Volume 6 Issue 3, March 2014

Volume 6 Issue 3

Copolymers of ethylene and other monomers bearing polar functional groups are typically produced using harsh conditions that make any fine structural control of the resulting material quite difficult. Now, Christophe Detrembleur and co-workers have shown that an organo-cobalt complex can be used to mediate the radical copolymerization of ethylene with polar monomers such as vinyl acetate or acrylonitrile under mild conditions. This approach affords a measure of control over the monomer composition of the final product as well as the distribution of the different monomers in the polymer chain, as shown schematically on the cover.Article p179IMAGE: CHRISTOPHE LEPOTCOVER DESIGN: ALEX WING

Books and Arts

Research Highlights

Blogroll

News and Views

  • News & Views |

    ATP synthase is an important enzyme for the storage and release of energy in cells. Ion-mobility mass spectrometry has now been used to study its structure, revealing important mechanistic details about its operation and regulation.

    • Jianhua Zhao
    •  & John L. Rubinstein
  • News & Views |

    Protein fibril formation is involved in many human diseases and thus has been mechanistically elucidated in the context of understanding — and in turn treating — them. This biological phenomenon has now also inspired the design of a supramolecular system that undergoes living polymerization.

    • Frank Würthner
  • News & Views |

    Pigment assemblies with high-efficiency electronic energy transfer have recently been observed to show unusual and persistent coherence, but its origin is not fully understood. Now, a combination of 2D electronic spectroscopy and theoretical modelling has allowed the excitonic coherence signal of a strongly coupled homodimer to be isolated.

    • Vivek Tiwari
    • , William K. Peters
    •  & David M. Jonas
  • News & Views |

    The amount of uranium in seawater vastly exceeds that in land-based deposits; but separating it from other more abundant metal ions requires high affinity, selectivity — and the ability to deal with an enormous volume of water. Now, two complementary approaches have made considerable contributions to overcoming these challenges.

    • Yi Lu
  • News & Views |

    Enzymes catalyse nearly all of the myriad chemical reactions that occur in every living organism. An easily understandable, visually appealing model has now been described that illustrates the fundamentals of how enzymes work.

    • Lawrence T. Scott

Articles

  • Article |

    Copolymers of ethylene and polar monomers are produced industrially using free radical polymerization that leads to broad molecular weight distributions of products with ill-defined structures. Now, an organo–cobalt complex is shown to control the radical copolymerization of ethylene with polar monomers under mild experimental conditions, and allows access to block-like copolymers with targeted compositions and monomer distributions.

    • Anthony Kermagoret
    • , Antoine Debuigne
    • , Christine Jérôme
    •  & Christophe Detrembleur
  • Article |

    Self-organization that occurs far from thermodynamic equilibrium is ubiquitous in nature but has remained challenging to control in synthetic supramolecular systems. A complex system has now been devised that displays such behaviour. Porphyrin derivative monomers undergo living supramolecular polymerization, a reaction underpinned by the interplay of two supramolecular polymerization pathways.

    • Soichiro Ogi
    • , Kazunori Sugiyasu
    • , Swarup Manna
    • , Sadaki Samitsu
    •  & Masayuki Takeuchi
  • Article |

    The observation of long-lived coherent oscillations in the nonlinear spectra of photosynthetic proteins has raised significant discussion on the role of quantum effects in biology. Using a model system, the signatures of inter-exciton coherence have been isolated, which has allowed the influence of vibronic coupling to be studied in unprecedented detail.

    • Alexei Halpin
    • , Philip J. M. Johnson
    • , Roel Tempelaar
    • , R. Scott Murphy
    • , Jasper Knoester
    • , Thomas L. C. Jansen
    •  & R. J. Dwayne Miller
  • Article |

    Light-driven proton pumps are used in biology to create a proton gradient that can be subsequently converted into chemical energy. Here, an artificial light-harvesting system based on a membrane doped with a spiropyran is described. Irradiation with UV light generates a proton flux across the membrane and results in the generation of an electrical current.

