Nature Chemistry Contents August 2013 Volume 5 Number 8 pp637-724

Advertisement Frontiers in Chemistry has a new specialty section - Polymer chemistry  Speciality section editor: Pellegrino Musto The section is devoted to the dissemination of significant findings, innovative ideas and non-conventional approaches in the broadly defined field of macromolecular science.   All articles must be submitted directly to speciality section where they are processed by the associate and review editors.  TABLE OF CONTENTS August 2013 Volume 5, Issue 8 Thesis Research Highlights Blogroll News and Views Articles In Your Element Subscribe   Facebook   RSS   Recommend to library   Twitter   Advertisement New Impact Factor The new impact factor for Nature Chemistry is 21.757*. This places the journal first among all primary research journals in the chemistry, multidisciplinary category.  *2012 Journal Citation Reports® (Thomson Reuters, 2013)   Thesis Top Sunlight and free radicals   pp637 - 639 Thomas Tidwell doi:10.1038/nchem.1703 Thomas Tidwell reflects on the overlooked — but prescient — proposal by the British chemists Arthur Downes and Thomas Blunt for photochemical free-radical formation, decades before Moses Gomberg launched the field of radical chemistry by preparing triphenylmethyl, the first stable organic radical. Research Highlights Top Scanning probe microscopy: Structural snapshots | Elemental mercury: State oddity | Infrared spectroscopy: Lifetime achievement | Iron catalysis: Easy ester reduction Blogroll Top Blogroll: Fraud and favourites   p641 Vinylogous doi:10.1038/nchem.1714 News and Views Top Antibiotics: Blocking bacterial defences   pp642 - 643 Ellis C. O'Neill and Robert A. Field doi:10.1038/nchem.1718 Electrochemical sensing of the function of cell-membrane proteins has led to the identification of inhibitors that could provide a new approach to the identification of antimicrobial drugs. See also: Article by Kong et al. Computational chemistry: A multitude of spins   pp643 - 644 Jeremy N. Harvey doi:10.1038/nchem.1719 Accurately representing molecules with many coupled unpaired electrons is currently impossible using conventional electronic-structure theories. Now, using a recently developed approach, the near-exact quantum wavefunction of the highly complex Mn4CaO5 cluster of photosystem II has been calculated See also: Article by Kurashige et al. Heparin sensing: Blue-chip binding   pp644 - 646 Zachary Shriver and Ram Sasisekharan doi:10.1038/nchem.1701 Heparin is an anionic polysaccharide that has tremendous clinical importance as an anticoagulant. Several dyes have been developed that can detect heparin, and the latest example — named Mallard Blue — has now been shown to have excellent sensing properties under biologically relevant conditions. Macrocyclic chemistry: A star is born   pp646 - 647 James A. Wisner doi:10.1038/nchem.1715 Macrocycles have been a mainstay of supramolecular chemistry since its beginnings. The latest addition to this rank of host compounds is the result of a simple and high-yielding one-step method that produces a star-shaped macrocycle able to bind anionic guests — and has the potential for generating a wide range of anion-responsive structures. See also: Article by Lee et al. Inorganic materials: Intuition weaved into computation   pp648 - 649 Richard Catlow doi:10.1038/nchem.1712 Structure prediction methods that build in chemical knowledge offer the real possibility of materials design. Metallacycles: Breaking the rules   pp649 - 650 Torsten Beweries and Uwe Rosenthal doi:10.1038/nchem.1702 Chemists have long been interested in synthesizing compounds that push the boundaries of conventional molecular structure. Incorporating metal centres into the ring unit of highly strained and unsaturated cyclic molecules can help reduce strain — a tactic that has now been used to render a previously inaccessible metallapentalyne isolable. See also: Article by Zhu et al. Chemistry JOBS of the week Environmental