Crown Ethers in Graphene Bring Strong, Selective Binding

Researchers discovered the long-sought crown ether structures with perfect rigidity in oxidized atomic-scale holes in graphene. Calculations indicate that these “super crown ethers” provide unprecedented binding strength and selectivity. Thus, new supramolecular materials in which metal ions are trapped into arrays within the graphene plane are possible. These new materials should provide electrical, magnetic and optical functionality to graphene.

Chemists have sought to control positioning of guest atoms in host spaces for the purpose of designing and synthesizing chemical systems with predetermined properties. The natural flexibility of ether molecules has largely prevented this from happening in the case of the crown ether family of structures. In contrast in graphene, crown ether structures are held rigid by the carbon lattice and the ether donor groups are flattened onto the graphene plane in such a way that the dipoles point directly at the center of the binding cavity. Using aberration-corrected scanning transmission electron microscopy and density-functional calculations, we find that the binding properties of these new structures exceed those obtained with individual crown ether molecules.

 

J. Guo, J. Lee, C. I. Contescu, N. C. Gallego, S. T. Pantelides, S. J. Pennycook, B. A. Moyer, and M. F. Chisholm, “Crown ethers in graphene,” Nature Commun. 5, 5389 (2014).   doi: 10.1038/ncomms6389.

 

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