Volume 10 Issue 10, October 2018

Volume 10 Issue 10

Magnetic MOF monolayers

Layered coordination polymers (LCPs) are usually too fragile to withstand the ‘Scotch-tape method’ widely used to mechanically exfoliate a variety of materials. Now a team led by Guillermo Mínguez Espallargas and Eugenio Coronado has successfully stripped a family of five isoreticular crystalline, magnetic LCPs – based on Fe(II) centres and five benzimidazole derivatives – down to monolayers (an artistic representation of a single sheet is shown on the cover). The use of functionalized ligands in the bulk LCPs means that the magnetic 2D materials obtained on exfoliation are already functionalized; this approach avoids the need for a surface-engineering step which is known to introduce defects.

See Coronado et al.

Image: Sr.Brightside Studio - José Moreno. Cover Design: Tulsi Voralia.

Thesis

  • Thesis |

    Michelle Francl considers how metaphor breathes life into chemistry.

    • Michelle Francl

News & Views

  • News & Views |

    Probing single-atom alloys has shown that, when interactions between the components are weak, the electronic structure of the dilute element resembles that of a free atom, making bonding with reactants more like that in molecular homogeneous catalysts.

    • Christian Papp
  • News & Views |

    Dynamic covalent chemistry combines the error-correcting behaviour of supramolecular chemistry with the robustness of covalent bonding, but relies on a somewhat limited set of reactions. Now, the classic nucleophilic aromatic substitution (SNAr) reaction has been shown to be reversible and self-correcting.

    • Yinghua Jin
    •  & Wei Zhang
  • News & Views |

    The structure of an antibiotic that is effective against Gram-positive bacteria, but not against Gram-negative bacteria, has now been modified to improve its effectiveness against Gram-negative bacteria. The approach could help broaden the spectrum of activity of other antibiotics.

    • Jed F. Fisher
    •  & Shahriar Mobashery

Articles

  • Article |

    Surface engineering is an attractive route to tune the processability, stability and functionalities of 2D materials, but typically introduces defects in the resulting structures. Now, the issue has been circumvented through pre-synthetic functionalization instead; an isoreticular family of robust layered coordination polymers has been mechanically exfoliated to give functionalized crystalline magnetic monolayers.

    • J. López-Cabrelles
    • , S. Mañas-Valero
    • , I. J. Vitórica-Yrezábal
    • , P. J. Bereciartua
    • , J. A. Rodríguez-Velamazán
    • , J. C. Waerenborgh
    • , B. J. C. Vieira
    • , D. Davidovikj
    • , P. G. Steeneken
    • , H. S. J. van der Zant
    • , G. Mínguez Espallargas
    •  & E. Coronado
  • Article |

    In solid metals, electron orbitals form broad bands and their binding of adsorbates depends on the bandwidth. Now, it is shown that a weak solute–matrix interaction in dilute alloys results in extremely narrow electronic bands on the solute, similar to a free-atom electronic structure. This structure affords unique adsorption properties important for catalysis.

    • M. T. Greiner
    • , T. E. Jones
    • , S. Beeg
    • , L. Zwiener
    • , M. Scherzer
    • , F. Girgsdies
    • , S. Piccinin
    • , M. Armbrüster
    • , A. Knop-Gericke
    •  & R. Schlögl
  • Article |

    Functional group interconversion typically requires reactive reagents to irreversibly generate a desired product in high yield and selectivity. Now, a CO-free catalytic functional-group-metathesis approach can be used to interconvert aroyl chlorides and aryl iodides—two important classes of electrophiles often employed in the preparation of pharmaceuticals and agrochemicals—with the help of metathesis-active phosphine ligands.

    • Yong Ho Lee
    •  & Bill Morandi
  • Article |

    Dynamic covalent chemistry offers promise for the formation of elaborate extended network materials in high yields, but the limited number of reactions available confines the scope and functionality of the materials synthesized. Now, nucleophilic aromatic substitution has been shown to be reversible, and thus self-correcting, enabling the easy synthesis of sulfur-rich materials.

    • Wen Jie Ong
    •  & Timothy M. Swager
  • Article |

    Light can selectively drive and control the reversible reaction between a nitrogen nucleophile and a photoswitchable carbonyl electrophile by inducing wavelength-specific tautomerization cycles. This enables external and bidirectional regulation of closed dynamic covalent systems via C=N exchange, resembling a light-powered bidirectional molecular-scale Dean–Stark trap.

    • Michael Kathan
    • , Fabian Eisenreich
    • , Christoph Jurissek
    • , Andre Dallmann
    • , Johannes Gurke
    •  & Stefan Hecht
  • Article |

    CO2 can be used as an activator for the direct transformation of abundant and unprotected primary aliphatic amines into valuable γ-lactams under photoredox and hydrogen-atom-transfer catalysis. Electrostatic interactions between the in situ generated alkylammonium carbamate and the positively charged quinuclidinium radical lead to regioselective hydrogen atom abstraction.

    • Juntao Ye
    • , Indrek Kalvet
    • , Franziska Schoenebeck
    •  & Tomislav Rovis
  • Article |

    The polyoxoanion [P2W18O62]6− has been shown to reversibly accept up to 18 electrons upon reduction in aqueous solution. The resulting highly reduced solution can then be used either for the on-demand generation of hydrogen over a catalyst bed, or as a high-energy-density electrolyte in a redox flow battery.

    • Jia-Jia Chen
    • , Mark D. Symes
    •  & Leroy Cronin
  • Article |

    Catalyst-controlled site selectivity without relying on the influence of a directing group within the substrate is a major challenge in C–H functionalization. Now a catalyst is described that selectively functionalizes non-activated primary C–H bonds in the presence of a variety of other C–H bonds and functional groups.

    • Kuangbiao Liao
    • , Yun-Fang Yang
    • , Yingzi Li
    • , Jacob N. Sanders
    • , K. N. Houk
    • , Djamaladdin G. Musaev
    •  & Huw M. L. Davies
  • Article |

    Layered coordination polymers are attractive for the preparation of advanced 2D materials but they are typically non-magnetic insulators. Now such a layered network, CrCl2(pyrazine)2, has been prepared that comprises a paramagnetic metal ion and a redox-active ligand. The material exhibits both magnetism — with a ferrimagnetic ground state — and high electrical conductivity.

    • Kasper S. Pedersen
    • , Panagiota Perlepe
    • , Michael L. Aubrey
    • , Daniel N. Woodruff
    • , Sebastian E. Reyes-Lillo
    • , Anders Reinholdt
    • , Laura Voigt
    • , Zheshen Li
    • , Kasper Borup
    • , Mathieu Rouzières
    • , Dumitru Samohvalov
    • , Fabrice Wilhelm
    • , Andrei Rogalev
    • , Jeffrey B. Neaton
    • , Jeffrey R. Long
    •  & Rodolphe Clérac
  • Article |

    Mechanistic studies of the hemilability of MIDA (N-methyliminodiacetic acid) boronates reveal the chameleonic behaviour of the BMIDA group. The superior migratory aptitude of BMIDA compared to hydride and the capacity to resemble a proton when nitrogen decoordinates from boron have now been exploited for the design of new boron transfer reactions.

    • C. Frank Lee
    • , Diego B. Diaz
    • , Aleksandra Holownia
    • , Sherif J. Kaldas
    • , Sean K. Liew
    • , Graham E. Garrett
    • , Travis Dudding
    •  & Andrei K. Yudin

Amendments & Corrections

In Your Element