Volume 8 Issue 4, April 2016

Volume 8 Issue 4

The regular repeating structure of covalent organic frameworks (COFs) makes these materials attractive for optoelectronic applications—in particular those made of two-dimensional covalent layers held together by π-stacking—but the necessary high crystallinity has remained difficult to engineer. Now, Florian Auras, Thomas Bein and co-workers have devised a building block (represented in yellow on the cover) with a shape that ensures successive units lock in position and promote long-range order by minimizing stacking faults and dislocations that otherwise typically occur in COF assembly (as demonstrated in green).Article p310IMAGE: CHRISTOPH HOHMANN, NANOSYSTEMS INITIATIVE MUNICHCOVER DESIGN: KAREN MOORE

Commentary

  • Commentary |

    Of all the things humans can bestow names upon, new chemical elements are about the rarest. Our group of periodic table experts attempts to read the tea leaves and predict the names for elements 113, 115, 117 and 118.

    • Shawn C. Burdette
    • , Philip Ball
    • , Kat Day
    • , Eric R. Scerri
    •  & Brett F. Thornton

Thesis

  • Thesis |

    It is easy to overlook just how important temperature is when it comes to chemistry and Michelle Francl wonders if thermometers had a role in turning alchemists into chemists.

    • Michelle Francl

News and Views

  • News & Views |

    Expanding the range of amino acids polymerizable by ribosomes could enable new functionalities to be added to polypeptides. Now, the genetic code has been reprogrammed using a reconstituted in vitro translation system to enable synthesis of unnatural peptides with unmatched flexibility.

    • Michael C. Jewett
    •  & Vincent Noireaux
  • News & Views |

    Controlling interfaces between transition-metal oxides and dissimilar structures is crucial for practical applications, yet has remained a quandary. Now, a coherent interface that bridges a perovskite and a fluorite structure has been formed using judiciously chosen metal cations.

    • Kenneth R. Poeppelmeier
    •  & James M. Rondinelli
  • News & Views |

    The properties of metal–organic frameworks — promising for a myriad of applications — can be commonly tuned by judicious choice of the building blocks used to prepare the material. Now, simply downsizing a rigid, non-porous MOF to a thin film has been shown to endow it with dynamic, gate-opening-type guest uptake behaviour.

    • Christopher J. Sumby
  • News & Views |

    A new click-style reaction based on a strain-release amination strategy has been developed. This approach can be used to append small, strained ring systems onto a core scaffold.

    • John A. Milligan
    •  & Peter Wipf

Review

  • Review Article |

    In enzyme-catalysed metabolic pathways, substrate channelling often directs the movement of intermediates from one active site to the next. Intramolecular tunnels, electrostatic interactions and chemical swing arms pass intermediates from one enzyme to the next, enhancing pathway catalysis. Introducing mechanisms of bounded diffusion in chemical cascades can increase selectivity, transient rates and overall yield.

    • Ian Wheeldon
    • , Shelley D. Minteer
    • , Scott Banta
    • , Scott Calabrese Barton
    • , Plamen Atanassov
    •  & Matthew Sigman

Articles

  • Article |

    Covalent organic frameworks (COFs) are attractive multifunctional porous materials that can be generated with atomic precision. However, endowing them with long-range order—desirable for applications—has remained challenging. Now, propeller-shaped building units have been used that allow consecutive layers to lock in position, resulting in highly crystalline COFs.

    • Laura Ascherl
    • , Torben Sick
    • , Johannes T. Margraf
    • , Saul H. Lapidus
    • , Mona Calik
    • , Christina Hettstedt
    • , Konstantin Karaghiosoff
    • , Markus Döblinger
    • , Timothy Clark
    • , Karena W. Chapman
    • , Florian Auras
    •  & Thomas Bein
  • Article |

    The repertoire of amino acids available for ribosomal peptide synthesis is limited by the genetic code. Now, a method to reduce the redundancy of codons has been developed based on the artificial division of codon boxes. This method enables non-proteinogenic amino acids to be included in peptides without sacrificing proteinogenic ones.

    • Yoshihiko Iwane
    • , Azusa Hitomi
    • , Hiroshi Murakami
    • , Takayuki Katoh
    • , Yuki Goto
    •  & Hiroaki Suga
  • Article |

    Achiral minerals often adopt a chiral shape when crystal growth proceeds in contact with chiral molecules. Now, detailed microscopic insight is provided into how the chiral footprint of hemifullerene (a buckybowl that is essentially half of C60) rearranges atoms at step edges on a copper surface into chiral motifs.

