Elusive Triangulene Created by Moving Atoms One at a Time Researchers Used Microscope Tip to Make Unstable Hydrocarbon with ‘Molecular Surgery’
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NEWS IN FOCUS peer-reviewed papers face myriad hurdles, Other funders that have come out in support central preprint service emphasize that it’s no from publisher copyrights to disparate web- of the central service include the UK Medical replacement for peer-reviewed journals. They sites that make bulk-downloading difficult. Research Council, the Howard Hughes Medical note that the vast majority (more than 80% in “We’re trying to think of preprints as data,” Institute (HHMI), the Canadian Institutes of some fields) of arXiv posts wind up in journals. says Vale. It would be both technically and Health Research and the European Research “We really see this as a complement to the jour- legally straightforward for computers to crawl Council. “That’s going to send a strong mes- nal system, rather than anything that could be through the collection of preprints on the sage to the science community that this kind threatening,” says Polka, who adds that a central central site, where they would appear under of communication is encouraged,” says Vale. service will not attempt to organize peer review. an open-access licence. That would be a missed opportunity, says Polka would not say how much ASAPbio CULTURAL CHALLENGE Rebecca Lawrence, managing director of expects the site to cost, but arXiv funding totals Jason Hoyt, chief executive of the journal London-based F1000Research, which posts about US$925,000 a year, paid for by a global PeerJ (which also operates a preprint service), papers before they are peer reviewed (but collective of more than 200 research institu- says he supports a central preprint site and does not consider these as preprints). She tions and funders. Ginsparg says expenses for that his company might bid to help create would like to see peer review occur through the life-sciences site should be around $5 a it. But such a site will succeed only if it can a central preprint service, thereby reducing manuscript, once it is publishing tens of thou- induce a large proportion of life scientists to the influence that traditional journals have sands of manuscripts each year. Funders who view preprints as the dominant currency for on scientists’ careers. support the site have not yet committed to pay- career progression, he says. “The challenge is “It’s a great shift in the right direction,” ing for it, but Kiley expects that they will do so to overturn the thinking in biology.” she says, “but I think we need to go a lot once details have been hammered out. ASAPbio and the funders supporting a further.” ■ CHEMISTRY Elusive triangulene created by moving atoms one at a time Researchers used microscope tip to make unstable hydrocarbon with ‘molecular surgery’. BY PHILIP BALL have tried hard, and failed, to make already,” the method is unlikely to work for those with says Leo Gross, who led the IBM team at the complicated shapes or structures. esearchers at IBM have created an firm’s laboratories in Zurich, Switzerland. Triangulene is similar to a fragment of elusive molecule by knocking around The creation of triangulene demonstrates graphene, the atom-thick material in which atoms using a needle-like microscope a new type of chemical synthesis, says Philip carbon atoms are joined in a hexagonal mesh. Rtip. The flat, triangular fragment of a mesh Moriarty, a nanoscientist who specializes in The new molecule is made up of six hexagons of carbon atoms, called triangulene1, is too molecular manipulation at the University of of carbon joined along their edges to form a unstable to be made by conventional chemical Nottingham, UK. In conventional synthesis, triangle, with hydrogen atoms around the synthesis, and could find use in electronics. chemists react molecules together to build up sides (see ‘Radical triangle’). Two of the outer This isn’t the first time that atomic manipula- larger structures. Here, by contrast, atoms on carbon atoms contain unpaired electrons that tion has been used to create unstable molecules individual molecules were physically manipu- can’t pair up to make a stable bond. that couldn’t be made conventionally — but this lated using a microscope. Such a molecule is highly unstable because one is especially desirable. “Triangulene is the But making molecules one at a time will the unpaired electrons tend to react with any- first molecule that we’ve made that chemists be useful only in particular situations. And thing around them. “As soon as you synthesize it, it will oxidize,” says Niko Pavliček, a member of the IBM team. So far, the closest conven- ADICAL TIANGLE tional synthesis has come to making molecules Triangulene is a at molecule made up of a hexagonal of this sort involves buffering the reactive mesh of carbon and hydrogen atoms (left). IBM researchers 2 made the molecule by manipulating atoms with a scanning edges with bulky hydrocarbon appendages . 