Sometimes, science does things just to see if it is possible. This seems to be one of those times. While I really wanted to have my long promised flying car by now, this is pretty cool too.
Controlled clockwise and anticlockwise rotational switching of a molecular motor
- U. G. E. Perera, F. Ample, H. Kersell, Y. Zhang, G. Vives, J. Echeverria, M. Grisolia, G. Rapenne, C. Joachim & S-W. Hla
- Nature Nanotechnology 8,46–51 (2013) doi:10.1038/nnano.2012.218
Abstract
The design of artificial molecular machines1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 often takes inspiration from macroscopic machines13, 14, 15, 16, 17, 18, 19. However, the parallels between the two systems are often only superficial, because most molecular machines are governed by quantum processes.
Previously, rotary molecular motors3 powered by light4, 5, 6 and chemical7, 8, 9, 10, 11 energy have been developed. In electrically driven motors, tunnelling electrons from the tip of a scanning tunnelling microscope have been used to drive the rotation of a simple rotor12 in a single direction and to move a four-wheeled molecule across a surface13. Here, we show that a stand-alone molecular motor adsorbed on a gold surface can be made to rotate in a clockwise or anticlockwise direction by selective inelastic electron tunnelling through different subunits of the motor. Our motor is composed of a tripodal stator for vertical positioning, a five-arm rotor for controlled rotations, and a ruthenium atomic ball bearing connecting the static and rotational parts. The directional rotation arises from sawtooth-like rotational potentials, which are solely determined by the internal molecular structure and are independent of the surface adsorption site.
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What a shame we can’t see their creation. But here’s a tribute anyway.
“Those magnificent men with their molecular machines,
They go ???? they go ????
They enchant all the ladies and steal all the scenes,
with their ? ?? ??
and their ? ?? ??
They’re frightfully keen,
Those magnificent men and their molecular machine
What was the rate of rotation?
“Sorry to be picayune but the headline needs correction; the bearing element is the platinum-group element Ruthenium, not Rubidium.”
And an obvious conclusion from the diagram is that the motor is not atomic (it has 2 meanings, 1 atom or nuclear), it is molecular – multiple atoms. The abstract even says that.
Neato!
I used to do chemistry sort of like this in graduate school.
This idea that the ruthenium is a ‘ball bearing” is pretty funny to me. This is pretty standard organometallic chemistry, from a synthetic point of view.
To address a couple of points made above- you know it is one ruthenium atom and not more precisely because of the way Ru coordinates to ligands.
Not true that you cannot ‘see’ atoms with AFM and related techniques. it is indirect, but you get a force map that is directly related to the structure. Graphite is the classic image like this. You can do gold and other metallic surfaces, but they are largely featureless. Graphite is cool because you see the hexagons one expects.
The S’s in the molecular diagram are sulfur, which sticks the whole thing to the gold surface.
[They] more or less had to rely on computational models. You can’t get a good read on what is happening or make sense of your data without them. They inject or remove electrons using the tip of the AFM . Various parts of the molecule will be where filled or empty molecular orbitals sit, which is where electrons live, or will go into if added, or come from if removed.
I have not looked at the paper in detail yet. I’m curious to find out exactly how this thing works.
Sometimes, it’s amazingly hard to get a handle on what is going on in nanocrap (a term I use in the affectionate way chemists do when discussing the field; i mean disrespect only in the same way you might call a good friend “Turd burglar” or something). I’ll have to stare at it a while to decide if it is anything.
The 4-wheeled molecule referred to in the abstract- I think they are talking about Jim Tour’s work. Many of you would probably really like James Tour. He is very well-funded and productive, a great scientist, but not at all interested in being PC about stuff like AGW.
Someone said it’s too bad we cannot see it. If you could get it to crystallize, you could an x-ray diffraction structure. Hard to beat. If what they are doing amounts to oxidation and reduction, and could get structures of the cation and anion salts, then, well, boy howdy!
Cool!
Add an escapement and a few extra molecular wheels and voila! A true atomic watch. Never needs winding!
—————————————————————————-sarc on…
Especially if one powers the watch using a CO2 atom that captures some of that loose evil earth warming IR. Mass market this to the greenblinded so that they capture wild CO2 atoms and tame them into useful productive sequestration. ;->
/sarc, but really a wheel is a wheel and building a new wheel is a terrific start in industrializing!
johanna says:
“If you said ‘counter-clockwise’, people would be looking for a counter, or otherwise simply looking confused.”
That sounds like fun. If I ever make it Down Under I’ll have to give that a try. Thanks for the free clue.
Happy New Year Everyone!
Dale McIntyre says:
December 31, 2012 at 3:27 pm
Sorry to be picayune but the headline needs correction; the bearing element is the platinum-group element Ruthenium, not Rubidium.
REPLY: Yup, got my Ru’s and Rb’s mixed up. Thanks for pointing it out – Anthony
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I’ve always been partial to the unun’s myself. (Maybe that’s why I prefer 7up to Coke?)