    • Wende Xiao
    • , Karl-Heinz Ernst
    • , Krisztian Palotas
    • , Yuyang Zhang
    • , Emilie Bruyer
    • , Lingqing Peng
    • , Thomas Greber
    • , Werner A. Hofer
    • , Lawrence T. Scott
    •  & Roman Fasel
  • Article |

    Theoretical electronic-structure methods are routinely used to estimate the parameters of complex kinetic models. It is now shown that uncertainty in such model parameters is correlated and that it can be quantified. An associated sensitivity analysis method is also derived that handles complex systems with many correlated reactions.

    • Jonathan E. Sutton
    • , Wei Guo
    • , Markos A. Katsoulakis
    •  & Dionisios G. Vlachos
  • Article |

    The glycoprotein gp120 is found on the surface of the HIV viron; it is essential for virus entry into cells. Now, an efficient modular synthesis of N-glycans and the preparation of a mixed-glycan array on aluminium-oxide-coated glass slide is described. This is a vital step in understanding the complex compositions of gp120 and thus important for the development of new HIV therapies.

    • Sachin S. Shivatare
    • , Shih-Huang Chang
    • , Tsung-I Tsai
    • , Susan Yu Tseng
    • , Vidya S. Shivatare
    • , Yih-Shyan Lin
    • , Yang-Yu Cheng
    • , Chien-Tai Ren
    • , Chang-Chun David Lee
    • , Sujeet Pawar
    • , Charng-Sheng Tsai
    • , Hao-Wei Shih
    • , Yi-Fang Zeng
    • , Chi-Hui Liang
    • , Peter D. Kwong
    • , Dennis R. Burton
    • , Chung-Yi Wu
    •  & Chi-Huey Wong
  • Article |

    The behaviour of heterostructures, crucial in nanodevices, largely depends on interfacial phenomena. These have proven difficult to control when the different materials adopt distinct crystal structures. Now, a coherent interface between perovskite and fluorite has been achieved that relies in particular on the coordination flexibility of judiciously chosen metal cations.

    • Marita O'Sullivan
    • , Joke Hadermann
    • , Matthew S. Dyer
    • , Stuart Turner
    • , Jonathan Alaria
    • , Troy D. Manning
    • , Artem M. Abakumov
    • , John B. Claridge
    •  & Matthew J. Rosseinsky
  • Article |

    Nature's speciality is to direct and control the reactivity of species, which are otherwise fatally destructive. However, the processes and design rules required to achieve such precise control are not clear. A de novo designed metalloprotein that stabilizes an otherwise unstable organic radical has now been developed to guide our understanding.

    • Gözde Ulas
    • , Thomas Lemmin
    • , Yibing Wu
    • , George T. Gassner
    •  & William F. DeGrado
  • Article |

    The ability to form multiple carbon–carbon bonds in a controlled sequence represents an important goal in modern chemical synthesis. Here, the in situ preparation of reactive allylic and benzylic boronic acids, obtained by reacting flow-generated diazo compounds with boronic acids, and their application in controlled iterative C–C bond forming reactions is described.

    • Claudio Battilocchio
    • , Florian Feist
    • , Andreas Hafner
    • , Meike Simon
    • , Duc N. Tran
    • , Daniel M. Allwood
    • , David C. Blakemore
    •  & Steven V. Ley
  • Article |

    Cyanuric acid, a small molecule with three thymine-like faces, reprogrammes the assembly of unmodified poly(adenine) into long fibres with a unique internal structure. The association of adenine and cyanuric acid units into a hexameric rosette motif brings together poly(adenine) triplexes with subsequent cooperative polymerization.

    • Nicole Avakyan
    • , Andrea A. Greschner
    • , Faisal Aldaye
    • , Christopher J. Serpell
    • , Violeta Toader
    • , Anne Petitjean
    •  & Hanadi F. Sleiman
  • Article |

    The sorption properties of a metal–organic framework (MOF) typically depend on its structure. Now, a MOF that consists of interdigitated layers has been prepared that does not take up guests in its bulk or thick-film form, yet does so—with a dynamic gate-opening behaviour—in thin-film form.

    • Shun Sakaida
    • , Kazuya Otsubo
    • , Osami Sakata
    • , Chulho Song
    • , Akihiko Fujiwara
    • , Masaki Takata
    •  & Hiroshi Kitagawa
  • Article |

    Proposed as the source of the light-dependent magnetic compass in migratory birds, the radical pair mechanism is thought to operate in flavoproteins in the retina. Now, it has been demonstrated that the primary magnetic field effect on flavin photoreactions can be chemically amplified by slow radical termination reactions under conditions of continuous photoexcitation.

    • Daniel R. Kattnig
    • , Emrys W. Evans
    • , Victoire Déjean
    • , Charlotte A. Dodson
    • , Mark I. Wallace
    • , Stuart R. Mackenzie
    • , Christiane R. Timmel
    •  & P. J. Hore

In Your Element

  • In Your Element |

    David Payne relates iridium's role in two very different ages.

    • David Payne