde and four bis-amine building blocks to generate two interwoven 68-membered-ring macrocycles with four crossings in 75 % isolated yield. The synthesis of the Solomon link, and an earlier pentafoil knot, demonstrate that cyclic helicates of different sizes can act as highly efficient and effective scaffolds for intricate molecular topologies.

Received March 29, 2013, published online May 06, 2013, DOI: 10.1002/anie.201302634 – read now.

Did you read this article? Was it important to you? Let us know...

 

 

Synergy between XANES Spectroscopy and DFT to Elucidate the Amorphous Structure of Heterogeneous Catalysts: TiO₂-Supported Molybdenum Oxide Catalysts

Asma Tougerti, Elise Berrier, Anne-Sophie Mamede, Camille La Fontaine, Valérie Briois, Yves Joly, Edmond Payen, Jean-François Paul, and Sylvain Cristol*

Using the 3D structural depiction of the environment around the absorbing atom provided by X-ray absorption near-edge structure (XANES) spectroscopy and DFT calculations, the molecular-scale structure of the TiO₂-supported molybdenum oxide catalysts has been unraveled and it consists of Mo octahedra arranged in a six-membered ring structure.

Received January 21, 2013, published online May 07, 2013, DOI: 10.1002/anie.201300538 – read now.

Did you read this article? Was it important to you? Let us know...

 

 

Click Synthesis of Pyrroles: Silver-Catalyzed Cycloaddition of Terminal Alkynes with Isocyanides

Meng Gao, Chuan He, Hongyi Chen, Ruopeng Bai, Ben Cheng, and Aiwen Lei*

A novel silver-catalyzed click synthesis of pyrroles by the co-cyclization of terminal alkynes and isocyanides has been developed. From the synthetic point of view, this protocol represents an extremely simple, efficient, and atom-economic way to construct substituted pyrroles in good yields with high selectivity, which complements the click method for the rapid construction of multifunctional heterocycles.

Received March 28, 2013, published online April 29, 2013, DOI: 10.1002/anie.201302604 – read now.

Did you read this article? Was it important to you? Let us know...

 

 

On the Structures of 55-Atom Transition-Metal Clusters and Their Relation to the Crystalline Bulk

Thomas Rapps, Reinhart Ahlrichs, Eugen Waldt, Manfred M. Kappes, and Detlef Schooss*

Electron diffraction measurements on a set of homonuclear 55-atom transition-metal clusters covering essentially all 3d and 4d elements are reported. The diffraction data obtained for cluster anions in gas phase at 95K show four main structure types. Elements with the same bulk lattice morphology generally have a common cluster structure type. To rationalize this, cluster geometries have been determined by fitting structural models from density functional theory calculations to the diffraction data. The four structure types differ in maximum atomic coordination numbers in analogy to the coordination numbers in the corresponding bulk lattices.

Received March 14, 2013, published online May 09, 2013, DOI: 10.1002/anie.201302165 – read now.

Did you read this article? Was it important to you? Let us know...

 

 

Enzyme-Labile Protecting Groups Add a New Orthogonal Dimension to the Synthesis of Natural Products: Solid-Phase Synthesis of Thiocoraline

Judit Tulla-Puche,* Miriam Góngora-Benítez, Núria Bayó-Puxan, Andrés M. Francesch, Carmen Cuevas, and Fernando Albericio*

The solid-phase synthesis of the potent antitumoral thiocoraline is accomplished for the first time by a combined approach involving chemical and enzymatic methods. With a sequence highly rich in Cys, consecutive NMe amino acids, and a bicyclic structure formed by a disulfide bridge flanked by two thioester moieties, an orchestrated protection group scheme becomes the cornerstone for the successful synthesis for thiocoraline. One-pot cleavage of the phenylacetamidomethyl moiety by the immobilized penicillin G acylase and disulfide formation are the key steps of the synthetic strategy.

Received February 27, 2013, published online April 25, 2013, DOI: 10.1002/anie.201301708 – read now. No. 22/2013.

Did you read this article? Was it important to you? Let us know...

