Volume 7 Issue 6, June 2015

Volume 7 Issue 6

If one of the hydrogen atoms on each carbon of a cyclohexane ring is replaced with a fluorine atom, it is possible to produce nine different isomers of 1,2,3,4,5,6-hexafluorocyclohexane. The highest-energy isomer is one in which all six fluorines are located on the same face of the cyclohexane ring. Now, a team of researchers at the University of St Andrews led by David O’Hagan have made this all-cis isomer in a 12-step procedure starting from myo-inositol. This facially polarized hydrofluorocarbon is predicted to have a high molecular dipole (μ = 6.2 D), the largest identified so far for any aliphatic or aromatic organic compound that is not ionic.Article p483;News & Views p467IMAGE: NEIL S. KEDDIECOVER DESIGN: KAREN MOORE

Research Highlights

Blogroll

News and Views

  • News & Views |

    The first synthesis of the all-cis isomer of 1,2,3,4,5,6-hexafluorocyclohexane, a molecule with one hydrocarbon face and one fluorocarbon face, is a tour de force of organofluorine chemistry and opens up new possibilities for molecular design.

    • Nico Santschi
    •  & Ryan Gilmour
  • News & Views |

    Bulk SiO2 is widespread in nature, and silicon oxide clusters are important to a variety of applications, yet molecular silicon oxides have remained elusive. Two molecular compounds featuring silicon oxide moieties, Si2O3 and Si2O4, have now been isolated by oxidation of a carbene-stabilized disilicon precursor.

    • Yitzhak Apeloig
  • News & Views |

    Incorporating mechanically interlocked molecular shuttles within a metal–organic framework that has enough free space in the crystal lattice to permit volume-conserving translational motion sets the stage for defect-free molecular-electronic device fabrication and more.

    • Mark A. Olson
  • News & Views |

    Supramolecular polymerizations typically proceed through stepwise intermolecular mechanisms, concomitant with many side reactions to yield aggregates of unpredictable size, shape and mass. Now, a chain-growth strategy is shown to allow assembly of molecules into supramolecular chain structures endowed with precisely controlled characteristics.

    • Renren Deng
    •  & Xiaogang Liu
  • News & Views |

    Computations of the energetics and mechanism of the Morita–Baylis–Hillman reaction are “not even wrong” when compared with experiments. While computational abstinence may be the purest way to calculate challenging reaction mechanisms, taking prophylactic measures to avoid regrettable outcomes may be more realistic.

    • Arthur Winter

Perspective

  • Perspective |

    One-pot tandem reactions are attractive for both waste and time reduction, but can also enable transformations otherwise unobtainable in single-step processes. This Perspective covers recent advances in orthogonal tandem catalysis, while introducing the concept of thermodynamically leveraging multiple catalytic systems together to perform challenging transformations.

    • Tracy L. Lohr
    •  & Tobin J. Marks

Articles

  • Article |

    The highest-energy stereoisomer of 1,2,3,4,5,6-hexafluorocyclohexane, with all the fluorines ‘up’, has been prepared in a 12-step protocol. The molecule adopts a chair conformation with three triaxial C–F bonds on one face generating a polarized ring. In the solid state the molecules pack in an orientation consistent with electrostatic ordering.

    • Neil S. Keddie
    • , Alexandra M. Z. Slawin
    • , Tomas Lebl
    • , Douglas Philp
    •  & David O'Hagan
  • Article |

    Two semi-synthetic processes for the production of the antimalarial natural product artemisinin have been developed by applying the principles of green chemistry. Solvent manipulation allows catalyst recycling and reduction of waste, ultimately leading to a purification-free process with lower environmental and economic costs; a potential contribution to the world-wide fight against malaria.

    • Zacharias Amara
    • , Jessica F. B. Bellamy
    • , Raphael Horvath
    • , Samuel J. Miller
    • , Andrew Beeby
    • , Andreas Burgard
    • , Kai Rossen
    • , Martyn Poliakoff
    •  & Michael W. George
  • Article |

    Better understanding of the chemistry of rechargeable metal–oxygen batteries is needed to fulfil their potential. It is now shown that proton phase-transfer catalysts drive Na–O2 batteries, transporting superoxide between the electrode surface and the electrolyte as HO2. The chemistry uncovered gives rise to the system's high reversible capacity.

    • Chun Xia
    • , Robert Black
    • , Russel Fernandes
    • , Brian Adams
    •  & Linda F. Nazar
  • Article |

    During the early stages of life on Earth sophisticated RNA catalysts must have formed from simple precursors. Here it is shown that freeze–thaw cycles can drive the assembly of complex RNA polymerase ribozymes from networks of short RNA oligonucleotides through an unanticipated RNA chaperone effect.

    • Hannes Mutschler
    • , Aniela Wochner
    •  & Philipp Holliger
  • Article |

    Molecular SiO2 and other simple silicon oxides have remained elusive despite the importance of silicon dioxide materials in advanced electronic devices. Clusters Si2O3 and Si2O4 have now been experimentally realized by direct oxidation of a carbene-stabilized disilicon using N2O and O2, respectively.

    • Yuzhong Wang
    • , Mingwei Chen
    • , Yaoming Xie
    • , Pingrong Wei
    • , Henry F. Schaefer III
    • , Paul von R. Schleyer
    •  & Gregory H. Robinson
  • Article |

    The piston-like, translational motion of a molecular shuttle — a process that is fundamental to many mechanically interlocked molecular switches and machines — has now been demonstrated to occur inside the highly organized and dense structure (containing approximately 1021 shuttles per cm3) of a metal–organic framework material.

    • Kelong Zhu
    • , Christopher A. O'Keefe
    • , V. Nicholas Vukotic
    • , Robert W. Schurko
    •  & Stephen J. Loeb
  • Article |

    Equilibrium adsorption of non-racemic mixtures of enantiomers onto an achiral surface is shown to lead to enantioenrichment by formation of homochiral clusters. Such auto-amplification must influence enantioselective processes such as heterogeneous catalysis, adsorption-based separations, and perhaps the processes that lead to the homochirality of life on Earth.

    • Yongju Yun
    •  & Andrew J. Gellman
  • Article |

    Metallacycles made up of six copper ions and six cyclotriguaiacylene-based ligands form a unique topological entanglement in the solid state. Individual metallacycles are interwoven into an infinite 2D chainmail network where each one forms multiple Borromean-ring-like associations with its neighbours. Crystals of the complex grow in an unusual tubular morphology.

    • Flora L. Thorp-Greenwood
    • , Alexander N. Kulak
    •  & Michaele J. Hardie

In Your Element

  • In Your Element |

    Brett F. Thornton and Shawn C. Burdette consider holmium's hotly contested discovery and later obscurity.

    • Brett F. Thornton
    •  & Shawn C. Burdette