Interlocked molecules

Interlocked molecules are molecular architectures formed from two or more components that are linked together mechanically; the entangled components are not connected through covalent bonds but cannot be separated without breaking a covalent bond. Examples of interlocked molecules include catenanes and rotaxanes.

Latest Research and Reviews

  • Research | | open

    Molecular knots and links continue to fascinate synthetic chemists. Here, the authors use stacking and hydrogen-bonding interactions between a set of similar building blocks to construct several complex molecular topologies, including a figure-eight knot and a trefoil knot.

    • Li-Long Dang
    • , Zhen-Bo Sun
    • , Wei-Long Shan
    • , Yue-Jian Lin
    • , Zhen-Hua Li
    •  & Guo-Xin Jin
  • Research |

    Helical structures play important roles in biological processes, yet their aggregation into fibres—which can in turn form gels—is poorly understood. Now, the self-assembly of a linear pentakis (urea) peptidomimetic compound into helices that further intertwine into well-defined braided structures has been described and analysed through braid theory. Homochiral gels may be formed by exposing the precursor sol to a chiral material.

    • Christopher D. Jones
    • , Henry T. D. Simmons
    • , Kate E. Horner
    • , Kaiqiang Liu
    • , Richard L. Thompson
    •  & Jonathan W. Steed
    Nature Chemistry 11, 375-381
  • Research | | open

    Mechanically interlocked molecules are widely studied, but the pathways by which they assemble are less well understood. Here the formation process of a quadruply-locked Pd4L8 cage is studied by NMR and mass spectrometry, with intermediates inferred by kinetic analysis.

    • Tomoki Tateishi
    • , Yuichi Yasutake
    • , Tatsuo Kojima
    • , Satoshi Takahashi
    •  & Shuichi Hiraoka
  • Research | | open

    For interlocking ring structures, knot theory predicts that the number of topologically different links increases with ring and crossing number. Here, the authors use a peptide folding-and-assembly strategy to selectively realize two highly entangled catenanes with 4 rings and 12 crossings, representing two of the 100 predicted topologies with this complexity.

    • Tomohisa Sawada
    • , Ami Saito
    • , Kenki Tamiya
    • , Koya Shimokawa
    • , Yutaro Hisada
    •  & Makoto Fujita
  • Research | | open

    Hierarchical non-intertwined ring-in-ring complexes are intriguing but challenging supramolecular targets. Here, the authors describe a box-in-box assembly based on radical-pairing interactions between two rigid diradical dicationic cyclophanes; the inner box can further accommodate guests to form Russian doll-like assemblies.

    • Kang Cai
    • , Mark C. Lipke
    • , Zhichang Liu
    • , Jordan Nelson
    • , Tao Cheng
    • , Yi Shi
    • , Chuyang Cheng
    • , Dengke Shen
    • , Ji-Min Han
    • , Suneal Vemuri
    • , Yuanning Feng
    • , Charlotte L. Stern
    • , William A. Goddard III
    • , Michael R. Wasielewski
    •  & J. Fraser Stoddart
  • Research | | open

    Molecular capsules typically bind only guests with volumes smaller than their cavities. Here, the authors find that a polyaromatic capsule accommodates linear amphiphilic oligomers in a length-dependent manner, whereas short chains are fully crammed into the cavity, long chains can be incorporated into the capsule in a threaded fashion.

    • Masahiro Yamashina
    • , Shunsuke Kusaba
    • , Munetaka Akita
    • , Takashi Kikuchi
    •  & Michito Yoshizawa

News and Comment

  • News and Views |

    Knots have been rigorously studied since the 1860s, but only in the past 30 years have they been made in the laboratory in molecular form. Now, the most complex small-molecule examples so far — a composite knot and an isomeric link, each with nine crossings — have been prepared.

    • Edward E. Fenlon
    Nature Chemistry 10, 1078-1079
  • News and Views |

    Both the topology and the mechanical strength of woven materials have inspired great synthetic efforts to replicate their structures at the nanoscale. Now, a triaxial weave has been prepared by self-assembly of a judiciously designed organic molecule through π–π and CH–π interactions.

    • Yi Liu
    Nature Chemistry 9, 1037-1038
  • News and Views |

    Molecular daisy-chain structures are typically made up of two interlocked components and can exhibit muscle-like contraction and extension in one dimension. Zinc-based multicomponent systems that can operate in two and three dimensions have now been designed and synthesized.

    • Karine Fournel-Marotte
    •  & Frédéric Coutrot
    Nature Chemistry 9, 105-106
  • News and Views |

    A chiral [2]rotaxane in which the asymmetry is derived from the way in which the two components are mechanically interlocked — rather than being encoded in the covalent connectivity of the components themselves — has been shown to act as an enantioselective organocatalyst.

    • Stephen M. Goldup
    Nature Chemistry 8, 404-406