 

 

Silver-Catalyzed Isocyanide–Alkyne Cycloaddition: A General and Practical Method to Oligosubstituted Pyrroles

Jianquan Liu, Zhongxue Fang, Qian Zhang,* Qun Liu, and Xihe Bi*

The first transition-metal-catalyzed cycloaddition of isocyanides and unactivated terminal alkynes has been realized by the discovery of silver carbonate (Ag₂CO₃) as a unique and robust catalyst. This protocol for silver-catalyzed reaction is highly efficient allowing a broad range of terminal and internal alkynes to react with isocyanides under base- and ligand-free conditions, regioselectively generating synthetically useful 2,3-disubstituted and 2,3,4-trisubstituted pyrroles in good to high yields.

Received March 11, 2013, published online May 06, 2013, DOI: 10.1002/anie.201302024 – read now.

Did you read this article? Was it important to you? Let us know...

 

 

Identifying Intermediates of Sequential Electron and Hydrogen Loss from a Dicarbonylcobalt Hydride Complex

Michael J. Krafft, Martina Bubrin, Alexa Paretzki, Falk Lissner, Jan Fiedler, Stanislav Záliš, and Wolfgang Kaim*

Combining the classical cobalt carbonyl hydride configuration with the question of how, mechanistically, cobalt hydrides effect the formation of H₂, a specific, structurally protecting and potentially electronically active ferrocenyldiphosphane co-ligand at Co(CO)₂H was used to characterize the native metal hydride, the one-electron oxidized form, and the sensitive, metal hydride-free byproduct of H₂ formation by structure analysis and low-temperature spectroelectrochemistry. The first identification of all elementary steps in the homolytic pathway for oxidative carbonylmetal hydride conversion is reported.

Received February 27, 2013, published online May 10, 2013, DOI: 10.1002/anie.201301706 – read now.

Did you read this article? Was it important to you? Let us know...

 

 

Carbon-Coated CdS Petalous Nanostructures with Enhanced Photostability and Photocatalytic Activity

Yong Hu*, Xuehui Gao, Le Yu, Yanrong Wang, Jiqiang Ning, Shijie Xu, and Xiong Wen (David) Lou*

CdS-based visible-light photocatalysts have intrinsic photocorrosion problems. Another great concern is the toxicity of leached Cd²⁺ ions. In this work, we show that by simply coating the CdS particles with a thin layer of amorphous carbon, the above problems can be largely solved. We demonstrate the concept by synthesizing novel carbon-coated CdS petalous particles using a one-pot solvothermal method. The carbon nanocoating serves multifold functions including surface protection of CdS, visible-light absorption enhancement and facilitated separation of photogenerated charges. As a result, this CdS–C nanohybrid photocatalyst exhibits significantly enhanced photostability and photocatalytic activity.

Received February 27, 2013, published online April 05, 2013, DOI: 10.1002/anie.201301709 – read now. No. 21/2013.

Did you read this article? Was it important to you? Let us know...

 

 

Synthesis and Characterization of a High–Valent Mixed-Metal [Cu^III(µ–O)₂Ni^III]²⁺ Core Involving Nucleophilic Oxo Groups

Subrata Kundu, Florian Felix Pfaff, Enrico Miceli, Ivelina Zaharieva, Christian Herwig, Shenglai Yao, Erik R. Farquhar, Uwe Kuhlmann, Eckhard Bill, Peter Hildebrandt, Holger Dau, Matthias Driess,* Christian Limberg,* and Kallol Ray*

A heterobimetallic high-valent CuNi bis(µ–oxo) complex is prepared by the reduction of a nickel superoxo complex with a Cu(I) reductant, and characterized by low–temperature UV/Vis, resonance Raman, electron paramagnetic resonance, and X–ray absorption spectroscopy in conjunction with reactivity and DFT studies. Unlike typical homodinuclear high–valent [M₂(µ–O)₂]ⁿ⁺ cores, which have electrophilic oxo groups, the oxo groups in [Cu(µ–O)₂Ni]²⁺ behave as nucleophiles, and can initiate deformylation of aldehydes. Mixed–metal bis(µ–oxo) cores are, therefore, viable intermediates during the deformylation of fatty aldehydes by cyanobacterial aldehyde decarbonylase, where a heterodinuclear cofactor has been suggested.

