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DBL%20Hendrix%20small.png College chemistry, 1983

Derek Lowe The 2002 Model

Dbl%20new%20portrait%20B%26W.png After 10 years of blogging. . .

Derek Lowe, an Arkansan by birth, got his BA from Hendrix College and his PhD in organic chemistry from Duke before spending time in Germany on a Humboldt Fellowship on his post-doc. He's worked for several major pharmaceutical companies since 1989 on drug discovery projects against schizophrenia, Alzheimer's, diabetes, osteoporosis and other diseases. To contact Derek email him directly: derekb.lowe@gmail.com Twitter: Dereklowe

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« Conference Thoughts | Main | Those Chemistry Bloggers »

October 14, 2010

Whoa! Time to Clean the Fishtank! Uh, Root Canal Appointment! Look at the Time!

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Posted by Derek

That would be my reaction if asked to take a look at the structures in this new paper in JACS. As the authors, who tiptoe gingerly every morning into the State Key Laboratory of Explosion Science and Technology in Beijing put it:

"The larger the number of directly linked nitrogen atoms, the more difficult the compound is to synthesize. The difficulties in synthesizing and handling polynitrogen compounds are a direct consequence of their high endothermicities; a further complication is the almost complete absence of methodology for preparing such compounds."

Every word of that is true, and doesn't it just sound appealing? Here, go invent some completely new chemistry in order to make some compounds that are just trembling with the desire to explode. And if the reactions don't work? No prob: all the side products will probably be horribly explosive, too. Good luck determining just which one of them it was that demolished your hood!
azo%20thing.png
But hold on. At first glance, this structure is terrifically unappealing, unless your chemical sensibilities are bent the right way, in which case, there's not much hope for you. The beast has eight nitrogens in a row, which I believe ties the current record. What's startling about the compound is that it's weirdly stable: it doesn't decompose until nearly 194 degrees C, which is quite bizarre. You'd think, by looking at it, that it would hop up and do its big death scene at about one-tenth that temperature. I mean, I've made potential drug candidates that fell apart at lower temperatures than that. (The amount of electron delocalization this compound has probably keeps its personality from coming through).

The other odd thing about this one is that it changes color on exposure to light. That central double bond will flip around to cis instead of trans, which changes the color of the crystals from yellow to blue. (I remember making a photochromic compound of this sort in an undergrad experiment, which I believe was some sort of Chichibabin pyridine thingie; it sure as heck wasn't this!) Exposing this sort of structure to UV light also isn't the first thing I'd want to do, either - the fact that it'll reversibly go through a transition like that also points to its mild, friendly nature.

But heck, we can fix that: hang some nitro groups off of it, guys! Put some more nitrogens in those rings! Go for the record! Surely the State Key Laboratory of Explosion Science can make some compounds that, you know, explode. Look, guys, I've had Chinese colleagues that seemed to have no problem making things that blew up. (To be sure, I've known people from a number of different backgrounds who had that talent; it springs up everywhere) So I know that you can do it.

I can't even decide whether to put this in the "Things I Won't Work With" category at all, since it looks like I could not only work with it, but beat on it with a ball-peen hammer. What kind of polyaza compounds are people turning out these days, anyway?

Comments (32) + TrackBacks (0) | Category: Things I Won't Work With


COMMENTS

1. kgutwin on October 14, 2010 11:32 AM writes...

The text of the missing second paragraph:

"The larger the number of directly linked nitrogen atoms, the more difficult the compound is to synthesize. The difficulties in synthesizing and handling polynitrogen compounds are a direct consequence of their high endothermicities; a further complication is the almost complete absence of methodology for preparing such compounds."

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2. DLIB on October 14, 2010 11:40 AM writes...

Lots of interest in various government labs - including ours - in metastable "high energy" compounds.

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3. Brian on October 14, 2010 11:50 AM writes...

I don't think I would like to scale that molecule in any case. It is probably great as a candidate for some optoelectronic endeavor, any mention of it being a liquid crystal ?

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4. Nick K on October 14, 2010 12:43 PM writes...

The relative thermal stability of this compound doesn't surprise me too much. To extrude nitrogen one N-N bond has to homolyse first, which requires a lot of energy. There is no concerted, low-energy mechanism available. This is reminiscent of some work by (I think) Waldemar Adam, who made a series of cyclic diazenes. Those diazenes which could extrude nitrogen by a retro Diels Alder mechanism or the like fell apart below 0, whereas those lacking the olefinic bond were stable in boiling toluene.

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5. Anonymous on October 14, 2010 1:04 PM writes...

I'm also not sure I would beat this thing with a hammer. Look up Klapotke's work on P3N21 (yes, 21 nitrogens)...stable to over 200 degrees, but incredibly shock sensitive.

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6. anchor on October 14, 2010 1:23 PM writes...

How about making push-pull analogs. Meaning e-donating groups on one of the triazole ring and EWG on the other ring. That could change the property with a tantalizing outcome, I bechya! Any takers????

