Volume 5 Issue 5, May 2013

Volume 5 Issue 5

Chemical reactions that proceed inside molecular capsules are often studied in solution. In the gas phase, the energy necessary to trigger inner-phase reactions typically results in the host–guest complex dissociating before the reaction occurs. Now, a team led by Elina Kalenius and Werner Nau have used mass spectrometry to study thermally activated retro-Diels–Alder reactions of guest molecules inside cucurbituril hosts in the gas phase. The cover picture conceptually shows the fate of a macrocyclic complex, from its formation, subsequent cycloelimination of the encapsulated guest, to the extrusion of a fragment.Article p376IMAGE: K. I. ASSAF, R. N. DSOUZA & H. OLSENCOVER DESIGN: ALEX WING

Editorial

  • Editorial |

    A collection of articles in this issue focuses on the chemical origin of life — how simple molecules present on the early Earth could have evolved into the complex dynamic biochemistry that we know today.

Thesis

  • Thesis |

    When elements 117 and 118 are finally named, should these new members of the halogen and noble gas families receive names ending in -ium as IUPAC has suggested? Brett F. Thornton and Shawn C. Burdette look at the history of element suffixes and make the case for not following this recommendation.

    • Brett F. Thornton
    •  & Shawn C. Burdette

Books and Arts

Interview

  • Interview |

    Matthew Powner from University College London talks with Nature Chemistry about his work on the chemical origin of life and how it has led him from PhD student to group leader.

Research Highlights

Blogroll

News and Views

  • News & Views |

    Non-enzymatic copying of an RNA template is appealing as a transition from pre-life to an RNA world, but it has been difficult to demonstrate in the laboratory. Now, two separate studies focusing on RNA's backbone connectivity offer partial solutions to some of the problems raised with this hypothesis for the origin of life.

    • Armando R. Hernández
    •  & Joseph A. Piccirilli
  • News & Views |

    The electrolysis of water provides a link between electrical energy and hydrogen, a high-energy-density fuel and a versatile energy carrier, but the process is expensive. Splitting the electrolysis reaction into two steps through an electrochemical 'buffer' offers a new way to think about improving the cost and efficiency of electrolysers.

    • Thomas E. Mallouk
  • News & Views |

    Four-dimensional electron microscopy has been applied to the detailed characterization of metal–organic-framework nanoparticles undergoing an electronic transition. The transition characteristics of a single particle were found to differ from those of an ensemble, and also to vary from one nanoparticle to the next.

    • Nigel D. Browning
  • News & Views |

    Tying molecules together in a link results in tremendous stabilization of the radical species they can form. Six clearly distinguishable charged states — which can be interconverted reversibly — have now been observed in a densely cationic system.

    • David B. Amabilino
  • News & Views |

    Designing a molecule that acts as both an initiator for a photo-controlled radical polymerization and as a reactive end-group for polymer chain crosslinking has enabled the preparation of polymeric gels whose properties can be controlled by exposure to sunlight.

    • David. M. Haddleton

Perspective

  • Perspective |

    Over the past decade, C–H bond activation has progressively become a well-established synthetic tool. An increased scope and understanding of this transformation has seen it being used in a wide range of contexts, not only in traditional organic synthesis, but also in late-stage diversification strategies for organic materials and biologically active molecules.

    • Joanna Wencel-Delord
    •  & Frank Glorius

Articles

  • Article |

    Reactions that occur inside macrocyclic hosts have been studied extensively in solution. Such inner-phase reactions have now been investigated in the gas phase using cucurbituril hosts and bicyclic azoalkane guests. Distinct structure–reactivity relationships have been identified, in which not only is the intrinsic activation energy critical, but also the degree of constrictive binding and the size of the void reaction space.

    • Tung-Chun Lee
    • , Elina Kalenius
    • , Alexandra I. Lazar
    • , Khaleel I. Assaf
    • , Nikolai Kuhnert
    • , Christian H. Grün
    • , Janne Jänis
    • , Oren A. Scherman
    •  & Werner M. Nau
  • Article |

    One theory for the abiogenesis of RNA involves ligation of shorter oligomers that are observed after dry-state condensation of mononucleotides. Here, the chemo- and regioselective acetylation of (oligo)nucleotides in water under prebiotically plausible conditions is described. This remarkable selectivity permits the rapid template-directed ligation of oligomers to favour extant 3′,5′-linkages.

