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Friendly, Welcoming Triazides. No, Really.

OK, now I’m confused. I can’t help but have doubts about this sentence: “Despite their high nitrogen content, the geminal triazides are easy to handle, even when preparative-scale syntheses are performed.” It’s from a new paper in Ang. Chem., and that just might take these things right out of the “Things I Won’t Work With” category. So consider this a marginal entry in the series. I have no “Things That Really Aren’t So Bad” category, unfortunately. But I still wondered if these people were pulling my leg. “Easy to handle” compared to what? Cocaine-soaked cobras?
But the authors (from the Kirsch group at the Bergische Universität Wuppertal), mean what they say. And they won my admiration quickly, starting their paper by saying “Over the last decade, the field of organic azides has witnessed a tremendous “boom” (a joke that works just as well in German as it does in English). I also like their summary of previous polyazide literature:

Besides the compounds described herein, only a limited number of polyazidated molecules have been reported with carbon atoms having a similarly high degree of azide substitution. For example, Banert et al. generated the highly explosive tetraazidomethane C(N3)4 in 2007. Hassner et al. described triazidomethane HC(N3)3, the handling of which is also not straightforward. Moreover, several polyazides from higher homologues of Group 14 elements are known, some of which are highly explosive. . .

I’ve covered some of those very compounds before, and yeah, “not straightforward” is one way to describe their handling. Although looked at from another angle, they’re very straightforward indeed: if you make them, they will blow you up.
So anyone who knows anything about azide chemistry would take a look at the current compounds, dive under the desk, and wait for the kaboom. Mystifyingly, it does not come. You can tell that the authors were puzzled, too – I’m sure that they arrived at the proposed structure somewhat reluctantly, because surely these compounds (well, what’s left of them) should be accelerating through the newly created skylight by now, right?
It took some analytical work to figure them out, since (as the manuscript points out) there’s not too much comparison data out there. I remember the triazidomethane paper having an NMR spectrum, but I always suspected that they ran it in somebody else’s magnet down the hall without telling them. But in this case, 15N labeling studies indicated the triazide, and reaction with cyclooctyne to give the (very odd looking) tris-triazole derivative nailed it down for sure. The chemistry to make them seems pretty robust, but looking at the reaction scheme, I still can’t shake the sensation, seeing stoichiometric IBX being used to make a geminal triazide, that I’m looking at crater bait. But the products are stable in solution up to 60C, and small amounts could be rota-vapped down without explosion.
The authors advise appropriate caution, of course – these things have to blow up under some sort of provocation, and they’ll be bad news when they do. I would not advise scraping them out of a sintered glass funnel with a metal spatula. But the Supplementary Information file describes the prep of two grams of one of these things, which is a convincing demonstration of confidence. If you tried that with any of the previously known organic polyazides, you’d want to get your affairs in order first, hand out earplugs as a courtesy to the crowd, and probably get the cameras running so your descendants can make money off the YouTube ad revenues. No, that’s really remarkable stability.
So are these things I won’t work with, or not? I’m still not too enthusiastic about trying any of these myself – I most particularly would not have wanted to be the person who made the two-gram batch. (I wonder if they’re figured out the structure before the guy did that or not? I hope that’s a joke). But under duress, forced to synthesize polyazides at gunpoint, that these are certainly the ones I’d pick. “Most stable triazide” isn’t a very reassuring endorsement, but you have to take what you can get.

23 comments on “Friendly, Welcoming Triazides. No, Really.”

  1. Hap says:

    But under duress, forced to synthesize polyazides at gunpoint, that these are certainly the ones I’d pick.

    That sounds like a scene from a chemist’s version of Se7en. I’m sure there would be plenty better candidates for representation of chemistry sins. I imagine there’s have to be a thermite reaction or two in the movie, no?

  2. David Borhani says:

    Add a little bit of NaOH, and get the “azidoform” reaction? And a nasty surprise from the so-generated HC(N3)3?

  3. Chemjobber says:

    @1: What’s in the flask?!? WHAT’S IN THE FLASK??