    • Xiaojiang Xie
    • , Gastón A. Crespo
    • , Günter Mistlberger
    •  & Eric Bakker
  • Article |

    Ion mobility–mass spectrometry has enabled the study of conformation and dynamics of membrane proteins in the gas phase. Here, the enhanced flexibility of macromolecular ATPase was investigated by comparing arrival time distributions of distinct species and relating them to different solution conditions, leading to the proposal of a nucleotide-triggered regulatory mechanism.

    • Min Zhou
    • , Argyris Politis
    • , Roberta B. Davies
    • , Idlir Liko
    • , Kuan-Jung Wu
    • , Alastair G. Stewart
    • , Daniela Stock
    •  & Carol V. Robinson
  • Article |

    When molecules collide with atoms or other molecules their quantum mechanical character can lead to the diffraction of matter waves. Making use of advances in molecular beam technology, such diffraction oscillations have now been observed with unprecedented sharpness and angular resolution in the benchmark NO + He, Ne, or Ar systems.

    • Alexander von Zastrow
    • , Jolijn Onvlee
    • , Sjoerd N. Vogels
    • , Gerrit C. Groenenboom
    • , Ad van der Avoird
    •  & Sebastiaan Y. T. van de Meerakker
  • Article |

    Enzymatic catalysis relies on stereoelectronic complementarity between the enzyme's active site and the substrate's transition state. A simple model system illustrating this tenet has now been devised. The bowl-to-bowl inversion of corannulene, catalysed inside the cavity of a synthetic receptor by an induced-fit mechanism, arises from ground-state destabilization combined with transition-state stabilization.

    • Michal Juríček
    • , Nathan L. Strutt
    • , Jonathan C. Barnes
    • , Anna M. Butterfield
    • , Edward J. Dale
    • , Kim K. Baldridge
    • , J. Fraser Stoddart
    •  & Jay S. Siegel
  • Article |

    Helices are found at every level of natural systems, where their dynamic potential is exploited to achieve a variety of functions. Here, liquid-crystalline molecular switches embedded in a polymer are used to prepare biomimetic spring-like materials that can convert molecular motion into macroscopic work.

    • Supitchaya Iamsaard
    • , Sarah J. Aßhoff
    • , Benjamin Matt
    • , Tibor Kudernac
    • , Jeroen J. L. M. Cornelissen
    • , Stephen P. Fletcher
    •  & Nathalie Katsonis
  • Article |

    The extraction of uranium from seawater is limited by the high concentrations of carbonate and competing metal ions. Now, a highly selective uranyl-binding protein with femtomolar affinity has been developed. This protein can extract up to 60% uranium from synthetic seawater when immobilized on bacterial cell surfaces or amylose resin.

    • Lu Zhou
    • , Mike Bosscher
    • , Changsheng Zhang
    • , Salih Özçubukçu
    • , Liang Zhang
    • , Wen Zhang
    • , Charles J. Li
    • , Jianzhao Liu
    • , Mark P. Jensen
    • , Luhua Lai
    •  & Chuan He
  • Article |

    A dye that both maximizes electrolyte compatibility and improves light-harvesting properties has been designed for dye-sensitized solar cells. In cells based on the cobalt(II)/(III) redox mediator, use of the dye resulted in a power-conversion efficiency of 13%, revealing the great potential of porphyrin dyes for future solar cell applications.

    • Simon Mathew
    • , Aswani Yella
    • , Peng Gao
    • , Robin Humphry-Baker
    • , Basile F. E. Curchod
    • , Negar Ashari-Astani
    • , Ivano Tavernelli
    • , Ursula Rothlisberger
    • , Md. Khaja Nazeeruddin
    •  & Michael Grätzel
  • Article |

    Non-noble-metal-based MoS2 nanostructures are hydrogen evolution catalysts whose active sites are known to be located at the edges. Supported thiomolybdate [Mo3S13]2− nanoclusters have now been prepared that exhibit a structural motif similar to that of MoS2 edges. The nanoclusters, synthesized by a scalable route, demonstrate a high turnover frequency.

    • Jakob Kibsgaard
    • , Thomas F. Jaramillo
    •  & Flemming Besenbacher

In Your Element

  • In Your Element |

    From fake gems to a fixture of nuclear plants, John Emsley considers the many uses of zirconium.

    • John Emsley