Chemistry Swedsih University of Agricultural Sciences W2-Professor for "Biomolecular Label Chemistry" Georg-August University Göttingen Institute Research Scientist - Computational Chemistry MD Anderson Cancer Center Ph.D. Studentship in Porous Organic Molecules, 2013 The University of Liverpool Graphene-based materials, nano-composites CNR-ISOF (Nanochemistry Labs) More Science jobs from Chemistry EVENT Frontiers of Computer Simulation in Chemistry and Materials Science 06.02.14 Newport Pagnell, UK More science events from Articles Top Single-molecule interrogation of a bacterial sugar transporter allows the discovery of an extracellular inhibitor   pp651 - 659 Lingbing Kong, Leon Harrington, Qiuhong Li, Stephen Cheley, Benjamin G. Davis et al. doi:10.1038/nchem.1695 Capsular polysaccharides (CPS) enclose many pathogenic strains of Escherichia coli, protecting the bacteria from the host. Here, an extracellular blocker of Wza, a pore-forming protein that transports CPS to the cell surface, has been discovered by single-channel electrical recording. Treatment with the blocker exposes the bacterial cell surface and thereby facilitates killing by the human immune system. See also: News and Views by O'Neill & Field Entangled quantum electronic wavefunctions of the Mn4CaO5 cluster in photosystem II    pp660 - 666 Yuki Kurashige, Garnet Kin-Lic Chan and Takeshi Yanai doi:10.1038/nchem.1677 Many-electron quantum modelling of the metal clusters in metalloenzymes is a long-standing ambition for theoreticians. Here, using the density matrix renormalization group, the many-electron wavefunctions of the Mn4CaO5 cluster of photosystem II are computed, providing new insights into the electronic structure and reactivity at the level of many-particle quantum mechanics and entanglement. See also: News and Views by Harvey Direct catalytic cross-coupling of organolithium compounds   pp667 - 672 Massimo Giannerini, Martín Fañanás-Mastral & Ben L. Feringa doi:10.1038/nchem.1678 A general and selective palladium-catalysed cross-coupling of aryl- and alkenyl-bromides with a wide range of alkyl-, aryl- and heteroaryl-lithium reagents is reported. The process proceeds quickly at room temperature, and avoids the notorious lithium–halogen exchange and homocoupling side-reactions commonly associated with these extremely reactive organometallic compounds. Magnetic relaxation pathways in lanthanide single-molecule magnets   pp673 - 678 Robin J. Blagg, Liviu Ungur, Floriana Tuna, James Speak, Priyanka Comar et al. doi:10.1038/nchem.1707 Dysprosium alkoxides and dysprosium-doped yttrium alkoxides show very large energy barriers, greater than 800 K, to magnetic relaxation. These barriers arise from the presence of a strongly axial pseudo-octahedral crystal field, which switches off relaxation through the first excited state that typically occurs in single-molecule magnets, and favours a competitive pathway through higher-energy states. Total synthesis of the Daphniphyllum alkaloid daphenylline    pp679 - 684 Zhaoyong Lu, Yong Li, Jun Deng and Ang Li doi:10.1038/nchem.1694 Daphenylline is an alkaloid containing a tetra-substituted arene within a sterically compact hexacyclic scaffold. Here, the first total synthesis of daphenylline is described. A gold-catalysed 6-exo-dig cyclization reaction was exploited to construct the bridged 6,6-bicycle at an early stage, the aromatic moiety was forged through a photoinduced olefin isomerization/6π electrocyclization cascade followed by oxidative aromatization. The Janus-faced role of external forces in mechanochemical disulfide bond cleavage   pp685 - 691 Przemyslaw Dopieralski, Jordi Ribas-Arino, Padmesh Anjukandi, Martin Krupicka, Janos Kiss et al. doi:10.1038/nchem.1676 Using ab initio simulations external mechanical forces are shown to trigger structural changes to disulfide bridges that result in conformations that are less susceptible to nucleophilic attack. This finding is crucial for the interpretation of recent force