Received January 31, 2013, published online April 15, 2013, DOI: 10.1002/anie.201300861 – read now. No. 21/2013.

Did you read this article? Was it important to you? Let us know...

 

 

Towards Structure Determination of Self-Assembled Peptides using Dynamic Nuclear Polarization Enhanced Solid-State NMR

Hiroki Takahashi, Bastien Viverge, Daniel Lee, Patrice Rannou, and Gaël De Paëpe*

Peptide self-assemblies have great potential for applications in nanotechnology. However, atomic-scale structure determination is not straightforward, which is essentially due to the difficulty associated with using X-ray crystallography. Dynamic nuclear polarization (DNP) enhanced solid-state NMR was performed on self-assembled peptide nanotubes prepared with a new DNP-friendly method. This approach achieves uniform distribution of polarizing agents around the sample without sample dilution and yields significant experimental time-savings of five orders of magnitude. This super-sensitivity was used to exemplify the feasibility of supramolecular structural studies of organic nanoassemblies using multidimensional ¹³C NMR at natural isotopic abundance.

Received December 18, 2012, published online April 05, 2013, DOI: 10.1002/anie.201210093 – read now.

Did you read this article? Was it important to you? Let us know...

 

 

First Near-Infrared-Light-Driven Photocatalyst Cu₂(OH)PO₄

Gang Wang, Baibiao Huang*, Xiangchao Ma, Zeyan Wang, Xiaoyan Qin, Xiaoyang Zhang, Ying Dai, and Myung-Hwan Whangbo

Photocatalysts active under near-infrared (NIR) light have been unknown. The libethenite Cu₂(OH)PO₄ absorbs strongly in the NIR light region and is an effective photocatalyst under NIR light irradiation, which decomposes 2,4-dichlorophenol in aqueous solution. Cu₂(OH)PO₄ consists of distorted CuO₄(OH)₂ octahedra sharing their corners with distorted CuO₄(OH) trigonal bipyramids. The NIR-light-driven photocatalytic ability of Cu₂(OH)PO₄ is due to a facile transfer of the photogenerated electrons from the trigonal bipyramidal Cu(II) sites to the adjacent octahedral Cu(II) sites.

Received February 14, 2013, published online March 28, 2013, DOI: 10.1002/anie.201301306 – read now.

Did you read this article? Was it important to you? Let us know...

 

 

A Facile Strategy for Selective Phosphoserine Incorporation in Histones

Sangsik Lee, Seunghee Oh, Aerin Yang, Jihyo Kim, Dieter Söll, Daeyoup Lee,* and Hee-Sung Park*

A general strategy for producing recombinant histones with site-specific serine phosphorylation is developed through engineering phosphoseryl-tRNA synthetase and an elongation factor. Serine-phosphorylated nucleosomes provide the first direct evidence for crosstalk between phosphorylation and acetylation in histone. This strategy should facilitate the study of histone phosphorylation and cross-regulatory mechanisms.

Received January 21, 2013, published online March 26, 2013, DOI: 10.1002/anie.201300531 – read now. No. 22/2013.

Did you read this article? Was it important to you? Let us know...

 

 

Twisted Cucurbit[14]uril

Xiao-Jie Cheng, Li-Li Liang, Kai Chen, Ning-Ning Ji, Xin Xiao, Yun-Qian Zhang, Sai-Feng Xue, Qian-Jiang Zhu, Xin-Long Ni,* and Zhu Tao*

Cucurbit[14]uril, the largest cucurbit[n]uril member with 14 normal glycoluril units linked by 28 methylene bridges using the traditional synthetic routes. However, it seems to be formed from 14 units of the –glycoluril-(CH₂)₂– moiety with a 360° twist. As a consequence, it does not have a normal cavity like the most cucubit[n]urils, and looks to have a folded, figure-of-eight conformation. We are naming it twisted cucurbit[14]uril (tQ[14]).

Coming soon.