Since their discovery in the mid 1980s, fullerenes have caused a sensation. The tiny hollow spheres made of 60 carbon atoms, constructed out of pentagons and hexagons like miniature soccer balls, have unusual physical properties.
In the meantime, a variety of fullerene-containing materials have been developed. Now a new variant has been made: A Russian and Japanese team has produced the first material made of two-dimensional fullerene layers that acts like a metal. As the researchers report in the journal Angewandte Chemie, this new class of compounds could open a route toward novel superconducting materials.
All previous fullerene-containing crystals with metallic properties have been one- or three-dimensional structures and contained metal elements. Dmitri V. Konarev, Gunzi Saito, and their co-workers from Chernogolovka, Kyoto, and Nagoya had the ambition to make a metallic conducting fullerene “salt” containing two-dimensional fullerene layers. In addition, they wanted it to be free of metal ions, containing only the elements carbon, hydrogen, and nitrogen.
For this to work, three different components were needed: 1) fullerene anions, negatively charged “miniature soccer balls”; 2) positively charged organic counterions (cations); and 3) large neutral organic molecules. Component 2, the cations, are needed to maintain the right distribution of electrical charge within the material. The neutral compound 3 assures the correct spatial arrangement of the individual building blocks within the crystal structure.
The problem: fullerene anions in a crystal have a tendency to form pairs. In order for the material to behave as a metal, the fullerene anions need to be densely packed within their layer. Only when the geometry and size of the neutral partner are exactly right does this work. The team chose to use triptycene as the neutral component; this is an aromatic ring system whose shape is reminiscent of a three-bladed propeller. The organic cation they used has a cage-like structure.
The result is a crystal in which fullerene layers alternate with layers made of the two other partners. The fullerene layer has a honeycomb structure in which every tiny, negatively charged “soccer ball” has six adjacent neighbors. The fullerene layers are highly conducting like a metal—even down to temperatures near absolute zero (1.9 K), which is very unusual.
It should be possible to produce other materials in this class by varying the individual partners. The researches expect that this will produce materials with exotic electronic properties, such as novel superconductors or spin liquids, which are materials that show an unusual magnetic state at absolute zero.
Author: Dimitri Konarev, Russian Academy of Science, Moscow (Russia), mailto:email@example.com
Title: A Two-Dimensional Organic Metal Based on Fullerene
Angewandte Chemie International Edition, Permalink to the article: http://dx.doi.org/10.1002/anie.201001463
Dimitri Konarev | Angewandte Chemie
A Map of the Cell’s Power Station
18.08.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau
On the way to developing a new active ingredient against chronic infections
21.08.2017 | Deutsches Zentrum für Infektionsforschung
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
21.08.2017 | Medical Engineering
21.08.2017 | Materials Sciences
21.08.2017 | Life Sciences