Supramolecular electronics

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Supramolecular electronics is the experimental field of supramolecular chemistry that bridges the gap between molecular electronics and bulk plastics in the construction of electronic circuitry at the nanoscale ¹. In supramolecular electronics, assemblies of pi-conjugated systems on the 5 to 100 nanometer length scale are prepared by self-assembly with the aim to fit these structures between electrodes. With single-molecules as researched in molecular electronics at the 5 nanometer scale this would be impractical. Nanofibers can be prepared from polymers such as polyaniline and polyacetylene ¹². Chiral oligo(p-phenylenevinylene)s self-assemble in a controlled fashion into (helical) wires ³.

[edit] Hexa-benzopericoronene self assembly

Hexa-benzopericoronenes are members of the coronene family and are known to self-assemble into a columnar phase. One derivative in particular forms nanotubes with interesting electrical properties ⁴. The columnar phase in this compound further organises itself into sheets which ultimately roll up like a carpet to form multi-walled nanotubes with an outer diameter of 20 nanometer and a wall thickness of 3 nanometer. In this geometry the stacks of coronene disks are aligned with the length of the tube. The nanotubes have sufficient length to fit between two platinum nanogap electrodes produced by scanning probe nanofabrication and are 180 nanometer apart. The nanotubes as such are insulating but after one-electron oxidation with nitrosonium tetrafluoroborate (NOBF₄) they conduct electricity.

Organic synthesis of this compound starts with an Aldol condensation reaction of an acetone derivative with a benzil derivative to substituted cyclopentadienone. This compound is reacted with an alkyne in a Diels-Alder reaction and subsequent expulsion of carbon monoxide to the hexaphenylbenzene which is oxidized by Iron(III) chloride in nitromethane

[edit] References

• ¹ Chemistry: Material marriage in electronics E. W. Meijer, Albert P. H. J. Schenning Nature 419, 353-354 (26 Sep 2002)
• ² Supramolecular electronics; nanowires from self-assembled -conjugated systems A. P. H. J. Schenning and E. W. Meijer Chemical Communications, 2005, (26), 3245 - 3258 Abstract
• ³ Towards supramolecular electronics A.P.H.J. Schenning et al. Synthetic Metals 147 (2004) 43–48 Article
• ⁴ Self–Assembled Hexa-peri-hexabenzocoronene Graphitic Nanotube Jonathan P. Hill, Wusong Jin, Atsuko Kosaka, Takanori Fukushima, Hideki Ichihara, Takeshi Shimomura, Kohzo Ito, Tomihiro Hashizume, Noriyuki Ishii, Takuzo Aida Science 4 June 2004; 304: 1481-1483 Experimental Details