    • Frank R. Bowler
    • , Christopher K. W. Chan
    • , Colm D. Duffy
    • , Béatrice Gerland
    • , Saidul Islam
    • , Matthew W. Powner
    • , John D. Sutherland
    •  & Jianfeng Xu
  • Article |

    An RNA aptamer and a ribozyme are both observed to retain a surprising degree of activity despite backbone heterogeneity caused by the presence of non-natural 2′–5′ phosphodiester linkages. These results suggest that absolute regioselectivity of non-enzymatic replication may not have been required for the emergence of RNA as the first biopolymer.

    • Aaron E. Engelhart
    • , Matthew W. Powner
    •  & Jack W. Szostak
  • Article |

    Introducing a small aperture in a 4D electron microscope has enabled researchers to visualize the phase transition of a single metal–organic framework particle with excellent spatio-temporal resolution. The spin-crossover dynamics of one nanoparticle are found to be distinct from those observed for an ensemble of heterogeneous nanoparticles.

    • Renske M. van der Veen
    • , Oh-Hoon Kwon
    • , Antoine Tissot
    • , Andreas Hauser
    •  & Ahmed H. Zewail
  • Article |

    Using a polyoxometalate as an electron-coupled-proton buffer, the decoupling of the water oxidation and proton reduction half reactions of electrolytic water splitting is achieved. This allows O2 and H2 to be produced separately in both time and space. The implications of these findings for electrolyser design and low-cost hydrogen production from water are discussed.

    • Mark D. Symes
    •  & Leroy Cronin
  • Article |

    Tatanans A, B and C, members of a family of complex sesquilignan natural products, were recently reported to possess potent anti-diabetic, glucokinase-activating properties. Here, a convergent enantioselective total synthesis of these tatanans enabled by catalytic allylic dearomatization is described. Contrary to previous reports, biological assays show that tatanans A–C are not allosteric activators of glucokinase.

    • Qing Xiao
    • , Jeffrey J. Jackson
    • , Ashok Basak
    • , Joseph M. Bowler
    • , Brian G. Miller
    •  & Armen Zakarian
  • Article |

    Complexes featuring rare gas atoms can be very strongly bonded even though these hypervalent molecules violate the octet rule. Now ab initio valence bond calculations on the XeF2 prototype highlight the essential role of charge-shift bonding, in which the covalent–ionic resonance energy is exceptionally large.

    • Benoît Braïda
    •  & Philippe C. Hiberty
  • Article |

    The development of new reaction methodology is a core activity for organic chemists, but the process can be slow and can rely on serendipity. Here, a reaction discovery platform is described that relies on the labelling of a reaction component with a chemical tag that enables rapid mass spectrometric detection of the derived products in complex mixtures.

    • Jaime R. Cabrera-Pardo
    • , David I. Chai
    • , Song Liu
    • , Milan Mrksich
    •  & Sergey A. Kozmin
  • Article |

    The development of methodology to convert biomass into fuels and chemical feedstocks is part of a drive to reduce the world's dependence on crude oil. Here, the catalytic defunctionalization of a series of biomass-derived molecules is described, which allows the selective generation of alkanes with carbon chain lengths between eight and sixteen for use as transportation fuels.

    • Andrew D. Sutton
    • , Fraser D. Waldie
    • , Ruilian Wu
    • , Marcel Schlaf
    • , Louis A. ‘Pete’ Silks III
    •  & John C. Gordon
  • Article |

    In situ catalysis of the formation of gelator molecules provides access to metastable gel states with improved mechanical strength compared with uncatalysed gels that have an identical composition. Acid or aniline catalysis enables the formation of hydrogels with tunable gel-strength in a matter of minutes under ambient conditions from simple building blocks.

    • Job Boekhoven
    • , Jos M. Poolman
    • , Chandan Maity
    • , Feng Li
    • , Lars van der Mee
    • , Christophe B. Minkenberg
    • , Eduardo Mendes
    • , Jan H. van Esch
    •  & Rienk Eelkema

In Your Element

  • In Your Element |

    Felice Grandinetti ponders on the peculiarity of neon among the noble gases — and whether it should occupy the top-right position in the periodic table.

    • Felice Grandinetti

Focus

  • Focus |

    Prebiotic chemistry

    Understanding how the simple molecules present on the early Earth may have given rise to the complex systems and processes of contemporary biology is widely regarded as one of chemistry's great unsolved questions. A collection of articles in this focus highlight some of the latest research in this area, including work that supports the RNA-world hypothesis.