Volume 10 Issue 1, January 2018

Volume 10 Issue 1

Accumulating multiple redox equivalents at catalytic sites is crucial to driving light-initiated multiple-electron-transfer reactions such as water splitting. However, generating and observing catalytic centres that have been reduced or oxidized twice under diffuse illumination is not a trivial task because of detrimental charge-recombination reactions. Now Hsiang-Yun Chen and Shane Ardo show that, on excitation with low-intensity visible light, a molecular proxy for a multiple-electron-transfer electrocatalyst can be oxidized twice by Ru—polypyridyl dye molecules when anchored to a titania film. This is depicted on the cover with the brown and red spheres representing the dye and proxy catalyst molecules, respectively.Article p17News & Views p3IMAGE: DARIUS SIWEKCOVER DESIGN: TULSI VORALIA

Thesis

  • Thesis |

    Michelle Francl muses on fantastic beasts of chemistry and why we try to find them.

    • Michelle Francl

News and Views

  • News & Views |

    The accumulation of multiple redox equivalents is essential in photo-driven catalytic reactions such as solar water splitting. However, direct spectroscopic observation of a twice-oxidized species under diffuse illumination has proved elusive until now.

    • Anna M. Beiler
    •  & Gary F. Moore
  • News & Views |

    Molecular crystals have recently started to shake their inflexible reputation. Now, copper(II) acetylacetonate needles have been shown to be very flexible, and their mechanical deformation has been assessed through materials constants using methods customarily reserved for non-molecular materials.

    • Bart Kahr
    •  & Michael D. Ward
  • News & Views |

    Water-oxidation catalysts that are fast and efficient in strong acid are rare even though there are several benefits for systems working at low pH. Such catalysts usually feature expensive noble metals such as ruthenium and iridum; however, an electrocatalytic system that is exceptionally efficient and based on cobalt has now been developed.

    • Qiushi Yin
    •  & Craig L. Hill

Review

  • Review Article |

    Given its ubiquity, the importance of understanding the properties of water cannot be understated. Now, stemming from discussions at a National Science Foundation-supported workshop, this Review Article highlights where there is latent chemical space for potential collaborations between the physical and supramolecular communities, both of which are interested in how molecules interact with each other in water.

    • Paul S. Cremer
    • , Amar H. Flood
    • , Bruce C. Gibb
    •  & David L. Mobley

Articles

  • Article |

    Photosynthesis uses sunlight to oxidize or reduce reaction centres multiple times and prepare them for multiple-electron-transfer reactions. Now, it has been shown that a molecular proxy for a multiple-electron-transfer electrocatalyst can be oxidized twice by dye molecules when both are anchored to a mesoporous TiO2 thin film and excited with low-intensity visible light.

    • Hsiang-Yun Chen
    •  & Shane Ardo
  • Article |

    Electrochemical water oxidation in acidic media is a promising water-splitting technique, but typically requires noble metal catalysts. Now, two polyoxometalate salts based on earth-abundant metals have shown excellent catalytic performance for the oxygen evolution reaction. The barium salt of a cobalt-phosphotungstate polyanion outperformed the state-of-the-art IrO2 catalyst at pHs lower than 1.

    • Marta Blasco-Ahicart
    • , Joaquín Soriano-López
    • , Jorge J. Carbó
    • , Josep M. Poblet
    •  & J. R. Galan-Mascaros
  • Article |

    Providing detailed structural descriptions of the ultrafast photochemical events that occur in light-sensitive proteins is key to their understanding. Now, excited-state structures in the reversibly switchable fluorescent protein rsEGFP2 have been solved by time-resolved crystallography using an X-ray laser. These structures enabled the design of a mutant with improved photoswitching quantum yields.

    • Nicolas Coquelle
    • , Michel Sliwa
    • , Joyce Woodhouse
    • , Giorgio Schirò
    • , Virgile Adam
    • , Andrew Aquila
    • , Thomas R. M. Barends
    • , Sébastien Boutet
    • , Martin Byrdin
    • , Sergio Carbajo
    • , Eugenio De la Mora
    • , R. Bruce Doak
    • , Mikolaj Feliks
    • , Franck Fieschi
    • , Lutz Foucar
    • , Virginia Guillon
    • , Mario Hilpert
    • , Mark S. Hunter
    • , Stefan Jakobs
    • , Jason E. Koglin
    • , Gabriela Kovacsova
    • , Thomas J. Lane
    • , Bernard Lévy
    • , Mengning Liang
    • , Karol Nass
    • , Jacqueline Ridard
    • , Joseph S. Robinson
    • , Christopher M. Roome
    • , Cyril Ruckebusch
    • , Matthew Seaberg
    • , Michel Thepaut
    • , Marco Cammarata
    • , Isabelle Demachy
    • , Martin Field
    • , Robert L. Shoeman
    • , Dominique Bourgeois
    • , Jacques-Philippe Colletier
    • , Ilme Schlichting
    •  & Martin Weik
  • Article |

    The biosynthesis of secondary metabolites such as stephacidin A and its congeners continues to intrigue both biochemists and synthetic chemists. Now, a laboratory chemical synthesis of these natural products has been achieved based on a bioinspired synthetic strategy, which may provide key insights into the possible biosynthesis of these captivating molecules.