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7. cookingwithsolvents on October 14, 2010 1:28 PM writes...

I'd think twice, three times about making it because even IF it isn't prone to explosions there are a few potential side reaction/contaminant-type products which could contaminate the stuff and make it go boom.

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8. Anonymous on October 14, 2010 1:32 PM writes...

@Anonymous:

Just looked that paper up. From the experimental section:

"The use of suitable protective
clothing,in particular a face shield, ear protectors, a bullet-proof vest,
arm protectors,and kevlar gloves,as well as appropriate shoes for
protection from electrostatic charge,is mandatory. Ignoring these
safety precautions can result in serious injury!"

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9. RB Woodweird on October 14, 2010 1:37 PM writes...

Coincidentally, State Key Laboratory of Explosion Science and Technology is the name of my new band!

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10. Hap on October 14, 2010 1:46 PM writes...

A molecule with six azides and no carbons...can't imagine what's up with the bulletproof vest thing.

I think this is another opportunity to pass, or to watch the festivities via YouTube. My lab technique is not good enough to make something with six azides without losing body parts I'd prefer remain attached.

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11. Wavefunction on October 14, 2010 2:00 PM writes...

Why do I keep getting reminded of John Clark's endearing "Ignition! An Informal History of Liquid Rocket Propellants" whenever I read about such things.

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12. Martin on October 14, 2010 4:12 PM writes...

Speaking of things that go bang, Klapƶtke's got a biography up in the latest Angewandte. I especially like the line about it promoting peace..

DOI: 10.1002/anie.201005058

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13. Christine on October 14, 2010 4:20 PM writes...

Holy mother of pity, that structure looks scary. I actually pushed away from my desk slightly when it came up in my RSS reader.
Also, it looks like the sorts of things I doodled during dry labs in O-chem when we were supposed to be learning to use ChemDraw (it was my third time "learning" the program).

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14. Bluto Blutarsky on October 14, 2010 5:51 PM writes...

Hey, they forgot to add some nitro groups on the 4 carbon atoms in the molecule......

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15. Rock on October 14, 2010 5:59 PM writes...

While working on an adenosine agonist project, we prepared a series of amino sugar precursors to the final nucleoside targets. The nitrogen was introduced in the discovery synthesis by use of an azide. As a precaution, all of the intermediates were checked for stability with DSC and shock sensitivity. Surprisingly, the compounds became more stable after the azide was introduced. Apparently, the protected sugar precursors had the right ratio of carbon and oxygen to be fairly energetic. I guess that is why our bodies use them as fuel....

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16. retread on October 14, 2010 9:00 PM writes...

Silly me ! Scared to death of diazomethane which I worked with back in '61 - '62. I managed to keep it from exploding. At least, in medicine if you get AIDS from an inadvertent needle stick, you die slowly.

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17. Jose on October 14, 2010 10:08 PM writes...

I think simply watching crystals of that satan-spawn change colour would be enough to several years off your lifespan!

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18. gippgig on October 14, 2010 11:23 PM writes...

Somebody check this for superconductivity (i.e., combined with TCNQ).

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19. sepisp on October 15, 2010 3:35 AM writes...

Make it a tetrazole and attach azides, and you have essentially solid nitrogen. By the way, a molecule with two tetrazoles linked by an azo group has been synthesized.

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20. John Spevacek on October 15, 2010 7:50 AM writes...

The conjugation would suggest that this molecule would be a reasonable conductor (compare it to polyacetylene, polyaniline and any other the other polyconjugates that won the 2000 Nobel Prize).

Would increasing the conjugation length increase stability? Probably best to model this first.

As was mentioned, the cis-trans transition upon exposure to light is well known in photochromic polymers.

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21. Froggie on October 15, 2010 11:56 AM writes...

I've been working on compounds such as the one shown above. Their applications is probably for airbags (lots of gas generated after initiation). What makes them so stable is usually their very high density (ability of molecules to stack over each other).
There are obviously some safety rules (max. 100 mg of final compounds you're supposed to work with) and pieces of equipment that you have to wear to stay safe. Tests have been run on the equipment (especially Kevlar gloves/shield) to resist in case of an explosion and keep you "intact". Actually, the only parts of your body that are supposed to be exposed when you are setting up such reactions are your hands/forearms, the sash of your hood is at all time closed. If you scale up, you are supposed to perform such reactions in designated bunkers, with automatic pilot.
I'm not saying it's not scary, but I felt sometines more secure working on those compounds and people that know to handle these materials than in my new "normal" lab with labmates ignoring basic safety principles.

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22. Anonymous on October 15, 2010 5:17 PM writes...

16. retread on October 14, 2010 9:00 PM writes...

Silly me ! Scared to death of diazomethane which I worked with back in '61 - '62. I managed to keep it from exploding. At least, in medicine if you get AIDS from an inadvertent needle stick, you die slowly.



