Braiding a molecular knot with eight crossings

@article{Danon2017BraidingAM,
  title={Braiding a molecular knot with eight crossings},
  author={Jonathan J. Danon and Anneke Kr{\"u}ger and David A. Leigh and Jean-François Lemonnier and Alexander J. Stephens and I{\~n}igo J. Vitorica-Yrezabal and Steffen L. Woltering},
  journal={Science},
  year={2017},
  volume={355},
  pages={159 - 162}
}
Three strands ironed closely together It is not uncommon when braiding hair or bread to intertwine three different strands. At the molecular level, however, synthetic knots have thus far been restricted to architectures accessible from two-strand braids. Danon et al. used iron ion coordination to guide three organic ligand strands to form a knot geometry with eight separate crossings. Science, this issue p. 159 Iron coordination helps to template a molecular knot formed from three distinct… 

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References

SHOWING 1-10 OF 48 REFERENCES

Discovery of an Organic Trefoil Knot

TLDR
Near-quantitative self-assembly of a trefoil knot from a naphthalenediimide-based aqueous disulfide dynamic combinatorial library is reported, demonstrating that the hydrophobic effect provides a powerful strategy to direct the synthesis of entwined architectures.

A synthetic molecular pentafoil knot.

TLDR
The synthesis of the most complex non-DNA molecular knot prepared to date, which features an exceptional number of different design elements within the context of directing the formation of (supra)molecular species, is reported on.

Influence of a knot on the strength of a polymer strand

TLDR
Ab initio computational methods are used to investigate the effect of a trefoil knot on the breaking strength of a polymer strand and find that the knot weakens the strand significantly, and that, like a knotted rope, it breaks under tension at the entrance to the knot.

Template synthesis of molecular knots.

TLDR
This tutorial review outlines the different template strategies that chemists have employed to synthesise knotted molecular topologies, including the active metal template strategy in which metal ions both organise crossing points and catalyse the bond forming reactions that close the loop to form the topologically complex product.

Allosteric initiation and regulation of catalysis with a molecular knot

TLDR
A synthetic molecular pentafoil knot is reported that allosterically initiates or regulates catalyzed chemical reactions by controlling the in situ generation of a carbocation formed through the knot-promoted cleavage of a carbon-halogen bond.

Automatic molecular weaving prototyped by using single-stranded DNA.

TLDR
This work has prototyped a planar woven arrangement, using the B-DNA conformation for all nodes by strategically combining D-nucleotides and L-n nucleotides in the same strands for topological or nanotechnological purposes.

Self-assembling knots of controlled topology by designing the geometry of patchy templates.

TLDR
By computer simulation, it is shown by computer simulation that one may design the geometry of string-like rigid patchy templates to promote their efficient and reproducible self-assembly into a selected repertoire of non-planar closed folds including several knots.

Synthesis of a molecular trefoil knot by folding and closing on an octahedral coordination template.

TLDR
A synthetic strategy for the preparation of a molecular trefoil knot from a flexible bipyridine oligomer and a zinc(II) octahedral coordination template is reported.

Molecular knots in biology and chemistry

TLDR
The current knowledge on the various molecular knots found in naturally occurring biological systems (DNA, RNA and proteins), and those created by synthetic chemists are discussed, including recent developments in experimental and computational studies which are beginning to shed light into the complex interplay between these topologically intricate molecules.

Tetrameric Cyclic Double Helicates as a Scaffold for a Molecular Solomon Link**

TLDR
The use of a tetrameric circular helicate as the basis for a Solomon link is reported on, illustrating the general utility of this approach for the assembly of complex molecular topologies.