    • Ken Mukai
    • , Danilo Pereira de Sant'Ana
    • , Yasuo Hirooka
    • , Eduardo V. Mercado-Marin
    • , David E. Stephens
    • , Kevin G. M. Kou
    • , Sven C. Richter
    • , Naomi Kelley
    •  & Richmond Sarpong
  • Article |

    Despite advances in peptide synthesis techniques, explicit control over the quaternary structure of synthetic peptides has remained elusive. Now, the dynamic covalent chemistry of hydrazide- and aldehyde-containing peptides has now been shown to enable the formation of unique quaternary structures with topological diversity. Using this method, oligomers were assembled into complex structures showing dramatic enhancements of antimicrobial effectiveness versus Staphylococcus Aureus.

    • James F. Reuther
    • , Justine L. Dees
    • , Igor V. Kolesnichenko
    • , Erik T. Hernandez
    • , Dmitri V. Ukraintsev
    • , Rusheel Guduru
    • , Marvin Whiteley
    •  & Eric V. Anslyn
  • Article |

    Rationally designed arrays of hydrogen bonds between aromatic oligoamide segments have now been shown to generate abiotic helix-turn-helix and unexpected dimeric and trimeric helix bundle motifs. These structures show kinetic and thermodynamic stability, and cooperative folding in nonpolar solvents.

    • Soumen De
    • , Bo Chi
    • , Thierry Granier
    • , Ting Qi
    • , Victor Maurizot
    •  & Ivan Huc
  • Article |

    The use of activating and directing groups can dramatically alter the course of a reaction. Now, it has been shown that an azo group can effectively perform as both in chiral phosphoric-acid catalysed formal nucleophilic aromatic substitution of azobenzene derivatives with indoles, affording axially chiral arylindoles with excellent enantioselectivities.

    • Liang-Wen Qi
    • , Jian-Hui Mao
    • , Jian Zhang
    •  & Bin Tan
  • Article |

    Crystals are typically thought to be brittle and fragile materials, but needles of copper(II) acetylacetonate have now been shown to be flexible enough to be reversibly tied into a knot. Mechanistic investigations using synchrotron X-ray diffraction determined that the elastic bending occurs through rotation of the molecules within the crystal lattice.

    • Anna Worthy
    • , Arnaud Grosjean
    • , Michael C. Pfrunder
    • , Yanan Xu
    • , Cheng Yan
    • , Grant Edwards
    • , Jack K. Clegg
    •  & John C. McMurtrie
  • Article |

    Steroids are arguably the most well studied and successful class of natural-product-inspired pharmaceuticals, yet step-economical and enantiospecific de novo synthesis remains challenging. Now, it is shown that the combination of metallacycle-mediated annulative cross-coupling and vinyl cyclopropane rearrangement chemistry can be used to deliver a variety of partially aromatic synthetic steroids in a concise, flexible and enantiospecific fashion.

    • Wan Shin Kim
    • , Kang Du
    • , Alan Eastman
    • , Russell P. Hughes
    •  & Glenn C. Micalizio
  • Article |

    Colloidal particles of metal–organic frameworks (ZIF-8 and UiO-66) with different polyhedral shapes can self-assemble into well-ordered, porous three-dimensional superstructures. These superstructures function as photonic crystals, with a photonic band gap that depends on the size of the MOF particles and shifts upon the sorption of guests within their pores.

    • Civan Avci
    • , Inhar Imaz
    • , Arnau Carné-Sánchez
    • , Jose Angel Pariente
    • , Nikos Tasios
    • , Javier Pérez-Carvajal
    • , Maria Isabel Alonso
    • , Alvaro Blanco
    • , Marjolein Dijkstra
    • , Cefe López
    •  & Daniel Maspoch
  • Article |

    Determining the structure­–activity relationships for complex structures can be quite challenging, but it is often the method by which many natural products are optimized for use as drugs. Now, the combination of a fluoroaryl borane catalyst, a phosphine additive and a silane reducing agent enables the late-stage selective modification of complex bioactive natural products in order to provide rapid access to a wide array of structures, and therefore functions.

    • Trandon A. Bender
    • , Philippa R. Payne
    •  & Michel R. Gagné
  • Article |

    The rate constant of DNA hybridization varies over several orders of magnitude and is affected by temperature and DNA sequence. A machine-learning algorithm that is capable of accurately predicting hybridization rate constants has now been developed. Tests with this algorithm showed that over 90% of predictions were correct to within a factor of three.

    • Jinny X. Zhang
    • , John Z. Fang
    • , Wei Duan
    • , Lucia R. Wu
    • , Angela W. Zhang
    • , Neil Dalchau
    • , Boyan Yordanov
    • , Rasmus Petersen
    • , Andrew Phillips
    •  & David Yu Zhang
  • Article |

    Although organocopper compounds are well known in organic chemistry, only recently has a set of catalytic reactions emerged that involve intermediates containing a copper-substituted stereogenic carbon centre. Now, a mechanistic study demonstrates that a better understanding of this distinction offers ways to address significant limitations in scope and enantioselectivity, explaining why unexpected variations in selectivity can occur.

    • Jaehee Lee
    • , Suttipol Radomkit
    • , Sebastian Torker
    • , Juan del Pozo
    •  & Amir H. Hoveyda

In Your Element

  • In Your Element |

    Geng Deng relates how terbium, a garden-variety lanthanide, has found its way into our daily lives owing to its green phosphorescence.

    • Geng Deng

Correction

Erratum