  4. WDR says:

    I’d think the problem with larger batches wouldn’t be the ‘friendly’ result, but all the impurities or alternative reaction products that could be in there too.

  5. Kris says:

    Does anyone else has this problem with this website, that some post do not load? Every now and then I get a blank page – no error message, no incompletely loaded page, just blank. I can read those posts from main page, but can’t load them separately.

  6. WDR says:

    I’d think the problem with larger batches wouldn’t be the ‘friendly’ result, but all the impurities or alternative reaction products that could be in there too.

  7. expr says:

    “scraping them out of a sintered glass funnel with a metal spatula” reminds me of my later-to-be-roommate who made up some silver azide in a 50 ml beaker (as a primer for the shaped charge he was going t make with picric acid). He forgot about it and later decided to clean up by scraping the stuff out of the beaker into a small peanut butter jar lid on a 1″ thick table. After getting most of it out he was scraping the last bit out when it went off.
    It punched a 1.5″ dia. hole in the table and sent pieces of the jar lid in all directions including one in his leg. The beaker pieces (with silver) went everywhere including his face. Fortunately, his glasses were “shatterproof”. As far as I know, he still has black freckles.

  8. Alex says:

    I noticed the azidoform reaction as well… I am struggling to rationalise the observed stability.

  9. Anonymous BMS Researcher says:

    “Where’s the kaboom? There was supposed to be an earth-shattering kaboom!”

  10. milkshaken says:

    I wonder if hexaazidoacetone is solid or liquid, and if it has a pleasant minty aroma…

  11. oldnuke says:

    Do these researchers put their NMR in a bunker? I don’t know if I would care much to carry the tube, much less spin it up.
    3 2 1 0 Houston, we have liftoff!

  12. Anonymous says:

    NMRRRRR in Space! gr

  13. Anonymous says:

    I’d like to see N(N3)3 and octaazacubane made.

  14. joeylawn says:

    I’d like to see N(N3)3 and octaazacubane made. Not because of their (supposed) explosive properties, but from a theoretical interest point of view.

  15. Project Osprey says:

    If you want something puzzling stable try cyanuric triazide. Basically the cyclic trimmer of cynogen azide.
    It does explode – as you would expect for something with the formula C3N12. However it’s been possible to grow single crystals of it (so its not surface sensitive) and it can be melted (at a hefty 94 °C), so it has so thermal stability too.

  16. fluorogrol says:

    When the recommended PPE includes a Kevlar vest, I’m out.

  17. Anonymous says:

    Are really going to ignore that Cocaine-Soaked Cobras is an excellent name for a rock-and-roll band? I can’t even!

  18. gippgig says:

    #13/14: I suspect octaazacubane cannot exist; it would probably separate into 4 nitrogen molecules on a quantum timescale. Nitrogen triazide is more promising; there’s no trivial way for it to decompose.

  19. Anonymous says:

    oldnuke: Most modern NMR facilities don’t spin their samples. Modern NMR have homogeneous enough fields that it doesn’t matter much, and you risk damage to the NMR if something goes wrong.

  20. NJBiologist says:

    @17 Anonymous: Wasn’t CSC the band that broke up and reformed as The Puking Shrews?

  21. Kempeth says:

    It’s great to see a new entry in this category! Thank you! They are always a joy to read!

  22. Vineyard says:

    Sounds like the next step is to fill a tank of that baby, put a lunar lander on top of it, and light it up! 😀
    (I am not a chemist)
    (I probably shouldn’t attempt anything related to chemistry ever)
    (It probably isn’t a good idea to let me out of my room unsupervised, either)

  23. loupgarous says:

    Remember when Daimler-Benz worked a deal out with one of the German state governments – “lend us some of your convicted murderers, because crash dummies are just too verdammt expensive… “?
    Reading about the efflorescence of metal azide chemistry in Germany, I wonder if today’s more promising young death row inmates aren’t being encouraged to seek graduate assistantships at places like der Bergische Universitat Wuppertal in exchange for “good time”….

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