17. Jose on October 14, 2010 10:08 PM writes...

I think simply watching crystals of that satan-spawn change colour would be enough to several years off your lifespan!

world-class comments!

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23. Anonymous on October 15, 2010 8:18 PM writes...

How about NI3. Scary stuff. I'd hate to see this stuff fall into the wrong hands.

http://en.wikipedia.org/wiki/Nitrogen_triiodide

simple but nasty

Permalink to Comment

24. Anonymous on October 15, 2010 8:51 PM writes...

Hey,
I was a summer intern at CIL explosives in Montreal back in 1985. I was making and testing emulsion based explosives. It was fun and cutting edge back then. It really sparked my interest in industry and I had the freedom to try new formulations...incorporating new sensitizers. I was doing exactly what these unfortunate souls were doing (see link). So, I am very thankful that I'm here. I remember these guys...they were my mentors...nice people! They always made me feel at home...


http://articles.orlandosentinel.com/1988-10-01/news/0070220223_1_explosives-scientists-emulsion

PS. It was in McMastervilee Quebec, not Ontario.

Permalink to Comment

25. Jonadab on October 18, 2010 6:10 AM writes...

Okay, so once synthesized it's stable. What did they have to do to make it, though? Do we even want to know what compounds were involved in the reactions that lead to this?

> Make it a tetrazole and attach azides,
> and you have essentially solid nitrogen.

Hey, if carbon can be made into fullerines, why not make something analogous out of nitrogen? Could be interesting, yeah?

You guys out on the coast get started on that right away. I'll be over here, in Ohio.

Kind of puts the dangers of network administration in perspective. If I mess up, a computer might get some malware and need to have its operating system reinstalled. We sysadmin types tend to think of that as a scenario that must be avoided at all costs lest the fabric of space-time collapse and the universe implode, but on the whole I have to admit it doesn't really sound as bad as working with chains of more than six nitrogens in a row. Yikes.

Oh, and I think if you shorten the name to just Laboratory of Explosion Science and Technology, that would be a *great* name for a band. They could play an integrated combination of jazz, industrial metal, and gangsta rap.

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26. Paul on October 18, 2010 10:09 AM writes...

> Hey, if carbon can be made into fullerines, why not make something analogous out of nitrogen? Could be interesting, yeah?

Diamond-like nitrogen was made in 2004. It's not stable at room temperature below 42 GPa, unfortunately.

http://pubs.acs.org/cen/news/8230/8230nitrogen.html

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27. Nile on October 19, 2010 7:54 AM writes...

@CookingWithSolvents has rudely drawn our attention to the elephant in the room - contaminants and by-products - and I will add to his observations with an uncomfortable question: what's in the storage jar after a week or so at room temperature?

Not that you'd store much of it... Would you?


Betcha there's a common material that catalyses an abrupt decomposition. Hopefully we find out about it before this stuff is seen outside a laminated hood in quantities exceeding 100g.

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28. No. 6 on October 19, 2010 7:37 PM writes...

@23, Nitrogen triiodide.

Eh. It's sufficiently unstable that you can't usually get very much of it to go off at once. If you have a big pile of it and let it dry out, little bits will go off, tossing other bits around that go off only when they dry out.

And, although it's a high explosive (and goes off with a distinctive 'SNAP!'), it's not terribly powerful.

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29. Richard Gadsden on November 8, 2010 11:23 AM writes...

You guys out on the coast get started on that right away. I'll be over here, in Ohio.

That reminds me of a line from John Ringo's Hell's Faire:

"You have one hundred and forty kilos of antimatter sitting around on my planet????"

...

"If it, for example, detonates on launch, there won't be a Knoxville left."
"And if the rest of your material sympathetically detonates, say goodbye to Tennessee!"

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30. David on March 10, 2011 3:14 PM writes...

http://pubs.acs.org/doi/pdf/10.1021/ic200071q

Turns out Klapoetke lab is back at it. This time they take the aforementioned compound, replace two CH groups with nitrogens to make a diazotetrazole (That's 10 nitrogens in a row for those of you counting!) And guess what... Their version falls in to the class of , and I quote: `unstable compounds on the borderline of existence and nonexistence.` Turns out you can touch the tetrazole variant and it'll very quickly revert to dinitrogen, to the tune of below the threshold of safety characterization equipment. What takes the cake in my opinion is their conclusion: While they would like to study even higher contiguous N-N compounds, 'the trend in increasing sensitivity from N8 to N10
compounds may present challenges for isolation.' Anyone up for making N12?

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31. Anonymous on January 9, 2012 5:40 PM writes...

They're going about it all wrong. Those carbons certainly look like they're needed to stabilize the nitrogens they're attached to. Instead, try attaching two nitrogens to the end of the chain, and cap it off with something nice to keep it from destabilizing the rest of the chain.
Then, you can see if this stuff will polymerize.

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