If it works as proposed then I can think of at least one more useful application, but not at the reported temperature of 80K. IIRC a rotational energy barrier of 0.25 eV will mean that the putative effect would be swamped by thermal motions at room temperature.
I am also interested to know how it is experimentally demonstrated that it (controllably) rotates in only one direction, if that is what is claimed. As Charles Gerard Nelson alludes to above, the nature of the STM tip is a critical issue which needs to be ruled out as a source of experimental artifacts. Others have reported electro-responsive molecules derived from ferrocenes attached to gold surfaces. Surface plasmon resonance offers the prospect of observing surface events without physical interference of a STM tip.
Unfortunately, neither the abstract nor the supplementary information appear to show any experimental (ex-silico) evidence. I’ve known some chemistry professors who roll their eyes when a speaker mentions DFT calculations as “showing” what the mechanism is for transition metal reactions.
Maybe the authors may have submitted the chemical synthesis of this molecule elsewhere, but I can’t find it. Does the molecule show a tendency to self-aggregate? Some self-assembled monolayers of thiolates/sulfides on gold sometimes also form bilayers and multilayers.
Tiny moving parts, cool, what will really impress me on this engineering issue is if these tiny moving parts can be constructed into a type of dynamo where instead of using huge amounts of energy to get tiny things to move, how about an Invention that makes tiny things move the big things, at this point in our current reverse development, I’d settle for a battery that holds a charge or is that to much to ask-for these days when all this so-called technological advancement is taking place? A small battery like a 1970’s calculator with a solar-cell and a good lifespan that would run a device such as a laptop or a smartphone, that would be great!
Why have smart phones or any other device that use a rechargeable battery not have a built-in solar cell to charge the battery when the device is not in use?
I’ll give you one guess, no wait, two guesses!
[sarcon] Building nanotoys – nice to see our tax dollars so well spent [sarcoff]
Happy New Year !!!
Neat! The world’s most expensive $/atom motor.
Guinness should be notified forthwith!
It has a certain charm and strangeness, but it’s all about putting the right spin on it, isn’t it?
John West responds to johanna’s comment that: “If you said ‘counter-clockwise’, people (in Australia) would be looking for a counter, or otherwise simply looking confused.”
Not so.
“Counter clockwise” is totally acceptable, understood, and frequently used downunder (well, for the 75 years I’ve lived here, anyway).
Why cant these newbie hippys and Al gore snake oil types use the Irish tax-free bases for big companies and all the UK tax avoidance loopholes to design a useful device that wont actually expire or be recycled before they release the latest useless fad. How is it that a lot of engineers are out of work after building everything from schools, hospitals, factories, your home and everything you use in it? yet complete ar*** continue to get royalties and noble prizes for their work? It’s just like that show created by Jim Henson “Fraggle Rock” Where the “Doozers” (engineers) spent all day making towers being productive, and what did the fraggles do? they took the Doozers for-granted those b*****s ate their hard work, and just like in life today the earth revolves around the Fraggles. The fraggles are opinionated freaks and only concerned about their own-self worth just like how the Universities of today just like in the past can turn a useless wealthy person into a politician /funny sarcastic tag.
@ur momisugly Roger Carr
Darn! I was rather looking forward to that.
Perhaps, I’ll just say levorotatory (CCW/ACW rotation of a plane of polarized light) and everyone will just point to the nearest bathroom.
If jmorpuss’ suggestion doesn’t get funded because it is a crap science scam, then why do windmills, solar panels, “carbon” capture schemes etc. etc get funded?
Maybe the inventor doesn’t know any politicians.
Oh, wait, …… they aren’t science scams, just scams.
Keep up the good work, Mr. Watts, and lang may yer lum reek.
@ur momisugly John West.
You say levorotatory to me and of course I’ll point you to the bathroom… well I would have.
Berényi Péter says:
December 31, 2012 at 6:57 pm
“What was the rate of rotation?”
Probably 10 ^ -38 RPM.
@ur momisugly John West,
Now come on old chap. This just won’t do. Can you imagine our gracious majesty Elizabeth II saying “counter clockwise”? Perish the thought.
It is the Queens English after all. Just because you lot keep changing words and spellings doesnt make you right you know!!
Nice to see our Aussie chums still know what’s what, although I dont doubt that awful Gizzard woman will make everything illegal soon.
Happy New Year
🙂
This a simple (pendulum) bearing design. It is primitive compared with the flagellum motor design, which also has thrust bearings, mounting frame and multiple stators.
http://preachrr.files.wordpress.com/2010/09/flagellar_motor.jpg
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Gunga Din says:
December 31, 2012 at 9:20 pm
I’ve always been partial to the unun’s myself. (Maybe that’s why I prefer 7up to Coke?)
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(In a Jamaican drawl) Never had it, never will. Hah, hah, hah, hah….
Be careful of nano, the neo-Luddites are already ranting its health effects and environMENTAL affect.
Still on track for hoverboards in 2015.
I always smile whenever I see a tris-pyrazolyl borate. Spent my post-doc years working with them.