microscopy experiments, and could be important for understanding protein regulation. A dendritic single-molecule fluorescent probe that is monovalent, photostable and minimally blinking   pp692 - 697 Si Kyung Yang, Xinghua Shi, Seongjin Park, Taekjip Ha and Steven C. Zimmerman doi:10.1038/nchem.1706 A far-red-fluorescent probe based on a ring-fused BODIPY core that is conjugated to a polyglycerol dendrimer is now reported. The most notable feature of this probe is its long-lasting fluorescence emission with a strikingly low level of blinking in single-molecule-imaging experiments, even in the absence of anti-fading agents such as Trolox. Stabilization of anti-aromatic and strained five-membered rings with a transition metal   pp698 - 703 Congqing Zhu, Shunhua Li, Ming Luo, Xiaoxi Zhou, Yufen Niu et al. doi:10.1038/nchem.1690 Pentalyne — a bicyclic anti-aromatic molecule that contains a strained five-membered ring — is a challenging synthetic target. Incorporation of an osmium centre has been shown to stabilize such features and enable the preparation of two osmapentalyne derivatives. Despite featuring the smallest angles observed so far at a carbyne moiety, these molecules benefit from Möbius aromaticity and reduced ring strain. See also: News and Views by Beweries & Rosenthal A pentagonal cyanostar macrocycle with cyanostilbene CH donors binds anions and forms dialkylphosphate [3]rotaxanes   pp704 - 710 Semin Lee, Chun-Hsing Chen and Amar H. Flood doi:10.1038/nchem.1668 Macrocycles are key compounds in supramolecular chemistry, yet their efficient preparation is an ever present challenge. Now, it has been shown that a C5-symmetric macrocycle, termed ‘cyanostar’, can be formed in high yields on multigram scales in one pot. Cyanostars form unusually strong sandwich complexes with large and weakly coordinating anions and can template the formation of a dialkylphosphate [3]rotaxane. See also: News and Views by Wisner Ultrafast above-threshold dynamics of the radical anion of a prototypical quinone electron-acceptor   pp711 - 717 Daniel A. Horke, Quansong Li, Lluís Blancafort and Jan R. R. Verlet doi:10.1038/nchem.1705 Quinones are key electron acceptors in nature, however, the role of their excited states is not fully understood. Femtosecond spectroscopy and quantum calculations on the prototypical parabenzoquinone radical anion provide insight into quinones’ intrinsic electron-accepting ability, revealing how unbound electronically excited states relax to form the ground-state radical anion. A frustrated-Lewis-pair approach to catalytic reduction of alkynes to cis-alkenes   pp718 - 723 Konstantin Chernichenko, Ádám Madarász, Imre Pápai, Martin Nieger, Markku Leskelä et al. doi:10.1038/nchem.1693 Frustrated Lewis pairs have been shown to be capable of heterolysis of strong covalent bonds such as those in molecular hydrogen, and have been used in the hydrogenation of polar multiple bonds. Here, a new type of ansa-aminohydroborane is shown to be active for the partial hydrogenation of alkynes under mild conditions. In Your Element Top Chlorine chronicles   p724 Barbara J. Finlayson-Pitts doi:10.1038/nchem.1717 Barbara Finlayson-Pitts muses on how chlorine has come to play a role in many aspects of our lives — for better or for worse. Top Advertisement Nature Geoscience web focus: 5 years after the Wenchuan Earthquake  Free online to registered nature.com users until 31 October 2013. Produced with support from the National Natural Science Foundation of China.   Natureevents is a fully searchable, multi-disciplinary database designed to maximise exposure for events organisers. The contents of the Natureevents Directory are now live. The digital version is available here. Find the latest scientific conferences, courses, meetings and symposia on natureevents.com. For event advertising opportunities across the Nature Publishing Group portfolio please contact natureevents@nature.com More Nature Events

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