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> Gawel and his collaborators have now created and imaged the long-sought ring molecule carbon-18. Using standard ‘wet’ chemistry, his collaborator Lorel Scrive
by apo 7y ago
> Gawel and his collaborators have now created and imaged the long-sought ring molecule carbon-18. Using standard ‘wet’ chemistry, his collaborator Lorel Scriven, an Oxford chemist, first synthesized molecules that included four-carbon squares coming off the ring with oxygen atoms attached to squares. The team then sent their samples to IBM laboratories in Zurich, Switzerland, where collaborators put the oxygen–carbon molecules on a layer of sodium chloride, inside a high-vacuum chamber. They manipulated the rings one at a time with electric currents (using an atomic-force microscope that can also act as a scanning-transmission microscope), to remove the extraneous, oxygen-containing parts. After much trial-and-error, micrograph scans revealed the 18-carbon structure. “I never thought I would see this,” says Scriven.
The molecule (an all-carbon cycle of 18 atoms) was prepared in a very unusual way - by directly manipulating the atoms using an atomic force microscope.
In other words, each molecule is made individually. This is not the way that chemists typically work, and will not result in quantities of material that can be seen.
The abstract says nothing about chemical stability, but I suspect C-18 quite unstable and may never be prepared in gram quantities.
Higher cycles containing more carbons may be more stable, but this is likely to remain a curiosity for some time.
Still, this is a new kind of "allotrope" of carbon. The cyclic, relatively rigid nature of the structure and the potential for electrons to circulate under applied fields could lead to some unusual applications.
- mjevans 7y agoIt's still a good first step towards that future being possible. Now "we" know that it's actually maybe possible as well as properties of the material which might lead to better techniques for producing it or similar things using less exotic processes.
- staticautomatic 7y agoCould you explain why you think it's probably unstable? Is it just that the pi bonds don't like those angles?
- Knufen 7y agoThe orbitals of the pi bonds are probably in awkward angles resulting in ring strain, and thus instability. It can be explained by the antibonding orbital overlap of the pi bonds. Edit: Expanded a bit
- gus_massa 7y agoIn the ideal configuration, when you have single-triple-single bond, they "want" to be in the same line. A molecule where they are bles have more energy. (Imagine that it's like a spring, but don't take the analogies to literally.) The molecules where the bonds have wrong angles usually have more energy and they end to decompose in other molecules where the bonds have the correct angles or they have other bonds. [Oversimplifying warning, Chemistry is more complicated.] Some nice graphics: https://www.sciencedirect.com/topics/chemistry/triple-bond https://www.sciencedirect.com/topics/chemistry/triple-bond Perhaps the text is too technical, but the graphics are nice.
- jeffwass 7y agoIn this case, since all atoms form a ring, everything is symmetric within the plane so forces cancel out. So maybe it’s more stable than one would think, similar to cubane. But upon further consideration , the potential energy surface may be more like a saddle point, with each atom having a stable local minimum in-plane but unstable local maxima perpendicular to the plane. (I’m not a chemist).
- gus_massa 7y agoThe atoms must be in a minimum of energy. They always oscillate a little due to thermodynamic and quantum effects. If they are in a saddle point the molecule blends until the atoms reach a minimum, until the atoms rearrange themselves in a different molecule or until the molecule split. (Or until they react with another molecule ...) I studied a little of Chemistry, but this is out of the scope that I know well. IIUC correctly from https://en.wikipedia.org/wiki/Cubane https://en.wikipedia.org/wiki/Cubane the stability of cubane is not due to symmetry. The stability comes from the fact that locally it looks like a alkane, i.e. a molecule with Carbon and Hydrogen that only have single bonds. They are quite stable, the most common example is gasoline that is mostly alkanes. Double bonds are more reactive. For example vegetable oils (that have also Oxygen, not only Carbon and Hydrogen) may have or not have double bonds. The one with many double bonds become rancid easier. https://en.wikipedia.org/wiki/Rancidification https://en.wikipedia.org/wiki/Rancidification
- 7y ago
- rkagerer 7y ago"One molecule at a time." What an incredible age we live in!
- twic 7y ago> In other words, each molecule is made individually. This is not the way that chemists typically work, and will not result in quantities of material that can be seen. Depends how many graduate students they can hire.
- logicallee 7y agoI was totally thrown off, because your second and third paragraphs aren't quoted. You write in the same style as the newspaper, and just as well. Good job! (For anyone else wondering, parent quoted just the paragraph >"Gawel... says Scriven", then added their thoughts.)
- lachlan-sneff 7y agoThis is exactly why we need Eric Drexler's molecular assemblers: so we can build large quantities of molecules that are "built" atom-by-atom!
- ZhuanXia 7y agoMolecular assemblers are almost taboo to discuss in chemistry and have been for decades. Sort of like the AI winter. Things feel like they are starting to thaw.
- jeffwass 7y agoWhy are they almost taboo?
- chinigo 7y agoGray goo? https://en.m.wikipedia.org/wiki/Gray_goo https://en.m.wikipedia.org/wiki/Gray_goo
- aftbit 7y agoBy analogy to the "AI winter" I assume they belong to the age of broken dreams... people are afraid to talk about them because too many people have been burned by too many enthusiastic promises and the problem turns out to be much harder to solve than originally expected.
- Rerarom 7y agohttps://en.wikipedia.org/wiki/Drexler%E2%80%93Smalley_debate_on_molecular_nanotechnology https://en.wikipedia.org/wiki/Drexler%E2%80%93Smalley_debate...
- jakeogh 7y agothere's a very interesting project/field that's starting with larger legos: https://www.youtube.com/watch?v=mbdXeRBbgDM https://www.youtube.com/watch?v=mbdXeRBbgDM
- 0xDEFC0DE 7y ago>In other words, each molecule is made individually. This is not the way that chemists typically work, and will not result in quantities of material that can be seen. Is there not merit in doing it via this 'hard way' first before optimizing stuff and finding a production pathway? (IANAchemist)
- apo 7y agoIt's not really a question of hard way vs easy way. It's more like the difference between having a balloon filled with helium and making a single helium atom in a collider. One you can buy at the grocery store, the other requires a team of trained scientists and a facility full of equipment. A milllimole (10^20 moleculess) is considered small scale by many chemists. Working with a single molecule as described in the artice is just short of science fiction, and hardly any chemists have ever done it. It requires one of the most expensive instruments in the world.
- azernik 7y agoIANAchemist either, but I've heard of this being done for prototyping in the semiconductor industry; manually creating single devices to test their electrical/quantum properties while the production teams are trying to figure out how to manufacture the things industrially.
- hyperpallium 7y agoBeing less stable also avoids an ice-nine situation.
- mirimir 7y agoWhat a trip. They brute forced the sucker. I have been a chemist, and also played with explosives as a child. So it's my experience that C≡C bonds are very unstable. I mean, liquid HC≡CH (acetylene) must be diluted with acetone, and stored in tanks packed with diatomaceous earth, to keep it from falling apart explosively. A lot like nitroglycerine, really. And AgC≡CAg (silver acetylide, with the Ag-C bonds being almost ionic) is a damn fine primary detonator. They used to use it in party poppers and cigarette/cigar "loads". But you could use it instead of lead azide or mercury fulminate, and it's much easier to make. But it's also much more expensive. So anyway, I can't imagine that you'd want gram quantities of this stuff. Even if you could prepare it. Edit: A gram of silver acetylide would punch a hole through 15-20 gauge mild steel. Uncontained. Just sitting there, in a little pile.