1 SOURCE: REF. probe microscope, and then imaged it (right). The IBM team turned to a scanning probe microscope, which has a needle-sharp tip that Unpaired ‘feels’ a material’s shape. The technique is usually electron used to image molecules, by measuring attrac- tive forces between the tip and sample, or the electric currents that pass between them. The IBM team has shown3 that, if the tip has a small molecule such as carbon monoxide attached to it, force microscopy can provide images of such high resolution that they resemble the ball-and- Hydrogen atoms on each corner not shown. stick diagrams of chemistry textbooks. Gross’s team has already demonstrated4 284 | NATURE | VOL 542 | 16 FEBRUARY©2017 M 2017ac millan Publishers Li mited, part of Spri nger Nature. All ri ghts reserved. ©2017 Mac millan Publishers Li mited, part of Spri nger Nature. All ri ghts reserved. IN FOCUS NEWS how the microscope can be used to direct of experiments, says Pavliček, the molecule need to make 100 such molecules “by hand”, the course of chemical reactions and make was still sitting on the copper four days after he says, “it would be worth going through that unstable ‘intermediate’ molecules. To produce the team made it. manual labour”. triangulene, the team began with a precursor The researchers also probed triangulene’s And although it’s not clear how easily the molecule called dihydrotriangulene, which magnetic properties. They found that, as they approach could be applied to molecules that lacks the reactive unpaired electrons. had expected, the two unpaired electrons have aren’t flat, Gross says that such atom manipu- The researchers deposited these molecules aligned spins — the quantum-mechanical prop- lation can be performed for 3D molecules to on a surface — salt, solid xenon and copper are erty that gives electrons a magnetic orientation. some extent. all suitable — and inspected them under the This could make triangulene useful in elec- Even with triangulene and related graphene- microscope. They then used two successive tronics, they say. Takui agrees, and foresees like fragments, “there’s a lot of exciting science voltage pulses from the tip, carefully positioned applications in quantum computing, quantum still to be done”, says Moriarty. The IBM team above the molecules, to blast off two hydrogen information processing and a field known as “continues to set a high bar for the rest of us”, atoms and create the unpaired electrons. The spintronics, in which devices manipulate elec- he adds. ■ 1 work is published in Nature Nanotechnology . tron spins to encode and process information. 1. Pavliček, N. et al. Nature Nanotechnol. http://dx.doi. The team then imaged the products with Making molecules one at a time might not org/10.1038/nnano.2016.305 (2017). the microscope, first picking up a carbon seem very promising, but Gross points out that 2. Morita, Y., Suzuki, S., Sato, K. & Takui, T. Nature Chem. 3, 197–204 (2011). monoxide molecule to acquire the high resolu- current quantum computers use only a handful 3. Gross, L., Mohn, F., Moll, N., Liljeroth, P. & Meyer, G. tion. The images had the shape and symmetry of quantum bits, or qubits, each of which could Science 325, 1110–1114 (2009). predicted for triangulene. Under the high- correspond to a single molecule. Even if you 4. Pavliček, N. et al. Nature Chem. 7, 623–628 (2015). vacuum, low-temperature conditions of the experiments, the molecules remained stable for as long as the researchers looked. CORRECTION petition she co-organized aimed to stop more “To my knowledge, this is the first synthe- The Editorial ‘Keep science on track’ (Nature countries being added to the blacklist. In fact, sis of unsubstituted triangulene,” says chemist 542, 137; 2017) wrongly attributed to Till El-Enany had referred to concerns about Takeji Takui of Osaka City University in Japan, Sawala and then to Nadine El-Enany the people who are not from the seven Muslim- who has previously synthesized triangulene- opinion that the proposed boycott of US-based majority countries stipulated in the travel ban, type molecules2. conferences is intended to demonstrate but who are nevertheless facing detention and Moriarty calls the work elegant, but is against a ban that hurts everyone. The article harassment at the border. Sawala had referred surprised that triangulene remained stable also misquoted Nadine El-Enany (originally to the unsustainable cost of the ban on science on a copper surface, where he might have incorrectly attributed to Sawala) as saying a and on the life of scientists. expected it to react with the metal. In one set ©2017 Mac millan Publishers Li mited, part of Spri nger Nature. All ri ghts reserved. ©2017 Mac millan Publishers Li mited, part of Spri nger Nature. All ri ghts reserved. .